C-reactive protein +1444CT (rs1130864) genetic polymorphism is associated with the susceptibility to systemic lupus erythematosus and C-reactive protein levels

The T rare allele of +1444CT (rs1130864) polymorphism of C-reactive protein (CRP) has been associated with increased CRP levels in some inflammatory conditions, but its role on systemic lupus erythematosus (SLE) susceptibility and on CRP levels in SLE patients remains uncertain. The objective of the study was to evaluate the association between the rs1130864 CRP polymorphism with SLE susceptibility, disease activity, and CRP levels in SLE Brazilian patients. The study enrolled 176 SLE patients and 137 controls. SLE disease activity was assessed using the SLE Disease Activity Index (SLEDAI). The rs1130864 CRP polymorphism was determined using polymerase chain reaction and restriction fragment length polymorphism. SLE patients presented higher body mass index (p = 0.046) and CRP levels (p = 0.017) than controls. The genotype and allele frequencies of patients differed from controls [CC vs. CT = odds ratio (OR) 1.730, 95% confidence interval (CI) 1.068–2.803, p = 0.035; CC vs. TT = OR 3.667, 95% CI 1.410–9.533, p = 0.009; C vs. T = OR 1.883, 95% CI 1.299–2.728, p = 0.001)]. Patients carrying the T allele presented higher CRP levels (p = 0.009), were more frequent Caucasians (p = 0.018), and with no use of immunosuppressive treatment (p = 0.004) than those carrying the C allele. However, the SLEDAI and anti-double-stranded DNA positivity did not differ from those carrying T vs. C allele (p = 0.595 and p = 0.243, respectively). The rs1130864 CRP polymorphism was associated with SLE susceptibility and CRP levels, but not with disease activity, suggesting that this polymorphism may play a role in the pathophysiology of SLE through increasing the CRP that, probably, plays an inflammatory role in SLE pathophysiology.