Decreased specific anti-polysaccharide antibody concentration Decreased circulating specific Haemophilus influenzae type b antibody concentration 2026-04-30T16:29:30Z The concentration in the blood circulation of specific immunoglobulins directed against the capsular polysaccharide of Haemophilus influenzae type b is below the lower limit of normal. Low Hib antibody titer Specific Haemophilus influenzae type b antibody deficiency Selective deficiency of anti-Haemophilus influenzae type b capsular polysaccharide antibodies can occur in the presence of normal total immunoglobulin levels and normal IgG subclasses. It is associated with recurrent sinopulmonary infections and invasive Hib disease including meningitis and septicemia. Decreased specific Haemophilus influenzae type b antibody level PMID:9356808 PMID:28379361 PMID:3259962