Characteristics of ANA-positive patients with primary ITP who developed CTD
| Developed CTD (n=19) | Did not develop CTD (n=106) | P value | |
| Basic characteristics | |||
| Age, years | 34.00 (26.00–45.00) | 32.50 (25.75–56.50) | 0.754 |
| Female/male (female, %) | 12/7 (63.16) | 90/16 (84.91) | 0.053 |
| Mean length of follow-up (months) | 38.42±18.46 | 34.80±22.35 | 0.507 |
| Bleeding score | 4.1±1.5 | 3.1±1.6 | 0.169 |
| Clinical features | |||
| Platelet count, ×109/L | 43.00 (10.00–61.00) | 32.00 (9.50–66.00) | 0.983 |
| Leucocyte, ×109/L | 5.85 (4.18–8.16) | 6.62 (5.03–8.74) | 0.261 |
| Neutrophils, ×109/L | 3.75 (2.10–6.60) | 4.65 (3.18–6.83) | 0.287 |
| Lymphocytes, ×109/L | 1.36 (0.90–2.15) | 1.61 (1.17–2.24) | 0.203 |
| Haemoglobin, g/L | 125.00 (109.00–146.00) | 125.00 (114.00–137.00) | 0.901 |
| Sedimentation rate, mm/hour | 17.75±16.19 | 24.95±17.75 | 0.461 |
| C reactive protein, mg/L | 2.11 (0.78–3.56) | 1.09 (0.69–4.61) | 0.303 |
| Anti-PAIgG positivity, n (%) | 3/7 (42.86) | 20/43 (46.51) | 1.000 |
| ANA pattern (speckled pattern), n (%) | 14/18 (77.78) | 67/94 (71.28) | 0.572 |
| ENA positivity, n (%) | 10/18 (55.56) | 38/103 (36.89) | 0.135 |
| Anti-SSA positivity | 7/18 (38.89) | 21/103 (20.39) | 0.157 |
| Anti-Ro52 positivity | 5/18 (27.78) | 21/103 (20.39) | 0.694 |
| Anti-SSB positivity | 0/18 (0.00) | 3/103 (2.91) | 1.000 |
| C3, mg/dL | 0.81 (0.73–1.02) | 1.03 (0.87–1.20) | 0.002 |
| C4, mg/dL | 0.17 (0.14–0.27) | 0.21 (0.17–0.27) | 0.177 |
| IgA, g/L | 1.81 (1.42–2.93) | 2.27 (1.72–2.86) | 0.250 |
| IgG, g/L | 13.90 (12.03–16.73) | 13.95 (11.65–15.60) | 0.522 |
| IgM, g/L | 0.95 (0.72–1.13) | 1.15 (0.84–1.73) | 0.081 |
Anti-SSA, anti-Sjogren’s syndrome A antibody; anti-SSB, anti-Sjogren’s syndrome B antibody; CTD, connective tissue disease; ENA, extractable nuclear antigen antibodies; ITP, immune thrombocytopaenia; PAIgG, platelet-associated IgG.