At baseline, CVID patients carrying biallelic TNFRSF13B mutations had higher IgM anti-23-valent polysaccharide antigens compared to wild-type CVID patients (19.2 U/mL ± 7.0 versus 3.8 U/mL ± 7.1, p = 0.01) and compared to CVID carrying monoallelic TNFRSF13B mutations (3.9 U/mL ± 9.1, p = 0.05). The gene discussed is TNFRSF13B; the disease is common variable immunodeficiency.