The role of CD8+ T cell clones in immune thrombocytopenia

Immune thrombocytopenia (ITP) is traditionally considered an antibody-mediated disease. However, a number of features suggest alternative mechanisms of platelet destruction. In this study, we use a multi-dimensional approach to explore the role of cytotoxic CD8+ T cells in ITP. We characterised patients with ITP and compared them to age-matched controls using immunophenotyping, next-generation sequencing of T cell receptor (TCR) genes, single-cell RNA sequencing, and functional T cell and platelet assays. We found that adults with chronic ITP have increased polyfunctional, terminally differentiated effector memory CD8+ T cells (CD45RA+CD62L-) expressing intracellular interferon-g, tumour necrosis factor-a, and Granzyme B defining them as TEMRA cells. These TEMRA cells expand when the platelet count falls and show no evidence of physiological exhaustion. Deep sequencing of the T cell receptor showed expanded T cell clones in patients with ITP. T cell clones persisted over many years, were more prominent in patients with refractory disease, and expanded when the platelet count was low. Combined single-cell RNA and TCR sequencing of CD8+ T cells confirmed that the expanded clones are TEMRA cells. Using in vitro model systems, we show that CD8+ T cells from patients with ITP form aggregates with autologous platelets, release interferon-g and trigger platelet activation and apoptosis through TCR-mediated release of cytotoxic granules. These findings of clonally expanded CD8+ T cells causing platelet activation and apoptosis provide an antibody-independent mechanism of platelet destruction, indicating that targeting specific T-cell clones could be a novel therapeutic approach for patients with refractory ITP

Doctors Improving Referrals project: a referrals toolkit for junior doctors

Every day in hospitals around the world, millions of interspecialty referrals are made to obtain advice on the optimal care and management of patients. In the UK, the brunt of this work is undertaken by junior doctors with less clinical experience than the specialist colleagues to which they refer. A survey of 283 junior doctors revealed that colleagues were underconfident when making referrals and struggled to know which specialty to contact, how to reach the specialty and what clinical information to include in the referral. More concerningly, 10% of those surveyed had experienced bullying or belittling behaviours and verbal aggression from colleagues when referring.The aim of this project was to design and implement a referrals toolkit for junior doctors to improve confidence making referrals and time to interspecialty advice, to improve patient care. Process mapping to understand the constituents of good referrals was combined with a failure modes and effects analysis describing how referrals fail to identify areas for intervention.A specialty referrals guide with all specialty contact information was created at the trust, demonstrating an increase in junior doctor median confidence from 3/5 (n=20) to 5/5 (n=23) (p<0.001); 65% found it quicker to refer with the guide and 81% found an improved time to discharge. A referrals cheat sheet was also created, containing specialty-specific information to be included when making a referral. This has been downloaded over 23 000 times from around the globe. Of survey respondents (n=43), 74% noted improved confidence in making referrals, 26% noted faster time to specialty advice and 19% found a positive impact on patient discharges. Overall, the referrals toolkit has been beneficial for both junior doctors and the patients for which they care and has been accessed by over 50% of new foundation doctors in 2021 and 2022