Tfh lymphomas feature a characteristic mutational landscape associating mutations in epigenetic modifyers (TET2, DNMT3A, IDH2), RHOA and other T-cell receptor signaling genes (43–46).Here, we sought to characterize subsets of reactive Tfh cells in the tonsil and neoplastic Tfh cells in the context of angioimmunoblastic T cell lymphoma (AITL). This evidence concerns the gene IDH2 and angioimmunoblastic T-cell lymphoma.