HALO CONGENITAL NEVUS UNDERGOING SPONTANEOUS REGRESSION - INVOLVEMENTOF T-CELL IMMUNITY IN INVOLUTION AND PRESENCE OF CIRCULATING ANTI-NEVUS CELL IGM ANTIBODIES

Background: Halo congenital nevus is a condition in which halo formati on is associated with congenital nevocellular nevi. Although several t heories have been proposed, the immunologic mechanisms of halo formati on and concomitant nevus regression still remain unclear. We presented immunologic findings in a case of halo congenital nevus with unique h istologic location of inflammatory cells. Observations: Histologically , the present case of halo congenital nevus undergoing spontaneous reg ression showed a marked inflammatory infiltrate with remnants of origi nal nevus cell nests. In the infiltrating T cells, CD8(+) cells outnum bered CD4(+) cells and the infiltrate of natural killer cells was not substantial. Direct and indirect immunofluorescence studies demonstrat ed the presence of IgM antibodies against nevus cells as well as melan oma cells and cultured melanocytes in the patient's serum. Conclusions : Our findings suggest that both T-cell-mediated immunity and IgM anti bodies may be involved in the regression of halo congenital nevus. How ever, it is important to point out that our results may simply be epip henomena and not directly responsible for the destruction of nevus cel ls.