Table 1: Demographic, Clinical and Laboratory Findings of 43 Patients Positive for IgG Anti-dsDNA Alone and 15 Patients with Both IgG and IgM Anti-dsDNA Isotypes

Characteristics IgG Anti-dsDNA(+)
n=43		 IgG+IgM Anti-dsDNA(+)
n=15 		p Valuea
Female gender (%) 40 (93) 13 (86.7) 0.596
Age (years±SD) 40.6±13.3 43.1±12.0 0.518
Age at diagnosis (years±SD) 29.7±12.4 32.1±10.2 0.554
Disease duration (years±SD) 10.5±87.6 11.3±9.1 0.913
Malar rash (%) 28 (65.1) 9 (60) 0.966
Discoid rash (%) 1 (2.3) 1 (6.7) 0.454
Photosensitivity  (%) 32 (74.4) 13 (86.7) 0.480
Nasal/oral ulcers (%) 17 (39.5) 7 (46.7) 0.858
Arthritis (%) 31 (72.1) 12 (80) 0.736
Serositis (%) 14 (32.6) 5 (33.3) 0.999
Neurologic manifestations  (%) 9 (20.9) 1 (6.7) 0.427
Hematologic manifestations  (%) 29 (67.4) 10 (66.7 ) 0.999
ANA (%) 43 (100) 15 (100)     -
Anti-Sm  (%) 12 (28.6) 3 (20) 0.693
Anticardiolipin antibodies  (%) 18 (41.9) 6 (40) 0.999
Lupus anticoagulant  (%) 7 (17.1) 3 (20) 0.999
False-positive VDRL  (%) 5 (11.6) 1 (6.7) 0.999
SLEDAIb 4 (2-6) 2 (1-8) 0.361
Active nephritisc (%) 15 (34.9) 1 (6.7) 0.046
C3 (mg/dL±SD)d 99.6±29.3 96.2±29.6  0.706
C4 (mg/dL±SD)d 16±8.9 16.67±8.7 0.894
Sjogren’s syndrome (%) 4 (9.5) 0 (0) 0.564
Antiphospholipid syndrome (%) 4 (9.5) 0 (0) 0.564

ANA: antinuclear antibody; SD: standard deviation; SLEDAI: systemic lupus erythematosus disease activity index; VDRL: venereal disease research laboratory test; (+): positive.
a Chi-square test for qualitative variables and Mann-Whitney U test for asymmetric quantitative variables or Student’s t test for symmetric quantitative variables.
b Median (interquartile interval).
c As defined in references 5 and 8, using fresh urine analysis in the day of appointment.
d Normal values for C3 and C4 were 88-165mg/dL and 14-44 mg/dL, respectively.