IgM deficiency.

Primary isolated IgM deficiency accounted for 0.1% of hospital admissions; secondary IgM deficiency for 2.0%. Although 19% were asymptomatic the rest of 89 subjects (4M:1F) suffered infection (60%), septicemia (36%), atopy (22%), splenomegaly (11%), neoplasia(7%) and autoimmune disorders (3%) with a mortality of 10%. Serious early treatment is needed to avert death from unopposed spread of organisms throughout the blood. Qualitative IgM deficiency (absence of isohemagglutinins) and delayed maturation of IgM can result in similar symptomatology.