IgM deficiency: clinical spectrum and immunologic assessment.

Selective IgM deficiency has been associated with recurrent infections and enteric protein loss. We have evaluated eight patients with IgM deficiency presenting with recurrent infections and manifestation of atopy. A variety of subtle immunologic aberrations were noted, including depressed IgM and elevated IgG responses to immunization with bacteriophage OX174. Despite normal quantitative IgG in most patients, IgG antibody responses to diphtheria-tetanus and/or pneumococcal polysaccharide antigens were generally depressed. No correlation could be made between antibody responses (or lack thereof) and the nature of infections in any given patient.