A Marker for Progression of Latent Tuberculosis Infection to Active Tuberculosis Infection in HIV Positive Individuals: CD4/CD8 Ratio

Abstract

Objective: We aimed to determine the utility of CD4 T lymphocyte counts and percentages and CD4/CD8 ratios as markers for the progression of latent tuberculosis infection (LTBI) to active tuberculosis (TB) infection in HIV-positive patients followed in the Acquired Immunodeficiency Virus (HIV) Polyclinic of our hospital. Methods: The files of 530 HIV-positive patients were retrospectively analyzed. "Tuberculin skin test" (TST) was applied after the anti-HIV test was positive. Asymptomatic patients with a TST =5 mm were considered TB negative, patients with a TST =5 mm were considered LTBI, and all symptomatic patients (fever, cough, night sweats, weight loss) regardless of TST result were considered as active TB infection. CD4 counts and percentages and CD4/CD8 ratios were calculated and the relationship between LTBI and active TB infection was evaluated using Mann-Whitney U test and independent sample t-test. Results: During the specified period, 530 patients were admitted to the HIV Outpatient Clinic. There were 43 (8.11%) patients in the LTBI group, of whom 4 (9.3%) were female and 39 (90.7%) were male. CD4 was <200 mm² in 7 (16.3%) patients and >200 mm² in 36 (83.7%) patients. The mean CD4/CD8 ratio was 0.55 (0.08-1.45). 21 (3.96%) patients had symptoms of fever, cough, night sweats and weight loss and were diagnosed with active TB infection. Among these patients, 1 (4.8%) was female and 20 (95.2%) were male. CD4 was <200 mm² in 5 (23.8%) patients and >200 mm² in 16 (76.2%) patients. The mean CD4/CD8 ratio was 0.38 (0.07-1.8). The difference in CD4 counts between patients with LTBI and active TB infection was not significant, but the difference in CD4/CD8 ratio was significant (p<0.05). Conclusion: Immune dysfunction that occurs in HIV and TB co-infection facilitates the activation of LTBI. While CD4 counts and CD4 percentages were not significant as risk markers, CD4/CD8 ratio was found as significant.