CD4+:neopterin ratio correlates with p24 antigenaemia in HIV infected patients

In an effort to improve the Walter Reed Staging System (WR), which mainly relies on immune depletion parameters, by introducing viral replication and T-cell activation markers, we examined by p24 antigenaemia and serum neopterin levels (SNL) 72 HIV positive PGL, ARC and AIDS patients (11 of whom classified as WR 2, 21 as WR 3, 16 as WR 5 and 24 as WR 6). While CD4 cell counts, already weakly correlating with the WR itself, did not significantly differ between p24 antigen (p24 AG) positive and negative patients, striking differences between the two groups, especially in PGL patients (p less than 0.0001), were found as far as SNL was concerned. In fact, SNL values, fluctuating around 10 and 30 nmol/l, respectively, in p24 Ag positive and negative patients regardless of their WR allocation, seemed rather to reflect, as global means of any given class, prevalence rate of p24 Ag positivity. We suggest, therefore, to use CD4/SNL ratio (R) for HIV infection and disease staging, as it not only may represent a compromise index between cellular immune depletion and T-cell activation, but also seems to take into account the viral replication component, already shown to be an important predictive marker of disease progression.