Background & objective : Three categories of prognostic markers are best documented as
having significance in relation to prognosis of HIV infection. These include HIV viral load,
CD4 T-cell levels and plasma levels of soluble markers of immune activation. The plasma
activation markers, like neopterin, tumor necrosis factor alpha (TNF-α), interleukins etc., are
products of cytokine activity and represent immunologic changes throughout the body. There
is not much information available on serum neopterin estimation in patients infected with
both HIV and tuberculosis (TB), though neopterin levels are known to be elevated in pulmonary
TB patients. In this study we attempted to correlate neopterin levels with the presence of
tuberculosis in HIV infected and uninfected individuals and studied the changes after antituberculosis
treatment.
Methods : Serum neopterin concentrations were measured by high performance liquid
chromatography (HPLC) in 25 HIV-seropositive (HIV-TB) and 10-seronegative (TB) patients
with tuberculosis before, during and at the end of antituberculosis therapy (ATT). S-neo was
also measured in 10 HIV-seropositive asymptomatic individuals and 10 healthy controls. The
results were correlated with clinical, bacteriological and immunological status.
Results : All TB patients regardless of HIV status had elevated s-neo concentrations at diagnosis,
which declined gradually during treatment. Patients with HIV/TB with CD4 counts < 200/mm3
had the highest levels at baseline with a steep fall during treatment. The median level at the
end of treatment was significantly higher in HIV/TB than in TB patients, despite clinical
improvement and bacteriological clearance of Mycobacterium tuberculosis. HIV infected
asymptomatic individuals had neopterin levels that were higher than healthy controls but
lower than HIV-TB patients.
Interpretation & conclusion : Serum neopterin levels are elevated in HIV-positive patients,
with the highest levels in those with tuberculosis and CD4 counts < 200/mm3. Though the
levels decrease with anti tuberculosis therapy, persistently elevated levels indicate progressive
HIV disease and a poor prognosis