Peripheral Blood Lymphocyte Subsets and Clinical Parameters in Patients Undergoing Renal Biopsy

Introduction Chronic kidney disease (CKD) is a major global health burden characterized by immune dysregulation. Peripheral blood lymphocyte subsets can reflect immune status across CKD pathologies. We evaluated associations between lymphocyte subsets and clinical parameters in patients undergoing renal biopsy in a contemporary cohort. Methods We conducted a retrospective cross-sectional study of adults (≥16 years) who underwent native renal biopsy at Tongji Hospital, China, from January 2012 to December 2024. The lymphocyte subsets assessed by flow cytometry included combined T/B/NK cells (TBNK), total T cells (CD3⁺CD19⁻), total B cells (CD3⁻CD19⁺), helper T cells (CD3⁺CD4⁺), cytotoxic T cells (CD3⁺CD8⁺), and natural killer cells (CD3⁻CD16⁺CD56⁺). Clinical data included demographics, comorbidities, medications, clinical and immunological markers. Multivariable linear regression was employed to investigate the relationships between lymphocyte subsets as continuous variables and clinical parameters, and nested regression using quartile categories to assess dose-response relationships. Results In total, 1,033 individuals were enrolled. TBNK levels declined with age (β = −4.33, 95% CI: −7.35 to −1.32) and were lower in females than males (β = −84.26, 95% CI: −157.29 to −11.23). Lymphocyte subset distributions varied by nephritis pathology: ANCA-GN and LN showed lower levels than other types, whereas purpura nephritis was relatively higher. TBNK counts correlated positively with eGFR (β = 11.48, 95% CI: 6.78 to 16.19), with similar patterns for total B, total T, CD4+ T, and CD8+ T cells. Lymphocyte counts were also positively associated with complement 3. Among IgAN, TBNK levels correlated positively with IgA (β = 0.31, 95% CI: 0.06 to 0.57) and complement 3 (β = 0.10, 95% CI: 0.06 to 0.14). Conclusions Lymphocyte and subset counts relate to renal function, immune indices, and pathology. Their measurement may help evaluate disease severity and immune status in nephritis and inform clinical management.