Aim: YKL-40 is a protein associated with acute and chronic inflammation and cancer. Neutrophils, macrophages, and cancer cells normally produce it. It plays a role in cell proliferation, differentiation, angiogenesis, inflammation, and extracellular matrix remodeling. It is also a marker of endothelial dysfunction and atherosclerosis. Serum YKL-40 has been reported to be associated with proteinuria in diabetic and renal transplant patients. In this study, we aimed to investigate, for the first time in the literature, the relationship between the amount of proteinuria and inflammatory markers and YKL-40 in patients with systemic lupus erythematosus (SLE). Material and Methods: Fifty-one patients with SLE who presented to the adult nephrology outpatient clinic between June 2022 and January 2023 were included in the study. Blood and urine test results were obtained from the patients' routine examinations. ELISA was used to determine YKL-40. Results: The mean age of the patients was 38±14 years and 94% were female. The median creatinine was 0.72 (0.36-2.62) mg/dl, the mean estimated glomerular filtration rate was 99±31 ml/min, the mean C-reactive protein (CRP) was 8±7 mg/L, the median erythrocyte sedimentation rate (ESR) was 14.5 (4-72) mm/hour, the median amount of proteinuria was 190 (69-4959) mg/g and the mean YKL-40 was 12.9±9.2 pg/ ml. In correlation analysis, YKL-40 was positively correlated with glucose, CRP, and ESR respectively (p=0.01, r=0.26), (p=0.02, r=0.06), (p=0.01, r=0.11), and negatively correlated with calcium, albumin, intact parathyroid hormone, and complement-3 [respectively (p
Öztürk et al. (Sun,) studied this question.