IgG subclasses specific to Staphylococcus epidermidis and Propionibacterium acnes in patients with acne vulgaris

IgG subclasses specific to Staphylococcus epidermidis and Propionibacterium acnes were determined in sera from patients with mild, moderate or severe acne and from a control group. Titres specific to S. epidermidis were all within the same range and did not differ between groups. The titres of IgG subclasses specific to P. acnes did vary between groups. IgG(1) and IgG(3) were significantly higher in severe acne patients compared with moderate acne patients, while IgG(2) was significantly higher in moderate and severe patients compared with controls. Titres of IgG(4) did not differ between groups. The pattern of titres observed suggests that, while the antibody response to S. epidermidis is relatively harmless, antibodies to P. acnes may be involved in the pathogenesis of acne vulgaris.