The number of effector CD8+ T (Teff) cells decreased in the BCR-ABL P210-elevated group, whereas naive CD8+ T cells and Treg cells increased in the same group, indicating that decreased T-cell immunity might contribute to the increase in the BCR-ABL P210 level of CML patients after contracting COVID-19. This evidence concerns the gene CD8A and chronic myelogenous leukemia, BCR-ABL1 positive.