[Evaluation of expression rate of chemokines receptor CCR5 on peripheral blood CD8[+] T cells of occult hepatitis B infected patients]

Occult hepatitis B infection [OBI] is defined as a form of hepatitis B that despite absence of detectable HBsAg, HBV-DNA is present in patient's peripheral blood. Genetic and immunological differences appear to play important roles in producing OBI. Therefore, this project was aimed to examine the expression of a chemokine receptor [CCR5] on CD8[+] T cells of OBI patients. In this experimental study, 3,700 HBsAg- plasma samples were collected. Samples were tested for anti-HBc antibody and all of HBsAg-/anti-HBc[+] samples were screened for HBV-DNA by PCR. HBV-DNA positive samples were assigned as OBI cases. Also, flow cytometry analysis was performed to examine the expression of CCR5 on CD8[+] T cells of OBI patients. Results of current study showed that 352 [9.5%] cases of samples were positive for anti-HBc. Examination of HBsAg/anti-HBc[+] samples for HBV-DNA by PCR showed that 57 [16.1%] cases had HBV-DNA. Flow cytometric studies indicated lymphocytosis in these patients; however, the number of cells which expressed CD8[+] and CCR5 is decreased significantly in patients, compared to healthy control. In addition to CD8[+] T cells, the expression of CCR5 is also decreased on all immune cells. One of the chemokine receptors which are expressed by CD8[+] T cells is CCR5 and these cells are recruited to infected tissues, including liver by CCR5. Therefore, based on results of this investigation, one may conclude that due to the decreased expression of CCR5, the CD8[+] T cells are unable to respond to the chemokines [CCR5 ligands] and, hence, can not immigrate to the infected liver and incorporate in clearance of hepatitis B virus

Increased number of CCR5+ CD4 T cells among south Indian adults probably associated with the low frequency of X4 phenotype of HIV-1 in India.

BACKGROUND & OBJECTIVE: The shift of the human immunodeficiency virus (HIV) from nonsyncytium inducing strains (NSI/R5) to syncytium inducing strains (SI/X4) seen in subtype B infections during progression to acquired immunodeficiency syndrome (AIDS) is less frequently reported in subtype C. NSI and SI strains differ in the co-receptor they utilize to infect a T-cell. We postulated that a larger pool of CD4 T cells expressing CCR5 would be present among individuals in the Indian population. To validate this hypothesis, we estimated the percentage of CD4 cells expressing CCR5 or CXCR4 molecules among healthy south Indian adults and HIV infected individuals. METHODS: HIV-1 infected and uninfected adult volunteers, belonging to the four southern states of India with Tamil/Malayalam/Kannada or Telugu as their spoken language were prospectively recruited. A two colour flowcytometry examination of the blood sample was done using the following monoclonals; anti-CD45 (FITC)/CD14 (PE), anti IgG1 (FITC)/IgG2a (PE), anti-CD3 (FITC)/CD4 (PE), anti-CD3 (FITC)/CD8 (PE), anti-CD4 (FITC) and anti CCR5 (PE) or anti CXCR4 (PE). RESULTS: In the healthy population (n = 30) studied, 24.6 per cent of CD4 T cells expressed CCR5 and the percentage of CD4 T cells expressing CXCR4 was 80.4. Among the HIV infected individuals (n = 51) the percentage of CD4 T cells expressing CCR5 and CXCR4 was 26.8 and 78.7 per cent respectively. INTERPRETATION & CONCLUSION: The percentage of CD4 cells expressing CCR5 and CXCR4 in both the HIV uninfected and infected adults was significantly higher in the south Indian population than in the West. The larger pool of CCR5 positive CD4 cells probably allows for the R5 HIV strain to have a replication advantage over X4 HIV strains. This may explain the lack of shift in the viral phenotype during disease progression and also the perceived rapid progression of the disease in India compared to the West.