Improved diagnosis of tuberculosis in HIV-positive patients using RD1-encoded antigen CFP-10.
OBJECTIVE
The present study was aimed at determining the serodiagnostic potential of 38-kDa (Rv0934, Mycobacterium tuberculosis complex-specific antigen) and CFP-10 (Rv3874, RD1 antigen) antigens among HIV-positive and HIV-negative patients with pulmonary TB.


METHODS
The diagnostic potential of native 38-kDa (n38-kDa) and recombinant CFP-10 (rCFP-10) antigens was ascertained in terms of sensitivity and specificity using an indirect ELISA. The study included 508 HIV-seronegative TB patients (TB), 54 HIV-seropositive TB patients (HIV-TB), 30 HIV-positive patients without TB (HIV), and 256 controls.


RESULTS
In HIV-TB, the sensitivities for individual antigens ranged from 14.8% to 31.5% and the specificity was >98% for IgG. When IgA results were added to IgG, the sensitivity increased to 25.9% for 38-kDa and 57.4% for CFP-10; specificity changed to 97.5% for 38-kDa and 98.1% for CFP-10. The combined results of both the antigens gave 59.3% sensitivity and 95.6% specificity. In TB, the sensitivity was 82.8% when the antigen results were combined. None of the HIV-infected controls showed positivity for IgG to either of the two antigens.


CONCLUSIONS
Use of CFP-10 enhances the sensitivity of 38-kDa, and therefore the 38-kDa and CFP-10 antigen combination can be a diagnostic marker in HIV-TB.
Rao
Parasa V Ramana
PV
Department of Immunology, Tuberculosis Research Centre (ICMR), Mayor V. R. Ramanathan Road, Chetput, Chennai 600031, India.
Murthy
Madhan Kumar
MK
Basirudeen
S
S
Sharma
Pawan
P
Swaminathan
Soumya
S
Raja
Alamelu
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology; D005260:Female; D018023:HIV Seronegativity; D006679:HIV Seropositivity / Q000150:complications*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D008074:Lipoproteins / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011994:Recombinant Proteins / Q000276:immunology; D012680:Sensitivity and Specificity; D012698:Serologic Tests; D014397:Tuberculosis, Pulmonary / Q000150:complications / Q000175:diagnosis*; D055815:Young Adult
C075966:Ag38 antigen, Mycobacterium tuberculosis; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D008074:Lipoproteins; D011994:Recombinant Proteins