Table 2.
HLA-DRB1 Alleles and C4 Gene CNVs in JDM and Controls
| A. Analysis of single genetic risk factors in JDM | ||||
|---|---|---|---|---|
| JDM (N=95) | Control (N=500) | p-value | OR (95% CI) | |
| a. Distribution, N (%) | ||||
| C4T GCN ≤ 3 | 48 (50.5%) | 146 (29.2%) | 7.5x10−5 | 2.48 (1.59–3.87) |
| C4A deficiency, GCN ≤1 | 38 (40.0%) | 91 (18.2%) | 8.2x10−6 | 3.00 (1.87–4.79) |
| C4B deficiency, GCN ≤1 | 28 (29.5%) | 153 (30.6%) | 0.83† | |
| HLA DRB1*1501 | 11 (11.6%) | 139 (27.8%) | 0.0004 | 0.34 (0.18–0.66) |
| HLA DRB1*0301 (DR3+) | 44 (46.3%) | 129 (25.8%) | 9.5x10−5 | 2.48 (1.58–3.89) |
| C4A-deficiency with DR3+ | 35 (36.8%) | 77 (15.4%) | 4.8x10−6 | 3.20 (1.98–5.19) |
| b. Mean GCN ± SD | ||||
| Total C4 genes | 3.49 ± 0.71 | 3.83 ± 0.69 | 1.8x10−5 | |
| C4A genes | 1.79 ± 0.86 | 2.09 ± 0.75 | 0.0004 | |
| C4B genes | 1.71 ± 0.58 | 1.73 ± 0.63 | 0.68† | |
| B. Multiple logistic regression models for genetic factors of JDM | ||||
|---|---|---|---|---|
| Models and parameters | R2 | χ2 | p-value | OR (95% CI) |
| a. C4A-deficiency, DRB1*1501 and DR3+ | 0.058 | 30.2 | 1.2x10−6 | |
| DRB1*1501 | 8.95 | 0.0028 | 0.39 (0.19–0.74) | |
| C4A-deficiency | 6.21 | 0.013 | 2.27 (1.19–4.40) | |
| DR3+ | 0.70 | 0.40† | 1.31 (0.69–2.44) | |
| b. C4A-deficiency and DR3+ | 0.041 | 21.3 | 2.4x10−5 | |
| C4A-deficiency | 6.05 | 0.014 | 2.26 (1.18–4.39) | |
| DR3+ | 1.39 | 0.24† | 1.47 (0.77–2.74) | |
| c. C4A deficiency and DRB1*1501 | 0.057 | 29.5 | 3.9x10−7 | |
| DRB1*1501 | 9.64 | 0.0045 | 0.38 (0.19–0.71) | |
| C4A-deficiency | 16.8 | 2.7x10−5 | 2.76 (1.71–4.43) | |
| d. DR3+ and DRB1*1501 | 0.046 | 24.0 | 6.1x10−6 | |
| DRB1*1501 | 8.80 | 0.003 | 0.40 (0.19–0.74) | |
| DR3+ | 11.3 | 0.0008 | 2.21 (1.39–3.49) | |
| e. C4A-deficiency with DR3+ and DRB1*1501 | 0.059 | 30.6 | 2.2x10−7 | |
| C4A-deficiency with DR3+ | 17.9 | 2.4x10−5 | 2.96 (1.81–4.80) | |
| DRB1*1501 | 9.7 | 0.0018 | 0.34 (0.21–0.55) | |
| C. Subgroup analyses of C4A-GCN, C4A-deficiency and HLA-DR3 in JDM | ||||
|---|---|---|---|---|
| JDM | Control | p-value | OR (95% CI) | |
| Mean C4A GCN, DR3+ | 1.18±0.54 | 1.47±0.72 | 0.015 | |
| Mean C4A GCN, DR3− | 2.31±0.73 | 2.31±0.63 | 0.97† | |
| C4A-deficient, DR3+, N (%) | 35 (79.6) | 77 (59.7) | 0.014 | 2.63 (1.17–5.92) |
| C4A-proficient, DR3+, N (%) | 9 (20.5) | 52 (40.3) | ||
| C4A-deficient, DR3−, N (%) | 3 (5.9) | 14 (3.8) | 0.50† | |
| C4A-proficient, DR3−, N (%) | 48 (94.1) | 357 (96.2) | ||
| DR3+, C4A-deficient, N (%) | 35 (92.1) | 77 (84.6) | 0.23† | |
| DR3−, C4A-deficient, N (%) | 3 (7.9) | 14 (15.4) | ||
| DR3+, C4A-proficient, N (%) | 9 (15.8) | 52 (12.7) | 0.53† | |
| DR3−, C4A-proficient, N (%) | 48 (84.2) | 357 (87.3) | ||
Abbreviations: C4T, total copies of C4 genes; CI, confidence interval; GCN, gene copy-number; N, number; OR, odds ratio. C4A-deficient: C4A GCN =0 or 1; C4A-proficient: C4A GCN ≥2
†
not statistically significant; categorical data were compared by χ2 analyses; continuous data were compared by t-tests.