Among the genes that were affected by dexamethasone and further affected by Pneumocystis infection, Mgst1 and Hspa1b genes were down-regulated, while Cd14, Irf8, Il1b, Cxcl13, Cxcr4, Fn1, Irf1, Cd74, S100a9, and Spp1 genes were up-regulated in all four groups (Table 2). The gene discussed is S100A9; the disease is Pneumocystis infectious disease.