SUMMARYThe possible role of complement in the pathogenesis of the Jarisch-Herxheimer reaction was assessed in cutaneous syphilitic lesions in two groups of rabbits treated with penicillin; in one group complement was depleted before penicillin therapy. Serial biopsy specimens were similar histologically in both groups. The activation of the complement pathways did not seem to play a role in the pathogenesis of early cutaneous syphilitic lesions in rabbits during the Jarisch-Herxheimer reaction.

Human alpha-fetoprotein (HAFP) was demonstrated in clusters of atypical cells of an extensive Bowen's disease involving the pubic area. Frozen sections were studied by indirect immunofluorescence using monospecific rabbit anti-HAFP antiserum or purified rabbit anti-HAFP antibody followed by staining with fluorescein isothiocyanate (FITC)-labeled goat anti-rabbit gamma-globulin and by a direct technique using FITC-labeled rabbit anti-HAFP Fab2 fragments. Sections of fetal liver served as positive controls and sections of adult human skin and liver were used as negative controls. Preabsorption of the anti-HAFP antibodies with purified HAFP blocked the fluorescence. This finding adds Bowen's disease to the list of premalignant disorders which possess HAFP as an oncofetal marker of their malignant potential. HAFP might possibly enhance malignant behavior through interference with cellular immunosurveillance mechanisms.

By direct immunofluorescence, with use of fluorescein-labeled sonified Treponema pallidum, specific antibodies were detected in the tissue infiltrates of cutaneous syphilomas in rabbits. Specimens from cutaneous and mucosal inflammatory lesions induced by intradermal injection of a keratinous substance from an epidermal cyst served as controls. Granular fluorescence was detected in the dermis of 11 of the 12 syphiloma specimens and corresponded to areas of heavy plasma cell infiltrates, and some fluorescence was found directly on plasma cells identified by subsequent staining with hematoxylin and eosin. This fluorescence could be blocked by preabsorption. Control slides did not show any fluorescence. Immunopathologic techniques using labeled antigens may be of diagnostic value in syphilis and other infectious disorders which feature specific infiltrates.