Background: The purpose of this study was to investigate the prevalence and contribution of humoral immunodeficiency in refractory chronic rhinosinusitis (RCRS). This study was performed at a tertiary care academic referral center.
Methods: RCRS patients who had at least three episodes of documented sinusitis in the previous year despite antibiotic therapy, who had endoscopic sinus surgery performed at University of Iowa Health Care (UIHC), and who were evaluated by the UIHC Adult Immune Disorder Clinic were included. Exclusion criteria included allergic fungal sinusitis, human immunodeficiency virus, and other causes of secondary immunodeficiency. Sixty-seven patients fulfilled the inclusion and exclusion criteria. The results of their immunologic evaluation for atopy and humoral immune function were examined.
Results: The average age of these patients was 50 years (±11.6 years). Twenty-eight (42%) patients had at least one positive result on allergy skin testing. Determination of quantitative immunoglobulins showed low IgG in 9%, low IgA in 3%, and low IgM in 12% of patients. Common variable immunodeficiency was diagnosed in one case. Immunoglobulin G subclasses were tested in 31 cases and found low in 6 patients. Fifty-one patients underwent a dynamic assessment of their antibody response by examining the increase in antibody titer to an unconjugated pneumococcal polysaccharide vaccine. Sixty-seven percent of patients failed to produce more than a fourfold increase in postimmunization antibody titer for >7 of 14 serotypes being tested and were considered to have functional antibody deficiency.
Conclusion: This retrospective review shows an unexpectedly high prevalence of humoral immune dysfunction in patients with RCRS. These findings suggest that assessment of immune function should be undertaken routinely in RCRS. Immune assessment should first include measurement of serum immunoglobulin levels; if these are normal, then functional antibody responses should be evaluated.