Saliva α-diversity was associated with CD4/CD8 T cell ratio, a measure of immune dysfunction inversely correlated with morbidity and mortality (31) (Shannon Padj = 0.08; Chao Padj = 0.03) and with activated CD8 T cells (percentage of HLA-DR+ CD38+ CD4 T cells, Chao Padj = 0.02). The gene discussed is CD4; the disease is immune system disorder.