Table 1.

Median values of ELISA OD₄₅₀ readings for IgG antibodies to EBNA-2(N) and EBNA-1(C) in patients with different connective tissue disease

	EBNA-2(N)		EBNA-1(C)
Diseases of patients groups (no. of specimens)	Median	Mann–Whitney test1	Median	Mann–Whitney test1
Systemic lupus erythematosus (SLE) (100)	0·124	P < 0·0001	0·424	n.s.
Primary Sjögrens's syndrome (primary SS) (73)	0·124	P < 0·0001	0·459	P = 0·0007
Rheumatoid arthritis (RA) (59)	0·118	P < 0·0001	0·361	n.s.
Systemic sclerosis (SSc) (13)	0·146	P < 0·008	0·541	P < 0·03
Mixed connective tissue disease (MCTD) (9)	0·123	P < 0·03	0·517	n.s.
Healthy control (120)	0·0525		0·381
Secondary SS
Secondary SS associated with SLE (19)	0·151	P = 0·0003	0·509	n.s.
Secondary SS associated RA (23)	0·197	P < 0·0001	0·499	P = 0·0009
Secondary SS associated with SSc (9)	0·104	P < 0·03	0·308	n.s.
Healthy control	0·065		0·376

¹P-values were calculated by comparing the medians of patient groups to that of normal healthy controls.²n.s.: non-significant.³SS associated with SLE, RA or SSc.