Haemophagocytic Lymphohistiocytosis

The purpose of this project is to study the survival of patients until Haematopoietic Stem Cell Transplantation following the use of Ruxolitinib as first-line treatment associated to corticosteroids in primary HLH.

Haemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening blood disease which causes severe inflammation with symptoms similar to severe sepsis. It is hard to diagnose. The most common cause of HLH in adults is lymphoma (blood cancer). Outcomes for adults with HLH and cancer are serious, and most die after days or weeks because they have been diagnosed or treated too late. It is likely that many cases where patients died of HLH with no underlying cause actually had cancer. Recently it has been found that patients with certain types of lymphoma have DNA which comes directly from their cancer (circulating tumour DNA; ctDNA). Aggressive lymphomas release a lot of ctDNA which can be detected in the blood of patients. This study will look for ctDNA in patients with HLH, and see if it is possible to use it to diagnose lymphoma earlier. Patients will provide a small additional blood sample for analysis. Diagnosing lymphoma more rapidly would mean more people could get the correct treatment for the lymphoma which has caused their HLH. They could receive the correct treatment sooner. Earlier diagnosis and treatment could improve survival for these patients.

The bacteria and viruses in the bowel (gut microbiota; GM) have powerful effects on the immune system. GM changes are seen in patients with auto-immune diseases, where the immune system attacks normal tissues, and cancer, and for those with some forms of blood cancer, and appears to affect both responses to, and side-effects of treatment. The investigators want to examine the GM and the associated small molecules (metabolites) in adults with different forms of blood cancer, particularly those undergoing immunotherapy, those with have newly diagnosed follicular lymphoma, and also those with a severe hyperinflammatory disorder which causes problems similar to sepsis called Haemophagocytic lymphohistiocytosis (HLH), which is also often caused by an underlying lymphoma. The investigators want to collect blood and stool samples from patients and use the results of tests already performed in the NHS as well as recording how well patients responded to treatment. The samples will be used to identify novel targets within the GM and associated metabolites which contribute to side effects of, or response to immunotherapy, or are responsible for causing HLH which can be targeted to make treatment better tolerated. For patients with newly diagnosed indolent lymphoma the aim is to see if there are differences which may account for patients needing early or late treatment, or no treatment ever.