Anti-Double-Stranded DNA Isotypes and Anti-C1q Antibody Improve the Diagnostic Specificity of Systemic Lupus Erythematosus

Table 3

Associations of the presence of anti-dsDNA isotypes and anti-C1q antibody with active/inactive SLE patients, LN/non-LN groups, and active/inactive LN cases.

	Activity of SLE ()			SLE with renal involvement ()			Activity of LN ()
	Active SLE	Inactive SLE	value	LN	Non-LN	value	Active LN	Inactive LN	value
Anti-dsDNA IgG	82.5% (47/57)	53.8% (21/39)	0.002	76% (38/50)	71.7% (33/46)	NS	78.8% (26/33)	58.8% (10/17)	NS
Anti-dsDNA IgM	49.1% (28/57)	38.5% (15/39)	NS	32% (16/50)	58.7% (27/46)	0.005	33.3% (11/33)	29.4% (5/17)	NS
Anti-dsDNA IgA	42.1% (24/57)	20.5% (8/39)	0.028	28% (14/50)	37.0% (17/46)	NS	30.3% (10/33)	29.4% (5/17)	NS
Anti-C1q	63.2% (36/57)	25.6% (10/39)	0.000	56% (28/50)	39.1% (18/46)	0.032	33.3% (11/33)	23.5% (4/17)	NS

SLE: systemic lupus erythematosus; LN: lupus nephritis; NS: no significance; , chi-squared test.