New autoantibodies in early rheumatoid arthritis

Table 3 Autoantibodies to WIBG, GABARAPL2, ZNF706 and PAD4 proteins in patients with early RA

								WIBG, ZNF706 and GABARAPL2
		Anti-CCP	RF	PAD4	WIBG	ZNF706	GABARAPL2	combination
RA <1 year (n = 124) vs 186 controls (AS, PsA, SLE, SSc, and healthy)	Sensitivity (%)	70	68	18.5	33	18.5	23	48
	Specificity (%)	98	nd	91	98	98	96	94
	PPV (%)	96	nd	57	93	85	80	84
	NPV (%)	81	nd	63	69	64	65	73
RA <1 year negative for anti-CCP (n = 37) vs 186 controls (AS, PsA, SLE, SSc, and healthy)	Sensitivity (%)	0	24	11	16	11	27	43
	Specificity (%)	nd	nd	91	98	98	96	94
	PPV (%)	nd	nd	19	67	50	59	59
	NPV (%)	nd	nd	84	86	85	87	89
RA <1 year negative for RF (n = 39) vs 186 controls (AS, PsA, SLE, SSc, and healthy)	Sensitivity (%)	23	0	10	15	15	28	44
	Specificity (%)	98	nd	91	98	98	96	94
	PPV (%)	69	nd	19	67	60	61	61
	NPV (%)	84	nd	83	85	85	86	89
RA <1 year negative for anti-CCP and RF (n = 28) vs 186 controls (AS, PsA, SLE, SSc, and healthy)	Sensitivity (%)	0	0	4	7	11	32	39
	Specificity (%)	nd	nd	91	98	98	96	94
	PPV (%)	nd	nd	5	40	43	56	50
	NPV (%)	nd	nd	86	87	88	90	91

WIBG, within BGCN homolog (Drosophila); GABARAPL2, GABA(A) receptor-associated protein-like 2; ZNF706, zinc finger protein 706; PAD4, peptidyl arginine deiminase 4; RA: rheumatoid arthritis; CCP, cyclic citrullinated peptide; RF, rheumatoid factor; AS, ankylosing spondylitis; PsA, psoriatic arthritis; SLE, systemic lupus eryth ematosus; SSc, systemic sclerosis; PPV, positive predictive value; NPV, negative predictive value; nd, not determined.

ISSN: 1478-6362