The Expansion of Myeloid-Derived Suppressor Cells Correlates With the Severity of Pneumonia in Kidney Transplant Patients.

Bo Peng,Pengpeng Zhang,Yu Zhang,Ke Cheng,Min Yang,Yingzi Ming,Yulin Luo,Quan Zhuang,Junhui Li,Gangcheng Kong

doi:10.3389/fmed.2022.795392

Abstract

BackgroundPneumonia is one of the most frequent but serious infectious complications post kidney transplantation. Severe pneumonia induces sustained immunosuppression, but few parameters concerning immune status are used to assess the severity of pneumonia. Myeloid-derived suppressor cells (MDSCs) are induced under infection and have the strong immunosuppressive capacity, but the correlation between MDSCs and pneumonia in kidney transplant recipients (KTRs) is unknown.MethodsPeripheral blood MDSCs were longitudinally detected in 58 KTRs diagnosed with pneumonia using flow cytometry and in 29 stable KTRs as a control. The effectors of MDSCs were detected in the plasma. Spearman's rank correlation analysis was performed to determine the correlation between MDSCs and the severity of pneumonia as well as lymphopenia.ResultsThe frequency of MDSCs and effectors, including arginase-1, S100A8/A9, and S100A12, were significantly increased in the pneumonia group compared with the stable group. CD11b+CD14+HLA-DRlow/−CD15− monocytic-MDSCs (M-MDSCs) were higher in the pneumonia group but showed no significant difference between the severe and non-severe pneumonia subgroups. CD11b+CD14−CD15+ low-density granulocytic-MDSCs (G-MDSCs) were specifically increased in the severe pneumonia subgroup and correlated with the severity of pneumonia as well as lymphopenia. During the study period of 2 weeks, the frequencies of MDSCs and G-MDSCs were persistently increased in the severe pneumonia subgroup.ConclusionsMDSCs and G-MDSCs were persistently increased in KTRs with pneumonia. G-MDSCs were correlated with the severity of pneumonia and could thus be an indicator concerning immune status for assessing pneumonia severity.

Highlights

Kidney transplantation has become the optimal treatment for patients with end-stage renal disease (ESRD)
A total of 90 kidney transplant recipients (KTRs) suspected of pneumonia with 179 Myeloid-derived suppressor cells (MDSCs) tests were first enrolled, but 32 KTRs with 50 MDSC tests were excluded according to the diagnostic criteria of pneumonia
The sex, age, donor source, calcineurin inhibitor (CNI) regimen, maintenance dosage of corticosteroids, and time from transplant to the first MDSC test showed no significant differences between the pneumonia group and the stable group

Summary

Introduction

Kidney transplantation has become the optimal treatment for patients with end-stage renal disease (ESRD). The long-term or even lifelong administration of immunosuppressive drugs remains essential for most kidney transplant recipients (KTRs) to prevent allograft rejection, but it dampens the host immune response to pathogens and increases the risk of infection at the same time [1]. Compared with the general population, KTRs have a substantially higher requirement for admission and a higher mortality rate due to infectious diseases [2, 3]. The cumulative infection incidence is as high as 78.0% at 5 years post-kidney transplantation [4]. Pneumonia is one of the most frequent but serious infectious complications post kidney transplantation. Myeloid-derived suppressor cells (MDSCs) are induced under infection and have the strong immunosuppressive capacity, but the correlation between MDSCs and pneumonia in kidney transplant recipients (KTRs) is unknown

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