Cell destruction results in plasma accumulation of cell-free DNA (cfDNA). Dynamic changes in circulating lymphocytes are features of COVID-19. We aimed to investigate if cfDNA level can serve in stratification of COVID-19 patients, and if cfDNA level is associated with alterations in lymphocyte subsets and neutrophil-to-lymphocyte ratio (NLR). This cross-sectional comparative study enrolled 64 SARS-CoV-2-positive patients. Patients were subdivided to severe and non-severe groups. Plasma cfDNA concentration was determined by real-time quantitative PCR. Lymphocyte subsets were assessed by flow cytometry. There was significant increase in cfDNA among severe cases when compared with non-severe cases. cfDNA showed positive correlation with NLR and inverse correlation with T cell percentage. cfDNA positively correlated with ferritin and C-reactive protein. The output data of performed ROC curves to differentiate severe from non-severe cases revealed that cfDNA at cut-off ≥17.31 ng/µl and AUC of 0.96 yielded (93%) sensitivity and (73%) specificity. In summary, excessive release of cfDNA can serve as sensitive COVID-19 severity predictor. There is an association between cfDNA up-regulation and NLR up-regulation and T cell percentage down-regulation. cfDNA level can be used in stratification and personalized monitoring strategies in COVID-19 patients.

Background:The clinical spectrum of COVID-19 is extremely variable. Thus, it is likely that the heterogeneity in the genetic make-up of the host may contribute to disease severity. Toll-like receptor (TLR)-4 plays a vital role in the innate immune response to SARS-CoV-2 infection. The susceptibility of humans to severe COVID-19 concerning TLR-4 single nucleotide polymorphisms (SNPs) has not been well examined. Objective: The goal of this research was to investigate the association between TLR-4 (Asp299Gly and Thr399Ile) SNPs and COVID-19 severity and progression as well as the cytokine storm in Egyptian patients. Methods: We genotyped 300 adult COVID-19 Egyptian patients for TLR-4 (Asp299Gly and Thr399Ile) SNPs using PCR-restriction fragment length polymorphism (PCR-RFLP). We also measured interleukin (IL)-6 levels by enzyme-linked immunosorbent assay (ELISA) as an indicator of the cytokine storm. Results: The minor 299Gly (G) and 399Ile (T) alleles were associated with a significant (P < 0.001) positive risk of severe COVID-19 (OR = 3.14; 95% CI = 2.02-4.88 and OR = 2.75; 95% CI = 1.66-4.57), their frequency in the severe group were 71.8% (84/150) and 70.7% (58/150), respectively. We detected significant differences between TLR-4 (Asp299Gly, Thr399Ile) genotypes with regard to serum levels of IL-6. Levels of IL-6 increased significantly with the presence of the mutant 299Gly (G) and 399Ile (T) alleles to reach the highest levels in the Gly299Gly (GG) and the Ile399Ile (TT) genotypes (170 pg/mL (145-208.25) and 112 pg/mL (24-284.75), respectively). Conclusion:The TLR-4 (Asp299Gly and Thr399Ile) minor alleles 299Gly (G) and 399Ile (T) are associated with COVID-19 severity, mortality, and the cytokine storm.

Background Anemia can negatively affect the outcome of many diseases, including infections and inflammatory conditions. Aim To compare the prognostic value of hemoglobin level and the neutrophil/lymphocyte ratio (NLR) for prediction of coronavirus disease 2019 (COVID-19) severity. Methods In this retrospective cohort study, clinical data from patients with laboratory-confirmed COVID-19 were collected from hospital records from 10 April 2020 to 30 July 2020. Results The proportions of patients with mild, moderate, and severe COVID-19 differed significantly in association with hemoglobin levels, neutrophil counts, lymphocyte counts, NLR, and total leukocyte counts. Patients with severe COVID-19 had significantly lower hemoglobin levels than those with moderate or mild COVID-19. There were statistically significant negative associations between hemoglobin and D-dimer, age, and creatinine. The optimal hemoglobin cut-off value for prediction of disease severity was 11.6 g/dL. Using this cut-off value, hemoglobin had higher negative predictive value and sensitivity than NLR (92.4% and 51.3%, respectively). The specificity of hemoglobin as a prognostic marker was 79.3%. Conclusion Both NLR and hemoglobin level are of prognostic value for predicting severity of COVID-19. However, hemoglobin level displayed higher sensitivity than NLR. Hemoglobin level should be assessed upon admission in all patients and closely monitored throughout the disease course.

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Objectives: Dysregulation of the immune response appears to play a significant role in recurrent aphthous stomatitis (RAS) development. The main objective of this case–control study is to investigate the blood levels of mannose-binding lectin (MBL) and the frequency of the MBL2 gene (gly54asp) polymorphism in RAS patients, including 40 RAS patients and 40 healthy controls. Methods: Serum MBL levels were determined by ELISA, while the PCR-restriction fragment length polymorphism was used in MBL2 genotyping. Results: The median serum MBL level was significantly lower in the RAS group than in the control group (975 ng/mL (545–1320) vs. 1760 ng/mL (1254–2134); p≤ 0.001). The MBL levels were significantly lower in the BB genotype, whereas they were significantly higher in the wild type AA with a median of 525 and 1340 ng/mL, respectively ( p =0.005). The B allele was expressed in significantly higher percentages of RAS patients than in controls. There was no significant association between MBL serum levels ( p=0.685) or MBL2 codon 54 genotypes ( p=0.382) with the type of ulcers. Conclusion: There was an association between low MBL serum levels and the variant allele B of the MBL2 (gly54asp) gene, and the susceptibility to RAS. As a result, potential novel therapeutic options for RAS patients with MBL deficiency should be investigated.