IgM deficiency: clinical spectrum and immunologic assessment.

Area of Science:

• Immunology
• Clinical Medicine

Background:

• Selective IgM deficiency is a rare primary immunodeficiency.
• It is often associated with recurrent infections and can present with atopic manifestations.
• Enteric protein loss is another potential complication.

Purpose of the Study:

• To evaluate immunologic aberrations in patients with selective IgM deficiency presenting with recurrent infections and atopy.
• To assess antibody responses to specific antigens in these patients.

Main Methods:

• Evaluation of eight patients with selective IgM deficiency.
• Assessment of antibody responses to bacteriophage OX174, diphtheria-tetanus, and pneumococcal polysaccharide antigens.
• Analysis of immunoglobulin G levels and correlation with clinical manifestations.

Main Results:

• Patients exhibited depressed IgM and elevated IgG responses to bacteriophage OX174 immunization.
• Despite normal quantitative IgG in most, IgG antibody responses to diphtheria-tetanus and/or pneumococcal polysaccharide antigens were generally depressed.
• No clear correlation was found between specific antibody responses and the type of infections experienced.

Conclusions:

• Selective IgM deficiency is associated with diverse immunologic abnormalities beyond just low IgM levels.
• Impaired antibody production against specific antigens is a common feature, even with normal IgG levels.
• The clinical presentation, including infections and atopy, may not directly correlate with specific antibody response deficits.