Expression of Schwann cell characteristics in pigmented nevus. Immunohistochemical study using monoclonal antibody to Schwann cell associated antigen.

A monoclonal antibody to the Schwann cell associated antigen (AHMY1) and a monoclonal antibody to neurofilament proteins (NFP) (AHNF1) each were produced. Using AHMY1, AHNF1, and anti-S-100 antibody, 90 pigmented nevi were examined immunohistochemically to clarify the relationship between nevus cells and Schwann cells. All nevus cells had S-100 protein, but did not have neurofilament proteins. The nevic corpuscle and Type C nevus cell were positively stained with AHMY1 indicating the presence of the Schwann cell associated antigen, while Type A and B nevus cells were entirely negative. This suggests that the nevic corpuscle and Type C nevus cell are closely related to the Schwann cell and differ from Type A and B nevus cells in their development.