Interleukin-10 promoter gene polymorphisms have no clear influence on interleukin-10 protein secretion in AIDS-associated B-cell lines

Genetic association of IL-10 gene promoter polymorphism and HIV-1 infection in North Indians

INTRODUCTION

Cytokines play a significant role in host immune defense. IL-10 is an anti-inflammatory, immunomodulatory cytokine that can both stimulate and suppress the immune response and inhibits HIV-1 replication in vivo. Interindividual variations in IL-10 production were genetically contributed to polymorphisms within IL-10 promoter region.

AIMS

The aim of this study was to investigate the association of IL-10 gene promoter -1082 G/A, -819 C/T, and 592 C/A polymorphism on HIV-1 transmission /progression in North Indian individuals.

PATIENTS AND METHODS

A total of 180 HIV-1 seropositive (HSP) stratified on the basis of disease severity (stage I, II, and III), 50 HIV-1 exposed seronegative (HES) and 305 HIV-1 seronegative (HSN) individuals were genotyped for IL-10 gene promoter by polymerase chain reaction-restriction fragment length polymorphism. A suggestive evidence of association was obtained for IL-10 592 C/A promoter polymorphism at the level of allele and genotype distribution. The frequency of IL-10 592 A allele and genotype was significantly increased in HSP compared to HSN (p = 0.013; OR = 1.412 and p = 0.034; OR = 1.685 respectively). Further comparison in between different clinical stages of HIV-1 infected patients of IL-10 592 A allele and genotype revealed a significant increase in its frequency in the stage III compared with those together in stage I (p = 0.004, OR = 2.181 and p = 0.002, OR = 4.156, respectively). This study reports for the first time that IL-10 gene promoter 592 C/A polymorphism may be a risk factor for HIV-1 transmission/progression in HIV-1 infected North Indian individuals.

Epstein-Barr virus infection and single nucleotide polymorphisms in the promoter region of interleukin 10 gene in patients with Hodgkin lymphoma

CONTEXT

Hodgkin lymphoma is a neoplastic disease in which the immune system plays a major role in its pathogenesis. Interleukin 10 (IL-10), an immunosuppressive cytokine actively produced in patients with Hodgkin lymphomas, favors the survival of the Hodgkin/Reed-Sternberg cells. Individual variations in IL-10 levels may be due, in part, to the presence of single nucleotide polymorphisms in the IL10 gene promoter.

OBJECTIVE

To evaluate whether particular single nucleotide polymorphisms in the IL10 gene are found more frequently in Hodgkin lymphoma cases associated with Epstein-Barr virus infection.

DESIGN

The identification of single nucleotide polymorphisms at positions -1082 and -819/-592 in the IL10 gene was performed by polymerase chain reaction and restriction length fragment polymorphisms analysis in 65 cases of Hodgkin lymphoma and 50 cases of reactive benign follicular lymphoid hyperplasia (non-Hodgkin lymphoma control group).

RESULTS

The frequency of the genotype GG at position -1082 was found to be significantly higher in patients with Epstein-Barr virus-positive Hodgkin lymphoma compared with Epstein-Barr virus-negative cases.

CONCLUSIONS

The results suggest that the presence of specific single nucleotide polymorphisms in the IL10 gene, notably those associated with high IL-10 production, may play a role in the susceptibility to Epstein-Barr virus-positive Hodgkin lymphoma development.

Juxtacrine function of interleukin-15/interleukin-15 receptor system in tumour derived human B-cell lines

Interleukin-15 (IL-15) is a cytokine that induces proliferation and promotes cell survival of human T, B and NK cells. IL-15 and interleukin-2 (IL-2) exhibit a similar spectrum of immune effects and share the IL-2 receptor (IL-2R) subunits IL-2Rbeta and IL-2Rgamma(c) for signalling in haematopoietic cells. Furthermore, each cytokine has a private alpha receptor, namely IL-2Ralpha for IL-2 and IL-15Ralpha for IL-15, that functions in ligand binding. Using reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) methods, the expression and secretion of IL-15 and IL-15Ralpha in tumour-derived B-cell lines were studied. The results as presented in this study identify that IL-15 mRNA is predominantly expressed in EBV positive (EBV(+)) B-cell lines, although IL-15Ralpha is ubiquitously and constitutively expressed in all these B-cell lines. Although no detectable levels of IL-15 protein secretion were observed in any of these cell lines, we were able to detect membrane-bound expression of IL-15 protein by FACS analysis in some cell lines. These data imply that the IL-15/IL-15R system requires complex regulatory mechanisms for protein secretion. Taken together, we speculate that these results suggest a juxtacrine, intracrine function for IL-15/IL-15R.