Correlation between cancer related anemia and abundance of SARS-CoV-2 specific memory CD8+ T cells

Objective To explore the effect of cancer related anemia on the abundance of SARS-CoV-2 specific memory CD8+ T cells in peripheral blood. Methods A total of 34 HLA-A*11∶01 positive patients with middle- and late-stage tumors admitted in the Rocket Force Medical Center of PLA from June to July 2023 were enrolled in this study. According to hemoglobin (HGB) level, they were divided into non anemia group (≥120 g/L, n=14), mild anemia group (90~120 g/L, n=14), and moderate to severe anemia group (< 90 g/L, n=6). After their peripheral blood mononuclear cells were isolated, memory CD8+ T cells were stimulated by the epitopes of SARS-CoV-2 and then expanded. Positive epitopes were screened using enzyme-linked immunosorbent spot (ELISPOT) assay, and then MHC-peptide Tetramers were constructed. The proportion and number of Tetramer+ cells and the number of ELISPOT spots were detected in the expanded cells to reflect the abundance of SARS-CoV-2 specific memory CD8+ T cells. The relevance of patients' HGB level with the proportion and number of Tetramer+ cells and the number of ELISPOT spots was analyzed. The differences of the proportion and number of Tetramer+ cells and the number of ELISPOT spots was analyzed in different groups. Results Among the 34 patients, there were 25 males and 9 females, at an age range of 36~78 (median 57) years. The proportion and number of Tetramer+ cells and the number of ELISPOT spots were positively correlated with HGB level (P