Propionibacterium acnes: interaction with complement and development of an enzyme‐linked immunoassay for the detection of antibody

OBJECTIVE: To characterize the immune response to Propionibacterium acnes in acne patients. DESIGN: Comparison of serologic responses in acne and normal patients using counterimmunoelectrophoresis for antibody and an enzyme-linked immunosorbent assay (ELISA) to detect immunoglobulin G (IgG) antibody. SETTING: The serum of acne and nonacne patients from the Dermatology Clinic at the Medical College of Ohio was utilized for analysis. RESULTS: Using counterimmunoelectrophoresis, antibody was detected in 13 of 20 acne patients. The antigen was detectable as an anion in the barbital buffer at pH 8.2, strongly suggesting a carbohydrate component. By ELISA, the antibody proved to be IgG, and the bacteria and its water-soluble fractions were capable of fixing complement. CONCLUSIONS: The primary instigator of inflammation in acne vulgaris is an immunologic reaction to extracellular products of P. acnes. The immunologic response involves both humoral and cell-mediated pathways. The antibodies to P. acnes have not been characterized fully, although they are largely of the IgG class. We have further characterized the dominant antigen to have a carbohydrate component.