In all groups (healthy controls, anti-IgA IgG-positive and -negative PID patients, with or without a history of IgP-HS), we observed that sC5b9 constantly increased when serum was incubated with IgP when compared to PBS (mean sC5b9 fold change 2.2 with IgP in comparison to PBS), consistent with a complement activation with IgP. The gene discussed is CD79A; the disease is pelvic inflammatory disease.