Table 2

Correlation between levels of specific ACPA in serum, synovial fluid and the immune complex fractions in serum and synovial fluid (correlation values are Spearman’s ρ values)

ACPA specificity	Serum vs SF	Serum vs serum IC	SF vs SF IC
Filaggrin 307-324 (CCP1)	0.85	0.31	0.61
Vimentin 2–17	0.87	0.13	0.19
Vimentin 60–75	0.93	0.15	0.38
Fibrinogen α36–50	0.73	0.10	0.34
Fibrinogen α563–583	0.85	0.24	0.49
Fibrinogen α580–600	0.70	0.18	0.22
Fibrinogen α621–635	0.87	0.33	0.55
Fibrinogen β36–52	0.83	0.27	0.42
Fibrinogen β60–74	0.82	0.28	0.53
Fibrinogen β62–81(Fib72)	0.56	0.01	0.17
Fibrinogen β62–81(Fib74)	0.63	0.04	0.43
α-Enolase 5–21(CEP-1)	0.88	0.41	0.58
hnRNP 1	0.76	0.10	0.31
hnRNP 5	0.78	0.36	0.34
hnRNP Z1	0.67	0.14	0.22
hnRNP Z2	0.82	0.32	0.55
hnRNP Bla26	0.58	0.11	0.06
Histone4 14–34	0.88	0.14	0.43
Histone4 31–50	0.78	0.21	0.45
Mean for 19 ACPA	0.78	0.20	0.38
Median for 19 ACPA	0.82	0.18	0.42
Anti-CCP2	0.82

ACPA, anti-citrullinated protein/peptide antibodies; IC, immune complexes; SF, synovial fluid.