[Analysis of HLA-G transcripts in PBMCs of normal and lupus individuals and effect of IFN-gamma on the expression of HLA-G]

ABSTRACT

HLA-G is a nonclassical major histocompatibility complex antigen and is expressed as seven isoforms, including four membrane bound [HLA-G1 to-G4] and three soluble [HLA-G5 to-G7] forms. The pattern of selective expression of HLA-G transcripts in tissues shows the existence of a tight transcriptional control on the gene expression. It has been revealed that cytokines including interfrons and IL-10 could cause stimulation of the HLA-G transcription. The purpose of this study was to examine the effects of IFN-gamma on the expression of HLA-G transcripts in both PBMCs of normal and SLE patients. Whole blood of 20 female SLE patients and 15 healthy donor candidates for Bone Marrow Transplantation were used. PBMCs were isolated from the whole blood by Ficoll gradient centrifugation and cultured with or without IFN-gamma /LPS for 48 hours. Total RNA was extracted from the cells by trizol method. After reverse transcription of RNA to cDNA and the performance of a multiplex PCR for beta actin and HLA-G, the PCR products were analyzed using electrophoresis on a 2% agarose gel and stained with ethidium bromide. The results showed that the transcription of HLA-G was higher in SLE patients compared to normal controls. Addition of IFN-gamma /LPS could influence the expression of this molecule by increasing the transcription of HLA-G in both normal and patient PBMCs [P?0.05]. Transcription of HLA-G gene could be increased by the cytokine IFN-gamma. This observation is in accordance with previous reports. This effect could be assigned to both normal and lupus Patients. The effects of the cytokine IFN-gamma /LPS in the induction of HLA-G transcription were higher in normal than lupus patients. Nevertheless, the total expression of HLA-G was higher in lupus patients