The clinical and laboratory evaluation of familial hemophagocytic lymphohistiocytosis and the importance of hepatic and spinal cord involvement: a single center experience

Familial hemophagocytic lymphohistiocytosis is an autosomal recessive, life-threatening condition characterized by defective immune response. A retrospective analysis was performed on 57 patients diagnosed with familial hemophagocytic lymphohistiocytosis at Hacettepe University Pediatric Hematology Department. Mutation analysis was performed on 37 patients and of these; 11 had UNC13D, 10 had PRF1 and 3 had STX11 gene mutation. Of these patients 44% were found to have central nervous system involvement on admission and spinal cord involvement was also seen in 5 patients. Remission was achieved in 24 patients with the treatment, in a median time of 76 days (min-max: 15-705 days). Time to get into remission was prolonged 3.1 times in patients with a ferritin level ≥1500 mg/dL. When patients were grouped according to age [Group 1 (≤ 2 years), Group 2 (>2 years)]; patients in Group 1 had higher ferritin and aspartate aminotransferase levels but lower fibrinogen levels. The five year survival rate was also lower in Group 1.When patients in Group 1were divided into two sub-groups according to hepatic involvement, the five year survival rate of patients who had hepatic involvement was significantly lower than those patients without hepatic involvement (0.7%, 27%, respectively) (p=0.002). The five year survival rate of patients with hematopoietic stem cell transplantation was significantly higher than the patients without it (44%, 16%, respectively) (p= 0.02). In conclusion, age being two years and under, ferritin level above 1500 mg/dL, spinal cord or hepatic involvement should be kept in mind as poor prognostic factors in familial hemophagocytic lymphohistiocytosis.