Table 2.
Comparison of serum anti-Cardiolipin (aCL) and anti-β2GPI (aβ2GPI) levels in P-C4d-positive vs. P-C4d-negative patients.
| Platelet-C4d | ||||
|---|---|---|---|---|
| All (n = 180) | Positive (n = 34) | Negative (n = 146) | p-Value (P-C4d+ vs. P-C4d−) | |
| aPL (aCL and/or aβ2GPI) antibodies positivity, n (%) | 48 (26.7) | 20 (58.5) | 28 (19.2) | <0.001 |
| aCL IgM positivity, n (%) † | 19 (10.6) | 8 (23.5) | 11 (7.5) | 0.012 |
| aCL IgM level (U/mL) median (IQR) * | 3.1 (2.0–6.5) | 4.2 (2.2–11.6) | 2.8 (2.0–6.0) | 0.068 |
| aCL IgG positivity, n (%) † | 17 (9.4) | 11 (32.4) | 6 (4.1) | <0.001 |
| aCL IgG level (U/mL) median (IQR) * | 5.0 (2.8–9.6) | 12.5 (5.6–37.9) | 4.6 (2.7–7.7) | <0.001 |
| aCL IgA positivity, n (%) † | 6 (3.3) | 4 (11.8) | 2 (1.4) | 0.012 |
| aCL IgA level (U/mL) median (IQR) * | 1.2 (0.6–2.3) | 1.3 (1.0–2.9) | 1.0 (0.5–2.0) | 0.053 |
| Any aCL positivity, n (%) | 32 (17.8) | 13 (38.2) | 19 (13.0) | 0.002 |
| aβ2GPI IgM positivity, n (%) | 10 (5.6) | 5 (14.7) | 5 (3.4) | 0.022 |
| aβ2GPI IgM level (U/mL) median (IQR) | 0.4 (0.0–1.3) | 1.0 (0.4–3.6) | 0.3 (0.0–0.9) | <0.001 |
| aβ2GPI IgG positivity, n (%) | 14 (7.8) | 11 (32.4) | 8 (5.5) | <0.001 |
| aβ2GPI IgG level (U/mL) median (IQR) | 1.6 (0.0–3.7) | 4.6 (1.1–76.1) | 1.3 (0.0–3.1) | <0.001 |
| aβ2GPI IgA positivity, n (%) | 21 (11.7) | 13 (38.2) | 16 (11.0) | <0.001 |
| aβ2GPI IgA level (U/mL) median (IQR) | 0.4 (0.0–2.6) | 3.9 (0.8–12.8) | 0.4 (0.0–1.2) | <0.001 |
| Any aβ2GPI positivity, n (%) | 34 (18.9) | 18 (52.9) | 16 (11.0) | <0.001 |
† Positivity for all aPL antibodies was defined based on the cutoff values provided by the ELISA kits used. * median (IQR). C4d−: C4d-negative; C4d+: C4d-positive; aβ2GPI: anti-β2 glycoprotein I.