Deficiencies in total IgG, IgG1, IgG2 and IgG3 were more frequently present in patients who exacerbated during follow-up, whereas the opposite was true for MBL deficiency (25% in patients who exacerbated vs. 35% in patients with no exacerbation); these differences were not statistically significant. The gene discussed is IGHG3; the disease is mannose-binding lectin deficiency.