The association of decreased HLA-G+ immune cell frequencies with critical COVID-19 patients.

INTRODUCTION: COVID-19 (coronavirus disease-2019) is an infectious disease caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). Immune dysregulation causes inflammation and massive production of inflammatory mediators that worsen the patients' status. Here, regulatory immune cells may ameliorate inflammation and improve the severity of the disease. MATERIALS AND METHODS: A total of 76 participants were enrolled in this study and divided into 3 groups as follows: patients with moderate/severe COVID-19 (n = 25), patients with critical COVID-19 (n = 26), and healthy controls (n = 25). After blood collection, peripheral blood mononuclear cells (PBMCs) were isolated and stained by FITC-conjugated anti-CD4 monoclonal antibodies (mABs), PE-conjugated anti-HLA-G mABs, PerCPCy5.5-conjugated anti-CD14 mABs, and APC-conjugated anti-CD8 mABs. RESULTS: Critical COVID-19 patients had a significantly lower frequency of CD4+ HLA-G+ T lymphocytes compared with moderate/severe COVID-19 patients (p value < 0.001; SMD, -1.27; 95% CI [-1.86, -0.66]) and healthy controls (p value < 0.05; SMD, -0.69; 95% CI [-1.25, -0.12]). Critical COVID-19 patients had a significantly lower frequency of CD14+ HLA-G+ monocytes compared with moderate/severe COVID-19 patients (p value < 0.001; SMD, -2.09; 95% CI [-2.77, -1.41]) and healthy controls (p value < 0.05; SMD, -0.83; 95% CI [-1.40, -0.25]). However, there was no difference between the groups regarding the frequency of CD8+ HLA-G+ T lymphocytes. CONCLUSION: The increased amount of immunomodulatory HLA-G+ cells may reduce the severity of the disease in moderate/severe COVID-19 patients compared with critical COVID-19 patients.

The association between vitamin D and acute rejection in human kidney transplantation: A systematic review and meta-analysis study.

BACKGROUND: Vitamin D (VitD) deficiency is associated with several diseases such as multiple sclerosis, rheumatoid arthritis, respiratory infection, and so forth. In the field of transplantation (kidney transplantation), some studies reported that patients with VitD deficiency are of increased chance of acute rejection, but other studies did not show such a chance. On the other hand, since VitD is a modulatory factor and can reduce the inflammatory response, understanding the exact role of it in transplantation may contribute to tolerance condition in these patients. METHODS: The electronic databases, including PubMed, Scopus, Embase, ProQuest, Web of Science, and Google Scholar, were searched for eligible studies. In general, 14 studies with a total of 4770 patients were included in this meta-analysis. Regarding the methodological heterogeneity, we selected a random-effects combination model. Moreover, OR was chosen as an effect size for this study. RESULTS: After the combination of 14 studies, we showed that patients in the VitD-deficient group had an 82% increased chance of acute rejection compared with patients in the VitD-sufficient group, and this effect was significant (OR 1.82; 95% confidence interval [CI] [1.29, 2.56]; I2 = 52.3%). This result was significant, and, regarding the narrow CI, it can be a conclusive result. Study quality and gender variables were the main sources of inconsistent results in the primary studies. Moreover, using meta-regression, we showed that VitD deficiency (independent from the estimated glomerular filtration rate (eGFR) of patients) increased the chance of acute rejection. CONCLUSION: The normal VitD status of patients a few days before and after transplantation can reduce the chance of acute rejection.