T Cell Subset Profile and Appearance of Donor-specific Antibodies in Primary and Retransplanted Kidney Recipients.

INTRODUCTION: Accelerated antibody-mediated rejection is a major challenge after kidney transplantation. While the clinical course, diagnosis, and treatment of cell-mediated acute rejection is agreed upon and has been successfully performed, the antibody-mediated rejection remains a problem. Biopsies cannot be repeated several times, are not always representative, and are refused by many patients. Analysis of T-cell subsets and donor-specific antibodies (DSAs) might be an additive diagnostic tool in the case of kidney transplantation. METHOD: Between 2015 and 2017, 50 kidney transplant patients were enrolled in the study. Patients were divided into 2 clinical groups: primary transplants and regrafted patients. Serum samples were collected right before the operation, then in 1 week; 30, 60, and 180 days; and yearly. Besides routine laboratory, multicolor flow cytometry was performed for T cell subsets, and Luminex Single Antigen Bead assay for the detection on donor-specific anti-HLA antibodies. Medical data were also fixed. RESULTS: The percentage of CD4+ and CD8+ cells (the CD4+/CD8+ rate) did not change much over time in either group. The percentage of CD19+ cells increased until week 1, then decreased back to its original level by day 180. CD56+/3-% was high in both groups and had no characteristic kinetics by the time. The CD4+ naïve absolute cell count increased in first-time transplants and did not decreased back to its original value until the end of year 1. This is in contrast to retransplants, where CD4+ naïve cell count rapidly dropped below its original value and remained low throughout the first year after transplantation. The CD8+ effector memory absolute cell-count was higher in first-time transplants compared to retransplanted patients in all time points. By the end of month 1, the CD19+ naïve absolute cell-count increased in first-time transplants to 170% of its original value; however, it remained or decreased in second transplants. By the end of the first year, the CD19+ naïve absolute cell count diminished to 70% in first-time transplants and 38% in second transplants. DSA was detected in 9 out of the 38 first-time transplants (23.7%) compared to 7 out of 12 (58.3%) in regrafted patients during the observational period (P = .001). It was typical for regrafted patients for DSAs to appear earlier after transplantation, and that more simultaneously different antibodies were detected against more antigens at the first time point compared to first-time transplants. DISCUSSION: The 2 groups were similar in demographics and there were no differences regarding the clinical course, complications, or output data. However, we found statistical differences regarding the dynamics of T cell subsets and DSAs. The parallel measurement of CD subsets and DSAs might be a sensitive and useful additive tool in diagnosing subclinical immunologic changes after transplantation.

Synthesis, in Vitro Biological Evaluation, and Oxidative Transformation of New Flavonol Derivatives: The Possible Role of the Phenyl-N,N-Dimethylamino Group.

Six new flavonols (6a⁻f) were synthesized with Claisen⁻Schmidt and Suzuki reactions and they were fully characterized by spectroscopic methods. In order to evaluate their antioxidant activities, their oxygen radical absorption capacity and ferric reducing antioxidant power were measured, along with their free radical scavenging activity against 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and 2,2-diphenyl-1-picrylhydrazylradicals. In addition, their cytotoxicity on H9c2 cardiomyoblast cells was also assessed by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Compounds bearing the phenyl-N,N-dimethylamino group (6a, 6c, and 6e) exhibited promising antioxidant potency and did not have any cytotoxic effect. After a consideration of these data, the oxidative transformation of the 6c compound was investigated in vitro with a chemical Fenton reaction and the identification of the formed oxidation products was performed by mass spectrometry. Two potential metabolites were detected. Based on these results, compound 6c can be a model compound for future developments. Overall, this work has proved the involvement of the phenyl-N,N-dimethylamino group in the antioxidant activity of flavonols.