Objective To investigate the change of cellular immunity and its prognostic significance in patients with diffuse large B-cell lymphoma.

Methods The clinical data of 28 patients with newly diagnosed diffuse large B-cell lymphoma in the Department of Hematology, Xiamen Branch, Zhongshan Hospital, Fudan University from February 2018 to December 2020 were retrospectively analyzed. T lymphocyte subsets in peripheral blood were detected by flow cytometry at different time after chemotherapy.

Results The absolute number of CD4⁺T lymphocytes and the CD4⁺/CD8⁺ ratio in peripheral blood of the patients decreased after chemotherapy. The absolute numbers of CD4⁺T lymphocytes were significantly lower after the fourth and sixth cycle chemotherapy than before chemotherapy (P < 0.05), and reached the lowest value (0.245±0.086×10⁹/L) after the fourth cycle chemotherapy. The CD4⁺/CD8⁺ ratios were significantly lower after the fourth and sixth cycle chemotherapy, at 3 months and 6 months after the end of chemotherapy than before chemotherapy (P < 0.05). The absolute number of CD4⁺T lymphocyte and the CD4⁺/CD8⁺ ratio after sixth cycle chemotherapy in the complete response group were higher than those in the incomplete response group (P < 0.05). The absolute number of CD4⁺T lymphocyte after the sixth cycle chemotherapy in the recurrent group was lower than that in the non-recurrent group (P＝0.030).

Conclusions The cellular immunity of patients with diffuse large B cell lymphoma is impaired after chemotherapy. The main manifestation is that the CD4⁺T lymphocyte count decreases first and then increases within 6 months after treatment and the severity of the CD4⁺T lymphocyte decrease in the early stage after chemotherapy is related to prognosis of the patients.