Evaluation of an indirect immunofluorescence assay for confirmation of human immunodeficiency virus type 1 antibody in U.S. blood donor sera

Immunofluorescence assay in India for confirmation of HIV-1 infection using a T-cell line infected with defective HIV-1

BACKGROUND

In India, the enzyme immunoassay (EIA)/rapid test is used for screening and confirmatory antibody testing of HIV infection, and all HIV reactive samples are further confirmed by two other rapid tests working on different principles; however, Western blotting (WB) and immunofluorescence (IF) assays are not routinely performed in this country.

METHODS

A total of 2104 sera from Indian subjects were tested for the presence of HIV-1 antibody using EIA/rapid tests, according to the guidelines of the National AIDS Control Organization of India, and were also subjected to IF test using L-2 cells persistently infected with defective HIV-1. WB and a nested reverse transcriptase polymerase chain reaction (RT-PCR) were performed on discrepant samples.

RESULTS

IF results were 100% concordant with EIA/rapid tests for 212 HIV-1-positive samples and 1889 HIV-1-negative samples. Interestingly, three (0.14%) samples negative by EIA/rapid tests were weakly or moderately positive (1+/2+) by IF test. All three of these samples were confirmed to be negative by WB (reactive with Gag/Pol, but not with Env), but positive by RT-PCR with primers targeting the C2-V5 fragment of the env gene. These three samples were from individuals who voluntarily reported for HIV testing because of high-risk practices, and they may have been at an early stage of HIV infection.

CONCLUSIONS

These results confirm that the IF test using L-2 cells is a sensitive and specific alternative method for confirmation of HIV-1 infection and could be included in the diagnostic algorithm in reference laboratories in developing countries.

HIV disease in primary care

During the past decade, a large number of new drugs for treating HIV and its complications have been developed. The increasingly sophisticated use of these drugs in combination has led to a marked reduction in HIV-related morbidity and mortality in countries where they are available. HIV/AIDS patients receiving treatment are now expected to live into old age. The beneficial effect of HIV treatment has resulted in an expanding population of persons living with HIV/AIDS who will need the care of an HIV specialist because of the complexity of the treatment regimens and the rapidly changing HIV/AIDS knowledge base. However, this growing and aging population will also benefit from the care of a primary care physician. The primary care generalist is in the best position to recognize and diagnose HIV infection, evaluate HIV risk in his or her patient population, and help prevent HIV infection in persons at risk. In patients known to be infected, the primary care generalist will be best able to manage hyperlipidemia, diabetes, cardiovascular disease, and other disorders of an aging population with an increased risk of these and other conditions. Patients with HIV infection frequently accumulate a large number of specialist physicians, and the unique ability of the primary care physician to monitor their care and act as a knowledgeable patient advocate is a great benefit to the patient.