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Sequential immunohistochemical study of depigmenting and repigmenting minigrafts in vitiligo

European Journal of Dermatology. Volume 13, Number 6, 548-52, November - December 2003, Investigative report

Summary

Author(s) : Marwa ABDALLAH, Mohamed B. ABDEL‐NASER, Manal H. MOUSSA, Chalid ASSAF, Constantin E. ORFANOS , Department of Dermatology and Venereology, Ain Shams University, Cairo, Egypt Department of Histology; Ain Shams University, Cairo, Egypt Department of Dermatology, University Medical Center Benjamin Franklin; The Free University of Berlin, Berlin, Germany .

Summary : The initial steps of melanocytic dysfunction in vitiligo are hitherto not well understood. The aim of the present study was to examine the sequence of early events that occur in melanocytes after autologous minigrafting in patients with vitiligo, depending on their clinical response. Six patients with non‐segmental widespread vitiligo were included in the study. Specimens of vitiliginous lesions were used as preoperative controls and sequential punch biopsies were taken from the grafted areas on days 14, 17, 21 and 28 after minigrafting. Immunohistochemical stains using the MoAbs HMB‐45, CD4, CD8, ICAM‐1, and LFA‐1 were performed in all biopsies and the labelled cells were counted by a digital image analyser. Results obtained show that in vitiligo patients not responding to minigrafting, significant numbers of cytotoxic T‐lymphocytes and LFA‐1 positive infiltrating cells occur in early phases (p <\; 0.05), suggesting that a cell‐mediated immune response takes place towards the grafted melanocytes. Possibly this cell‐mediated mechanism causing unresponsiveness to minigrafts may also play a role in the pathogenesis of vitiligo.

Keywords : immune response, minigrafts, vitiligo, CD8, CD4

Pictures

Figure 1. HMB-45 staining of minigrafts of non-responders showing a sequential decrease of melanocytes from day 14 (a), 17 (b) and 21 (c), with a complete disappearance on day 28 (d). Meanwhile, keratinocytes show striking cytoplasmic vacuolation.

Figure 2. ICAM-1 expression of basal epidermal cells in vitiliginious skin at the time of operation (a). On day 17 marked increase of ICAM-1expression in non-responders (b) in contrast to the low expression in responders (c).

Figure 3. LFA-1 in vitiligo skin (day 0) showing few perivascular leukocytes (a). LFA-1 positive leukocytes present subepidermally between keratinocytes at dermo-epidermal junction and the papillary dermis in minigrafts of responders (b). LFA-1-expression in minigrafts of non-responders (c).