The clinical significance of complete class switching defect in Ataxia telangiectasia patients

• Published in: Expert review of clinical immunology Vol. 13; no. 5; p. 499
• Main Authors: Ghiasy, Saleh, Parvaneh, Leila, Azizi, Gholamreza, Sadri, Ghazal, Zaki Dizaji, Majid, Abolhassani, Hassan, Aghamohammadi, Asghar
• Format: Journal Article
• Language: English
• Published: England 04.05.2017
• Subjects: Ataxia Telangiectasia - diagnosis; Ataxia Telangiectasia - immunology; Child; Child, Preschool; Consanguinity; Diagnosis, Differential; Female; Humans; Hyper-IgM Immunodeficiency Syndrome - diagnosis; Hyper-IgM Immunodeficiency Syndrome - immunology; Immunoglobulin A - blood; Immunoglobulin Class Switching; Immunoglobulin M - blood; Infection - diagnosis; Infection - immunology; Iran; Male; Retrospective Studies; immune deficiency; IgA deficiency; infection; humoral immune defects; Ataxia telangiectasia; class switching defect; hypogammaglobulinemia; hyper IgM syndrome
• ISSN: 1744-8409
• DOI: 10.1080/1744666x.2017.1292131

Ataxia telangiectasia (AT) is a primary immunodeficiency associated with recurrent infections. We aimed to investigate clinical and immunological classification in AT patients who suffer from a different spectrum of humoral immune defects. AT patients were categorized according to the ability of class switching and patients with hyper IgM (HIgM) profile were defined as class switching defect (CSD). Serum immunoglobulin profile in 66 AT patients showed normal immunoglobulin level (22.8%), IgA deficiency (37.9%) and hypogammaglobulinemia (18.1%) in the majority of patients, while 21.2% had HIgM profile revealing CSD. CSD does not affect the frequency of infections, however, the frequency of lymphoproliferation (p < 0.001), and autoimmunity (p = 0.004) were significantly higher in this group. Neurologic symptoms in CSD patients are mild or appear after recurrent infections, therefore these patients were usually misdiagnosed as HIgM syndrome. Although most of AT patients have reduced IgA levels or normal immunoglobulin levels, but a fraction of these patients may show CSD ensuing HIgM-profile. CSD poses affected individuals at higher risk of non-infectious complications.