The Clinical Significance of Specific Antibody Deficiency (SAD) Severity in Chronic Rhinosinusitis (CRS)

Background Despite the increased identification of specific antibody deficiency (SAD) in chronic rhinosinusitis (CRS), little is known about the relationship between SAD severity and the severity and comorbidities of CRS. The prevalence of an impaired antibody response in the general population is also unknown. Objective The objective of this study was to determine if the SAD severity stratification applies to real-life data of patients with CRS. Methods An electronic health record database was used to identify patients with CRS evaluated for humoral immunodeficiency with quantitative immunoglobulins and Streptococcus pneumoniae antibody titers before and after pneumococcal vaccine. SAD severity was defined, according to the guidelines, based on the numbers of titers ≥1.3 μg/dL after vaccination: severe (≤2 serotypes), moderate (3-6 serotypes), and mild (7-10 serotypes). Comorbidities and therapeutic response were assessed. The prevalence of an impaired antibody response in a normal population was assessed. Results Twenty-four percent of the patients with CRS evaluated for immunodeficiency had SAD, whereas 11% of a normal population had an impaired immune response to polysaccharide vaccination (P <.05). When evaluated by the practice parameter definition, 239 of 595 (40%) met the definition of SAD. Twenty-four (10%) had severe SAD, 120 (50%) had moderate SAD, and 95 (40%) had mild SAD. Patients with moderate-to-severe SAD had worse asthma, a greater likelihood of pneumonia, and more antibiotic courses in the 2 years after vaccination than patients with mild SAD. Conclusions This study provides real world data supporting stratification of SAD by severity, demonstrating a significant increase in the comorbid severity of asthma and infections in CRS patients with moderate-to-severe SAD compared with those with mild SAD and those without SAD.