CD8A and obstructive sleep apnea syndrome: Generally, increase in CD4+/CD8+ ratio indicates an enhanced cell immune function, whereas decrease in the ratio suggests a weakened function.7 By detecting the lymphocyte subsets in peripheral blood, Qin et al. found that adult patients with moderate or severe OSAHS had significantly lower percentages of CD4+ T lymphocytes but significantly higher percentages of CD8+ T lymphocytes than those of the control group.