Page 214 - 2019_03-Haematologica-web

T. Shahin et al.
cells and T lymphoblasts compared to PN404Y who had some retained signaling.
To investigate the effects of aberrant GP130 signaling pathways on T cells, we aimed to characterize T-cell phe- notype and function in PP498L and PN404Y. Both patients had low CD8+CCR6+ T cells. CD8+CCR6+ T cells co-expressed RORγt and intermediate level of TBET reminiscent of non-conventional CD8+ T cells, including mucosal-associ- ated invariant T cells (MAIT cells) that are enriched in the CD161+ and CCR6+ fraction of CD8+ T cells and express a high level of RORγt but an intermediate level of TBET.37-39 These data support previous observations of the critical role of STAT3 signaling for the development of non-con- ventional T cells including MAIT cells.36 In addition, both patients presented with low CCR6+CCR4+CXCR3– Th17- enriched T cells and IL-17A production that were more prominent in PP498L, possibly explaining the development of a tongue fungal lesion only in PP498L. Reminiscent of low Th17 cells and IL-17A production in HIES patients,24,40-42 these findings highlight the importance of IL-6 in the development of CCR6-expressing and IL-17A-producing human Th-cells despite the presence of functional IL-1b, IL-23 and IL-21 signaling pathways that are critical for human Th17 differentiation.43,44 While reduced CD8+CCR6+ T cell and Th17 cell frequencies are common to both patients, we also identified non-shared phenotyp- ic aberrations. PN404Y showed increased Th2 frequencies similar to that observed in STAT3 and DOCK8-deficient patients. The PN404Y patient also presented with greater GATA3 expression in both Th2 and Th17-enriched sub- sets, pointing towards a Th2-biased polarization to the detriment of classical Th1 and Th17 cells. On the other hand, PP498L showed lower CXCR3 expression with reduced CCR6–CCR4–CXCR3+ Th1-enriched T cells and low IFNγ production by CD4+ and CD8+ memory T cells. This can also be compared to STAT3 LOF patients with normal levels of Th1 cells with a defective IL-27/STAT3 axis but functional IL-27/STAT1 axis, leading to a normal IFNγ response upon IL-27 stimulation.45 Hence, we specu- late that the characteristic T-cell features of PP498L might be due to complete loss of IL-27 signaling that has been shown to play a role in Th1 and CD8+ T-cell memory development and effector responses.
In summary, by characterizing a novel mutation in
IL6ST and comparing phenotypic and functional features of patients with two independent mutations, we define IL-6 and IL-11 signaling as the dominant defects in GP130/STAT3 HIES. Our data suggest that a shared GP130-STAT3 signaling module is the functional basis of the striking phenotypic similarities of patients with path- ogenic IL6ST and STAT3 variants. IL-6 signaling plays a critical role in vivo in the development of human CD4+CCR6+ helper T cells including Th17 and contributes to the development of human CD8+CCR6+ T cells. The discovery of two IL6ST non-synonymous mutations among hundreds of patients with overlapping immune and skeletal problems supports a model whereby only a limited number of non-synonymous combinatorial defects that affect selected signaling cascades are viable, despite severe systemic pathology due to embryological effects, but have sufficient pathogenicity to drive an immunopathology of combined immunodeficiency, ele- vated IgE levels, and skeletal anomalies.
Acknowledgments
We are grateful to all patients, their families and the healthy donors who have given their blood samples for this study. We also thank the nurses including Feride Özkan, Meliha Erol. We are grateful that Tatjana Hirschmugl and Raúl Jiménez Heredia and Jasmin Dmytrus performed exome sample preparation and assisted in data interpretation. We acknowledge the contribution of the Oxford Gastrointestinal Illness Biobank, which is support- ed by the NIHR Biomedical Research Centre, Oxford.
Funding
Supported by an ERC Starting grant (agreement 310857), a doctoral fellowship program (Cell Communication in Health and Disease (CCHD) from the Medical University of Vienna (both to KB), the contribution of the Oxford Gastrointestinal biobank, which is supported by the NIHR Oxford Biomedical Research Centre, the Leona M. and the Harry B. Helmsley Charitable Trust (to HHU), the Department of Health, UK, Quality, Improvement, Development and Initiative Scheme (grant to AOMW), the Wellcome Trust (project grant 093329 to AOMW and SRFT), Investigator Award 102731 and grant 090532/Z/09/Z supporting the Wellcome Trust Centre for Human Genetics both to AOMW and the Deutsche Forschungsgemeinschaft (grant SCHW1730/1-1 to TSc).
References
1. Grimbacher B, Holland SM, Gallin JI, et al. Hyper-IgE Syndrome with Recurrent Infections — An Autosomal Dominant Multisystem Disorder. N Engl J Med. 1999; 340(9):692-702.
2. Grimbacher B, Holland SM, Puck JM. Hyper-IgE syndromes. Immunol Rev. 2005; 203(1):244-250.
3. Holland SM, DeLeo FR, Elloumi HZ, et al. STAT3 Mutations in the Hyper-IgE Syndrome. N Engl J Med. 2007;357(16): 1608-1619.
4. Minegishi Y, Saito M, Tsuchiya S, et al. Dominant-negative mutations in the DNA- binding domain of STAT3 cause hyper-IgE syndrome. Nature. 2007;448(7157):1058- 1062.
5. Schwerd T, Twigg SRF, Aschenbrenner D, et
al. A biallelic mutation in IL6ST encoding the GP130 co-receptor causes immunodefi- ciency and craniosynostosis. J Exp Med. 2017;214(9):2547-2562.
6. O’Shea JJ, Plenge R, Mohseni M, et al. JAK and STAT signaling molecules in immunoregulation and immune-mediated disease. Immunity. 2012;36(4):542-550.
9. Kopf M, Baumann H, Freer G, et al. Impaired immune and acute-phase respons- es in interleukin-6-deficient mice. Nature. 1994;368(6469):339-342.
10. van der Poll T, Keogh C V, Guirao X, Buurman WA, Kopf M, Lowry SF. Interleukin-6 gene-deficient mice show impaired defense against pneumococcal pneumonia. J Infect Dis. 1997;176(2):439-
7. Yoshida K, Taga T, Saito M, et al. Targeted
disruption of gp130, a common signal trans- 444.
ducer for the interleukin 6 family of cytokines, leads to myocardial and hemato- logical disorders. Proc Natl Acad Sci U S A. 1996;93(1):407-411.
8. Betz UA, Bloch W, van den Broek M, et al. Postnatally induced inactivation of gp130 in mice results in neurological, cardiac, hematopoietic, immunological, hepatic, and pulmonary defects. J Exp Med. 1998; 188(10):1955-1965.
11. Puel A, Picard C, Lorrot M, et al. Recurrent staphylococcal cellulitis and subcutaneous abscesses in a child with autoantibodies against IL-6. J Immunol 2008;180(1):647-54.
12. Hunter CA, Jones SA. IL-6 as a keystone cytokine in health and disease. Nat Immunol. 2015;16(5):448-457.
13. Yoshida H, Hunter CA. The Immunobiology of Interleukin-27. Annu Rev Immunol. 2015;33:417–443.
620
haematologica | 2019; 104(3)