And for those patients whose preoperative CD4 counts ≤ 200 cells/μ L, the antibiotic and antifungal medications (sulfamethoxazole/trimethoprim (SMZ/TMP) and fluconazole) are started preoperatively as prophylaxis against Pneumocystis carinii pneumonia (PCP) and fungal infection. The gene discussed is CD4; the disease is fungal infectious disease.