In our previous study, we introduced the platelet endothelial cell adhesion molecule 1 (PECAM-1)/thrombus ratio, which is a parameter indicating the proportion of PECAM-1 in laser-induced thrombi in mice. Because PECAM-1 is an antithrombotic molecule, the higher the PECAM-1/thrombus ratio, the less activated the platelets. In this study, we used an extracorporeal model of thrombosis (flow chamber model) to verify its usefulness in the assessment of the PECAM-1/thrombus ratio in animal and human studies. Using the lipopolysaccharide (LPS)-induced inflammation model, we also evaluated whether the PECAM-1/thrombus ratio determined in the flow chamber (without endothelium) differed from that calculated in laser-induced thrombosis (with endothelium). We observed that acetylsalicylic acid (ASA) decreased the area of the thrombus while increasing the PECAM-1/thrombus ratio in healthy mice and humans in a dose-dependent manner. In LPS-treated mice, the PECAM-1/thrombus ratio decreased as the dose of ASA increased in both thrombosis models, but the direction of change in the thrombus area was inconsistent. Our study demonstrates that the PECAM-1/thrombus ratio can more accurately describe the platelet activation status than commonly used parameters such as the thrombus area, and, hence, it can be used in both human and animal studies.

Background: The host factors influencing the susceptibility to and the severity of tick-borne encephalitis (TBE) are poorly defined. The loss-of-function Δ32 mutation in the chemokine receptor gene CCR5 was identified as a risk factor for West Nile encephalitis and possibly for TBE, suggesting a protective role of CCR5 in Flavivirus encephalitis. Methods: We studied the CCR5 genotype in 205 TBE patients stratified by a clinical presentation and 257 controls from the same endemic area (Podlasie, Poland). The genotype distribution between the groups and differences between TBE patients with different genotypes were analyzed. Results: There were 36 (17.6%) CCR5Δ32 heterozygotes and 3 (1.5%) homozygotes in the TBE group, with no statistically significant difference in comparison with the controls. The CCR5Δ32 allele did not associate with the clinical presentation or the severity of TBE. The cerebrospinal fluid (CSF) inflammatory parameters did not differ between the wild-type (wt/wt) and wt/Δ32 genotype patients. The TBE clinical presentation and CSF parameters in three Δ32/Δ32 homozygotes were unremarkable. Conclusions: The lack of association of CCR5Δ32 with the risk and clinical presentation of TBE challenges the suspected CCR5 protective role. CCR5 is not indispensable for the effective immune response against the TBE virus.

Autohemotherapy with ozonated blood is used in the treatment of a broad spectrum of clinical disorders. Ozone demonstrates strong oxidizing properties and causes damage to cell membranes. The impact of whole-blood ozonation on the release of microparticles from blood and endothelial cells and the concentration of selected markers in the hemostatic system (APTT, PT, D-dimer, fibrinogen) were investigated. Venous blood, obtained from 19 healthy men, was split into four equal parts and treated with air, 15 µg/mL ozone, or 30 µg/mL ozone, or left untreated. The number and types of microparticles released were determined using flow cytometry on the basis of surface antigen expression: erythrocyte-derived microparticles (CD235⁺), platelet-derived microparticles (CD42⁺), leukocyte-derived microparticles (CD45⁺), and endothelial-derived microparticles (CD144⁺). The study is the first to demonstrate that ozone induces a statistically significant increase in the number of microparticles derived from blood and endothelial cells. Although statistically significant, the changes in some coagulation factors were somewhat mild and did not exceed normal values.

Neutrophils are the most numerous population of peripheral blood leukocytes and play a key role in innate immunity, participating in antibacterial, antifungal, antiviral, and antitumor responses. Their activity can be modulated by endogenous and exogenous factors, including pesticides, among which fungicides such as the commonly used imazalil (IMZ) constitute a significant group. The objective of this study was to assess the effect of IMZ (at an environmental dose of 0.07 ng/mL, as well as 10- and 100-fold higher doses) on selected functions of neutrophils. This study demonstrated that neutrophils incubated with IMZ at a dose detectable in the serum, exhibited lower phagocytotic capacity. In addition, at a 10-fold higher dose, this compound reduced the chemotactic capacity of neutrophils and led to increased activity of NADPH oxidase in these cells. Furthermore, it was observed that at the highest concentration used in this study IMZ intensified the production of nitric oxide. The exposure of neutrophils—the first line of defense—to IMZ affected their locomotion and pathogen-eliminating function. Moreover, the response of neutrophils was not proportionate to the concentration of IMZ used in the study.

Objectives: The present study evaluated the association between plasma concentrations of selected endocrine-disrupting chemicals (EDCs)—bisphenol A (BPA), methylparaben (MeP), propylparaben (PrP), 4-nonylphenol (4-NP), 4-octylphenol (4-OP), bis(2-ethylhexyl) phthalate (DEHP), and imazalil (IMZ)—and prior coronavirus disease 2019 (COVID-19) status. Methods: Plasma EDC levels were quantified via gas chromatography–mass spectrometry in 262 voluntary blood donors (121 convalescents and 141 controls) at the Regional Centre for Transfusion Medicine in Bialystok, Poland. Results: The cohort exhibited widespread environmental exposure to all selected EDCs (BPA: 1.14 ng/mL, MeP: 1.20 ng/mL, PrP: 1.38 ng/mL, 4-NP: 1.90 ng/mL, 4-OP: 0.57 ng/mL, DEHP: 49.68 ng/mL, IMZ: 20.06 ng/mL). Convalescents had significantly higher concentrations of MeP, PrP, 4-OP, and 4-NP. Logistic regression revealed that MeP, PrP, and 4-NP were significantly associated with prior COVID-19 status, increasing infection odds by 80%, 70%, and 63%, respectively. While 4-OP was strongly associated with prior COVID-19 status (odds ratio > 300 per unit change and 1.79 per 0.1 unit change), the wide confidence interval for the unit change estimate requires cautious interpretation. Conclusions: These findings suggest a strong link between selected paraben and alkylphenol exposure and prior COVID-19 status in blood donors. Additionally, the high IMZ levels highlight the need for urgent evaluation of its safety and environmental prevalence.

Background: The aim of the study was to investigate whether red blood cell antigens (A, B, D, C^w, C, c, E, e, K, k, Jk^a, Jk^b, Fy^a, Fy^b, Le^a, Le^b, M, N, S, s, and P1) from clinically relevant blood group systems were associated with susceptibility to COVID-19. Methods: This exploratory case-control study was carried out on a group of 263 donors from the Regional Center for Transfusion Medicine, Bialystok, Poland (including 121 convalescents and 142 healthy subjects). The microplate method was applied to examine the expression of 21 antigens from eight clinically relevant systems in the donors’ red blood cells. Results: No significant correlation was found between any single blood group and susceptibility to COVID-19. For a more detailed analysis, we adopted an approach involving 3-, 4- and 5-element mutual combinations of antigens. In this exploratory analysis of multi-antigen combinations, nominal statistical significance was found for a number of associations, but none remained statistically significant after adjustment for multiple testing. In the case of three-antigen associations, the strongest association was observed for cc combined with Ee and kk, with the effect size showing approximately 4× higher odds of COVID-19 (OR = 4.49, p = 0.020); in the case of four-antigen combinations, the strongest association was found for RhD(+) combined with kk, Fy^b and P1(−), as well as RhD(+) combined with cc, Ee and kk, also indicating 4× higher odds of COVID-19 (OR = 4.49 p = 0.016). For five-antigen combinations, the strongest association was observed for blood type O combined with kk, Le^b, P1(+) and MM, with the association strength reaching an OR = 4.44, p = 0.025. Conclusions: The findings suggest that analyses based solely on single blood group antigens may have limited value for assessing the susceptibility to COVID-19. In contrast, combinations of red blood cell antigens may provide more reliable correlations with the susceptibility to COVID-19. However, these findings should be interpreted with caution and require confirmation on larger and more representative populations.