Melanocyte Transplantation
The methods for melanocyte transplantion are as follow:
A- Transfer of a non-cultured melanocyte suspension
In this method, a thin biopsy specimen of the normal skin is obtained under local anesthesia and the specimen is treated in order to detach the superficial part of the skin (epidermis). Melanocytes are located in the basal layer of the epidermis. The obtained epidermis as such is again mechanically treated in order to obtain a solution containing melanocytes. The vitiligo patches are abraded with dermabrasion (or by laser) and the melanocyte containing solution is applied to the dermabraded areas. A bandage is placed on the treated area which will remain untouched for a few days.
In this method, not the whole epidermis, but the “cells of importance” are transferred to the vitiligo lesions. Light UVB phototherapy is performed after the lesion is healed, in order to stimulate the transferred melanocytes to proliferate and populate the grafted area.
Advantages
Compared to some other methods (such as the suction blister method, see below) in which the surface of grafted area is equal to the surface of blisters, in this method a relatively large area can be treated using a rather small skin specimen (the grafted area can be up to10 times larger than the biopsied specimen).
B- Transfer of cultured melanocytes
In this method, a biopsy specimen is taken from the normal skin and is then trypsinized and treated in several mechanical steps to obtain melanocytes. Melanocytes are then cultured in a special medium and incubated for several days. During this incubation period the melanocytes proliferate and permits to obtain a higher number. Due to the higher number of cells, this method allows to treat a larger total surface of vitiligo lesions compared to the other method. The surgical process of method is identical to the previous described method (transfer of non-cultured melanocytes).
Advantages
– Very large surface areas can be treated using this method.
– Cultured cells can be frozen and stored for future use and cells can be prepared and shipped to any other country in the world for the treatment of a patient.
Comments
– Specially equipped laboratory is required which add to the cost.
– The time needed for cell proliferation in culture conditions is about 2 weeks, which means that the patient first need to come for a sample taking of a small skin specimen and thereafter come back about 2 weeks later for the surgery (transplantation of the new pigment cells).
C- Suction blister grafts
In this case, a blister is formed on an area of normally pigmented skin using a suction device. The blister roof contains melanocytes. The vitiligo lesion which is to be grafted, is abraded by laser (or other methods such as dermabrasion) in order to remove the very superficial part of the skin (called epidermis). The blister roof produced by the suction device is then applied to this dermabraded area to cover it. Therefore, this method permits to replace the epidermis of the vitiligenous areas, that lack melanocytes, with an epidermis containing melanocytes. A bandage is placed on the area for a few days. UVB phototherapy is performed to stimulate melanocytes to proliferate and populate the grafted area.
Advantages
– Except for the blister formation that may take 1 to 2 hours, the rest of the method is not very time consuming.
– The method is done under local anesthesia and is ambulatory.
Disadvantages
– In dark-skinned patients, hyperpigmentation or depigmentation hypopigmentation might later occur in the site of blister formation (donor site). This method is thus more suitable for skin phototypes 1 to 3.
– Handling of the excised blister roof is delicate and folding might happen if the surgeon is not experienced enough.
– The border of the grafted areas may sometimes not respond to this method. UVB phototherapy can reduce the appearance of this type of halo depigmentation.
D- Ultra-thin epidermal grafting
In this method very thin skin specimens are harvested from the normal pigmented skin of the buttock area by a special machine. Dermabrasion or laserablation is performed on the recipient (vitiliginous) areas to remove the depigmented epidermis. The pigmented epidermis is placed on the denuded skin, locked in place and special bandages are applied on the area.
This method can give very satisfactory cosmetic results if the harvested skin it thin enough and the area for such a graft is well-chosen (but this method is not possible to perform in all body areas).
Miniaturic (ultra-fine) punch grafting (vs. large punch grafting)
In this method, very minute skin pieces (1mm in diameter in the case of miniaturic punch grafts) are obtained from normal skin areas (eg. thigh or buttock skin) by a 1mm punch (see photo) and are grafted into the vitiligenous skin areas. The procedure is ambulatory and is done under local anesthesia. A multi-layer bandage is placed on the grafted areas. The bandage on the grafted area should not be removed for a few days (4 to 7 days). The bandage is then removed and UVB phototherapy is done on the grafted areas in order for the transferred melanocytes to proliferate and spread throughout the depigmented area.
Advantages:
– The method does not need any pre-treatment or cell culture.
– The method is performed under local anesthesia and is ambulatory.
– This method can be used for the treatment of vitiligo in almost any part of the body (including lips, fingers, toes etc).
– The response rate can be very good if the patient is selected well (patients with stable vitiligo) and if the “miniaturic” punch grafting is performed.
– There are no sutures in the donner or the recipient areas in the case punchs with a diameter of less than 2mm are used.
– Minimal scar formation in the donor areas.
Disadvantages
– If large punchs are used instead of miniaturic 1mm punchs, a cobblestone aspect might occur: This might happen in the case of using punches with a diameter of 2-3 mm or higher. The risk of cobblestone aspect is considerably reduced using small punchs with a diameter of 1.5 mm or smaller.
– The method can be time-consuming. A session of several hours should be foreseen in order to graft somewhat larger vitiligo areas.
How to choose the most suitable method to be used?
We will evaluate and discuss the options and choose the most suitable melanocyte transfer method for the patient according to the surface area of the vitiligo lesions, the body zone to be grafted, the skin type and several other factors that determine the most suitable method for each patient.