Analysis of IL-4 promoter and VNTR polymorphisms in Thai patients with pulmonary tuberculosis

Tuberculosis (TB) is a leading cause of morbidity and mortality in Thailand. Cytokines play important roles in defense against Mycobacterium tuberculosis infection. Interleukin (IL)-4 is one of the anti-inflammatory cytokines and has been found to be elevated in TB patients. The common polymorphisms in IL-4 gene, including IL-4-590C/T, IL-4-33C/T, and IL-4-variable number of tandem repeats (VNTR) intron 3 have been reported to be associated with risk for some diseases. The purpose of this study was to investigate possible associations between the above mentioned three common functional polymorphisms in the IL-4 gene in patients with pulmonary tuberculosis (PTB) in a Thai population. Forty three patients with PTB and 90 healthy control subjects were studied. The three common polymorphisms of the IL-4 gene were determined using polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP). The allele and genotype frequencies of IL-4 -590 C/T, -33 C/T, VNTR intron 3 polymorphisms did not show significant differences between PTB patients and healthy controls (genotype: p=0.88, p=0.92, p=0.40; allele: p=0.38, p=0.44, p=0.53, respectively). However, the allele distribution of the IL-4 -590 C, -33 C, and VNTR R3 was higher among PTB patients (25.58%, 25.58%, 25.58%, respectively) than among control subjects (20%, 20.48%, 19.44%, respectively). This may suggest that IL-4-590C/T, -33C/T and VNTR intron 3 might play a role in susceptibility to PTB. A larger cohort may possibly help conclude our findings.

Lymphocyte subpopulations in malaria infected individuals living in an endemic area

Development of partial immunity in people living in malaria endemic area is complex. For better understanding, the lymphocyte subpopulations from infected patients were evaluated by flow cytometer before any antimalarial treatment. In P. vivax infection, the frequency of T-helper type 1 (Th1) was decreased significantly (p = 0.042). In contrast, the number of T- helper type 2 (Th2) was increased significantly (p = 0.001). These trends have also been observed in P. faciparum infection. The Th2 predominant response to the natural malaria infection is likely due to persistent stimulation by Plasmodium species. In P. falciparum infection, CD8+ cytotoxic lymphocytes were significantly reduced (p = 0.007). However, such changes were not found in P. vivax infection. This might suggest that CD8+ cell responses to different Plasmodium spp in a different way. Both Th2 activation and CD8+ cell suppression may reflect less protective effects and chronic malaria infection could be established.

Molecular and phenotypic characteristics of neurotropic HIV-1 subtype E

Although HIV-1 subtype E associated with neurological dysfunction is common, the virological characteristics of HIV-1 isolated from the CNS for this subtype have not yet been identified. In this study, paired blood and CSF isolated from patients with AIDs-defining illnesses were cultured, sequenced and aligned. Phylogenetic tree and nucleotide-distances from both blood and CSF were investigated. Cytopathicity and co-receptor usage of paired blood and CSF isolates were compared to define the specific characteristics of CNS isolates. The results confirmed that CSF isolates showed less cytopathicity. It was found that both blood and CSF isolates used either CXCR4 or CXCR4 and CCR5 as co-receptors. Interestingly, one CSF isolate using CCR3 as a co-receptor was identified. By sequence analysis, the pair-wise distances of envelope gp 120 sequence and those of all variable regions (except V3 region) between blood and CSF isolates were significantly different. The genetic distances in V1/V2 regions of CSF isolates showed more diversity than those of blood isolates. These findings suggest that the evolution of V1/V2 regions of CSF isolates seems to be an advantage for HIV-1 in CNS infection. In contrast, the genetic distance in V4 and V5 regions of CSF isolates showed less diversity, suggesting that conservation in these regions might be necessary during the process of HIV-1 CNS infection.

Differential susceptibility of quiescent CD4+ lymphocytes to syncytial-inducing and non-syncytial-inducing isolates of HIV-1

It is generally believed that quiescent CD4+ T cells are not susceptible to HIV-1 infection. However, infection of unstimulated peripheral mononuclear cells by syncytial-inducing (SI) viruses has been shown to be much more efficient than with non-syncytial-inducing (NSI) viruses. This suggested that SI, CXCR4-tropic viruses may be able to infect quiescent CD4+ T cells. We studied the infection of highly purified quiescent CD4+ T cells by SI and NSI viruses. In this article we show that although NSI viruses failed to significantly infect quiescent cells, SI viruses consistently infected these cells and produced viruses upon cellular activation by interleukin-2, 2 to 7 days after initial infection. To examine whether the difference was the result of viral or host factors, we purified CCR5+ quiescent CD4+ T cells and showed that these cells can be infected by dual tropic (R5X4) but not by R5 virus. This indicated that CCR5+ quiescent T cells were also susceptible to HIV-1 infection, and the failure of NSI, CCR5-tropic viruses to infect quiescent cells may be due to some intrinsic properties of these viruses.

The effects of cigarette smoking on peripheral blood leukocytes and lymphocyte subpopulations: an urban population-based study in Thailand

Preliminary studies for peripheral blood leukocytes and lymphocyte subsets were done in smokers and non-smokers. There were 20 smokers (smoked more than 10 cigarettes per day) for more than a year and 20 non-smokers (smoked less than 20 cigarettes/20 years). Ages of smokers and non-smokers were respectively 21-57, and 18-55 years. Cigarette smoking was associated with a statistically significant increase in the number of neutrophils, activated lymphocytes, CD25 and CD19; but a statistical decrease in the percentage of CD7 and CD3. (P < 0.05)

The effect of standardized ginseng extract on peripheral blood leukocytes and lymphocyte subsets: a preliminary study in young health adults

The present study was undertaken in twenty young, healthy Thai males to investigate the effects of prolonged administration of standardized ginseng extract on peripheral blood leukocytes and lymphocyte subsets. The subjects were divided into two equal groups as ginseng and placebo groups. The first group received two capsules daily of standardized ginseng extract 150 mg per capsule for 8 weeks. The second group received placebo and served as control. Circulatory levels of total and differential leukocyte counts and percentage of lymphocyte subsets were determined prior to and at the 4th and 8th week of the experimental period. There were no significant differences in the total and differential leukocyte counts as well as the lymphocyte subpopulations: CD3 (T cells), CD 19 (B cells), CD4 (T-helper cells), CD8 (T-suppression cells), CD4/CD8 ratio, and CD25 (Interleukin-2-receptor cells) between the two subject groups throughout the experimental period. We concluded that oral administration of standardized ginseng extract, 300 mg/day for 8 weeks caused no significant changes in peripheral blood leukocytes and lymphocyte subsets in young, healthy Thai males.

Effect of zinc supplementation on zinc status, copper status and cellular immunity in elderly patients with diabetes mellitus

This preliminary study was to investigate the effects of zinc supplementation on Zn status, Cu status, serum macrominerals and lymphocyte subsets in elderly diabetic patients. The results of Zn supplementation can correct plasma Zn levels to normal values. However, this treatment did not affect the cellular Zn, copper status and serum macrominerals. Enhancement of the percentage of CD4 cells was observed after Zn therapy but had no effect on the percentage of CD8 cells and CD4/CD8 ratios. Our finding implicated that zinc supplementation might be useful to enhance the immune status in these patients.