Secondary hemophagocytic lymphohistiocytosis (HLH): Five years’ experience at the UTHealth McGovern Medical School at Houston, Texas.

Abstract

e19578 Background: Secondary HLH in adults is associated to infections, malignancies, and autoimmune disorders. HLH in children has been the basis for the management and treatment of HLH in adults. Despite their clinical similarities there are fundamental differences. Children’s HLH is caused by gene mutations in granule-mediated cytotoxicity while secondary HLH does not have known apparent genetic causes. This may affect the clinical outcomes based in how we approach the diagnosis and management of secondary HLH in adults. Methods: We reviewed 49 cases of secondary HLH at our institution over a five-year period. Patients median age was 47 years, with 31 males, 18 females. Fifteen were Caucasian, 10 Asians, 8 African American and 15 Hispanics. One was not specified. Results: Fever, hyperferritenemia and cytopenia correlated with 100% elevation of sCD25R, the most important biomarker of HLH. Patients with these three criteria were urgently treated with dexamethasone-etoposide (HLH-94 protocol) or dexamethasone alone (autoimmune related) while completing identification of other criteria described in the pediatric population together with treatment of the secondary cause. Conclusions: Secondary HLH is not rare. Etoposide and dexamethasone (preferred dose:40 mg total/day initially) are the most important current therapeutic approaches. Secondary HLH must be treated urgently and independently of the secondary cause. Treatment should not be delayed awaiting results of sCD25R, NK-cell activity and presence of hemophagocytosis in the bone marrow (often absent). Further work needs to be done to elucidate the physiopathology of secondary HLH.[Table: see text]