We have studied a series of 98 n-PTCLs samples (comprising 57 AITL and 41 PTCL-NOS cases) with five TFH antibodies (CD10, BCL-6, PD-1, CXCL13, ICOS), and looked for mutations in five of the genes most frequently mutated in AITL (TET2, DNMT3A, IDH2, RHOA, PLCG1) using the NGS Ion Torrent platform. The gene discussed is ICOS; the disease is angioimmunoblastic T-cell lymphoma.