Clinical characteristics of platelet-mediated killing circulating parasite of major human malaria

AbstractObjective Microscopy was used to characterize platelet-Plasmodium-infected erythrocyte interactions in patients infected with Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale or Plasmodium malariae, and to investigate the relationship between platelet-associated parasite killing and parasite clearance.Methods Data from 244 malaria patients admitted to the Fourth People’s Hospital of Nanning between 1 January 2011 and 30 September 2022, and 45 healthy controls, were collected prospectively and assessed retrospectively. Characteristics of platelet–erythrocyte interactions were visualized by microscopy, and blood cell count and clinical profiles of these participants were obtained from the electronic medical records. ANOVA, contingency tables and Cox proportional hazards regression models were used to do statistical analysis on the subgroups.Results Platelet enlargement and minor pseudopodia development were observed. Platelets were found directly attaching to parasitized erythrocytes by all Plasmodium species studied, especially mature stages, and lysis of parasitized erythrocytes was connected to platelet-mediated cytolysis. Platelet counts were correlated inversely with parasitaemia and duration of parasite clearance. Artemisinin combination therapy was more effective than artemisinin alone in clearing Plasmodium in patients with thrombocytopenia.Conclusions Platelet-parasitized erythrocytes cell-to-cell contacts initiated platelet-associated parasite killing and helped to limit Plasmodium infection in cases of human malaria. The weakening platelet-associated parasite killing effects could be counteracted by artemisinin combination therapy in patients with thrombocytopenia

Clinical utilization of multiple antibodies of Mycobacterium tuberculosis for serodiagnosis evaluation of tuberculosis: a retrospective observational cohort study

AbstractObjectives We aimed to investigate clinical uncertainties by characterizing the accuracy and utility of commercially available antibodies of Mycobacterium tuberculosis in the diagnostic assessment of suspected tuberculosis in high-burden countries.Methods We conducted a retrospective, descriptive, cohort study among participants aged ≥ 18 years with suspected tuberculosis in Nanning, Guangxi, and China. Participants were tested for M. tuberculosis infection using commercially available antibodies against Mycobacterum tuberculosis. Specificity, sensitivity, negative and positive predictive values, and negative and positive likelihood ratios of the tests were determined. Sputum specimens and bronchoalveolar lavage fluid were sent for mycobacterial culture, Xpert MTB/RIF assay, and cell-free M. tuberculosis DNA or RNA assay. Blood samples were used for IGRAs, T-cell counts (CD3 + CD4+ and CD3 + CD8+), and antibodies to tuberculosis test.Results Of the 1857 participants enrolled in this study, 1772 were included in the analyses, among which, 1311 were diagnosed with active tuberculosis. The specificity of antibody against 16kD for active tuberculosis was 92.7% (95% confidence interval [CI]: 89.3–95.4) with a positive likelihood ratio for active tuberculosis cases of 3.1 (95% CI: 2.1–4.7), which was higher than that of antibody to Rv1636 (90.5% [95% CI: 86.6–93.5]), antibody to 38kD (89.5% [95% CI: 85.5–92.7]), antibody against CFP-10 (82.6% [95% CI: 77.9–86.7]), and antibody against LAM (79.3% [95% CI: 74.3–83.7]). Sensitivity ranged from 15.8% (95% CI: 13.9–17.9) for antibody against Rv1636 to 32.9% (95% CI: 30.4–35.6) for antibody to LAM.Conclusions Commercially available antibodies against to Mycobacterium tuberculosis do not have sufficient sensitivity for the diagnostic evaluation of active tuberculosis. However, antibody against Rv1636 and 16kD may have sufficiently high specificities, high positive likelihood ratios, and correspondingly high positive predictive values to facilitate the rule-in of active tuberculosis

Genomic epidemiology reveals early transmission of SARS-CoV-2 and mutational dynamics in Nanning, China

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants are a fatal pathogen resulting in substantial morbidity and mortality, and posing a great threat to human health with epidemics and pandemics. Methods: Next-generation sequencing (NGS) was performed to investigate the SARS-CoV-2 genomic characterization. Phylogenetic analysis of SARS-CoV-2 genomes was used to probe the evolutionary. Homology protein structure modelling was done to explore potential effect of the mutations. Results: The eighty genome sequences of SARS-CoV-2 obtained from the thirty-nine patients with COVID-19. A novel variant with mutation H625R concomitant with S50L in spike glycoprotein had been identified. Phylogenetic analysis revealed that SARS-CoV-2 variants belong to several distinct lineages. Homology modelling indicated that variant with mutation H625R and S50L increases flexibility of S1 subunit. Conclusions: SARS-CoV-2 genomes are constantly evolving by accumulation of point mutations. The amino acid H625R in combination with S50L may have a significant impact on the interaction between spike glycoprotein and ACE2