Immunological study of keratoacanthomas.

Twelve patients with keratoacanthoma were studied to assess the role and importance of immunological factors in tumor regression. Direct immunofluorescence was determined with immunoglobulins, complement (C3), and fibrin to estimate the deposition of these factors in the lesion area. Indirect immunofluorescence was also undertaken using pemphigus and bullous pemphigoid sera against the keratoacanthoma lesion to study the presence or absence of tissue-specific antigens (T.S.A.) in intercellular substance and basement membrane. Finally, the cell-mediated immunity was studied using two in vitro parameters: (a) The estimation of T-lymphocytes through the formation of E-rosettes and (b) the estimation of the leukocyte migration inhibition factor (LIF). Our findings show that specific humoral immune mechanisms are apparently not involved in the spontaneous regression of keratoacanthoma. Cell-mediated immune mechanisms are evidently not responsible for the resolution of the tumor.