Serum levels of PECAM-1, ICAM-1, and VCAM-1 in patients with systemic lupus erythematosus: associations with disease activity and clinical features from a single-center study

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by complex disturbances in both innate and adaptive immune responses, often leading to multi-organ involvement. One of the key features of SLE pathogenesis is endothelial dysfunction, which contributes to immune cell infiltration and vascular inflammation. In this context, adhesion molecules such as platelet endothelial cell adhesion molecule-1 (PECAM-1), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) may reflect the degree of endothelial activation. Therefore, we aimed to evaluate serum levels of PECAM-1, ICAM-1, and VCAM-1 in patients with SLE to investigate their potential role as biomarkers of disease activity and future relapse. We investigated 52 patients with SLE: 15 (28.8%) with disease exacerbation (SLE disease activity index [SLEDAI] ≥ 5 points) and 37 (71.2%) in remission (SLEDAI < 5 points), and 12 controls matched by sex and age. All patients met the 2019 EULAR/ACR criteria for SLE. Serum levels of selected adhesion molecules were determined in all participants with the Luminex Discovery Assay Human Premixed Multi-Analyte Kit. We observed no significant differences in the serum levels of PECAM-1 and ICAM-1 between active and inactive SLE patients or between active/inactive SLE patients and healthy controls, but also considering all SLE cases and the control group. However, VCAM-1 levels were 96.8% higher in the active SLE patients (p < 0.001) and 35.4% increase in inactive SLE as compared to controls (p = 0.016), with a similar level between active and inactive SLE patients (p = 0.11). There were no differences in the selected cytokine levels between patients with renal flare and those without renal flare in the active SLE group, but also in inactive SLE group regarding the presence of lupus nephritis despite from 43.3% higher level of ICAM-1 in patients with lupus nephritis (p = 0.016). There were no observed correlations between the levels of these individual cytokines themselves. Furthermore, regarding clinics, only PECAM-1 correlated with disease duration (r_s = 0.42, p = 0.010) and VCAM-1 was associated with SLEDAI (r_s = 0.47, p = 0.003). In the follow-up analysis, during a median observation period of 5.5 years, 10 out of 37 enrolled inactive SLE patients developed a disease flare, but no cytokine differences in baseline levels were found between those with or without a flare in the follow-up period. In our study, VCAM-1 levels were elevated in SLE patients compared to controls, with no significant differences between active and inactive SLE; however, they correlated with laboratory markers of disease activity. PECAM-1 and ICAM-1 showed limited diagnostic utility, though PECAM-1 positively correlated with disease duration.