Haematopoietic stem cell transplantation in haemophagocytic lymphohistiocytosis

Haemophagocytic lymphohistiocytosis (HLH) poses major therapeutic challenges, and the primary inherited form, familial haemophagocytic lymphohistiocytosis (FHL), is usually fatal. We evaluated, including Cox regression analysis, survival in 86 children (29 familial) that received HLH‐94‐therapy (etoposide, dexamethasone, ciclosporin) followed by allogeneic stem cell transplantation (SCT) between 1995 and 2000. The overall estimated 3‐year‐survival post‐SCT was 64% [confidence interval (CI) = ±10%] (n = 86); 71 ± 18% in those patients with a matched related donor (MRD, n = 24), 70 ± 16% with a matched unrelated donor (MUD, n = 33), 50 ± 24% with a family haploidentical donor (haploidentical, n = 16), and 54 ± 27% with a mismatched unrelated donor (MMUD, n = 13). After adjustment for potential confounding factors, estimated odds ratios (OR) for mortality were 1·93 (CI =0·61–6·19) for MUD, 3·31 (1·02–10·76) for haploidentical, and 3·01 (0·91–9·97) for MMUD, compared with MRD. In children with active disease after 2‐months of therapy (n = 43) the OR was 2·75 (1·26–5·99), compared with inactive disease (n = 43). In children with active disease at SCT (n = 37), the OR was 1·80 (0·80–4·06) compared with inactive disease (n = 49), after adjustment for disease activity at 2‐months. Mortality was predominantly transplant‐related. Most HLH patients survived SCT using MRD or MUD, and survival with partially mismatched donors was also acceptable. Patients that responded well to initial pretransplant‐induction therapy fared best, but some persisting HLH activity should not automatically preclude performing SCT.