Patients with TB (n = 86) were next stratified using four different indices of disease severity: CD4 cell count (<100, 100 to 200 and >200 cells/μL), increasing symptom severity (as defined above), CRP concentration (<20, 20 to 60, 61 to 200 and >200 mg/L) and hemoglobin concentration (<8, 8 to 11 and >11 g/dL). This evidence concerns the gene CD4 and tuberculosis.