OC-64 Hemopahagocytic lymphohistiocytosis: is it really important to make a difference between primary and secondary cases?

Abstract

Background and aims Despite HLH-04 diagnostic criteria and treatment protocol for hemophagocytic lymphohistiocytosis (HLH) were proposed for both primary (pHLH) and secondary (sHLH) cases, several experts have criticised they are not optimum for the latter. The aims of this investigation are to describe the features of HLH patients that can help to differenciate between primary and secondary cases. Methods Retrospective descriptive study in of HLH patients from 0 to 14 years, diagnosed according to HLH-04 criteria, in a tertiary Paediatric Hospital during the last 10 years (Jan2007-Jan2017). Clinical, analytical and therapeutic data were retrospectively collected from medical records. pHLH and sHLH features were compared in a bivariant analysis. Statistical significance was considered as p Results We found 13 patients, 3pHLH and 10sHLH, whose features are described in Table 1. The median age was 1.5 years (IR: 0.75–3.3), earlier in primary cases (1.0y vs 1.8y), though not significantly. 2 of 3 pHLH had grey hair and neurological impairment and were part of a consanguineous Moroccan family, with cousins diagnosed with Griscelli syndrome, so pHLH was suspected since the begining. CNS injury was more frequent in pHLH (66%) than in sHLH (10%)(p=0.04). There were no significant differences between other organ involvement. At onset, ferritin (p=0.043), neutrophils (p=0.05) and platelets (p=0.28) values were higher in sHLH than in pHLH. Lowest number of neutrophils (p=0.028), highest LDH levels (p=0.036) and minimum platelets count (p=0.07) were higher in sHLH too. There were no differences in other analytical features. Regarding treatment, pHLH cases needed steroids more often (p=0.06), as well as agressive therapies as etoposide (p=0.05) and intrathecal methotrexate (p=0.05). Mortality was significantly higher in primary group (p=0.03). ConclutionS In our experience pHLH and sHLH have important disparities according to evolution, mortality and treatment. Although 2 of our pHLH had physical appereance and family background that helped with etiological diagnosis, it is not always that easy. In this study, we found pHLH and sHLH have important differences, according to clinical and laboratory findings, that may have implications in subsequent management. Larger multicentric More studies are required to establish specific diagnostic criteria and therapeutic schemes depending on the aetiology.