Risk for developing tuberculosis among anergic patients infected with HIV

Area of Science:

• Infectious Diseases
• Immunology
• Public Health

Background:

• Tuberculosis (TB) remains a significant opportunistic infection in individuals with human immunodeficiency virus (HIV).
• Assessing TB risk in HIV-infected patients with impaired immune responses, such as anergy, is crucial for effective prevention strategies.

Purpose of the Study:

• To evaluate the risk of developing active tuberculosis in HIV-infected patients who exhibit anergy (lack of skin test reactivity).
• To compare TB risk among anergic, positive PPD, and non-anergic HIV-infected individuals.

Main Methods:

• Retrospective cohort study involving 374 HIV-infected patients at a tertiary referral center.
• Patients were categorized based on baseline purified protein derivative (PPD) and delayed-type hypersensitivity skin test results.
• Development of active tuberculosis and response to isoniazid chemoprophylaxis were monitored.

Main Results:

• Anergic HIV-infected patients (30%) had a high risk of active TB (12.4 cases per 100 person-years), similar to those with positive PPD tests (10.4 cases per 100 person-years).
• The risk was significantly higher than in non-anergic patients with negative PPD tests (5.4 cases per 100 person-years).
• Isoniazid preventive therapy reduced TB development from 31% to 4% (P = 0.008).

Conclusions:

• Anergic HIV-infected patients are at substantial risk for tuberculosis development.
• Preventive therapy with isoniazid should be considered for anergic and positive PPD HIV-infected patients in high TB prevalence areas, particularly when CD4 counts fall below 500 cells/mm³.