[Hemophagocytic lymphohistiocytosis. Experience in 27 patients]

Hemophagocytic lymphohistiocytosis (HLH) is an aggressive and life-threatening syndrome of excessive immune activation Aim: To describe the clinical characteristics, causes and survival associated with HLH.

Review of medical records of patients with HLH attended between 2004 and 2016. They were classified according to their probable cause in: associated with immunosuppression, cancer, post-infectious or idiopathic. Kaplan-Meier survival analysis was performed.

Twenty seven patients with HLH aged 18 to 87 years (59% men), were detected. Fourteen (52%) were secondary to immunosuppression, six (22%) were post-infectious, five (18%) were associated with cancer and two (7%) were of unknown cause. There were no significant differences in clinical or laboratory features between these etiologies. Within the immunosuppressed group, 12 (86%) were patients with oncologic or hematologic diseases or bone marrow transplantation. Associated cancers were mostly oncohematologic diseases. Thirty-day mortality was 53.4% (95% confidence intervals (CI) 32.7-70.3%), despite the treatment. Mortality was significantly associated with the presence of renal failure with a hazard ratio (HR) of 3.4 (95% CI of 1.2-9.9, p =0.025). Treatment of the underlying disease proved to be protective against mortality with an HR of 0.3 (95% CI 0.1 to 0.98, p = 0.046).

The prognosis of HLH could be related to the treatment of the underlying disease. The study of the pathophysiology of this syndrome will allow a better understanding and treatment.