TH17 Cells in STAT3 Related Hyper-IgE Syndrome.

Objectives: To assess the utility of T helper17 (TH17) cell enumeration vis-à-vis National Institutes of Health (NIH) scoring in Hyper IgE syndrome (HIES).

Methods: Clinical phenotypes of Hyper IgE syndrome patients with and without STAT3 mutation were analysed and correlated with absolute eosinophil count, serum IgE levels and TH17 cell numbers in 19 patients with clinically suspected HIES and compared with healthy controls (n = 20).

Results: The difference in serum IgE between patients with and without STAT3 mutation and healthy controls was statistically significant (p < 0.05). Six patients had NIH score > 40; of which 4 were positive for STAT3 pathogenic variants, whereas two patients in the group with no identifiable STAT3 pathogenic variant had NIH score > 40. NIH score had sensitivity of 80 % and specificity of 87.5 % to detect cases with STAT3 pathogenic variants. TH17 cells were markedly low in all cases with STAT3 pathogenic variants. Among patients without STAT3 pathogenic variants, none had low TH17 cell numbers.

Conclusions: Low TH17 cell numbers together with NIH scores can be a better indicator for presence of STAT3 mutations.