Table 1.

Characteristics of RA patients and the control group

	RA patients (n = 90)	Control group (n = 90)
Sex‐ratio	1.6	1.6
(F/M)	(56/34)	(56/34)
Mean age	53 ± 15 y	37 ± 11 y
Age range	22‐83 y	20‐64 y
Positive anti‐CCP	100% (90/90)	3.3% (3/90)
Positive IgG‐RF	78.8% (71/90)	2.2% (2/90)
Positive IgA‐RF	78.8% (71/90)	0% (0/90)
Positive IgM‐RF	90% (81/90)	5.5% (5/90)