Identification of antigen specific T-cells for diagnosis of sarcoidosis
Lead Research Organisation:
Imperial College London
Department Name: National Heart and Lung Institute
Abstract
Sarcoidosis is a potentially fatal disease that can affect any organ within the body. It is due to the
build up of clumps of tissue called granulomas. Current diagnosis involves a needle-biopsy of a
granuloma which can have complications such as bleeding or infection. The Kveim reaction is an old test which involved injecting a piece of sarcoidosis spleen or lymph node into a patient. It often produced a local reaction but we cannot use it anymore due to the potential to transmit infectious diseases. Recent work has shown that the reaction resulted from an influx of special immune cells called T-cells.
We believe we can measure these specific T-cells in the blood of a person to see if they
have the disease, without the need for a biopsy. Our Group has used a similar approach in
tuberculosis and created the first new test for that infection in over 100 years. A new simple T-cell based blood test for sarcoidosis would be revolutionary for patients and lead to important new insights for the disease.
build up of clumps of tissue called granulomas. Current diagnosis involves a needle-biopsy of a
granuloma which can have complications such as bleeding or infection. The Kveim reaction is an old test which involved injecting a piece of sarcoidosis spleen or lymph node into a patient. It often produced a local reaction but we cannot use it anymore due to the potential to transmit infectious diseases. Recent work has shown that the reaction resulted from an influx of special immune cells called T-cells.
We believe we can measure these specific T-cells in the blood of a person to see if they
have the disease, without the need for a biopsy. Our Group has used a similar approach in
tuberculosis and created the first new test for that infection in over 100 years. A new simple T-cell based blood test for sarcoidosis would be revolutionary for patients and lead to important new insights for the disease.
Technical Summary
Sarcoidosis is a potentially fatal multi-organ granulomatous disease of unknown aeitiology with no simple diagnostic test. The immunopathogenesis is poorly understood and the antigenic targets of the granuloma-associated CD4+ T-cells are unknown. Granulomatous reaction to intrcutaneous innoculation with Kveim reagent was historically used as a sensitive and specific diagnostic tool. The CD4+ T-cell infiltrate that characterises Kveim reaction is oligoclonal, implicating a small number of Kveim reagent-derived protein targets. We will isolate and identify candidate antigens within Kveim reagent using proteomic fingerprinting. Our initial approach will involve 2d gel electrophoresis to identify the candidate proteins. An alternative approach will apply trypsin digests and MALDI to produce peptide mass fingerprints. State of the art bioinformatics will be used to analyse the produced data and identify the novel candidate antigens. In addition, we will perform multiplex cytometric bead-array analysis on blood and bronchoalveolar lavage fluid (incubated with Kveim-derived antigens) from recently diagnosed sarcoidosis patients. These results will be combined to develop a novel ex-vivo antigen specific T-cell assay for use in diagnosis. Ethical approval for the entire project is in place. We have begun collecting patient blood and bronchoalveolar samples and protein work has commenced to identify the novel Kveim-derived candidate antigens.