Journal of Clinical Immunology vol:36 issue:3 pages:259-259
CIS Annual Meeting on Immune Deficiency and Dysregulation North American Conference location:Boston: MA date:APR 14-17, 2016
Chronic mucocutaneous candidiasis and hyperimmunoglobulinaemia E syndrome are rare PIDs, both characterized by defective T helper 17 (Th17). This Th17 defect is mainly caused by STAT1 gain of function (GOF) mutations and STAT3 loss of function (LOF) mutations, respectively (Liu L. 2011, Ma C. 2008). Moreover, a significant reduction of circulating T follicular helper cells (cTfh) was observed in patients with mutations in STAT3 (Ma C. 2012).
The percentage of CD4+CD45RA-CXCR5+ cTfh of patients (n=70) or controls (n=15) were determinate by flow cytometry (FC). Simultaneous, PBMCs were stimulated with S. aureus enterotoxin B. IL-17A and IFN-γ production was measured. STAT1 and STAT3 were sequenced.
Four patients with low percentage of cTfh cells, an decreased IL-17A but a normal IFN-γ production had heterozygous STAT3 mutations. Whereas three patient with normal cTfh cells but decreased IFN-γ and abolished IL-17A production had heterozygous STAT1 mutations. On the other hand, STAT1 and STAT3 were WT in eight individuals younger than two years of age. Although they showed decreased percentage of cTfh cells (n=3), low IFN-γ production (n=6), and reduced IL-17A production (n=6).
Combined use of percentage of cTfh cells and intracellular IFN-y/IL-17A production is an useful tool for identification and discrimination of patients (>2y) with STAT1 GOF and STAT3 LOF mutations.