Western blot profile in HIV infection

Abstract

Background: Although the overall sensitivity and specificity of the western blot (WB) test for detection of antibodies to various viral proteins is high, there has been a substantial difference in the timing of the appearance of antibody bands and their intensities during different stages of HIV infection.

Aims: Mapping different band patterns of Western blot results and correlating them with stages of HIV infection.

Methods: We performed a retrospective study with 1,467 HIV-1 infected cases confirmed by WB test between January 2002 to July 2005, with the objective of mapping different band patterns of western blot results and determining whether the presence or absence of certain bands was associated with any specific stage of HIV infection. For the interpretation of the WB results in this study, the guidelines recommended by NACO, India were followed.

Results: Reactivity with all the bands was the most commonly observed WB pattern, occurring in 92.91% (1363/1467) of cases, whereas the other 7.09% showed uncommon band patterns. Of all individual bands, p31 band was the most frequently missing one, absent in 7.09% cases. On classifying the WB reactive cases by the WHO clinical staging system, 38.45% (564/1467) were in Stage 1, 47.99% (704/1467) in stages 2 and 3 and 13.56% in stage 4. Correlation of CD4 cell counts with the various uncommon band patterns showed that only 5.56% (4/72) had counts in the 200-500 cells/microl range, whereas 45.83% and 48.61% had counts of < 200 and> 500 cells/microl respectively.

Conclusion: Interpretation of the WB band pattern in combination with clinical features may be occasionally useful in predicting the stage of HIV infection.