Antibodies to early EBV, CMV, and HHV6 antigens in systemic lupus erythematosus patients

Figures & data

Table 1. Characteristics of SLE patients.

No. of individuals	77
Gender (female), % (n)	92.2 (71)
Age (years), median (IQR)	38 (31–44)
On immunosuppressive medication, % (n)	72.7 (56)
C-reactive protein (mg/L), median (IQR)	2 (0–7)
Low C3 (< 0.79 g/L), % (n)	46.8 (36)
Low C4 (< 0.16 g/L), % (n)	66.2 (51)
Thrombocyte count (10^9/L), median (IQR)	237 (181–296)
Leucocyte count (10^9/L), median (IQR)	5.8 (4.4–8.7)
Lymphocyte count (10^9/L), median (IQR)	1.11 (0.78–1.6)
Disease manifestations*, % (n)
Arthritis	15.6 (12)
Vasculitis	5.2 (4)
Rash	6.5 (5)
Thrombocytopenia (< 50 × 10^9/L)	13 (10)
Leucopenia (< 4 × 10^9/L)	19.5 (15)
Lymphopenia (< 1.5 × 10^9/L)	68.8 (53)
Positivity for autoantibodies†
ANA, % (n)	81.8 (63)
dsDNA-directed antibodies, % (n)	45.5 (35)
SLEDAI score, median (IQR)	4 (2–8)

SLE, Systemic lupus erythematosus; ANA, antinuclear antibodies; ds, double-stranded; IQR, interquartile range; SLEDAI, SLE Disease Activity Index.

*Information regarding nephritis was not available for all SLE patients.

†Information regarding extractable nuclear antigen (ENA)-directed antibodies was not available for all SLE patients.

The continuous and categorical variables are presented as medians and percentages, respectively.

Table 2. Characteristics of healthy controls.

No. of individuals	29
Gender (females), % (n)	75.9 (22)
Age (years), median (IQR)	42 (32–52)

IQR, Interquartile range.

The continuous and categorical variables are presented as medians and percentages, respectively.

Figure 1. Two-group comparisons of (A) EBV EA/D-, (B) CMV pp52-, and (C) HHV6 p41-directed (i) IgM, (ii) IgG, and (iii) IgA levels between SLE patients (n = 77) and healthy controls (n = 29). The antibody levels are presented in arbitrary units (AU). The horizontal bars represent medians and interquartile ranges. *p < 0.05, **p < 0.01, ***p < 0.001.

Table 3. Patterns of EBV EA/D- and CMV pp52-directed IgG levels in SLE patients.

Variable	Group 1 (n = 20)	Group 2 (n = 18)	Group 3 (n = 18)	Group 4 (n = 21)	p-value
Gender (female)	85 (17)	88.9 (16)	94.4 (17)	100 (21)	0.274
Age (years)	33 (29–39)	38 (33–41)	41 (30–46)	41 (37–46)	0.144
On immunosuppressive medication	80 (16)	66.7 (12)	66.7 (12)	76.2 (16)	0.748
SLEDAI score	4.5 (2–9)	5.5 (2–9.5)	4 (2–9.8)	2 (0–5)	0.227
ANA positivity	85 (17)	88.9 (16)	83.3 (15)	71.4 (15)	0.557
dsDNA-directed antibody positivity	60 (12)	55.6 (10)	50 (9)	19.1 (4)	0.034
Low C3	45 (9)	50 (9)	61.1 (11)	33.3 (7)	0.391
Low C4	60 (12)	77.8 (14)	72.2 (13)	57.1 (12)	0.505
Leucocyte count (10^9/L)	6.3 (4.4–9.2)	4.9 (3.7–6.0)	7.7 (5.0–9.0)	5.8 (4.2–8.1)	0.170
Lymphocyte count (10^9/L)	1.11 (0.84–1.43)	0.65 (0.51–0.90)	1.45 (0.90–2.00)	1.40 (1.00–1.80)	0.004
HHV6 p41-directed IgG (AU)	0.36 (0.25–0.52)	0.35 (0.28–0.38)	0.38 (0.28–0.47)	0.38 (0.26–0.56)	0.872
EBV EA/D-directed IgG (AU)	0.09 (0.05–0.29)	0.97 (0.72–1.10)	0.04 (0.02–0.17)	1.02 (0.94–1.11)	< 0.001
CMV pp52-directed IgG (AU)	0.32 (0.22–0.39)	0.32 (0.20–0.34)	1.04 (0.95–1.15)	1.25 (1.16–1.31)	< 0.001

SLE, Systemic lupus erythematosus; SLEDAI, SLE Disease Activity Index; ANA, antinuclear antibodies; ds, double-stranded; AU, arbitrary units; Group 1, SLE patients with lower IgG levels against both EBV EA/D and CMV pp52; Group 2, SLE patients with higher/lower IgG levels against EBV EA/D/CMV pp52; Group 3; SLE patients with lower/higher IgG levels against EBV EA/D/CMV pp52; Group 4, SLE patients with higher IgG levels against both EBV EA/D and CMV pp52 (the lower IgG levels were defined as < median AU, and higher IgG levels as ≥ median AU).

Continuous and categorical variables are presented as medians (interquartile range) and percentage (number), respectively.

Significant p-values are in bold.