Immunoglobulin deficiency and determination of pneumococcal antibody titers in patients with therapy-refractory recurrent rhinosinusitis.

We examined 245 patients with chronic rhinosinusitis not responding to prolonged antibiotic treatment and tested each patient for humoral antibody deficiencies. Low immunoglobulin levels were found in 22 patients. Five of them had defects of two or more immunoglobulin isotypes that were diagnosed as common variable immunodeficiency (CVI). Seventeen had an IgG-subclass deficiency. Before and after immunization with pneumococcal vaccine, serotype-specific pneumococcal antibody levels were determined to further evaluate the relevance of the underlying deficiency. Significantly reduced antibody titers of pneumococcal serotypes were found in CVI patients (n = 5), while immunization of 17 patients with IgG-subclass deficiency gave different results. Three of the 17 patients responded poorly to pneumococcal immunization and were prone to a polysaccharide specific immunodeficiency. Patients with CVI or IgG-subclass deficiency failing to produce protective antibody levels in more than five serotypes were chosen for antibiotic and/or immunoglobulin substitution therapy. Since recurrent sinusitis in these patients did not resolve with adequate conservative therapy, endonasal microsurgery was then performed and was seen to be a valuable therapeutic option. Our study suggests that an IgG-subclass deficiency may be the first sign of a basic immunological change, resulting in persisting sinus infections.