selective IgM deficiency

Epidemiology

• children & adults
• no gender bias Pathlogy:
• humoral immune dysfunction
• innate immunity is relatively intact
• T cell subsets, & T cell functions are normal

Genetics

• 22q11.2 chromosome deletion in some cases

Clinical manifestations

• infections with extracellular & intracellular bacteria, viruses, & fungi
• allergies
• increased prevalence of autoimmune disease

Laboratory

• serum IgM
• serum IgG, serum IgA. serum IgG subclasses for exclusion
• Flow cytometry for B cells with surface IgM may be helpful

Management

• patients with impaired pneumococcal antibody responses appear to respond to immune globulin
• fresh frozen plasma may be considered for severe infections

Notes

• originally described in children with memingococcemia

More general terms

• humoral immune dysfunction