Primary selective
immunoglobulin (Ig) M deficiency usually presents early in life with recurrent or severe
infections caused by encapsulated and gram-negative organisms. Primary selective
IgM deficiency in adults is rare and is usually associated with
autoimmune diseases or
malignant neoplasm. We performed an extensive immunological analysis of innate and adaptive immunity in an adult patient with possible primary selective
IgM deficiency who presented with life-threatening Streptococcus pneumoniae
septic shock and invasive Aspergillus fumigatus
infection. The patient had no evidence of
autoimmune disease or
malignant neoplasm. Serum
IgG,
IgA, and
IgE were normal; however, serum
IgM levels and specific antibody titers against all 14 pneumococcal
polysaccharide serotypes were consistently low.
Complement CH50, C3, C4, and neutrophil phagocytosis and oxidative burst were normal.
Toll-like receptor expression on monocytes was also normal. Therefore, adult patients with serious life-threatening and unusual
infections should be investigated for possible selective primary
IgM deficiency.