Selective IgM deficiency (IGMD) is defined as serum IgM levels below 2 SD of mean with normal serum IgG and IgA. IGMD can be associated with severe and/or recurrent infections, atopy and autoimmunity.
Objective: to describe the clinical and biological aspects of IGMD.
This is a retrospective study over a 14-year period (2005 to 2019) including patients with selective IGMD followed within the National Center of Bone-Marrow Transplant of Tunisia.
Eight patients were enrolled ( 4 males and 4 females). Consanguinity was found in five cases. Median age at diagnosis was 66 months (3 months, 14 years). Revealing signs were mostly infectious in six cases: bronchopulmonary infectious (n=6), upper and lower respiratory tract infections (n=4), skin infection with pseudomonas aeroginosa affecting the vulva and inguinal region (echthyma gangrenosum) (n=1). Tow patients had both infections and atopy. Other symptoms infections were hypotrophy (n=3) and hepatosplenomenomegaly (n=1). The two other cases presented isolated autoimmune manifestations: the first developed autoimmune haemolytic anemia and the second had an Evans syndrome.
The mean serum IgM level was 0,33 g/l (range 0,23-0,47). Mean serum levels of other immunoglobulins and IgG subclasses were normal. Lymphocytes immunophenotyping and lymphoblastic proliferation assays were normal.
Selective IgM deficiency is a rare type of Predominantly antibody deficiencies. It was characterized by isolated low levels of serum IgM. The clinical spectrum is broad, essentially associating infectious and autoimmune manifestations