AstuteClinician Report: A Novel 10 bp Frameshift Deletion in Exon 2 ofICOSCauses a Combined Immunodeficiency Associated with an Enteritis and Hepatitis
ICOS encodes the Inducible T-cell Co-Stimulator (ICOS). Deficiency of this receptor in humans causes a common variable immunodeficiency (CVID) characterised by an absence of class-switched memory B cells and hypogammaglobulinemia. Three pathogenic mutations in ICOS have been described to date in a t...
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Published in | Journal of clinical immunology Vol. 35; no. 7; pp. 598 - 603 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
New York
Springer US
23.09.2015
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Subjects | |
Online Access | Get full text |
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Summary: | ICOS
encodes the Inducible T-cell Co-Stimulator (ICOS). Deficiency of this receptor in humans causes a common variable immunodeficiency (CVID) characterised by an absence of class-switched memory B cells and hypogammaglobulinemia. Three pathogenic mutations in
ICOS
have been described to date in a total of 13 cases. Here we report a novel homozygous 10 base pair frameshift deletion in exon 2 discovered by whole exome sequencing of two siblings from a family of Pakistani origin. Both patients presented in early childhood with diarrhea, colitis and transaminitis and one showed defective handling of human herpesvirus 6. Activated patient CD3
+
CD4
+
T lymphocytes demonstrated a complete absence of ICOS expression and, consistent with previous reports, we detected a reduction in circulating T follicular helper cells. Findings in this kindred emphasise the phenotypic variability of ICOS deficiency and, in particular, the variably impaired antiviral immunity that is a poorly understood facet of this rare disorder. |
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ISSN: | 0271-9142 1573-2592 |
DOI: | 10.1007/s10875-015-0193-x |