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Comparative Analysis of HLA‐G Expression by Keratinocytes Derived from Pemphigus Vulgaris Patients vs. Normal Individuals

Abstract

Background: Human leukocyte antigen‐G (HLA‐G), is a non‐classical HLA class I molecule. Over the past few years, HLA‐G has been considered as a tolerogenic antigen and a tissue protective molecule in inflammatory diseases. Objectives: This study was performed to analyze HLA‐G expression in pemphigus vulgaris (PV) patients and to assess its possible anti‐inflammatory role in skin disorders. Methods: With observing ethical issues, skin biopsies from 4 normal subjects and 3 PV patients were prepared. The epidermal layer of these biopsies was separated using Dispase enzyme treatment. After trypsinization, single cell suspensions of keratinocytes were cultured in MCDB‐153 serum‐free medium. Three weeks supernatants were collected and applied for a sandwich ELISA to detect total soluble isoforms of HLA‐G antigen. Two species of antibodies used for ELISA were made in our laboratory, i.e. anti‐HLA‐G polyclonal and 5E6H7 monoclonal. A reverse transcriptase polymerase chain reaction (RT‐PCR) was developed for pan HLA‐G transcript to assess the regulation level of HLA‐G expression. Results: The data on ELISA experiments showed significant HLA‐G expression by PV kertainocytes (p < 0.001). No traces of HLA‐G production were seen in normal cells. RT‐PCR revealed, however, variation in HLA‐G mRNA expression. These findings indicate that regulation of HLA‐G gene might occur both at transcriptional and translational levels. Conclusions: Collectively, our data show the presence, and hence, advocate the possible protective contribution of HLA‐G isoforms in skin inflammatory processes.