Giant cell arteritis (GCA) is a large vessel vasculitis for which triggering factors remain unknown. Clonal hematopoiesis (CH) was associated with atherosclerosis through the induction of inflammation in myeloid cells, and data suggest that CH expansion and inflammation may support each other to induce a proinflammatory loop. Our objective was to describe the impact of JAK2p.V617F-mutated myeloproliferative neoplasms (MPN) on GCA and to screen MPN-free patients for CH mutations.We performed a retrospective case-control study comparing characteristics of 21 GCA patients with MPN and 42 age and gender-matched GCA patients without MPN. Also, 18 GCA patients were screened for CH through Next Generation Sequencing.The most frequent associated MPN was essential thrombocythemia (ET) (n = 11). Compared to controls, GCA patients with MPN had less frequent cephalic symptoms (71.4 vs. 97.6%, p = 0.004) and higher platelets count at baseline [485 (346-586) vs. 346 [IQR 296-418] x 109/L, p = 0.02). There was no difference between groups for other clinical features. Overall survival was significantly shorter in patients with MPN compared to controls [HR 8.2 (95% CI 1.2-56.6), p = 0.03]. Finally, screening for CH using NGS in 15 GCA patients without MPN revealed CH in 33%.GCA patients with MPN display higher platelets count and shorter overall survival than controls. This association could not be fortuitous given the possible pathophysiological relationship between the two diseases. CH was found in one third of GCA patients, which may be higher than the expected prevalence for similar age, what should be confirmed in a larger cohort.
Matthias Papo, Chloé Friedrich, Laure Delaval, Hubert de Boysson, Jean-François Viallard, Claude Bachmeyer, Thomas Sené, Sébastien Humbert, Pierre Duffau, Anne Contis, Christian Agard, Bruno Gombert, Mathieu Puyade, Aurélie Foucher, Anne-Sophie Alary, François-Xavier Danlos, Alexis Régent, Luc Mouthon, Loïc Guillevin, Maxime Samson, Olivier Kosmider, Benjamin Terrier, French Vasculitis Study Group (FVSG)