Occurrence of HLH phenomenon post-transplant, although rare, is a well - known entity. It can complicate both allogeneic and autologous transplants leading to high mortality [4,5]. It could be related to infections, mainly viral, or could be independent of any reason [7]. One of the challenging tasks for a clinician is to differentiate HLH from other variety of systemic inflammatory syndromes with including disseminated intravascular coagulation, capillary leak syndrome, engraftment syndrome and infection-associated macrophage activation syndrome [8]. Also, ferritin is a ubiquitously expressed protein and specificity of ferritin for HLH is questionable particularly in transplant settings.

However, primary engraftment failure is a rare complication post autologous transplant; few case reports support this evidently. Fukuno et al reported a case of B-NHL with graft failure post auto SCT [9]. Although patient received high dose methylprednisolone, patient succumbed to multiorgan failure. Similarly, HLH post autologous for multiple myeloma has also been reported [10]. On the other hand, reporting of secondary HLH in allogeneic transplants is relatively common in literature. Abe et al has shared his experience of two cases of secondary HLH post allogeneic transplant for lymphoma [11]. An interesting prospective observational study by Abdelkefi et al reported the incidence of HLH after SCT in a single institution over 18 months. They found 8.8% incidence in alloSCT vs 0.9% in auto SCT. In spite of aggressive treatment, half of the patients with HLH died in their study which emphasize the dreadfulness of this rare complication [6].

Recently EBMT has reported an estimated rate following allogeneic HSCT of 1.09% and much lower estimate of 0.15% following autologous HSCT. In their report, the median cut-off value of ferritin deemed significant was 3,000 μg/L (1,000–10,000 μg/L). However, EBMT commented that what constitutes significant hyperferritinemia in the post-HSCT setting is still undefined and further study is needed to define appropriate cut-off ranges to inform novel screening and diagnostic criteria [12] In the experience of Colita A et al, there was only one case of HLH out of the 22 patients receiving auto- SCT in 18 months (incidence 4.5%.) [3]. It was also emphasized that the conditioning regimen like BEAM which contains Etoposide has no protective effect against HLH.

As showed in various studies and case reports, HLH has a poor outcome despite aggressive therapy. Albeit there is no specific recommendation for posttransplant HLH, therapy ranges from corticosteroids, cyclosporine A, low dose etoposide, intravenous immunoglobulins to second transplant in case of refractory cases [3,10]. In this present report, our patient faced primary graft failure secondary to HLH post autologous transplant. He attained neutrophil engraftment post steroids and cyclosporine. Nonetheless, platelet engraftment could not be achieved which prompted us to start thrombopoietin receptor agonist (Eltrombopag). We also encountered renal toxicity due to cyclosporine and hence it could not be continued for a longer duration.