HLA CLASS II ALLELES AS RISK FACTORS

HLA CLASS II ALLELES AS RISK FACTORS FOR THE DEVELOPMENT OF SCLERODERMA FOLLOWING OCCUPATIONAL EXPOSURE TO ORGANIC SOLVENTS.
MS Pollack and JP Pandey, University of Texas Health Science Center, San Antonio, TX and Medical University of South Carolina, Charleston, SC

Scleroderma or systemic sclerosis (SSc) is a multisystem disease characterized by cutaneous and visceral fibrosis and is believed to involve both genetic and environmental pathogenic factors. The autoimmune nature of this disease is evident from the presence of autoantibodies to nuclear, nucleolar and specific glycoprotein connective tissue antigens. Previous studies have found several different associations of particular HLA types with risk for the disease in general and with the risk for the expression of particular SSc-specific autoantibodies. Different allele associations have been found in different ethnic populations and with different forms of the disease (diffuse vs. limited). The present case-control study was designed to compare the HLA class II allele frequencies present in a population of individuals exposed to a specific organic solvent, trichloroethylene (TCE) who developed SSc with the allele frequencies in exposed individuals who did not develop this disease. The analysis was further subdivided for ethnic background, Caucasian vs. African American. Preliminary analyses indicate that the frequencies of DRB1*08 and DRB1*15 were both increased among the African American patients in comparison with the African American case controls while the frequencies of DRB1*01 and its associated allele, DQB1*05, were both increased among the Caucasian patients in comparison with the Caucasian case controls. Further analyses, including high resolution allele typing and the association of the development of specific autoantibodies with HLA allele distribution, will also be reported.