Germline HAVCR2 mutations altering TIM-3 characterize subcutaneous panniculitis-like T cell lymphomas with hemophagocytic lymphohistiocytic syndrome.
Gayden T, Sepulveda FE, Khuong-Quang DA, Pratt J, Valera ET, Garrigue A, Kelso S, Sicheri F, Mikael LG, Hamel N, Bajic A, Dali R, Deshmukh S, Dervovic D, Schramek D, Guerin F, Taipale M, Nikbakht H, Majewski J, Moshous D, Charlebois J, Abish S, Bole-Feysot C, Nitschke P, Bader-Meunier B, Mitchell D, Thieblemont C, Battistella M, Gravel S, Nguyen VH, Conyers R, Diana JS, McCormack C, Prince HM, Besnard M, Blanche S, Ekert PG, Fraitag S, Foulkes WD, Fischer A, Neven B, Michonneau D, de Saint Basile G, Jabado N.
2019 Apr 24
Subcutaneous panniculitis-like T cell lymphoma (SPTCL), a non-Hodgkin lymphoma, can be associated with hemophagocytic lymphohistiocytosis (HLH), a life-threatening immune activation that adversely affects survival1,2. T cell immunoglobulin mucin 3 (TIM-3) is a modulator of immune responses expressed on subgroups of T and innate immune cells. We identify in ~60% of SPTCL cases germline, loss-of-function, missense variants altering highly conserved residues of TIM-3, c.245A>G (p.Tyr82Cys) and c.291A>G (p.Ile97Met), each with specific geographic distribution. The variant encoding p.Tyr82Cys TIM-3 occurs on a potential founder chromosome in patients with East Asian and Polynesian ancestry, while p.Ile97Met TIM-3 occurs in patients with European ancestry. Both variants induce protein misfolding and abrogate TIM-3's plasma membrane expression, leading to persistent immune activation and increased production of inflammatory cytokines, including tumor necrosis factor-α and interleukin-1β, promoting HLH and SPTCL. Our findings highlight HLH-SPTCL as a new genetic entity and identify mutations causing TIM-3 alterations as a causative genetic defect in SPTCL. While HLH-SPTCL patients with mutant TIM-3 benefit from immunomodulation, therapeutic repression of the TIM-3 checkpoint may have adverse consequences.