CD45 + C1q + CCR8+ Cells as Emerging Indicators of Kidney Disease Severity and Progression Risk

Fibrosis is a common mechanism underlying the progression of kidney and other organ failures. Complement protein C1q and chemokine receptor 8 (CCR8), whose ligand is CCL1, are implicated in fibrosis. This study aimed to evaluate the clinical significance of CD45+ mononuclear cells coexpressing C1q and CCR8 (CD45 + C1q + CCR8+ cells) in kidney disease. This prospective observational study included 44 patients with kidney disease. The percentage of CD45 + C1q + CCR8+ cells among CD45+ mononuclear cells in the peripheral blood was measured using flow cytometry at baseline. Correlations between these percentages and clinical parameters, including serum creatinine (Cr) and urinary protein levels, were examined using linear regression models. The association between baseline percentages of CD45 + C1q + CCR8+ cells and kidney outcomes-defined as end-stage kidney disease or a 30% decrease in the estimated glomerular filtration rate-was examined using Cox proportional hazards models in patients with serum Cr data during follow-up. The median age of the cohort was 57 years, and 61.4% were male. The median serum Cr and urinary protein levels were 1.73 mg/dL and 1.99 g/g Cr, respectively. Baseline percentages of CD45 + C1q + CCR8+ cells positively correlated with serum Cr (p = 0.028) and urinary protein (p = 0.015). Among 21 patients with follow-up data, 10 (48%) reached kidney outcomes. Patients with moderately elevated percentages had a higher risk of kidney outcomes than those with low levels (HR: 27.31, 95% CI: 1.08-692.3; p = 0.04). CD45 + C1q + CCR8+ cell percentages in peripheral blood may reflect kidney function and are associated with disease progression, indicating their potential as biomarkers.