CXCL2 levels in serum and CD14+ cell supernatant
CXCL2 levels in sera were detected in 70 ACPA+ RA patients, 37 ACPA- RA patients and 40 healthy controls. Age and sex were balanced between the groups, whereas the disease duration, RF positive rate and bone erosion positive rate were significantly different among ACPA+ RA patients and ACPA- RA patients (Table 1).
Median serum CXCL2 in RA patients (1083.43, (586.94,1569.50) pg/ml) was significantly higher than in healthy controls (301.44, (217.62,422.26) pg/ml) (p < 0.001; Fig, 2B). And median serum CXCL2 was significantly higher in ACPA+ RA patients than in ACPA- RA patients (p < 0.05; Fig. 2C). Correlation analysis showed that CXCL2 was positively correlated with DAS28 (r=0.4594, p < 0.001), ESR (r=0.3985, p <0.001) and CRP (r=0.3726, p < 0.001) (Fig. 2D). However, the CXCL2 level was not related to disease duration (r=-0.084, p=0.391) and RF titer (r=0.1358, p=0.309). Serum CXCL2 was significantly higher in RA patients with bone erosion than in RA patients without bone erosion (p < 0.05; Fig. 2E).
CXCL2 expression was significantly higher in the supernatant of CD14+ monocyte cultures derived from ACPA+ RA patients than from the ACPA- RA patients (Fig. 2F).