Consistent with a proposed role as an inhibitory co-signaling receptor, BTLA-deficient T cells show increased proliferation [25], [27], [28], and BTLA-knockout mice have enhanced susceptibility to autoimmune disease and increased inflammatory responses [15], [25], [27], [29], [30], [31], [32], [33], [34]. The gene discussed is BTLA; the disease is autoimmune disease.