Biological characteristics of patients with primary Sjogren’s syndrome according to anti-RNP positivity
| Primary Sjögren with anti-RNP, n=21 | Primary Sjögren without anti-RNP (Paris-Sud cohort), n=446 | P value | |
| Positive ANA antibodies | 21(100.0) | 328/439(74.7) | 0.0035 |
| Positive RF | 10 (47.6) | 205/436 (47.0) | 0.9570 |
| Anaemia* | 3 (14.3) | 63/430 (14.7) | 1 |
| Thrombopenia* | 0 (0.0) | 4/429 (0.9) | 1 |
| Neutropenia* | 0 (0.0) | 3/433 (0.7) | 1 |
| Lymphopenia* | 5 (23.8) | 57/433 (13.2) | 0.1866 |
| Gammaglobulins or IgG >16 g/L | 16(76.2) | 154/438(35.2) | 0.0001 |
| Cryoglobulinemia | 1 (4.8) | 7/423 (1.7) | 0.3235 |
| Low C4† | 7 (33.3) | 88/406 (21.7) | 0.2781 |
| Increased CK* | 4/13 (30.8) | 3/25 (12.0) | 0.2025 |
| Median ANA value | 1/1280 | 1/640 | 0.0369 |
| Median gammaglobulins, g/L | 22.5(16.5–30.0) | 13.0(10.1–16.3)/422 | <0.0001 |
| Median IgG, g/L | 21.4(15.5–32.3) | 13.1(9.9–16.9)/409 | 0.0005 |
| Median beta-2 microglobulin, mg/L | 2.8(2.3–4.3) | 2.2(1.7–2.7)/384 | 0.0321 |
| Median C4 value, g/L | 0.18 (0.14–0.22) | 0.21 (0.16–0.26)/406 | 0.1054 |
| Median CK value, U/L | 119.0 (80.0–508.0) | 81.0 (57.0–125.0)/25 | 0.1029 |
Results are presented as number (%), or median (IQR).
Bold values are statistically significant.
*Normal CK value <170 U/L, lymphocytes count <1.0 G/L, Hb level <12 g/dL, neutrophils count <1.0 G/L, platelet count <100 G/L.
†C4 value≤0.15 g/L.
ANA, antinuclear antibodies; CK, creatine kinase; EMG, electromyogram; Hb, haemoglobin; RF, rheumatoid factor.