目的：探讨新型冠状病毒（以下简称新冠）肺炎患者外周血淋巴细胞亚群百分比及细胞绝对计数改变与其临床特征间的关系。方法：回顾性分析2022 年4月25日至6月5日期间上海交通大学医学院附属第九人民医院收治的244例新冠肺炎患者临床资料，并按疾病分型（轻型、普通型、重型）、疫苗接种情况及合并基础疾病进行分组，采用流式细胞术检测各组淋巴细胞不同亚群[CD3⁺T淋巴细胞、CD3⁺CD4⁺T淋巴细胞、CD3⁺CD8⁺T淋巴细胞、CD16⁺CD56⁺自然杀伤（natural kill，NK）细胞以及CD19⁺B淋巴细胞]绝对值及百分比，分析外周血淋巴细胞亚群改变与患者临床特征间的关系。结果：与新冠肺炎轻型组比较，重型组患者各淋巴细胞亚群绝对值均显著下降（P<0.05），CD3⁺T淋巴细胞百分比下降（58.0%比66.0%，P<0.05）；与普通型组相比，重型组患者的CD3⁺T、CD3⁺CD4⁺T、CD3⁺CD8⁺T、CD19⁺B淋巴细胞绝对值下降（P<0.05），CD3⁺T淋巴细胞百分比下降（58.0%比68.6%，P<0.05）。与未接种新冠疫苗的患者相比，接种疫苗者的CD3⁺T（1 061个/μL比858.2个/μL）、CD3⁺CD4⁺T（514.4个/μL比645.1个/μL）、CD19⁺B（151.7个/μL比249.6个/μL）淋巴细胞绝对值上升（P<0.05），CD19⁺B淋巴细胞百分比上升（11.7%比15.4%，P<0.05）。与无基础疾病组相比，合并高血压/糖尿病患者的CD3⁺T（1 063个/μL比891.4个/μL）、CD3⁺CD4⁺T（637.7个/μL比540.3个/μL）、CD3⁺CD8⁺T（353.3个/μL比299.5个/μL）、CD19⁺B（253.7个/μL比154个/μL）淋巴细胞绝对值下降（P<0.05），CD19⁺B淋巴细胞百分比下降（14.1%比11.8%, P<0.05）。结论：新冠肺炎患者淋巴细胞亚群的改变与患者的症状轻重、疫苗接种史以及基础疾病史密切相关，重症、合并基础疾病和未接种疫苗者各淋巴细胞亚群绝对值及百分比下降，其下降可能提示患者免疫功能降低，故检测淋巴细胞亚群水平变化对新冠肺炎患者的诊治、评估病情进展及预后可能有重要的参考价值。

Objective: To explore changes in the percentage and cell absolute count of lymphocyte subsets in peripheral blood of patients with novel coronavirus pneumonia (COVID-19). Methods: The clinical data of 244 patients with COVID-19 admitted to the Ninth People′s Hospital, Shanghai Jiao Tong University School of Medicine from April 25 to May 16, 2022 were retrospectively analyzed and classified into difterent groups according to the types of diseases (mild, ordinary and severe), vaccination status and co-existing underlying diseases. Flow cytometry was used to detect the absolute counts and percentages of different lymphocyte subsets(CD3⁺T lymphocytes, CD3⁺CD4⁺T lymphocytes, CD3⁺CD8⁺T lymphocytes, CD16⁺CD56⁺NK cells and CD19⁺B lymphocytes) in each group. Further, we analyzed the relationship between the changes in peripheral blood lymphocyte subsets and the above clinical characteristics in patients. Results: Compared with those in the mild group, the absolute count of each lymphocyte subsets (P<0.05) and the percentage of CD3⁺T lymphocytes in the severe group were significantly decreased (58.0% vs 66.0%, P<0.05); Compared with the ordinary group, the absolute counts of CD3⁺T, CD3⁺CD4⁺T, CD3⁺CD8⁺T, CD19⁺B lymphocytes (P<0.05) were all decreased and the percentage of CD3⁺T lymphocytes in the severe group was decreased (58.0% vs 68.6%, P<0.05). Compared with those in the non-vaccinated group, the absolute counts of CD3⁺T (1 061/μL vs 858.2/μL), CD3⁺CD4⁺T (514.4/μL vs 645.1/μL), CD19⁺B (151.7/μL vs 249.6/μL) lymphocytes (P<0.05) and the percentage of CD19⁺B lymphocytes in the vaccinated group were increased (11.7% vs 15.4%, P<0.05). Compared with those without underlying diseases, the absolute counts of CD3⁺T (1 063/μL vs 891.4/μL), CD3⁺CD4⁺T (637.7/μL vs 540.3/μL), CD3⁺CD8⁺T (353.3/μL vs 299.5/μL), CD19⁺B (253.7/μL vs 154/μL) lymphocytes (P<0.05) and the percentage of CD19⁺B lymphocytes in patients with hypertension/diabetes were decreased (14.1% vs 11.8%, P<0.05). Conclusions: The changes in lymphocyte subsets in patients with COVID-19 are closely related to the severity of symptoms, vaccination history and history of underlying diseases. The decline in the level may indicate that the immune function of patients is reduced, and lymphocyte subsets measurement has essential reference value for the diagnosing, treating, and evaluating disease progression and prognosis in patients with COVID-19.