Evaluation of the BCL-2 gene locus as a susceptibility locus linked to the clinical expression of systemic lupus erythematosus (SLE).

Systemic lupus erythematosus (SLE) is an autoimmune disease characterised by the production of a large number of autoantibodies. It has been postulated that this may be the result of prolonged longevity of auto-reactive B cells due to defective regulation of programmed cell death (apoptosis). The proto-oncogene bcl-2 is involved in the control of apoptosis in immunocompetent cells, and its over-expression is noted in T and B cells from SLE patients. This study examined the genetic linkage between the bcl-2 gene locus and SLE susceptibility using the affected sib-pair method in SLE families. Seventeen caucasian multiplex families were evaluated. A polymorphic microsatellite marker closely linked to the bcl-2 gene on 18q21.3 was used to determine the bcl-2 genotype. We demonstrated that haplotype sharing among the affected sibling pairs was not statistically different from random (P > 0.5). This suggests that the bcl-2 gene locus does not confer a genetic susceptibility to SLE expression.