The Microbiome in Blood Cancer and HLH

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.