Search

Objective: Genetic susceptibility to systemic lupus erythematosus (SLE) is conferred not only by various genes within the major histocompatibility complex (MHC) region, but also by several other non-MHC linked genes. The negatively signalling molecule CTLA-4 is involved in establishing and maintaining of peripheral T cell tolerance, which controls T cell activation and reactivity. Its attenuating action helps to prevent an inappropriate initiation of T cell responses to self antigens and to terminate ongoing T cell responses. We tested if there was an association between CTLA-4 and SLE, a disease with B and T cell hyperreactivity and impaired peripheral T cell tolerance., Methods: Using the polymerase chain reaction--restriction fragment length polymorphism method with Bbv I digestion, we assessed an exon 1 transition dimorphism (49 A/G) of the CTLA-4 gene in 102 SLE patients and in 76 healthy controls., Results: The distribution of CTLA-4 exon 1 genotypes in the SLE group was significantly different from that in the controls (chi 2 = 6.178, p < 0.05). 17.6% of the SLE patients were G/G homozygotes compared to 5.3% of the controls; 36.3% were A/G heterozygotes vs 40.8% of controls; and 46.1% were A/A homozygotes vs 53.9% of the controls. The frequency of the G allele was significantly higher in SLE patients (35.8%) than in controls (25.7%; chi 2 = 4.142, p = 0.042)., Conclusion: Our results indicate that the non-MHC linked CTLA-4 gene could confer susceptibility in SLE, as it does in various other autoimmune diseases (Hashimoto thyroiditis, Graves' disease, IDDM).

Objective: ACE takes part in the renin-angiotensin and kallikrein-kininogen systems by creating angiotensin-II and inactivating bradykinin. ACE gene insertion/deletion polymorphism is associated with the level of circulating enzymes--subjects with the DD genotype have higher levels of circulating ACE than subjects with the II genotype and show an increased tendency towards impaired vascular function and structure. Patients with systemic lupus erythematosus (SLE) suffer from differentially expressed vascular pathology. We attempted to determine whether the type of ACE polymorphism could contribute to this pathology., Methods: 101 SLE patients fulfilling the ACR criteria were investigated. The I/D polymorphism was ascertained by PCR, followed by electrophoresis of the amplified fragments and UV visualization., Results: The frequency of the D allele was higher in the SLE group (0.623) than in the controls (0.520) (chi 2 test, p < 0.025). The distribution of the ACE genotype in SLE group was different from that in the control group (p < 0.05). An association between the DD genotype and visceral damage (p < 0.006) was observed., Conclusion: Our results suggest that in the multifactorially determined vascular pathology of SLE, changes associated with I/D polymorphism could influence vessel wall inflammation (monocyte adhesion and activation with cytokine release, T-lymphocyte metabolism), a tendency towards vascular impairment (neointimal proliferation, vasospasm, platelet activation, myocyte proliferation) and lead to the subsequent ischemia. The ACE gene could serve as the visceral damage indicator in SLE.