Laboratory evaluation of primary immunodeficiencies

Primary immunodeficiencies are congenital disorders caused by defects in different elements of the immune system. Affected patients usually present clinically with recurrent infections, severe infections, or both, as well as autoimmune phenomena that are associated with many of these disorders. Early diagnosis is essential for referral to specialized care centers and the prompt initiation of appropriate therapy. In this article the authors describe a general approach for the investigation of the most common primary immunodeficiencies, outlining the typical clinical symptoms and most appropriate laboratory investigations.

Key words: Primary immunodeficiency, laboratory assessment, immunologic diagnosis, immunity

Abbreviations used: ALPS, Autoimmune lymphoproliferative syndrome, APECED, Autoimmune polyendocrinopathy, candidiasis, ectodermal dystrophy syndrome, DHR, Dihydrorhodamine 123, FOXP3, Forkhead box protein 3, HLH, Hemophagocytic lymphohistiocytosis, IFNGR1, IFN-γ receptor 1 gene, IFNGR2, IFN-γ receptor 2 gene, IL12RB1, IL-12 receptor β1 gene, IPEX, Immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome, IRAK4, IL-1 receptor–associated kinase 4, LAD, Leukocyte adhesion deficiency, NEMO, Nuclear factor κB essential modulator, also called IKK-γ, NK, Natural killer, PID, Primary immunodeficiency, SCID, Severe combined immunodeficiency, STAT, Signal transducer and activator of transcription, TCR, T-cell receptor, TLR, Toll-like receptor, TREC, T-cell receptor excision circle, XLP, X-linked lymphoproliferative syndrome