MELANOCYTE-KERATINOCYTE TRANSPLANTATION IN ...

MELANOCYTE-KERATINOCYTE TRANSPLANTATION INPOST-B U R N LE U KODE R MA SCAR S: PR E LI M I NARYEXPE R I E NCE USING A MODIFIED TECHNIQUE

TRANSPLANTATION MÉLANOCYTES-KÉRATINOCYTES (TMK) DANS LEVITILIGO CICATRICIEL APRÈS BRÛLURE: RAPPORT PRÉLIMINAIRECONCERNANT UNE TECHNIQUE MODIFIÉE

Louri N.A.,1*Dey N.,1,2 De Sousa R.F.,1 AlHasan R.N.,1 Abdelhamid M.M.1

1Plastic Surgery and Burn Unit, Bahrain Defence Force Royal Medical Services, Military Hospital, Bahrain2Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, India

SUMMARY. Post-burn leukoderma, commonly affecting the African and Asian communities, results fromdeep dermal burns. The associated stigma exacerbates the condition and significantly affects the rehabilita-tion and reintegration of post-burn survivors into society. Melanocyte-keratinocyte transplantation (MKTP)is a promising single-stage treatment for repigmentation in vitiligo. However, its use in post-burn leukodermais undetermined. This study aims to evaluate the MKTP treatment in post-burn leukoderma patches. Six pa-tients (five males and one female, mean age = 29±5.51 years) with ten patches of post-burn leukoderma un-derwent single-stage MKTP without adjuvant pigmentation therapy. The postoperative follow-up periodranged from twelve to twenty-four months for all the patients. The average size of leukoderma treated was16.25±9 cm2. Repigmentation was observed in 92.16±11.05% of the total treated area by the end of oneyear after MKTP application. All six patients were satisfied with the treatment outcome. MKTP without ad-juvant therapy is an effective surgical treatment to treat post-burn leukoderma patches. Future studies shouldcover a larger sample over a longer follow-up period.

Keywords: post-burn leukoderma, melanocyte-keratinocyte transplantation, repigmentation

RÉSUMÉ. Le vitiligo cicatriciel après brûlure est fréquent dans les populations africaines et asiatiques,affectant significativement la réintégration sociale des patients. La TMK est une technique en 1 temps derepigmentation du vitiligo, prometteuse, qui n’a pas été évaluée dans ce contexte. Nous l’avons utilisée,sans traitement adjuvant, chez 6 patients (5 hommes et 1 femme de 29 +/- 5,51 ans) sur 10 zones dépigmen-tées (surface de 16,25 +/- 9 cm²), avec un recul de 12 à 32 mois. À un an, une repigmentation a été observéesur 92,16 +/- 11,05% de la surface traitée et tous les patients étaient satisfaits du résultat. La TMK isoléesemble donc être efficace pour traiter le vitiligo cicatriciel après brûlures, des études sur des zones plusétendues et avec un suivi à plus long terme restant nécessaires.

Mots-clés: vitiligo, séquelles, brûlure, transplantation mélanocytes-kératinocytes, repigmentation

___________* Corresponding author: Col. Dr. Nayef A. Louri, Consultant, Plastic, Reconstructive and Burn Surgeon, Head of Department of Plastic Surgery and Burn Unit, Bahrain

Defence Force Military Hospital, Riffa, Southern Governorate, Bahrain-28743. Tel.: +973 17767950; email:[email protected]: submitted 18/08/2021, accepted 16/09/2021

Annals of Burns and Fire Disasters - Meditline - Pending Pubblications

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Introduction

Burn is an important cause of morbidity and mor-tality worldwide, and a major proportion of theglobal burden of burn injuries is borne by develop-ing countries, such as South Asian and African coun-tries belonging to the low-to-middle incomecategory.1,2 Fortunately, the post-burn mortality ratehas declined substantially over the past decades dueto advances in burn management and revolutionaryclinical research in this field.3 Consequently, thenumber of burn survivors with extensive post-burnscarring and disfigurement has increased.4 Theirpresentation includes, and is not limited to, contrac-tures, extensive scars, and post-burn pigmentation;unfortunately, such patients require lengthy treat-ment to address the aforementioned issues.4 Pigmen-tation disorder after partial or full-thickness burns is acommon problem for dark-complexioned people, es-pecially the African and Asian populations;5,6 eitherform of the disorder can present hyperpigmentation(the skin is darker than the normal adjacent skin) or hy-popigmentation (skin is lighter than normal skin). Hy-perpigmentation usually occurs after superficial burns,while hypopigmentation occurs after full-thicknessburns.5 Hypopigmentation that happens after deepburns in dark-complexioned burn patients is known aspost-burn leukoderma.7

After a full-thickness burn, melanocytes andmelanocyte-precursor cells present in the skin are de-stroyed, and the melanocytes residing at the woundedges are unable to migrate to the wound site. Addi-tionally, post-burn scarring disturbs the normal reloca-tion of melanocytes and melanin synthesis.8 Thus,post-burn leukoderma is an irreversible process that re-sults in a permanent cosmetic defect; the disordergravely affects the African and Asian populationswhere the hypopigmentation is more conspicuous thanin fair-complexioned patients because of the stark con-trast in skin color.9,10

Multiple surgical techniques have been employedto manage post-burn leukoderma, namely very thinskin grafting,11 chip skin grafting,12 and punch graft-ing,13 with variable success. Melanocyte cell transplan-tation, either cultured or non-cultured, is anothertreatment option for leukoderma.14 The current paperelucidates the results of single-stage non-cultured

melanocyte-keratinocyte transplantation (MKTP) treat-ment for post-burn leukoderma. Areas over joints inupper and lower extremities and acral regions areknown to be ‘difficult to treat’ but are highly visible,and MKTP is a promising alternative to treat hypopig-mentation in these areas.15-17

Materials and methods

Study designA prospective design was selected to conduct this

open-level pilot study at the burn unit of a tertiary caremilitary hospital in Bahrain. The study was approvedby the hospital’s Research Ethics Committee.

Study participantsBurn patients who had received treatment at our

burn unit and were visiting the outpatient clinic for theirroutine long-term follow-up were assessed for suitabil-ity for recruitment into the study – those presentingwith a hypopigmented post-burn scar and desirous totreat their hypopigmentation were considered. Detailsof the study, including the treatment benefits and sideeffects, were explained to the patients by the attendingplastic surgeon from the burn unit.

The inclusion criteria followed were:Post-burn hypopigmented scar of the limbs,•ankle, foot, hand and wrist.The post-burn leukodermal patch should be•a minimum of 12 months old (no upperlimit).Age between 18 to 60 years.•Otherwise healthy individuals with BMI less•than 30 and no history of smoking.

Patients were excluded based on the following cri-teria:

Presence of other conditions of dermatosis•causing hypopigmentation, for example, vi-tiligo or albinism.Unstable burn scar with eczema.•Evidence of coagulopathy which caused•bleeding on derma-abrasion.

Patients who provided written informed consentto participate and agreed to comply for the follow-up were included in the study. The study was con-ducted between January 2018 and July 2018, and

patients were followed up in the burn unit outpatientclinic after derma-abrasion and MKTP application.Six patients with a total of ten hypopigmented scarswere included in the study – two patients had a sin-gle hypopigmented burn scar, while the other fourhad multiple scars.

The intervention was done as a day-case proce-dure under local anesthesia and required a six-hourstay in the hospital. Patients were admitted to theburn ward on the day of the procedure; pre-operativeevaluation in the clinic consisted of general fitnessfor surgery, written informed consent, photography,and marking the hypopigmented scars to be treatedwith MKTP. The surgical procedure was performedunder asepsis in the Operating Theatre (OT). Pho-tography was performed at each follow-up visit byan independent outcome assessor.

ProcedureThe MKTP application process involved four

consecutive procedures: a) donor skin harvesting;b) preparation of the recipient area; c) preparationof melanocyte- keratinocyte cell suspension solu-tion; and d) cell application. The first two procedureswere done in the OT setting. The donor skin so har-vested was sent to the in-house laboratory (IVF &Cytogenetic Laboratory) where the necessary equip-ment was used to prepare the cell suspension. Afterpreparing the recipient site, the patient was sent to adaycare bed (set adjacent to the OT) without anywaiting period inside the OT to prepare the cell sus-pension to be applied. This arrangement ensuredminimal occupancy of the OT time and the surgeon’stime. The MKTP application was done at the pa-tient’s bedside in the daycare unit by the cell thera-pist.

Donor skin harvest. The medial thigh was useduniformly in all patients as the donor site. An ap-proximate area of 1/10th of the recipient area wasmarked on the medial thigh for the donor skin graft;in case the recipient area was small, a minimum di-mension of 2 x 2 cm2 of the donor skin was takenfor the ease of MKTP cell preparation. The area wasprepared with betadine scrub. A 1% Lignocaine so-lution via infiltration was given to induce local anes-thesia. A thin split-thickness skin graft was harvestedwith an electric dermatome adjusted at 200μ thick-

ness (Fig. 1). After harvesting, the donor area wasdressed in paraffin gauze and a tight crepe bandage.The harvested skin was cleaned in normal salineonce before transferring into a 50ml centrifuge tubecontaining sterile phosphate buffer saline. Then, theskin sample was transferred to the in-house labora-tory in a clean insulated box maintained at roomtemperature.

Recipient area preparation. The patient was dressedin a gown, prepped, and draped with 10% betadine.First, the demarcated recipient area was anesthetizedusing local anesthesia (1% Lignocaine solution via in-filtration). Individual contiguous areas of hypopig-mentation were identified as separate patches withinthe selected area of treatment. Individual patcheswithin the recipient area were dermabraded with a di-amond dermabrasion burr at 500-1500rpm; dermabra-sion was done for 1mm beyond the margins of thehypopigmented patch to prevent the halo effect. Der-mabrasion was done till the epidermal-dermal junctionwas reached, characterized by pin-prick bleeding.

For measurement, the largest diameter and a per-pendicular diameter for each patch were determinedusing a sterile millimeter scale. The area for eachpatch was calculated by multiplying these two diam-eters and the sum of all patch areas was the total re-cipient area. After adequate dermabrasion, the sitewas covered with a gauze soaked in 0.9% normalsaline and crepe bandage to achieve hemostasis; ap-proximately 60 minutes were allowed to achieve he-mostasis while the patient was shifted to a daycarebed and the cell solution was prepared.


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Fig. 1 - Harvested ultra-thin skin graft for cell suspension preparation

Preparation of melanocyte keratinocyte suspension.The reagents used for the cell isolation process were:0.25% (w/v) Trypsin (Gibco, GmbH, Heidelberg, Ger-many), TrypLE™ Select Enzyme (1X) (Gibco,GmbH, Heidelberg, Germany), phosphate buffersaline (Lonza, Walkersville, USA), and Dulbecco’sModified Eagle Medium (DMEM) (Gibco, GmbH,Heidelberg, Germany). The procedure for cell isola-tion was followed as described by Mulekar et al.7 withtwo modifications: 1. an additional cell dissociatingenzyme (TrypLE™ Select Enzyme (1X)) was usedalong with trypsin for better cell yield; 2. the dermo-epidermal junction was scraped to isolate melanocytesand proliferating keratinocytes.

In brief, the harvested skin was transferred from thetube to a two-chamber (90mm diameter) sterile Petriplate containing an appropriate amount of 0.25% w/vtrypsin solution. The skin sample was then incubatedin a normal incubator at 37°C for 25-30 minutes. Theincubation time depended on the ease of separation ofthe dermis from the epidermis. After the incubation,the trypsin solution was pipetted out with a 5 ml sero-logical pipette. Then, about 8ml PBS (phosphate-buffered saline) was added to the same chamber of thePetri plate to remove the excess trypsin. The skin sam-ple was transferred to the other chamber of the Petriplate and placed flat on the surface with the epidermalside facing upward. The epidermis was mechanicallyseparated from the dermis using fine dissecting forcepsand a suitable amount of the TrypLETM select enzyme(1X) solution was added to the separated skin. Theplate containing both the epidermal and dermal layerswas incubated at 37°C for another 5-10 minutes to iso-late the cells in the enzyme solution. After the incuba-tion, the solution turned cloudy (Fig. 2). Further, thedermo-epidermal junction surface was scraped with aNo. 10 surgical blade to release the remaining junc-tional melanocyte and keratinocyte basal cells. Then,the epidermis was cut into small pieces with finecurved scissors. An appropriate amount of DMEMwas added to the TrypLETM select enzyme (1X) solu-tion to dilute the concentrated cell suspension. The so-lution was pipetted in and out a few times to releasemaximum cells from the epidermal layer into the so-lution. The cell suspension was then strained througha 40μ cell strainer (BD, USA) into a 50ml centrifugetube to remove dead corneocytes of the upper epider-

mis. The cell suspension was centrifuged at 1200rpmfor 10 minutes. The supernatant was decanted and therequired amount of PBS was added to the cell pellet(Fig. 3). The amount of PBS used for suspension was

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Fig. 2 - Two-step enzymatic cell isolation process - separation of the epi-dermis from the dermis by trypsin in chamber no-1, followed by isolationof cells from both skin layers by TrypLE enzyme in chamber no-2

Fig. 3 - Cell pellet containing epidermal cells obtained after centrifugationof isolated cells to be used for MKTP


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based on the size of the recipient area (approximately0.2ml per 10cm2 recipient area). The cell suspensionwas pipetted to a 2ml sterile vial and brought to thedaycare ward in a sterile container maintained at roomtemperature.

Melanocyte-keratinocyte transplantation. The cellsuspension was mixed using a 1ml syringe to homog-enize the suspension. Then, it was aspirated into the1ml syringe and kept ready for application. The der-mabraded area previously covered with wet salinewas opened and the wound surface was again wipedwith fresh wet saline gauze, followed by dry gauze.Then, the cells were sprayed slowly using a 27G nee-dle onto the wound uniformly (approximately 0.2mlper 10 cm2 of the recipient area). The cells were al-lowed to settle down for about 10-15 seconds and thewound was covered with paraffin gauze backed by asaline wet gauze and two layers of dry gauze andcrepe bandage to secure the dressing. The patient wasadvised to immobilize the limb for at least 2 hourspost application to allow the cells to settle. The patientwas discharged after 3 hours of the cell application.

Discharge advice and post-op follow upThe first follow-up was done on day 6 in the burn

unit outpatient dressing clinic. The outer layer of thedressing was changed. Subsequently, the patientswere called for follow-up at 2, 3, and 4 weeks, fol-lowed by 2, 4, 6, 8, and 12 months after the MKTPapplication. All the patients were given four choices(extremely satisfied, satisfied, happy, and not happy)to evaluate their satisfaction with the outcome dur-ing the last in-person follow up at 12 months afterMKTP application. Thereafter, all six patients werefollowed up via telephone at the end of 24 monthsto assess the status of repigmented patch to assessthe long term outcomes of the treatment.

Data collection and statistical analysisData collected from the medical records and the

study performance were tabulated using MS Excel.All measurements were made using a millimeterscale. Photography was standardized using a stan-dard light setting, a single camera, and a photogra-pher. Repigmentation was assessed by measuring thearea of pigmentation within the scar and dividing it

by the total treated area (in cm2). It was assessed ateach visit and the visit records at 12 months followup were used as data values for calculating repig-mentation percentage. Statistical analyses were doneusing Statistical Package for Social Science (SPSS,version 23.0). Continuous data were expressed asmean and standard deviation (SD), while categoricaldata were expressed as frequency and percentage.

Results

Out of the six patients included in this study, fivewere male and one was female, with a mean age of29±5.51 years. Table I describes the demographiccharacteristics of these patients. The average size ofleukoderma treated was 16.25±9 cm2. The durationbetween the burn and the MKTP treatment variedfrom a minimum of 12 months to a maximum of 38months. The postoperative follow-up period of all thepatients ranged from a minimum of 12 months to amaximum of 24 months. The wound photographydone for all six patients at the 12-months follow-upwas considered for calculating repigmentation percent-

Variable Result

Age (years) (Mean ± SD) 29. ± 5.51

Gender

Male Female

5 (83.33%) 1 (16.66%)

Skin type

III 6 (100%)

Type of Burn

Flame 5 (83.33%)

Hot metal 1 (16.66%)

Degree of Burn

2nd degree deep 2 (33.33%)

Mixed 2nd degree superficial & deep 1 (16.66%)

Mixed 2nd degree deep & 3rd degree 3 (50%)

Anatomic sites Number of patients

Left hand webspace dorsum 1 (16.66%)

Right. Lateral malleolus 2 (33.33%)

Right. Lateral malleolus and right foot dorsum 1 (16.66%)

Right foot 1 (16.66%)

Right leg 1 (16.66%)

Table I - Patients’ demographic data


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age. Repigmentation was observed in all the patients(Fig. 4) and was assessed by comparing the pre andpostoperative photographs by an independent clinicalobserver who was not a part of the study. The percent-

age of repigmentation ranged from 73-100% (averagere-pigmentation was 92.16%±11.05%). In long termfollow-up, four of the six patients could be reached viatelephone 24 months after treatment, and all four con-

Fig. 4 - Comparative photographs of the treated area (pre and post-op) of six patients

Mean+/- SD Minimum Maximum

12 24

A

92.16 ± 11.05 73% 100%

Pt.No. Age/Sex Months from burn Site Area (cm2) Repigmentation

(%) at 12 months Follow-up (months)

Patient satisfaction

1 20/F 36 Rt. Lateral malleolus (Single patch)

20 100 24 Satisfied

2 30/M 26

Rt. Lateral malleolus (Single patch) + Right foot dorsum (Single patch)

31.5 100 24 Fully satisfied

3 37/M 12 Right. Lateral malleolus (2 patches)

11 73 12 Satisfied

4 27/M 24 Rt. foot dorsum (Single patch) 5 95 12 Satisfied

5 30/M 34 Left hand webspace dorsum (3 patches)

14 85 24 Satisfied

6 30/M 38 Right Leg (2 patches) 16 100 24 Fully satisfied

Table II - Treatment outcome of six patients


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firmed the retention of pigmentation achieved at 12months post-treatment. The remaining two patientscould not be reached. Details of the treatment outcomesfor all six patients are described in Table II. Each of thesix patients was satisfied with the outcome, which mettheir expectations. The findings of the study are sum-marized in Table III.

Discussion

Post-burn leukoderma is a term attributed to the post-burn scar tissue residue that remains after deep dermalburns heal by secondary intention. However, this scar-ring acts as a barrier to both melanocytic migration tothe healed areas and the transfer of melanin by the den-dritic processes of melanocytes.7,8

The existing literature supports the efficacy of man-aging post-burn leukoderma through tissue graftingtechniques11-13,18 and cell transplantation.7,19 Tissue graft-ing includes full-thickness skin grafts, split-thicknessskin grafts, punch-grafting or chip grafting, and epider-mal grafts or suction blister grafts. Whereas cell trans-plantation techniques involve the application of culturedor non-cultured melanocytes. Skin grafts are the ac-cepted gold standard treatment for improving the colorof hypopigmented skin patches;11 however, this proce-dure cannot be applied on leukodermal patches with alarger surface area because of insufficient donor areasof normal skin.20 Large hypopigmented patches requirebigger donor areas, which lead to increased complica-tions such as pain, infection, delayed healing, and hy-pertrophic scarring.21

Cultured melanocyte transplantation is a procedurethat is done in two stages: first, the cells are harvestedand cultured over a few weeks in an advanced labora-tory setting, and then the cultured cells are used to cover

a prepared recipient wound.22 It is an expensive proce-dure as it requires two surgical operations and advancedlaboratory equipment. Furthermore, studies using cul-tured skin cell transplantation have reported contradic-tory results concerning repigmentation.22,23

Repigmentation following skin trauma remains a per-plexing issue despite extensive clinical research on themelanocytic activity during wound healing.2

MKTP is a simplified form of the cultured cellmethod. It comprises separation of the epidermal cellsand melanocytes from the harvested skin without cul-turing the cells; therefore, it is a rather economical tech-nique that is feasible and can be performed in a singlestage.24 MKTP also can expand the harvested donor-sitecells by up to 80 times, rendering it superior to split-thickness skin graft. This expansibility allows minimiz-ing the donor site area and, in turn, decreases the risk ofdonor site morbidity often seen as delayed healing, in-fection, excessive scarring, and dyspigmentation.4

Nevertheless, there is a lack of consensus on the roleof MKTP in the repigmentation of post-burn leuko-derma. Response rates with MKTP in vitiligo have beenvariable with 13-86% of patients achieving 95-100%repigmentation.25 Henderson et al.26 and Mulekar et al.7have reported good and excellent results, respectively,about the role of MKTP in the treatment of post-burnleukoderma. On the contrary, Back et al.17 and Iman etal.19 reported that MKTP applied on the prepared hy-popigmented skin yielded results that did not satisfyboth the patients and the researchers. However, ourstudy yielded an average of 92.16% repigmentation inthe six patients at 12 months after the MKTP procedure,with a good color match on observer-satisfaction rating.This is comparable to Mulekar et al.,7 who reported 90-100% repigmentation with MKTP and postoperativephototherapy in seven patients with post-burn leuko-derma patches. Six out of those seven patients hadleukoderma in acral areas. However, unlike them, wedid not administer any additional therapy after theMKTP procedure.

Interestingly, the management of leukoderma in cer-tain anatomic areas is known to be more difficult thanin other areas. For instance, exposed joint areas of thebody including the hands, fingers, feet, toes, eyelids andknees are highly visible and yet more difficult to treatthan the head, neck and trunk.15,16 Our study focused onthe joint regions of the limbs and also identified the need

Variable Mean+/- SD Minimum Maximum

Duration between burn and MKTP treatment (months)

28.33 ± 9.75 12 38

Length of follow-up (months) 20 ± 6.19 12 24

Average treatment area (cm2) 16.25 ± 9 5 31.5

Re-pigmentation % 92.16 ± 11.05 73% 100%

S

1

(

Table III - Summary of study result

BIBLIOGRAPHY

Cheng, Wang et al.: Epidemiology of 1974 burn patients at a1major burn center in Beijing: a nine-year study. J Burn Care Res,33(5): e228-e233, 2012.Dai, Niann-Tzyy et al.: Restoration of skin pigmentation after2deep partial or full-thickness burn injury. Adv Drug Del Rev,123: 155-164, 2018.McGwin G. et al.: Long-term trends in mortality according to age3among adult burn patients. J Burn Care Rehabil, 24(1): 21-25, 2003.Busch KH et al.: Combination of medical needling and non-cul-4tured autologous skin cell transplantation (ReNovaCell) for

repigmentation of hypopigmented burn scars. Burns, 42(7):1556-1566, 2016.Lin JY, Fisher DE: Melanocyte biology and skin pigmentation.5Nature, 445(7130): 843-850, 2007.Chadwick S, Heath R, Shah M: Abnormal pigmentation within6cutaneous scars: a complication of wound healing. Ind J PlastSurg, 45(2): 403, 2012.Mulekar SV, Al Issa A, Al Eisa A: Treatment of post-burn leuco-7derma with non-cultured melanocyte–keratinocyte transplanta-tion (MKTP). Burns, 37(3): 448-452, 2011.Chadwick SL et al.: Repigmentation of cutaneous scars depends8on original wound type. J Anat, 223(1): 74-82, 2013.


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for immobilization for three hours postoperatively toallow successful melanocyte survival. Mulekar et al.7had also described that absolute immobilization is notnecessary for melanocyte survival. Similarly, Busch etal.4 immobilized the recipient areas for 24 hours to allowmelanocyte penetration through channels created byskin needling.

Mulekar et al.7 utilized collagen sheets in their studyon MKTP. Due to logistic constraints, the retainingdressing in our study was done using paraffin gauzewithout the use of collagen sheets. However, we did notencounter any unfavorable change in the recipient site,like desiccation, infection, hematoma or pain at the re-cipient site.

Furthermore, many studies utilized adjuvant treat-ments to improve melanocyte activity for repigmenta-tion after grafting. Excimer laser and topical Psoralen +ultraviolet light A (PUVA) activate the melanocytereservoirs in the outer root sheath of hair follicles, mar-gins of a lesion, intralesional melanocytes, or stop theimmune-mediated melanocyte destruction.27,28 Like-wise, the use of topical cyclosporine to reduce the per-ilesional halo and low-dose betamethasone forrecalcitrant vitiligo has also been studied.14 Our studyfocused on the efficacy of melanocyte transfer withoutthe confounding effects of other modalities.

For graft recipient preparation, dermabrasion, frac-tional CO2 laser and medical needling have been eval-uated. Silpa-Archa et al.29 described dermabrasion to besuperior to the fractional laser. We refined the dermabra-sion technique as:

Dermabrasion of a normal area of skin around•the hypopigmented area to prevent the halo ef-fect.Dermabrasion under loupe-magnification to vi-•sualize the bleeding points for cautery.

Monitoring the clotting profile preoperatively•to avoid excessive bleeding.Application of topical adrenaline-soaked saline•gauze for hemostasis of the dermabraded bed.

We were able to complete each MKTP sessionwithin six hours (including the pre-op evaluation andthree hours of post-op immobilization). This waspossible because dermabrasion and the skin graftharvest were done in OT under local anesthesia,while the application of the cell suspension was car-ried out at the bedside. Graft harvesting was per-formed with an electrical power-driven dermatomeat a thickness of 200μ to obtain an ultrathin skingraft and to avoid scarring of the donor area.

Limitations of this study include small samplesize and limited follow-up duration. Future re-searchers should work on the inclusion of largerareas of leukoderma for the MKTP-aided repigmen-tation and a comparison of MKTP with skin graft ina randomized-control trial for post-burn leukoderma.The study’s second limitation was the absence of ob-jective analytic tools such as colorimetry and com-puterized planimetry for objectively measuringleukoderma patch repigmentation and surface area.

The study was conducted in a burn unit where thepatients had previously received treatment. Theywere followed up during all phases of wound heal-ing and the subsequent development of scarring andhypopigmentation. This study may encourage otherburn units to indulge in melanocyte-related treat-ment and research to ensure comprehensive burncare. Treating the post-burn leukoderma patients inthe same setting where they received acute burn carehas a positive impact on the patient’s complianceand satisfaction.


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Fitzpatrick TB: The validity and practicality of sun-reactive skin9types I through VI. Arch Dermatol, 124(6): 869-871, 1988.Grover R, Morgan BDG: Management of hypopigmentation fol-10lowing burn injury. Burns, 22(8): 627-630, 1996.Onur OE, Atabay K: The treatment of burn scar hypopigmenta-11tion and surface irregularity by dermabrasion and thin skin graft-ing. Plast Reconstr Surg, 85(5): 754-758, 1990.Harashina T, Ryosuke I: The treatment of leukoderma after burns12by a combination of dermabrasion and “chip” skin grafting. BritJ Plast Surg, 38(3): 301-305, 1985.Fujii M et al.: Thin mini-grafting technique for post-burn leuko-13derma. Dermatol Surg, 33(11): 1368-1373, 2007.Vakharia PP, Lee DE, Khachemoune A: Efficacy and safety of14noncultured melanocyte-keratinocyte transplant procedure forvitiligo and other leukodermas: a critical analysis of the evi-dence. Int J Dermatol, 57(7): 770-775, 2018.Mulekar SV, Al Issa A, Al Eisa A: Treatment of vitiligo on diffi-15cult‐to‐treat sites using autologous noncultured cellular graft-ing. Dermatol Surg, 35(1): 66-71, 2009.Silpa-Archa N et al.: Long-term follow-up of patients undergoing16autologous noncultured melanocyte-keratinocyte transplantationfor vitiligo and other leukodermas. J Am Acad Dermatol, 77(2):318-327, 2017.Back C et al.: Noncultured keratinocyte/melanocyte co-suspen-17sion: effect on reepithelialization and repigmentation - a random-ized, placebo-controlled study. J Burn Care Res, 30(3): 408-416,2009.Kahn AM, Cohen MJ: Treatment for depigmentation following18burn injuries. Burns, 22(7): 552-554, 1996.Iman A et al.: Comparison of intradermal injection of autologous19epidermal cell suspension vs. spraying of these cells on der-mabraded surface of skin of patients with post-burn hypopig-mentation. Ind J Dermatol, 58(3): 240, 2013.Mysore V, Salim T: Cellular grafts in management of leuco-20derma. Ind J Dermatol, 54(2): 142, 2009.

Schulz III JT, Tompkins TG, Burke JF: Artificial skin. Annu Rev21Med, 51(1): 231-244, 2000.Stoner ML, Wood FM: The treatment of hypopigmented lesions22with cultured epithelial autograft. J Burn Care Rehabil, 21(1):50-54, 2000.Phillips J et al.: Keratinocytes suppress TRP‐1 expression and23reduce cell number of co‐cultured melanocytes - implications forgrafting of patients with vitiligo. Pigment Cell Res, 14(2): 116-125, 2001.Mulekar SV et al.: Treatment of vitiligo lesions by ReCell® vs.24conventional melanocyte–keratinocyte transplantation: a pilotstudy. Brit J Dermatol, 158(1): 45-49, 2008.Huggins RH et al.: Melanocyte-keratinocyte transplantation pro-25cedure in the treatment of vitiligo: the experience of an academicmedical center in the United States. J Am Acad Dermatol, 66(5):785-793, 2012.Henderson MD et al.: Autologous noncultured melanocyte-ker-26atinocyte transplantation procedure in an African American manwith post-burn leukoderma. Arch Dermatol, 147(9): 1025-1028,2011.Hofer A et al.: The efficacy of excimer laser (308 nm) for vitiligo27at different body sites. J Eur Acad Dermatol Venereol, 20(5):558-564, 2006.Falabella R, Barona MI: Update on skin repigmentation therapies28in vitiligo. Pigment Cell Melanoma Res, 22(1): 42-65, 2009.Silpa‐Archa N et al.: Prospective comparison of recipient‐site29preparation with fractional carbon dioxide laser vs. dermabrasionand recipient‐site dressing composition in melanocyte–ker-atinocyte transplantation procedure in vitiligo: a preliminarystudy. Bri J Dermatol, 174(4): 895-897, 2016.

Acknowledgments. We are grateful to Dr. Mohamed Ahmed Mortada ElSakkafor his contribution as an independent outcome assessor in our study.

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