Plasma acrolein level in rheumatoid arthritis increases independently of the disease characteristics.

This study aimed to clarify whether plasma acrolein level actually increases in rheumatoid arthritis (RA) patients, and to elucidate whether any relationship exists between the levels and the RA background variables. Plasma levels of protein-conjugated acrolein (PC-Acro) in 84 patients (RA group) and 298 normal individuals (Control group) were measured by enzyme-linked immunosorbent assay procedures. The data were statistically analyzed with Wilcoxon rank-sum test, multiple logistic regression analyses and Spearman's rank correlation coefficient. The RA group showed significantly higher PC-Acro levels than the Control group (median [interquartile range]: 80.5 [63.2-105.2] and 65.9 [58.9-78.1] nmol/ml, respectively). Of background factors giving influence to PC-Acro level in the combination of the two groups, 'diagnosis of RA positive' indicated strong correlation to high PC-Acro level (odds ratio: 2.96; 95% confidence interval: 1.54-5.71). These increases of PC-Acro in the RA patients did not correlate to their disease duration and/or inflammatory variables: PC-Acro level could elevate even in early RA patients showing negative inflammatory findings. Plasma levels of PC-Acro increased with RA, but the levels did not correlate with RA background variables. This report provides the basis for further studies of early diagnosis of RA as well as its pathogenesis.