Hemophagocytic Lymphohistiocytosis: Single-Center Series of 12 Cases from Saudi Arabia.

Hemophagocytic lymphohistiocytosis (HLH) is a rare but potentially fatal disease that commonly appears in infancy, although it has been reported in adults. Chemoimmunotherapy-based treatments have improved the survival of patients with HLH; however, overall survival is still poor. We retrospectively analyzed the data of 12 HLH patients who were admitted between 2005 and 2014. All patients were Saudi Arabia in origin with a female predominance (75%) and a median age of onset of 9.5 months. The consanguinity rates were significantly high (75%) with a positive family history in 41% of cases. Of the 12 patients, nine were defined as primary HLH patients and three were confirmed to be secondary HLH patients. All patients fulfilled the 2004 diagnostic criteria for HLH and received HLH-2004 treatment. Six of these patients showed a good response to chemotherapy, while the remainder of the patients showed partial or no response to chemotherapy. Five patients in this cohort received stem cell transplant, and these patients are currently in remission. The mortality rate of this cohort is currently 50%. Genetic mutational analysis showed a positive STX11 mutation in five patients and a PRF1 (perforin) mutation in two patients. To the best of our knowledge, this is the first case series of HLH from Saudi Arabia.