#5000 DIFFERENCES IN CIRCULATING IMMUNE CELLS PROFILE BETWEEN MALES WITH CARDIORENAL SYNDROME TYPE II AND CKD PATIENTS WITHOUT CARDIOVASCULAR DISEASE
Authors: Duni Anila , Kitsos Athanasios , Bechlioulis Aris , Markopoulos Georgios , Lakkas Lampros , Baxevanos Gerasimos , Theodorou Ioanna , Naka Katerina , Vartholomatos George , Ntounousi Evangelia 
Published: June 2023

Abstract

Background and Aims
Maladaptive activation of the immune system plays an important role in the pathogenesis of cardiovascular disease (CVD) and chronic kidney disease (CKD). The immune system components can act as mediators of organ cross-talk and may be involved in the reciprocal dysfunction that occurs in cardiorenal syndromes (CRS). The aim of our study was to investigate potential differences in blood levels of specific immune cells subsets between a cohort of type II CRS patients and CKD patients without established CVD.

Method
40 stable male patients with CRS type II and 30 male CKD patients without CVD, matched for eGFR (CKD-EPI) were enrolled in this cross-sectional study. Exclusion criteria were history of malignancy, autoimmunity and active or chronic infections. The peripheral blood immune cell subsets CD14++CD16-, CD14++CD16+ and CD14+CD16++ absolute values and percentages out of total monocytes and NK cells (CD3+CD16+56+), CD3-CD19+ B lymphocytes, CD3+ CD4+ T cells, CD3+CD8+ T cells and Tregs (CD4+CD25+FoxP3+) absolute values and percentages out of total lymphocytes were measured by flow cytometry. Simultaneously, clinical, laboratory and echocardiographic data were assessed. Multiple regression analyses to assess independent relationships were performed by building separate models with each of the immune cells as the dependent variable and respective univariate correlates including patient group.

Results
Mean age of patients with CRS and CKD was 72±10 versus 66±10 years respectively (p = 0.01), mean eGFR was 37±14 and 33±16ml/min/1.73 m2 respectively (p = 0.28) and median urinary protein to creatine ratio (UPCR) was 0.19 (IQR, 0.10-0.52) versus 1.03 (IQR, 0.17-2.09) gr protein/gr creatinine (p = 0.02) respectively. CRS patients displayed increased levels of pro-inflammatory, intermediate CD14++CD16+ monocytes [41 (IQR, 24-78)/µL] compared to their CKD counterparts [35 (IQR, 18-43)/µL] (p = 0.04). A higher Tregs percentage was found in CRS patients [2.7% (IQR, 2.0%-3.9%)] compared to CKD patients [2.0% (IQR, 1.6%-2.6%)] (p = 0.03). Lower mean levels of lymphocytes were observed in CRS patients (1557±691/µL) compared to the CKD cohort (1920±545/µL) (p = 0.04). Finally, CRS patients displayed lower NK cell counts [148 (IQR, 103-258)/µL] compared to CKD patients [324 (IQR, 179-368)/µL] (p = 0.001). Age and UPCR did not correlate with immune cells subsets in the whole cohort, neither in the two groups separately. At multivariate regression analysis, the differences in immune cells between the two groups remained statistically significant. Specifically, in patients with CRS the intermediate CD14++CD16+ monocytes counts correlated positively with CRP (p = 0.002) and ESR (p = 0.02). A positive correlation was found between eGFR and total lymphocytes (p = 0.009), T cells (p = 0.005) and CD4+ T cells (p = 0.005) counts. The number and percentage of nonclassical CD14+CD16++ monocytes were higher in CRS patients with left ventricular ejection fraction (LVEF) less than 30% compared to patients with LVEF above 30% [33 (IQR, 18-37)/µL versus 13 (IQR, 10-29)/µL (p = 0.02) and 4.5% (IQR, 3.4%-7.2%) versus 2.7% (IQR, 1.9%-5.4%) (p = 0.03) respectively]. With regard to etiology, patients with dilated cardiomyopathy compared to patients with ischemic CVD displayed increased counts of intermediate CD14++CD16+ monocytes [75 (IQR, 41-104)/µL versus 36 (IQR, 22-61)/µL (p = 0.01)] and non-classical CD14+CD16++ monocytes [37 (IQR, 35-49)/µL versus 21 (IQR, 12-32)/µL (p = 0.02)]. Finally, NK cells and Tregs levels were lower in patients with atrial fibrillation compared to those without [133 (IQR, 79-173)/µL versus 260 (IQR, 151-314)/µL (p = 0.01)] and [32 (IQR, 21-43)/µL vs 47 (IQR, 34-85)/µL (p = 0.006)] respectively.

Conclusion
Patients with CRS type II exhibit alterations of the immune cells subsets profile in the peripheral blood compared to CKD patients of similar kidney function but without CVD. Our findings suggest that distinct immune mechanisms might be involved in the pathogenesis or the chronic course of CRS type II as compared to CKD. Future research is required to evaluate their pathophysiological or prognostic significance.