Isolated primary immunoglobulin M deficiency
Isolated primary immunoglobulin M deficiency[1] (or selective IgM immunodeficiency (SIgMD)) is a poorly defined dysgammaglobulinemia characterized by decreased levels of IgM while levels of other immunoglobulins are normal. The immunodeficiency has been associated with some clinical disorders including recurrent infections, atopy, Bloom's syndrome, celiac disease, systemic lupus erythematosus and malignancy, but, surprisingly, SIgMD seems to also occur in asymptomatic individuals.[2] High incidences of recurrent upper respiratory tract infections (77%), asthma (47%) and allergic rhinitis (36%) have also been reported.[3] SIgMD seems to be a particularly rare antibody deficiency with a reported prevalence between 0.03% (general population) and 0.1% (hospitalized patients).[2]
The etiology of selective IgM deficiency remains unclear, although various mechanisms have been proposed, such as an increase in regulatory T cell functions, defective T helper cell functions and impaired terminal differentiation of B lymphocytes into IgM-secreting cells among others.[2] It is however puzzling that class switching seems to happen normally (serum levels of other antibodies are normal), while dysfunctioning of IgM synthesis is expected to occur together with abnormalities in other immunoglobulins. Notwithstanding a clear pathogenesis and commonly accepted definition, a cutoff for SIgMD could be the lower limit of the serum IgM reference range, such as 43 mg/dL[4] in adults or even 20 mg/dL.[5]
See also
References
- ↑ Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. ISBN 1-4160-2999-0.
- 1 2 3 Yel L, Ramanuja S, Gupta S (2009). "Clinical and Immunological Features in IgM Deficiency". Int Arch Allergy Immunol 150 (3): 291–8. doi:10.1159/000222682. PMID 19494527.
- ↑ Goldstein MF, Goldstein AL, Dunsky EH, Dvorin DJ, Belecanech GA, Shamir K (2006). "Selective IgM immunodeficiency: retrospective analysis of 36 adult patients with review of the literature". Ann Allergy Asthma Immunol 97 (6): 717–30. doi:10.1016/S1081-1206(10)60962-3. PMID 17201230.
- ↑ UC Davis Medical Center. "Revised reference range IgM" (PDF). Retrieved 30 December 2011.
- ↑ The Merck Manual of Diagnosis and Therapy. Merck Sharp & Dohme Corp. 2004. pp. Appendix II.