Clinical and laboratory characteristics of 75 patients with specific polysaccharide antibody deficiency syndrome

Background: There are limited studies of large cohorts of patients with specific polysaccharide antibody deficiency (SPAD) syndrome. Objective: To study the clinical and laboratory characteristics of patients with specific polysaccharide antibody deficiency syndrome. Methods: We retrospectively studied 75 patients with total IgG levels of at least 500 mg/dL and fewer than 9 of 12 responses to vaccination with pneumococcal vaccine polyvalent. Exclusion criteria included an IgG level less than 500 mg/dL, established immunodeficiency syndrome, and secondary immunodeficiency. Results: The most common clinical presentation was frequent infections (n = 69; 92%), including sinusitis (n = 53; 77%), pneumonia (n = 29; 42%), ear infections (n = 18; 26%), and bronchitis (n = 19; 28%). Other presentations were systemic infections (n = 5; 7%), autoimmune or rheumatic diseases (n = 6; 8%), and chronic diarrhea (n = 4; 5%). The median IgG2 level of patients with no response to pneumococcal vaccine polyvalent tended to be lower than that of patients with at least I response (150 vs 193 mg/dL, respectively; P = .06). There was no association between total IgG level (categorized as 500-600 or >= 600 mg/dL) and frequency of infection (P = .43). Patients with fewer responses to pneumococcal vaccine polyvalent and a higher frequency of infections were more likely to receive intravenous immunoglobulin (IVIG) therapy (P = .01 and .003, respectively). Treatment with IVIG significantly reduced the number of infections (P <.001). Conclusion: Patients with no response to pneumococcal vaccine polyvalent tended to have lower IgG2 levels; those with fewer responses were more likely to receive IVIG therapy.