Tumour‐immune microenvironment in duodenal‐type follicular lymphoma

• DOI: 10.1111/bjh.16715
• Publication Date: 2020-05-08T13:35:58Z
• Authors: Hiroaki Inoue; Shinya Rai; Hirokazu Tanaka; J. Luis Espinoza; Yosaku Watatani; Takahiro Kumode; Kentaro Serizawa; Shoko Nakayama; Yasuhiro Taniguchi; Yasuyoshi Morita; Yoichi Tatsumi; Takashi Ashida; Itaru Matsumura
• Keywords: Adult; Aged, 80 and over; Male; CD8-Positive T-Lymphocytes; Middle Aged; T-Lymphocytes, Regulatory; 3. Good health; 03 medical and health sciences; Lymphocytes, Tumor-Infiltrating; 0302 clinical medicine; Duodenal Neoplasms; Tumor Microenvironment; Humans; Female; Lymphoma, Follicular; Aged

SummaryDespite duodenal‐type follicular lymphoma (DTFL) being morphologically, immunophenotypically and genetically indistinguishable from nodal FL (nFL), this entity typically shows a significantly better prognosis. Here, we analysed the tumour immune microenvironments of diagnostic specimens from patients with DTFL (n = 30), limited‐stage FL (LSFL; n = 19) and advanced‐stage FL (ASFL; n = 31). The mean number of CD8+ tumour‐infiltrating lymphocytes (TILs) in the neoplastic follicles was higher in DTFL (1,827/mm2) than in LSFL (1,150/mm2) and ASFL (1,188/mm2) (P = 0·002, P = 0·002, respectively). In addition, CD8+PD1− T cells with non‐exhausting phenotype were more abundant in the peripheral blood (PB) of DTFL than in LSFL and ASFL, indicating that DTFL may exhibit a better and longer‐lasting T cell‐mediated immune response. Moreover, whereas FOXP3+CTLA‐4+ effector regulatory T cells (eTregs) were rarely observed in the neoplastic follicles of DTFL (mean: 12/mm2), they were more abundant in LSFL (78/mm2) and ASFL (109/mm2) (P = 2·80 × 10−5, P = 4·74 × 10−8, respectively), and the numbers of eTregs correlated inversely with those of CD8+ TILs (r = −0267; P = 0·018). Furthermore, DTFL showed significantly fewer circulating FOXP3hiCD45RA‐CD25hi eTregs (0·146%) than ASFL (0·497%) and healthy controls (0·639%) (P = 0·0003, P = 6·79 × 10−7, respectively). These results suggest that the augmented anti‐tumour immune reactions may contribute to a better prognosis on DTFL.