LAUSR

Background Associations between clinical manifestations of systemic lupus erythematosus (SLE), presence of antiphospholipid antibodies (aPL) and HLA-DRB1 alleles have been established, these associations however need clarification. Objectives Clarify the associations between clinical features of APS in patients with SLE and the presence of aPL and the HLA-DRB1 alleles. Methods 79 SLE patients were enrolled in the study (M/F 7/72; mean age 11.0 years, range (18,0;78,0). The main group consisted of 41 aPL carriers (28 of them with antiphospholipid syndrome (APS), a comparison group consisted of 38 aPL-negative SLE patients. The groups were comparable in age, duration and SLE activity. ELISA was used to test for aPL. Lupus anticoagulant (LA) was evaluated using the DRVV test method. The HLA-DRB1 alleles were identified using HLA-typing. Results While comparing both groups, HLA-DRB1*03 allele was found significantly less frequently in aPL-carriers group (p=0.04). In APS group HLA-DRB1*08 allele was present significantly more often (p=0.002), both HLA-DRB1*03 and *15 alleles were found significantly less often (p=0.008) in comparison with the aPL-negative group. SLE patients with HLA-DRB1*16 allele were more likely to develop an early pregnancy loss (OR=19, p=0.04), patient with HLA-DRB1*11 allele – more likely to develop a fetal loss (OR=4.9, p=0.04) in comparison with other alleles; in patients with HLA-DRB1*01 allele both early pregnancy loss and fetal loss occurred less often (OR=0.18, p=0.04; OR=0.29, p=0.04) compared with other alleles. The highest level of anti-double-stranded DNA was found in patients with HLA-DRB1*13 allele (Me=54, [17.0, 290.0 IU/ml], p=0.005), and lowest level – in patients with HLA-DRB1*04 (Me=0.15, [0.0; 14.2 IU/ml], p=0.005). In the group of aPL carriers significant correlations between the HLA-DRB1*08 allele and elevated level of anticardiolipin antibodies (aCL) IgM (r=−0.42, p=0.005) and anti-annexin V antibodies IgG (r=0.3, p=0, 01), between HLA-DRB1 * 04 allele and elevated level of aCL IgG (r=0.31, p=0.008), between the HLA-DRB1*12 allele and an elevated level of anti-annexin V antibodies IgM (r=0.31, p=0.01) were found. Correlations between HLA-DRB1*16 allele and early pregnancy loss (r=0.37, p<0.001), between HLA-DRB1*11 allele and fetal loss (r=0.30, p<0.001) were observed. Conclusions HLA-DRB1*08 allele is a risk factor for the development of APS in SLE patients. HLA-DRB1*03 and *15 alleles were more often detected in aPL-negative SLE patients. The presence of HLA-DRB1*16 and *11 alleles in SLE patients is a risk factor for the development of obstetric complications. In the group of aPL carriers significant correlations between HLA-DRB1 alleles and elevated levels of aPL were found. SLE patients with HLA-DRB1*01 were less likely to develop any obstetric complications. Disclosure of Interest None declared