Laboratory profiling of patients with long COVID in the Brazilian Amazon region: A cross-sectional study.

The condition commonly referred to as long coronavirus disease (COVID) is characterized by the continuation of symptoms, sometimes accompanied by new symptoms that persist after the resolution of acute coronavirus disease 2019 (COVID-19). This observational cross-sectional study investigated 332 patients with long COVID in the Brazilian Amazon region. The study aimed to elucidate the systemic interactions associated with long COVID by compiling the findings related to hematological, coagulation, immunological, metabolic, hepatic, renal, and muscular profiles. Participants with long COVID were identified using rigorous criteria and underwent thorough laboratory examinations. The obtained data were subsequently analyzed, allowing for comparisons, associations, and correlations between findings within distinct groups in the study. Significant associations were observed between hospitalization during the acute phase and persistent laboratory abnormalities, suggesting a potential link between acute severity and long-term effects. Notably, individuals with long COVID for over a year exhibited elevated levels of monocytes, prolonged prothrombin times, reduced prothrombin activity, high levels of lactate dehydrogenase, and an increased frequency of qualitative C-reactive protein detection. This study provides valuable insights into the laboratory risk profile of patients with long COVID, particularly in the unique context of the Amazon region, where patients exhibit persistent symptoms lasting up to 1261 days.

Cytokine Profiles Associated With Acute COVID-19 and Long COVID-19 Syndrome.

The duration and severity of COVID-19 are related to age, comorbidities, and cytokine synthesis. This study evaluated the impact of these factors on patients with clinical presentations of COVID-19 in a Brazilian cohort. A total of 317 patients diagnosed with COVID-19 were included; cases were distributed according to clinical status as severe (n=91), moderate (n=56) and mild (n=170). Of these patients, 92 had acute COVID-19 at sample collection, 90 had already recovered from COVID-19 without sequelae, and 135 had sequelae (long COVID syndrome). In the acute COVID-19 group, patients with the severe form had higher IL-6 levels (p=0.0260). In the post-COVID-19 group, there was no significant difference in cytokine levels between groups with different clinical conditions. In the acute COVID-19 group, younger patients had higher levels of TNF-α, and patients without comorbidities had higher levels of TNF-α, IL-4 and IL-2 (p<0.05). In contrast, patients over age 60 with comorbidities had higher levels of IL-6. In the post-COVID-19 group, subjects with long COVID-19 had higher levels of IL-17 and IL-2 (p<0.05), and subjects without sequelae had higher levels of IL-10, IL-6 and IL- 4 (p<0.05). Our results suggest that advanced age, comorbidities and elevated serum IL-6 levels are associated with severe COVID-19 and are good markers to differentiate severe from mild cases. Furthermore, high serum levels of IL-17 and IL-2 and low levels of IL-4 and IL-10 appear to constitute a cytokine profile of long COVID-19, and these markers are potential targets for COVID-19 treatment and prevention strategies.