Toward this end, a report by Binder et al. in 1998 (1 year before perforin-deficiency was identified as a cause for primary HLH) described the development of an HLH-like syndrome in perforin-deficient mice following infection with Lymphocytic Choriomeningitis Virus (LCMV) (17). The gene discussed is PRF1; the disease is hemophagocytic syndrome.