Platelet parameters and leukocyte morphology is altered in COVID-19 patients compared to non-COVID-19 patients with similar symptomatology.

In this nested case-control study, we evaluated haematological and morphological parameters of hospitalised patients with real-time polymerase chain reaction verified COVID-19 infection compared to patients with similar symptomatology but without COVID-19 infection. Seventy-four COVID-19 positive and 228 COVID-19 negative patients were evaluated with routine haematological parameters. Severe disease was defined as death and/or need of intensive care treatment. Twenty-seven COVID-19 positive and 18 COVID-19 negative patients were furthermore included for morphological evaluation using smear examination. Significant differences were found for platelet indices and white blood cell parameters. Thus, platelet count and plateletcrit was lower in COVID-19 patients, whilst mean platelet volume, platelet distribution width, and platelet large cell ratio was significantly higher than in non-COVID-19 patients. Leukocyte, neutrophil, immature granulocyte, lymphocyte, monocyte, eosinophil, and basophil count was lower in COVID-19 patients. No significant differences were found for red blood cell count, haemoglobin, haematocrit or mean corpuscular haemoglobin for COVID-19 versus non-COVID-19 patients. COVID-19 patients with a severe disease course had higher levels of immature granulocytes, but lower lymphocyte and platelet counts compared to patients with non-severe COVID-19. In terms of morphology, 14.8% of COVID-19 patients had a normal smear examination, compared to 83.3% of non-COVID-19 patients. Hypogranulated neutrophils were more frequent in COVID-19 patients (p < .001), but non-COVID-19 patients had higher levels of reactive lymphocytes, compared to COVID-19 patients. In conclusion, several haematological morphological abnormalities are more frequent in patients with COVID-19 disease, and several findings indicate that platelets play a fundamental role in the pathophysiology of the disease.

Severity of COVID-19 at elevated exposure to perfluorinated alkylates.

BACKGROUND: The course of coronavirus disease 2019 (COVID-19) seems to be aggravated by air pollution, and some industrial chemicals, such as the perfluorinated alkylate substances (PFASs), are immunotoxic and may contribute to an association with disease severity. METHODS: From Danish biobanks, we obtained plasma samples from 323 subjects aged 30-70 years with known SARS-CoV-2 infection. The PFAS concentrations measured at the background exposures included five PFASs known to be immunotoxic. Register data was obtained to classify disease status, other health information, and demographic variables. We used ordered logistic regression analyses to determine associations between PFAS concentrations and disease outcome. RESULTS: Plasma-PFAS concentrations were higher in males, in subjects with Western European background, and tended to increase with age, but were not associated with the presence of chronic disease. Of the study population, 108 (33%) had not been hospitalized, and of those hospitalized, 53 (16%) had been in intensive care or were deceased. Among the five PFASs considered, perfluorobutanoic acid (PFBA) showed an unadjusted odds ratio (OR) of 2.19 (95% confidence interval, CI, 1.39-3.46) for increasing severities of the disease. Among those hospitalized, the fully adjusted OR for getting into intensive care or expiring was 5.18 (1.29, 20.72) when based on plasma samples obtained at the time of diagnosis or up to one week before. CONCLUSIONS: Measures of individual exposures to immunotoxic PFASs included short-chain PFBA known to accumulate in the lungs. Elevated plasma-PFBA concentrations were associated with an increased risk of a more severe course of COVID-19. Given the low background exposure levels in this study, the role of exposure to PFASs in COVID-19 needs to be ascertained in populations with elevated exposures.