Avaliação do TREM-1 solúvel sérico como marcador de atividade de doença na nefrite lúpica

Abstract

Context: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of multifactorial etiology, characterized by periods of activity and remission. Lupus nephritis is one of the most severe manifestations and a major determinant of morbidity and mortality in SLE. Predicting and confirming disease activity in lupus nephritis remains a challenge, highlighting the need for reliable biomarkers to assist in clinical monitoring. The Triggering Receptor Expressed on Myeloid Cells-1 (TREM-1) has been identified as an amplifier of the innate inflammatory response and has been associated with various inflammatory and autoimmune conditions. Objective: To evaluate soluble serum TREM-1 (sTREM-1) as a biomarker of disease activity in lupus nephritis, as well as to compare its levels between patients with active nephritis, inactive SLE, and healthy controls, and to assess the association between sTREM-1 levels and the use of medications. Methodology: This was a cross-sectional observational study conducted at the rheumatology service of the Getúlio Vargas University Hospital (HUGV/UFAM). Patients were divided into two groups (active nephritis and inactive SLE) based on clinical and laboratory findings. Data were collected from medical records, and blood samples were analyzed using ELISA for sTREM-1 quantification. Statistical analysis included nonparametric tests, ROC curve analysis, and linear regression models to assess the association between sTREM-1 levels and medication use. Results: A total of 176 SLE patients were included, of whom 85 had active nephritis and 91 had inactive SLE, in addition to a control group of 88 healthy individuals. The results showed that serum sTREM-1 levels were significantly higher in SLE patients compared to healthy controls (p < 0.0001), with a ROC curve indicating excellent discriminatory ability (AUC = 1.00). However, no statistically significant difference in sTREM-1 levels was observed between patients with active nephritis and those with inactive SLE (p = 0.293), suggesting a limited ability of this biomarker to identify active lupus nephritis. Additionally, an association was observed between increased sTREM-1 levels and tacrolimus use in the active nephritis group (p = 0.049), while antimalarial use was associated with lower sTREM-1 levels in the inactive SLE group (p = 0.007). Conclusion: The findings of this study indicate that while serum sTREM-1 is a biomarker that distinguishes SLE patients from healthy controls, its utility in assessing disease activity in lupus nephritis remains limited. The potential influence of medications used in SLE treatment on sTREM-1 levels is a novel finding. This study is pioneering in analyzing serum sTREM-1 in SLE patients in the Northern region of Brazil and highlights the need for further longitudinal studies to better understand the role of this biomarker in the disease.