It has been shown that DNA repair is reduced in patients with systemic lupus erythematosus (SLE) and that the X-ray repair cross-complementing (XRCC1) Arg399Gln (rs25487) polymorphism may contribute to DNA repair. We evaluated the frequency of the XRCC1 Arg399Gln substitution in patients with SLE (n = 265) and controls (n = 360) in a sample of the Polish population. The odds ratio (OR) for SLE patients with the Gln/Gln versus Gln/Arg or Arg/Arg genotypes was 1.553 (95% confidence interval [CI] = 0.9573-2.520; p = 0.0729). OR for the Gln/Gln or Gln/Arg versus Arg/Arg genotype was 1.551 (95% CI = 1.122-2.144, p = 0.0077). The OR for the 399 Gln allele in patients with SLE was 1.406 (95% CI = 1.111-1.779, p = 0.0045). There was also a statistically significant p-value of the w 2 test for the trend observed in the XRCC1 Arg399Gln polymorphism (ptrend = 0.0048). We also found a significant contribution of the Gln/Gln or Arg/Gln versus Arg/Arg genotype to the presence of either the malar rash or phototosensitivity manifestations of SLE OR = 2.241 (1.328-3.781, p = 0.0023, pcorr = 0.0414). Moreover, the meta-analysis of Taiwanese Han Chinese, Brazilian, and Polish populations showed that the Gln/Gln or Gln/Arg genotype and Gln allele were associated with SLE incidence. OR for the Gln/Gln or Gln/Arg versus Arg/Arg genotype was 1.440 (95% CI = 1.15-1.80, p = 0.0019) and OR for the Gln allele was 1.27 (95% CI = 1.08-1.51, p = 0.0051). Our studies may confirm that the XRCC1 Arg399Gln polymorphism may increase the risk of incidence of SLE and the occurrence of some SLE manifestations.

It has been reported that stromal cell-derived factor-1 (SDF1), currently also designated CXCL12, plays a significant role in the development of nephritis and death in the lupus mice model. Using restriction length fragment polymorphism (RFLP) analysis we assessed the frequencies of SDF1-3' G801A (rs 1801157) polymorphic variants between systemic lupus erythematosus (SLE) patients (n = 150) and controls (n = 300). There were no significant differences in the prevalence of SDF1-3' G801A polymorphic variants in SLE patients and healthy individuals. However, we observed that the SDF1-3' A/A and G/A genotypes (recessive model) contributed to renal manifestations of SLE OR = 3.042 (95% CI = 1.527-6.058, P = 0.002), and the p value stayed statistically significant after Bonferroni correction (p(corr) = 0.032) in SLE patients. We also found an association of the SDF1-3' A/A and G/A genotypes (recessive model) with dermal manifestations of SLE OR = 2.510 (95% CI = 1.247-5.052, P = 0.0122), (p(corr) = 0.1952) but this did not remain statistically significant after Bonferroni correction. Our observations suggest that the SDF1-3' G801A genotype may be associated with some clinical manifestations in patients with SLE.

SummarySystemic lupus erythematosus (SLE) is a multisystem autoimmune connective tissue disorder characterized by various aberrations including increased production of IL-18.Since IL-18 105 A>C polymorphic variants have been linked to increased production of this cytokine, we investigated the prevalence of IL-18 105 A>C (rs549908) polymorphic variants in SLE patients (n=111) and controls (n=152).There were no significant differences in the distribution of IL-18 105 A>C polymorphic variants in SLE patients and controls. However, there was a significant association between the IL-18 105 AA genotype (recessive model) and renal manifestations OR=3.360 (1.523-7.415, P=0.0039) and the P value remained statistically significant after Bonferroni correction (P corr = 0.0351).Our findings indicate that the IL-18 105 AA genotype variant can contribute to renal manifestations in patients with SLE.

Recently, a family-based association analysis showed that the haplotype carrying a low expression of the variant CD3Z 844 T>A (rs1052231) polymorphism located in the 3'-untranslated region of CD3Z predisposes to systemic lupus erythematosus (SLE) incidence. We analyzed the prevalence of the CD3Z 844 T>A polymorphism in SLE patients (n = 152) and controls (n = 304) in Poland. We observed that women with the CD3Z AA and CD3Z AT genotypes exhibited a 1.845-fold increased risk of SLE [95% confidence intervals (95% CI) = 1.222-2.787, P = 0.0038]. However, we did not find an increased risk for the homozygous CD3Z AA genotype (odds ratio = 1.204, 95% CI = 0.2838-5.108, P = 1.0000). This observation confers that genetic factors causing a decreased level of CD3-zeta in T cells may predispose to SLE incidence.

It has been reported that reactive oxygen species contribute to pathogenesis of systemic lupus erythematosus (SLE). Catalase (CAT) -330C>T transition, known also as -262C>T, generates three genotypes. The CAT -330CC genotype is associated with a significantly lower CAT expression in comparison to -330CT and -330CT genotypes. Therefore, using restriction length fragment polymorphism analysis, we compared the frequencies of CAT -330C>T polymorphic variants between SLE patients (n = 102) and controls (n = 199). We did not observe significant differences in the prevalence of CAT -330C>T polymorphic variants in SLE patients and controls. However, we found that the CAT -330CC genotype (recessive model) showed a significant association with thrombocytopenia OR = 7.314 (1.977-27.057, P = 0.0017). We also observed that the CAT -330CC genotype (recessive model) is linked with leukopenia OR = 3.232 (1.361-7.676, P = 0.0118), renal manifestations OR = 2.403 (1.085-5.321, P = 0.0471) and presence of anti-snRNP Ab OR = 4.206 (95% CI = 1.405-12.590, P = 0.0131), and anti-Scl-70 Ab, OR = 3.143 (95% CI = 1.171-8.433, P = 0.0343) in SLE patients. Our findings suggest that the CAT -330CC genotype may contribute to some clinical manifestations in patients with SLE.