HAVCR2 and hemophagocytic syndrome: The association between germline loss of function mutations in HAVCR2 and two diseases resulting from hyperactivated T and myeloid cells, hemophagocytic lymphohistocytosis (HLH) and subcutaneous panniculitis-like-T-cell(SPTCL), establish Tim-3 as a negative regulator or “immune checkpoint” (111, 112).