Predicting cardiopulmonary involvement in patients with systemic sclerosis: complementary value of nailfold videocapillaroscopy patterns and disease-specific autoantibodies

Abstract

Objective: To evaluate the prevalence of anti-extractable nuclear antigen (anti-ENA) antibodies in Dutch SSc patients and the predictive power of the combination of specific anti-ENA antibodies and nailfold videocapillaroscopy (NVC) patterns to improve identification of patients with high risk for cardiopulmonary involvement.

Methods: A total of 287 patients (79%) from the Leiden SSc-Cohort had data available on NVC-pattern (no SSc-specific, early, active, late) and anti-ENA antibodies. Associations between anti-ENA/NVC combinations with cardiopulmonary parameters were explored using logistic regression.

Results: Prevalence of ACA was 37%, anti-Scl-70 24%, anti-RNP 9%, anti-RNAPIII 5%, anti-fibrillarin 4%, anti-Pm/Scl 3%, anti-Th/To 0.3% and anti-Ku 1.4%. NVC showed a SSc-specific pattern in 88%: 10% early, 42% active and 36% late. The prevalence of different NVC patterns was equally distributed among specific anti-ENA antibodies, except for the absence of early pattern in anti-RNP positive patients. Fifty-one percent had interstitial lung disease (ILD), 59% had decreased diffusion capacity for carbon monoxide and 16% systolic pulmonary artery pressure >35 mmHg (sPAP↑). Regardless of ENA-subtype, NVC-pattern showed a stable association with presence of ILD or sPAP↑. For ILD, the odds ratios (ORs) were 1.3-1.4 ( P < 0.05 for analyses with anti-RNAPIII, anti-RNP). For diffusion capacity for carbon monoxide, the OR was 1.5 ( P < 0.05 for analyses with ACA, anti-Scl-70, anti-RNAPIII, anti-RNP). For sPAP↑, the ORs were 2.2-2.4 ( P < 0.05 for analyses with anti-RNAPIII, anti-RNP).

Conclusion: In Dutch SSc patients, all SSc-specific auto-antibodies were found, with ACA and anti-Scl-70 being the most prevalent. Strikingly, the association between NVC-pattern and heart/lung involvement was independent of specific anti-ENA antibodies, which might indicate microangiopathy is an important cause of organ involvement.

Keywords: anti-ENA; autoantibodies; cardiopulmonary involvement; nailfold videocapillaroscopy; screening; systemic sclerosis.