Anti-P. acnes antibody in comedonal extracts.

Extracts of comedonal material obtained from patients with acne vulgaris were analyzed for albumin, IgG, IgM, IgA, and anti-Propionibacterium acnes antibodies using immunodiffusion and anti-immunoglobulin hemagglutination tests. Extracts were obtained from comedones of patients with (1) comedonal, (2) papulopustular, (3) nodular-cystic, (4) "burned out" acne, (5) patients under oral tetracycline treatment, and (6) with pustules. In all comedonal extracts analyzed, albumin and IgG (ratio approximately 1:2.5) could be detected. IgM, IgA, and C3 could not be found in noninflamed comedones by the techniques used; pustules, however, contained all immunoglobulin classes and albumin in ratios found in serum as well as C3. The anti-P. acnes antibody activity in the comedonal extracts was associated with the IgG class. Immunofluorescence microscopical examination of material from single comedones obtained by the cyano-acrylate technique showed IgG antibody on rod-shaped bacteria. The amount of IgG and albumin in comedonal extracts from the various patient groups was not different. It is concluded that IgG (and antibody of the IgG class) in comedones is derived from the serum and selectively accumulated in the follicle by an unknown mechanism.