[Clinical characteristics and follow-up of 60 patients with recent diagnosis of giant cell arteritis, NEWTON study]. / Caractéristiques et profils évolutifs des patients avec un diagnostic récent d'artérite à cellules géantes, étude NEWTON.

INTRODUCTION: The management of giant cell arteritis (GCA) has evolved with the arrival of tocilizumab (TCZ) and the use of PET/CT. Our objective is to describe the characteristics and followup of patients with recent diagnosis of GCA in current care. PATIENTS AND METHODS: The NEWTON cohort is a monocentric retrospective cohort based on data collected from 60 GCA patients diagnosed between 2017 and 2022 according to the ACR/EULAR 2022 criteria. RESULTS: The median age at diagnosis was 73 [68.75; 81] years old. At diagnosis, the main manifestations were unusual temporal headaches in 48 (80 %) and an inflammatory syndrome in 50 (83 %) patients. Temporal artery biopsy confirmed the diagnosis in 49/58 (84 %) patients. Doppler of the temporal arteries found a halo in 12/23 (52 %) patients. The PET/CT found hypermetabolism in 19/43 (44 %) patients. Prednisone was stopped in 17.5 [12.75; 24.25] months. During follow-up, 22 (37 %) patients received TCZ. At least one complication of corticosteroid therapy was observed in 22 (37 %) patients. After a median follow-up of 24 [12; 42] months, 25 (42 %) patients relapsed. At the end of the follow-up, 29 (48.3 %) patients were weaned from corticosteroid therapy and 15 (25 %) were on TCZ. CONCLUSION: Despite the increasing use of TCZ in the therapeutic arsenal and of the PET/CT in the imaging tools of GCA patients, relapses and complications of corticosteroid therapy remain frequent, observed in more than a third of patients.

Acidic pH as a determinant of TRI gene expression and trichothecene B biosynthesis in Fusarium graminearum.

Reducing production of type B trichothecenes by Fusarium graminearum on cereals is necessary to control contamination, prevent yield reduction and protect human and animal health. Thus, an understanding of how trichothecene biosynthesis is induced is essential. The effect of ambient pH on fungal growth, toxin biosynthesis and expression of TRI genes was studied during in vitro liquid culture of F. graminearum on minimal medium. Fungal development stopped at day 3 after a sharp pH drop in the medium. At the same time, induction of TRI gene expression was observed and toxin began accumulating 1 day later. Acidification seems a determinant of induction, as neither the toxin nor the TRI genes were detected when the pH was maintained neutral. Shifting from neutral to acidic pH by mycelium transfer induced TRI gene expression and toxin accumulation. The regulation of toxin production by ambient pH appears to be specific to some TRI genes since TRI5, located in the core FgTRI5 cluster, showed an immediate induction while TRI101, located elsewhere in the genome, showed a more progressive response. The regulation of trichothecene biosynthesis by the ambient pH appears to be a general mechanism, independent of strain or chemotype, as all tested strains, including F. graminearum and F. culmorum species, showed a regulation of toxin production in response to the ambient pH. We conclude that, in vitro, external acidification is required for induction of TRI gene expression.