Old marker, new face: anti-RNP as a sentinel of coronary and peripheral endothelial dysfunction in systemic lupus erythematosus
Amany M. Ebaid, Mona Rabie, Wedad Mahmoud Ghazy, Shaimaa Wageeh, Mohammad Eltahlawi, Doaa Alhssein Abo-alella, Wafaa Metwally, Basma Magdy Elkholy, Lobna I KotbObjective
To investigate the association between anti-ribonucleoprotein (anti-RNP) antibodies and endothelial dysfunction (ED) in patients with SLE and their ability to predict early ED manifestations, both coronary and peripherally.
Methods
A cross-sectional study was conducted at a tertiary hospital involving 70 patients with SLE meeting American College of Rheumatology (ACR)/Systemic Lupus International Collaborating Clinics (SLICC) criteria. All study participants underwent a full clinical and laboratory evaluation, including testing for Cardiovascular Diseases serum anti-RNP antibodies. Conventional transthoracic 2-dimensional echocardiography, tissue Doppler imaging and a transthoracic dobutamine stress echocardiography to assess coronary microvasculature by measuring coronary flow velocity reserve (CFVR). Peripheral microvascular morphology was evaluated via nailfold dermoscopy. The primary outcome measures were the mean CFVR values and the presence of dermoscopic abnormalities (capillary drop-out, tortuosity and density) in relation to anti-RNP titres.
Results
In 70 patients with SLE, those with high disease activity (n=45) exhibited significantly impaired cardiac function compared with low-activity patients (n=25), showing lower ejection fraction (EF) and CFVR, alongside higher Wall Motion Score Index (p<0.05). Anti-RNP levels correlated positively with Systemic Lupus Erythematosus Disease Activity Index (SLEDAI, r=0.653, p<0.001), erythrocyte sedimentation rate, proteinuria and Raynaud’s phenomenon. Significant negative correlations existed between anti-RNP and stress EF (r=−0.33), CFVR (r=−0.30), C3 and C4 (p<0.05). Furthermore, elevated anti-RNP levels were significantly associated with clinical manifestations such as myositis and avascular necrosis, as well as dermoscopic microvascular changes, including microhaemorrhage and capillary dropouts (p<0.05).
Conclusions
High anti-RNP titres are significantly associated with subclinical coronary microvascular impairment and peripheral capillary architectural changes in SLE. These results suggest that anti-RNP acts as a sentinel marker for early ED, providing potential for improved cardiovascular risk stratification independent of traditional risk factors.