Urinary Tumor Necrosis Factor-Like Weak Inducer of Apoptosis (uTWEAK) and Urinary Monocyte Chemo-attractant Protein-1 (uMCP-1): Promising Biomarkers of Lupus Nephritis Activity?

There is no single biomarker to detect lupus nephritis (LN) activity. Renal biopsy is still the gold standard method but it is invasive and mainly used in the initial assessment of the patients. Urinary tumor necrosis factor-like weak inducer of apoptosis (uTWEAK) and urinary monocyte chemo-attractant protein-1 (uMCP-1) can be secreted in the urine of active LN. The aim of the study is to assess the potential role of uTWEAK and uMCP-1 in lupus patients and to determine their correlation with disease activity. This is a case-control study conducted on a total of 114 subjects; 92 systemic lupus erythematosus (SLE) patients and 22 healthy volunteers. The patients were recruited from the rheumatology unit at the internal medicine department, Tanta University Hospital, Tanta, Egypt. The patients and controls were subjected to full history taking, complete clinical examination, routine laboratory tests, uTWEAK and uMCP-1 measurement, assessment of the disease activity using SLE Disease Activity Index (SLEDAI), and renal SLEDAI (rSLEDAI) scores. uTWEAK and uMCP-1 levels were higher in SLE with active nephritis group than those of other SLE groups and controls. There was a significant positive correlation between uTWEAK and uMCP-1 levels in lupus patients with proteinuria, anti-dsDNA, SLEDAI and r-SLEDAI and a negative correlation with C3 and C4. TWEAK showed a sensitivity of 80.43% and 100% and specificity of 50% and 100% in detecting lupus activity and LN activity, respectively. Furthermore, uMCP-1 showed a sensitivity of 82.6% and 100% and specificity of 50% and 100% in detecting lupus activity and LN activity, respectively. uTWEAK and uMCP-1 are new, easily obtained, accurate markers with high sensitivity and specificity in the detection of LN activity.