ABSTRACT
It is unclear whether prior endemic coronavirus infections affect COVID-19 severity. Here, we show that in cases of fatal COVID-19, antibody responses to the SARS-COV-2 spike are directed against epitopes shared with endemic beta-coronaviruses in the S2 subunit of the SARS-CoV-2 spike protein. This immune response is associated with the compromised production of a de novo SARS-CoV-2 spike response among individuals with fatal COVID-19 outcomes.
ABSTRACT
A major issue in identification of protective T cell responses against SARS-CoV-2 lies in distinguishing people infected with SARS-CoV-2 from those with cross-reactive immunity generated by exposure to other coronaviruses. We characterised SARS-CoV-2 T cell immune responses in 168 PCR-confirmed SARS-CoV-2 infected subjects and 118 seronegative subjects without known SARS-CoV-2 exposure using a range of T cell assays that differentially capture immune cell function. Strong ex vivo ELISpot and proliferation responses to multiple antigens (including M, NP and ORF3) were found in those who had been infected by SARS-CoV-2 but were rare in pre-pandemic and unexposed seronegative subjects. However, seronegative doctors with high occupational exposure and recent COVID-19 compatible illness showed patterns of T cell responses characteristic of infection, indicating that these readouts are highly sensitive. By contrast, over 90% of convalescent or unexposed people showed proliferation and cellular lactate responses to spike subunits S1/S2, indicating pre-existing cross-reactive T cell populations. The detection of T cell responses to SARS-CoV-2 is therefore critically dependent on the choice of assay and antigen. Memory responses to specific non-spike proteins provides a method to distinguish recent infection from pre-existing immunity in exposed populations.
ABSTRACT
<p><b>INTRODUCTION</b>Anorexia nervosa (AN) and eating disorders not otherwise specified (EDNOS) are on the rise in Singapore. Abnormal liver function tests have been reported for up to 12.2% of patients with AN. These patients are also known to present with comorbid psychiatric disorders. This study aims to investigate the correlation between body mass index (BMI) and the severity of abnormal liver function tests, and between BMI and the presence of comorbid psychiatric disorders.</p><p><b>METHODS</b>A retrospective cohort analysis of 373 patients diagnosed with AN or EDNOS at a tertiary hospital was performed. The clinical course of transaminitis and comorbid psychiatric disorders was correlated with the patient's BMI.</p><p><b>RESULTS</b>Patients with a BMI of ≥ 16.6 kg/m(2) at their first consult had a significantly lower risk of having comorbid psychiatric disorders (χ(2) = 32.08, p < 0.001). These patients were five times less likely to have comorbid psychiatric disorders as compared to patients from the other BMI groups (odds ratio [OR] 0.21). On the other hand, patients with a BMI of < 14.6 kg/m(2) had a significantly higher risk of having transaminitis (χ(2) = 72.5, p < 0.001). They were 11.1 times more likely to develop transaminitis as compared to patients with a BMI of ≥ 14.6 kg/m(2) (OR 11.05).</p><p><b>CONCLUSION</b>Severity of BMI can be used by clinicians as an indicator to assess for secondary psychiatric comorbidities and/or transaminitis during the first consultation. This could help reduce the morbidity and mortality rates in patients with AN or EDNOS.</p>