Immunological work-up of patients with recurrent invasive pneumococcal disease with unknown underlying risk factors.

P, Patient identification; LIP, Lymphocyte immune-phenotype (T/B/NK); NA, Not available; ND, Not determined; Data for patient 10 were not available. a In blood smear and/or abdominal ultrasound study. b Range for age. c Criteria of positive isohemagglutinins: antiA > 1/16, antiB > 1/8; Criteria of positive antibody (ab) levels of diphtheria and tetanus: > 0.1 UI/mL. Protective antibody (ab) levels > 250 UI/mL. Measurement of antibodies to 23 pneumococcal capsular polysaccharides through enzyme-linked immunosorbent assay. d Complement pathway includes CH50 (normal between 42–95 UI/mL), C3, C4 for all patients. AH50, properdin and MBL for patient 6. Immunological work-up of patients with recurrent invasive pneumococcal disease with unknown underlying risk factors.