Prospective Validation of the OHI Index

Hemophagocytic lymphohistiocytosis (HLH) associated with hematologic malignancies (HM-HLH) is a syndrome with an abysmal prognosis (10-30% 5 years overall survival). The investigators have recently established an improved diagnostic and prognostic index for HM-HLH, termed the Optimized HLH Inflammatory (OHI) index. The OHI index is comprised of the combined elevation of soluble CD25 (sCD25) \> 3,900 U/mL and ferritin \>1,000 ng/mL . However, the true incidence and outcomes of HLH/OHI+ in an unselected cohort are unknown, and so is the mechanism of HM-HLH.