Predominance of three NF-kappaB binding sites in the long terminal repeat region of HIV Type 1 subtype C isolates from Zambia.

Human immunodeficiency virus type-1 (HIV-1) is a leading cause of mortality and morbidity in the world, with almost 46 million people infected globally. HIV-1 subtype C accounts for 55% of these infections. In Zambia, the majority of HIV-1 infections are subtype C. However, to its north most countries have non-subtype C as the most predominant HIV-1 subtype while to its south most of them are predominantly subtype C. The aim of this study was to determine the subtype distribution and to analyze the long terminal repeat (LTR) region of HIV-1 isolates from the northern part of Zambia. We amplified as well as directly sequenced the LTR, gag, and env regions of 78 HIV-1 peripheral blood samples from adult Zambians. Our results show 95% (74/78) of our isolates were HIV-1 subtype C. Furthermore, of the subtype C samples analyzed across the LTR, 61% (25/41) carried 3 NF-kappaB signature binding site sequences.

HLA-B polymorphism in Japanese HIV-1-infected long-term surviving hemophiliacs.

Approximately 30% of patients with hemophilia in Japan were infected with human immunodeficiency virus (HIV) in early 1980s through contaminated blood products. In 1995, a cohort of HIV-infected, asymptomatic patients with hemophilia was set up for follow-up study. Although the patients met the criteria for long-term non-progressor (LTNP) at the entry to the cohort, some of them later developed lymphopenia during five more years of observation. We collected blood samples from 80 long-term survivors; 42 of them did not require antiviral therapy, but the rest were under treatment. Analysis of HLA-B genotype revealed that carriers of known HIV-resistant alleles such as HLA-B*5701, B*5801, and alleles of B27 antigenic group were not increased in frequency, but that HLA-B*1507 was increased in the cohort (6.25% vs. 1.03%, OR = 6.40, p = 0.039). We also observed the decrease in carriers of HLA-B*5401 (3.75% vs. 14.95%, OR = 0.22, p = 0.016). HLAB* 5401 is a relatively common allele in East Asian populations and belongs to the same B22 antigenic group as B55 and B56 which were reported to associate with rapid progression. Our data indicated that HLA class I is one of the host factors involved in the retardation of HIV disease progression as also reported in the previous studies; however, the alleles associated with this resistance were not the same because of divergent host genetic background.

Prevalence of drug-resistance-associated mutations in antiretroviral drug-naive Zambians infected with subtype C HIV-1.

The ability of HIV-1 to evolve resistance to antiretroviral drugs leads to treatment failure. By nucleotide sequencing of HIV-1 subtype B isolates, amino acids responsible for drug resistance have been identified. Less information is available, however, on the extent and distribution of these amino acids in HIV-1 nonsubtype B viruses circulating mainly in developing countries. More HIV-infected patients in the developing world are now using antiretroviral drugs, and hence there is a need to monitor drug resistance mutations in HIV-1 non-subtype B viruses. This study examines the prevalence of drug resistance mutations in 28 antiretroviral drug-naive HIV-1-infected Zambians. HIV-1 proviral DNA was extracted from peripheral blood mononuclear cells. The region encompassing gag p17 to env C2-V3-C3 was amplified by the polymerase chain reaction followed by direct sequencing. Sequence analyses for drug resistance-associated mutations in th e protease and reverse transcriptase genes, and HIV-1 subtyping, were done. Overall, 92.8% of the generated sequences were HIV-1 subtype C. The generated sequences revealed only secondary associated, but no primary, drug-resistance mutations The most frequent secondary mutations in the protease and RT genes were, respectively, I93L(91.7%), L89M (79.2%), M3611V (79%, 4.2%), and R211K (70.8%), S48T (62.5%). The atypical residues M41N (3.6%) and D67A (3.6%) were detected in the RT gene. This study reveals many naturally occurring polymorphisms in HIV-1 subtype C isolates from antiretroviral drug-naive individuals. Such polymorphisms could lead to rapid treatment failure and development of drug-resistant HIV-1 mutants in individuals undergoing antiretroviral therapy.

Rapid detection of active and latent tuberculosis infection in HIV-positive individuals by enumeration of Mycobacterium tuberculosis-specific T cells.

OBJECTIVES: An accurate test for Mycobacterium tuberculosis infection is urgently needed. The tuberculin skin test (TST) lacks sensitivity, particularly in HIV-infected individuals, and has poor specificity because of antigenic cross-reactivity with Bacillus Calmette-Guérin (BCG) vaccination. ESAT-6 and CFP-10 are antigens expressed in Mycobacterium tuberculosis, but not in Mycobacterium bovis BCG and most environmental mycobacteria. We investigated whether T cells specific for these antigens could serve as accurate markers of M. tuberculosis infection in an area of high tuberculosis and HIV prevalence. METHODS: Using the rapid ex-vivo enzyme-linked immunospot (ELISPOT) assay for IFN-gamma, we enumerated T cells specific for ESAT-6, CFP-10 and purified protein derivative (PPD) in blood samples from 50 Zambian tuberculosis patients, 75 healthy Zambian adults, and 40 healthy UK residents. TSTs were performed in 49 healthy Zambian adults. RESULTS: All (100%; n = 11) and 90% (n = 39) of HIV-negative and HIV-positive tuberculosis patients, respectively, had detectable ESAT-6- or CFP-10-specific T cells. The ESAT-6/CFP-10-based ELISPOT assay was positive in 37 out of 54 HIV-negative healthy Zambians, suggesting a 69% prevalence of latent M. tuberculosis infection. Fewer HIV-positive Zambians possessed ESAT-6/CFP-10-specific T cells, but the impact of HIV infection was less on this assay than on the PPD-based ELISPOT or TST. CONCLUSION: The ESAT-6/CFP-10-based ELISPOT assay detects active tuberculosis in HIV-positive individuals with high sensitivity. It is more specific, and possibly more sensitive, than PPD-based methods of detecting latent M. tuberculosis infection, and may potentially improve the targeting of isoniazid preventative therapy to HIV-positive individuals with latent tuberculosis infection.

Morbidity and nutritional impairment in relation to CD4 count in a Zambian population with high HIV prevalence.

The HIV epidemic has greatly increased morbidity in many African cities and severe undernutrition is a prominent feature of the clinical presentation. However, there is little information about the relationship of morbidity or nutritional status to immune damage at a population level. We report a cross-sectional study of morbidity and nutritional status in relation to CD4 count in an impoverished urban community in Lusaka, Zambia, at enrollment into a longitudinal study. Over a 2 month period in 1999, 261 (52%) of 506 adults resident in one area were interviewed and examined. Of 186 adults who consented to testing, 33 (51%) of 65 who were HIV seropositive reported symptoms of disease compared to 39 (32%) of 121 who were HIV seronegative (OR 2.2, 95%CI 1.1-4.2; P=0.02). Peripheral blood CD4 counts in HIV seronegative individuals were broadly similar to norms in developed countries, but 8 (7%) had CD4 counts below 500 cells/microl. Morbidity in HIV seropositive adults was dominated by tuberculosis (n=11), other respiratory infections (5) or persistent diarrhoea (4), and affected individuals had a wide range of CD4 counts. Nutritional impairment was evident in HIV seropositive adults with clinical evidence of opportunistic infection (OI), not those with asymptomatic HIV infection. Unexpectedly, we also noted that systolic blood pressure was reduced progressively in HIV infection and in those with OI. In conclusion, HIV-related morbidity was dominated by a small number of treatable infectious diseases occurring over a wide range of CD4 count. Nutritional impairment was associated with OI.