Utility of Antiphosphatidylserine/Prothrombin and IgA Antiphospholipid Assays in Systemic Lupus Erythematosus

Article Figures & Data

Table 1.

Demographic characteristics (n = 326). Data are mean (SD) unless otherwise indicated.

Characteristics
Age, yrs	45.7 (14.0)
Sex, n (%)
Female	298 (91.4)
Male	28 (8.6)
Ethnicity, n (%)
White	163 (50.0)
African-American	131 (40.2)
Other	32 (9.8)
Measures of disease activity
Physician global assessment (0 to 3 VAS)	0.63 (0.66)
SELENA-SLEDAI	2.28 (3.12)
Serologies
C3, mg/dl	115.7 (35.7)
C4, mg/dl	22.1 (10.6)
Anti-dsDNA ≥ 10, n (%)	67 (20.6)
Medications
Prednisone, mg	4.17 (7.87)
Immunosuppressive, n (%)	117 (35.9)
Hydroxychloroquine, n (%)	254 (77.9)

VAS: visual analog scale; SELENA-SLEDAI: Safety of Estrogens in Lupus Erythematosus National Assessment-Systemic Lupus Erythematosus Disease Activity Index.

Table 2.

Association of antiphospholipid assays with a history of lupus anticoagulant (LAC).

	Assay	LAC-positive, n = 71 No. (% positive)	LAC-negative n = 212 No. (% positive)	OR (95% CI)	p
Anti-PS/PT	IgM	35 (49)	16 (8)	11.9 (6.0, 23.7)	< 0.0001
	IgG	26 (37)	8 (4)	14.7 (6.3, 34.7)	< 0.0001
	IgG/M	34 (48)	16 (8)	11.3 (5.6, 22.4)	< 0.0001
Anticardiolipin	IgM	17 (24)	10 (5)	6.4 (2.8, 14.7)	< 0.0001
	IgG	20 (28)	9 (4)	8.8 (3.8, 20.6)	< 0.0001
	IgA	10 (14)	0 (0)		< 0.0001
Anti-ß₂-GPI	IgM	10 (14)	4 (2)	8.5 (2.6, 28.1)	< 0.0001
	IgG	16 (23)	3 (1)	20.3 (5.7, 72.1)	< 0.0001
	IgA	29 (41)	30 (14)	4.2 (2.3, 7.7)	< 0.0001
Anti-ß₂-GPI D1	IgG	9 (13)	5 (2)	6.0 (1.9, 18.6)	0.0005
Anti-ß₂-GPI D4/5	IgA	21 (30)	35 (17)	2.1 (1.1, 4.0)	0.0167

Anti-PS/PT: antiphosphatidylserine/prothrombin; anti-ß₂-GPI: anti-ß₂-glycoprotein I; anti-ß₂-GPI D1: anti-ß₂-glycoprotein I domain 1; anti-ß₂-GPI D4/5: anti-ß₂-glycoprotein I domain 4/5.

Table 3.

Association of antiphospholipid assays with all thrombosis (venous or arterial).

	Assay	Thrombosis, n = 164 No. (% positive)	No Thrombosis, n = 162 No. (% positive)	OR 95% CI^*	p (adjusted)^*
IgG	Anti-ß₂-GPI	18 (11)	6 (4)	3.3 (1.2, 8.9)	0.021
	Anti-ß₂-GPI D1	11 (7)	9 (6)	1.1 (0.4, 2.9)	0.79
	aCL	22 (13)	16 (10)	1.4 (0.7, 2.9)	0.34
	Anti-PS/PT	26 (16)	14 (9)	2.2 (1.0, 4.8)	0.045
IgM	Anti-ß₂-GPI	8 (5)	9 (6)	0.8 (0.3, 2.3)	0.69
	aCL	19 (12)	14 (9)	1.3 (0.6, 2.8)	0.47
	Anti-PS/PT	43 (26)	25 (15)	1.9 (1.1, 3.3)	0.033
IgA	Anti-ß₂-GPI	48 (29)	24 (15)	2.4 (1.3, 4.2)	0.0028
	aCL	11 (7)	1 (1)	9.5 (1.2, 75.8)	0.034
	Anti-ß₂-GPI D4/5	35 (21)	28 (17)	1.3 (0.7, 2.3)	0.38
IgG/M	Anti-PS/PT	38 (23)	24 (15)	1.7 (0.9, 3.1)	0.087
LAC^**	dRVVT	52 (37)	19 (13)	3.8 (2.0, 7.3)	< 0.0001

↵* Adjusted for age, sex, and ethnicity.
↵** Forty-three patients did not have dilute Russell viper venom test (dRVVT) results available. Thus, the total number of patients for the thrombosis group was 44, and the no-thrombosis group, 239. Anti-ß₂-GPI: anti-ß₂-glycoprotein I; anti-ß₂-GPI D1: anti-ß₂-glycoprotein I domain 1; aCL: anticardiolipin; anti-PS/PT: antiphosphatidylserine/prothrombin; LAC: lupus anticoagulant; anti-ß₂-GPI D4/5: anti-ß₂-glycoprotein I domain 4/5.

Table 4.

Association of antiphospholipid assays with venous thrombosis.

	Assay	Thrombosis, n = 103 No. (% positive)	No Thrombosis, n = 223 No. (% positive)	OR 95% CI^*	p (adjusted)^*
IgG	Anti-ß₂-GPI	15 (15)	9 (4)	3.7 (1.5, 9.1)	0.0048
	Anti-ß₂-GPI D1	9 (9)	11 (5)	1.7 (0.7, 4.2)	0.29
	aCL	17 (17)	21 (9)	1.7 (0.8, 3.5)	0.14
	Anti-PS/PT	21 (20)	19 (9)	2.7 (1.3, 5.8)	0.0082
IgM	Anti-ß₂-GPI	6 (6)	11 (5)	1.1 (0.4, 3.1)	0.88
	aCL	13 (13)	20 (9)	1.4 (0.7, 3.1)	0.36
	Anti-PS/PT	27 (26)	41 (18)	1.5 (0.8, 2.6)	0.19
IgA	Anti-ß₂-GPI	31 (30)	41 (18)	1.9 (1.1, 3.3)	0.024
	aCL	8 (8)	4 (2)	4.3 (1.2, 14.8)	0.023
	Anti-ß₂-GPI D4/5	20 (19)	43 (19)	1.0 (0.6, 1.9)	0.97
IgG/M	Anti-PS/PT	29 (28)	33 (15)	2.1 (1.2, 3.8)	0.015
LAC^**	dRVVT	36 (41)	35 (18)	3.3 (1.8, 6.0)	< 0.0001

↵* Adjusted for age, sex, and ethnicity.
↵** Forty-three patients did not have dilute Russell viper venom test (dRVVT) results available. Thus, the total number of patients for the thrombosis group was 88, and the no-thrombosis group, 195. Anti-ß₂-GPI: anti-ß₂-glycoprotein I; anti-ß₂-GPI D1: anti-ß₂-glycoprotein I domain 1; aCL: anticardiolipin; anti-PS/PT: antiphosphatidylserine/prothrombin; LAC: lupus anticoagulant; anti-ß₂-GPI D4/5: anti-ß₂-glycoprotein I domain 4/5.

Table 5.

Association of antiphospholipid assays with stroke.

	Assay	Stroke, n = 53 No. (% positive)	No Stroke, n = 273 No. (% positive)	OR 95% CI^*	p (adjusted)^*
IgG	Anti-ß₂-GPI	5 (9)	19 (7)	2.0 (0.7, 6.2)	0.21
	Anti-ß₂-GPI D1	3 (6)	17 (6)	1.1 (0.3, 4.1)	0.89
	aCL	7 (13)	31 (11)	1.6 (0.6, 4.1)	0.33
	Anti-PS/PT	8 (15)	32 (12)	2.5 (1.0, 6.3)	0.062
IgM	Anti-ß₂-GPI	2 (4)	15 (5)	0.7 (0.2, 3.3)	0.66
	aCL	8 (15)	25 (9)	1.6 (0.7, 4.1)	0.28
	Anti-PS/PT	14 (26)	54 (20)	1.6 (0.8, 3.2)	0.21
IgA	Anti-ß₂-GPI	17 (32)	55 (20)	1.9 (1.0, 3.7)	0.070
	aCL	4 (8)	8 (3)	2.0 (0.6, 7.4)	0.28
	Anti-ß₂-GPI D4/5	16 (30)	47 (17)	2.2 (1.1, 4.4)	0.033
IgG/M	Anti-PS/PT	11 (21)	51 (19)	1.5 (0.7, 3.2)	0.35
LAC^**	dRVVT	17 (39)	54 (23)	2.3 (1.1, 4.8)	0.022

↵* Adjusted for age, sex, and ethnicity.
↵** Forty-three patients did not have dilute Russell viper venom test (dRVVT) results available. Thus, the total number of patients for the thrombosis group was 44, and the no-thrombosis group, 239. Anti-ß₂-GPI: anti-ß₂-glycoprotein I; anti-ß₂-GPI D1: anti-ß₂-glycoprotein I domain 1; aCL: anticardiolipin; anti-PS/PT: antiphosphatidylserine/prothrombin; LAC: lupus anticoagulant; anti-ß₂-GPI D4/5: anti-ß₂-glycoprotein I domain 4/5.