Detection of HIV-1 p24 antigen in patients with varying degrees of viremia using an ELISA with a photochemical signal amplification system.

BACKGROUND

We describe a photochemical signal amplification method (PSAM) for increasing the sensitivity of enzyme-linked immunosorbent assays (ELISAs) for the detection of HIV-1 p24 antigen, and present a preliminary validation study on ELISA+PSAM technology for detection of HIV-1 p24 antigen in clinical samples.

METHODS

ELISA+PSAM is compatible with commercially available microtiter plate readers, employs an inexpensive illumination device and the amplification takes around 10 min.

RESULTS

The PSAM technology not only increases the analytical sensitivity for detection of HIV-1 p24 antigen by approximately 40 times, but also significantly increases the clinical sensitivity of the ELISA: in instances where viral RNA load is <3000 copies/ml, conventional heat mediated immune complex disruption ELISA (HM-ELISA) cannot detect any HIV positive samples whereas HM-ELISA+PSAM can detect HIV infection in approximately half of the samples (clinical sensitivity is 52.63%). For viral RNA loads between 3000 and 30,000 copies/ml, the clinical sensitivities of the HM-ELISA and HM-ELISA+PSAM are 32.6% and 91.3%, and for that >30,000 copies/ml, clinical sensitivities of HM-ELISA and HM-ELISA+PSAM are 52.3% and 100%, respectively.

CONCLUSIONS

The HM-ELISA+PSAM represents an advancement in monitoring HIV-1 disease progression and treatment in the global healthcare setting.