Human GPR174 deficiency drives polyclonal lymphoproliferative disease via defects in T cell function

GPR174 deficiency may lead to dysregulated T cell responses, contributing to conditions like lymphadenopathy and autoimmunity.

Summary and findings

Six individuals with function-disrupting variants in GPR174 were studied, revealing a clinical phenotype of lymphadenopathy and autoimmunity. Histological analysis showed necrotizing lymphadenitis and lymphoproliferation resembling Kikuchi-Fujimoto disease. The study suggests that GPR174 loss may predispose individuals to exaggerated lymphoproliferation and autoimmunity following viral infection.

Abstract

The X-linked G-protein coupled receptor GPR174 is highly expressed in T and B lymphocytes and has immunoregulatory roles in mice, but its function in humans is unknown. We describe a cohort of six individuals who have function-disrupting variants in GPR174 and a clinical phenotype of lymphadenopathy and autoimmunity. Histological analysis of two patient lymph nodes revealed necrotizing lymphadenitis and lymphoproliferation resembling Kikuchi-Fujimoto disease. In-depth analysis of three patients and related carriers revealed overaccumulation of CD8 terminally differentiated effector memory cells re-expressing CD45RA (T EMRA ). Patient cells and GPR174- deficient CD8 T cells generated from controls showed less repression of proliferation by the GPR174 ligand lysophosphatidylserine (lysoPS) and an effector-biased gene expression program. GPR174-deficient CD4 T cells were resistant to lysoPS-mediated suppression of IL2 production. In mice, chronic viral infection led to over-accumulation of GPR174-deficient effector CD8 T cells. We describe an inborn error of immunity associated with dysregulated lymphocyte responses that we propose predisposes to exaggerated lymphoproliferation and autoimmunity following viral infection. <h4>Summary</h4> Six individuals with function-disrupting variants in the G-protein coupled receptor GPR174 provide insight into its immunoregulatory role. GPR174 loss emerges as a potential genetic risk factor for histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease) and autoimmunity via defects in T cell regulation.

Limitations

• Not reported in abstract.

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