Table 1.

Characteristics of individual studies included in the meta-analysis

Study	Study design	Sample size (SLE/control)	Gender of SLE(F/M)	Mean age of SLE(y)	Criteria of SLE diagnosis	Type of tissue/cell used in studies	Characteristics of controls
Belmont 1997 [32]	Case-control	36(25/11)	NG	NG	ACR	Skin: endothelial cell, keratinocyte	Skin biopsy samples obtained from young, healthy, female volunteers
Kuhn 1998 [22]	Case-control	26(21/5)	NG	NG	ARA	Skin: keratinocyte	Non-lesional skin from healthy people
Gong 2002 [33]	Case-control	64(34/30)	30/4	29.8	ARA	Peripheral blood: PBMC	Healthy volunteers, mean age was 25.6, gender ratio was 26/4
Xu 2003 [34]	Case-control	58(38/20)	38/0	32.2	ACR	Peripheral blood	Healthy volunteers, mean age was 28.2, gender ratio was 20/0
Zheng 2006 [35]	Case-control	59(49/10)	43/6	30.85	ARA	Kidney: tubular cell	Normal kidney biopsies without SLE, but accompanied by renal cell carcinoma
Bollain 2009 [36]	Case-control	34(17/17)	14/3	25.9	ACR	kidney	Normal kidney biopsies without renal pathology

F Female, M Male, SLE Systemic lupus erythematosus, ARA American Rheumatism Association, ACR American College of Rheumatology, NG Not given