Purpose SLE is associated with premature and accelerated atherosclerosis. Atherosclerotic processes are associated with impaired renal function and may be driven by inflammatory pathways, including interferon type 1 responses; both conditions with relevance to SLE. Plasma levels of B2MG are correlated to interferon-alpha activity in SLE as well as dependent of renal function. In this study plasma B2MG was correlated to markers of atherosclerosis in patients with SLE.

Methods Patients with SLE (n=147) were included in the cross-sectional study. Traditional cardiovascular risk factors were accounted for. Markers of atherosclerosis included 1) coronary artery calcium (CAC) assessed by computed tomography without contrast and identified in accordance with the Agatston scoring method and 2) carotid plaque (CP) assed by ultrasound and identified as either 1) a local thickening of the intima-media thickness of >50% compared with the surrounding vessel wall, 2) an IMT of more than 1.5 mm thick or 3) a local thickening of the arterial wall of more than 0.5 mm; bilateral examination. P-B2MG was measured by a routine immunoturbidimetric assay. The Cockgroft-Gault formula was used to calculate the estimated glomerular filtration rate (eGFR) (mL/min/1.73 m² body surface area) which was stratified into quartiles.

Results CAC, CP or any of them (CAC/CP) were found in 57, 29 and 62 patients, respectively; eGFR <90 was found in 74 patients. P-B2MG having a median of 216 nmol/L (range: 101–2810). Among the patients with the highest quartile of P-B2MG the frequency of CAC/CP was around 65% irrespective of eGFR. However, in a full logistic regression model taking into account traditional and disease related cardiovascular risk factors, patients with normal eGFR and a high quartile P-B2MG where found to have the highest odds ratio for having CAC/CP, see table 1.

Conclusion We found a high prevalence of atherosclerotic markers in patients with SLE with the highest among those within the top quartile of P-B2MG in combination with normal renal function. These results suggest that atherosclerosis in SLE may be associated with interferon-alpha activity irrespective of renal function.