Fig. 1

Box plots showing the levels of ACPA fine specificities and isotypes in PR. Box plots shows reactivity profiles as optical density values of anti-cyclic citrullinated peptide (ACPA) for IgG (a, b, c, d), IgM (e, f, g), and IgA (h, i, j) isotypes. The p18 α-fibrin, p55 vimentin, and CEP-1 enolase fine specificities were analyzed for IgG, IgM, and IgA isotypes and p48 vimentin for only IgG. ACPA reactivity profiles were compared in 54 patients with palindromic rheumatism (PR) and 54 patients with rheumatoid arthritis (RA). Mann Whitney p values for between-group differences were calculated. Caution should be taken with these results because OD values are related to the quantity of antibody present in a nonlinear fashion. When only patients positive (above cut-off levels) for the respective ACPA isotypes were analyzed, the p values for IgG p18 α-fibrin, p48 vimentin, p55 vimentin, and CEP-1 Enolase were 0.963, 0.667, 0.445, and 0.02, respectively. The p values for IgM p18 α-fibrin, p55 vimentin, and CEP-1 enolase were 0.126, 0.690, and not calculable (no patients [+] in the RA group), respectively. The p values for IgA for p18 α-fibrin, p55 vimentin, and CEP-1 enolase were 0.230, 0.929, and 0.500, respectively. Box plots show the median, percentile 25, percentile 75, minimum, and maximum. Dots represent the value of the observation of one patient. Broken lines indicate the cut-off values