Evaluation of a dry format reagent for CD4+ and CD8+ T-cell enumeration with FACSCount and Guava polymerase chain reaction.

Purpose: In all CD4+/CD8+ T-cell estimation systems, the reagents used are liquid in nature and have to be transported and stored at 2°-8°C. This causes problems in countries where the ambient temperature is high for most parts of the year or where the laboratories are at remote places. Materials and Methods: We evaluated a dry format of CD4/CD8 reagents from ReaMetrix (Bangalore, India) against the existing liquid reagents from Becton Dickinson (San Jose, CA, USA) and Guava PCA system (Guava Technologies, Hayward, CA, USA). Blood samples collected during March 2009 through May 2009 from 102 HIV-infected individuals and 31 normal healthy individuals in a tertiary care centre in India (south) were tested by Guava; EasyCD4™ System (PCA) and FACSCount using the respective reagents and the corresponding ReaMetrix reagents. Results: Overall, the correlation (r) of the new Rea T Count and FACSCount reagents for the CD4+ T-cell estimation was 0.98, while with ReaPan 3 4 G reagent in the Guava PCA system with the Guava reagent was 0.97. The mean bias for CD4+ T-cell measurements between Rea T count and BD reagent was -6 cells/ml, while the same with ReaPan 3 4 G reagent in the Guava PCA system was 78 cells/ml. The mean bias for the Rea T count and the ReaPan 3 4 G reagent tested in the FACSCount and Guava PCA system was 17 cells. Conclusions: The dry reagents were found to be reliable and cheaper compared to the existing liquid reagents. This allows the transportation of reagents in the absence of cold chain and will facilitate a more user-friendly CD4+ T-cell testing system.

Frequency of HIV type 2 infections among blood donor population from India: A 10-year experience.

Purpose: In India, HIV-2 epidemic is alongside with HIV-1. Blood banks are introducing nucleic acid testing (NAT) for screening. The limitation of NAT systems is the inability to detect HIV-2. Materials and Method : An analysis of HIV screening of a blood bank at a tertiary care center from 1998 to 2007 was carried out. Results : A total of 175026 donors were screened by serological assays and 789 were reactive for HIV antibody. Only 478 (61%) were confirmed positive by Western blot/immunoblot. There were 465 (97.2%) donations positive for HIV-1, 6 (1.3%) for HIV-2 (monotypic infection) and 7 (1.5%) for HIV-1 and HIV-2 (dual infection). Conclusion : We show the presence of HIV-2 infection among the blood donors and the need for incorporating HIV-2 detection also in the NAT systems.

An unusual seroconversion profile in a pregnant woman infected with the human immunodeficiency virus-1: need for using later generations HIV screening assays.

The first HIV-1 marker that appears in blood following infection is HIV-1 RNA and usually the load is in millions of copies/ ml preceding seroconversion. A 24-year-old pregnant woman, gravida 2, parity 1 was tested for HIV as part of antenatal screening. Three samples were collected and tested from this individual over a period 70 days. The HIV-1 RNA level during seroconversion phase was very low, contrary to the well understood natural history of HIV infection. The reactivity rate in the ELISA and the Western Blot profile showed a gradual increase over the 70 days with a weak reactivity in a second generation assay (detects IgG only) for the third sample. This case illustrates the uncertainties regarding the serological window period in HIV infection and the need to use at least a third generation assay in testing centres for early detection of HIV infection.