Proof of concept for a rapid diagnosis of infection with non-tuberculous mycobacteria in immune compromised patients

"Although infection with _Mycobacterium tuberculosis_, the cause of TB, is very widely studied, non-tuberculous mycobacteria (NTMs) are much more common in the environment but generally do not present any human health problems. However, they are a significant problem in patients whose immune systems are compromised. Thus, up to 10-20 % of cystic fibrosis patients are infected with _Mycobacterium abscessus_. Infection prevents transplantation, and is spread from patient to patient, requiring isolation; treatment can take two years - with a 60 % chance of failure. The problem is so severe that all patients currently are screened; this uses an expensive method, compromised because patients can be positive in the assay but not show clinical disease. **A rapid, cost effective method of diagnosis, which could also monitor the progression of infection and treatment, would represent a step change for clinicians.**

**Diagnostig Ltd.** has prepared, in the laboratory, a suite of molecules identical to individual components of complex mixtures present in mycobacteria, the detailed compositions of which are characteristic of a particular species. These molecules bind to antibodies present in the blood of patients with TB, and this antigen-antibody binding can very effectively identify active tuberculosis disease even in patients who have been vaccinated or have 'latent' disease. With appropriate antigens, it can also detect bovine TB and distinguish infection by _Mycobacterium avium_ paratuberculosis in cattle, the cause of Johne's disease. This project will establish that, by appropriate choice of antigens, it can provide a rapid, cheap diagnosis of infection by NTMs, demonstrated using _M.abscessus,_ and also _M. avium_, infection in cystic fibrosis. The company will use its proprietary antigens to evaluate sera from patients with no infection, those positive by standard blood assays but with no clinical signs, and those also showing clinical signs. Samples will be provided, with appropriate ethical approvals, by **Royal Papworth Hospital** **Trust** and expert clinical input on assay development will be provided by Prof. Floto."