Increased expression of PRKCB mRNA in peripheral blood mononuclear cells from patients with systemic lupus erythematosus

The polymorphism of PRKCB has been proven to be associated with systemic lupus erythematosus (SLE) in our previous study. We aimed to investigate the relationship between expression of PRKCB mRNA and the Disease Activity Index (SLEDAI) and manifestations of SLE. Quantitative reverse transcription polymerase chain reaction (RT-PCR) was applied to examine the expression of PRKCB mRNA in peripheral blood mononuclear cells of 60 patients with SLE and 62 controls. The Sequenom MassArray System was used to detect genotype SNP rs16972959. The expression levels of PRKCB mRNA in SLE cases were significantly increased compared with those in healthy controls (P<0.001). In addition, PRKCB mRNA expression levels were negatively correlated with the SLEDAI (P<0.05, r=-0.322), with lower mRNA expression levels of PRKCB in patients found with higher SLEDAI, presence of a new rash (P<0.01), and proteinuria (P<0.05). No association evidence was observed between the genotype of the variant rs16972959 and PRKCB mRNA expression levels; however, SNP rs16972959 was found to be an expression quantitative trait loci for PRKCB with the SLE risk allele correlated with increased expression in naive monocytes (P-FDR=9.12x10(-13)) and stimulated monocytes (9.24x10(-6)>P-FDR>2.75x10(-17)). On the other hand, SNP rs16972959 of PRKCB was found to have suggestive significant associations with vasculitis (P=0.00718) of SLE. These results indicated that expression of PRKCB mRNA may be correlated with the pathogenesis of SLE; however, more investigation is still needed.