Tuberculosis (TB) and HIV infection are independently associated with elevated serum concentrations of tumour necrosis factor receptor type 1 and beta(2)-microglobulin, respectively

The aim of this study was to identify immune markers that are independently associated with HIV infection or TB in vivo. Using commercially available assays, we measured concentrations of five immune markers in sera from 175 out-patients attending medical clinics in Cote D'Ivoire and Ghana, West Afr ica. Patients were categorized into groups with TB only (TB+HIV-, n = 55), TB and HIV coinfection (TB+HIV+, n = 50), HIV infection only (TB-HIV+, n = 35), or neither infection (TB-HIV-, n = 35). TB+HIV+ and TB-HIV+ groups wer e matched for blood CD4(+) lymphocyte count. Mean +/- s.d, concentrations o f beta(2)-microglobulin were similarly increased in both the TB-HIV+ (5.3 /- 2.1 mu g/ml, P < 0.0001) and the TB+HIV+ (5.0 +/- 1.5 mu g/ml, P < 0.000 1) groups compared with the TB-HIV- group (2.2 +/- 1.8 mu g/ml), but were o nly slightly increased in the TB+HIV- group (3.2 +/- 1.8 mu g/ml, P = 0.01) . In contrast, mean serum concentrations of soluble tumour necrosis factor receptor type I (sTNF-RI) were similarly elevated in the TB+HIV- (1873 +/- 749 pg/ml, P < 0.0001) and TB+HIV+ (1797 +/- 571 pg/ml, P < 0.0001) groups compared with uninfected subjects (906 +/- 613 pg/ml), but there was only a small increase in sTNF-RI in the TB-HIV+ group (1231 +/- 165 pg/ml, P = 0. 03). Both TB and HIV infection were associated with substantial elevation o f serum concentrations of soluble CD8, soluble CD54, and sTNF-R type II. An alysis of additional samples from groups of TB+HIV- and TB+HTV+ patients re ceiving anti-TB treatment showed significant and equal reductions in mean s erum sTNF-RI concentrations, but no significant change in mean beta(2)-micr oglobulin. Thus, serum beta(2)-microglobulin and sTNF-RI serve as relativel y independent markers of HIV infection and TB, respectively, in studies of co-infected persons.