A35-30 Sars-CoV-2 Spike and Nucleocapsid Proteins Persist Within Bal Fluid in Patients With New Interstitial Lung Disease and No Known Covid History

Rationale

We and others have previously described the persistence of SARS-CoV-2 spike protein and nucleocapsid protein in bronchoalveolar lavage (BAL) fluid of patients with severe COVID infection that have developed Interstitial Lung Disease (ILD) or Cryptogenic Organizing Pneumonia (COP). Given the pervasive spread of the virus, a significant portion of the population has likely been infected with COVID-19 without confirmed testing. The primary goal of this work was to determine whether SARS-CoV-2 proteins are found within the BAL fluid of newly diagnosed ILD without a previously known COVID-19 infection that may contribute to disease progression.

Methods

BAL was obtained from samples sent to the Clinical BAL Laboratory at Indiana University for evaluation. Three groups of samples were identified: patients with history of severe COVID infection with possible post-COVID lung disease, newly diagnosed ILD with no history of COVID infection, and patients without ILD. All samples were collected since the start of the COVID pandemic. Acellular BAL was assayed for SARS-CoV-2 spike and nucleocapsid protein antigens using commercially available ELISA kits (Kerafast).

Results

Analysis of SARS-CoV-2 proteins in BAL fluid by ELISA demonstrated that 50% of severe COVID patients and 66.7% of new ILD patients had spike protein above all COVID negative controls (p = 0.0076 and p = 0.0117, respectively), and 100% of severe COVID patients and 66.7% of new ILD patients had nucleocapsid protein above all COVID negative controls (p < 0.0001 and p = 0.0271, respectively). There was no significant difference in spike protein between severe COVID and new ILD patients (p = 0.3545), but severe COVID patients had significantly more nucleocapsid protein than new ILD patients (p < 0.0001). Severe COVID patients also had Genome analysis that demonstrated persistence of viral clades no longer circulating up to 401 days after known infection in severe patients.

Conclusion

Spike and nucleocapsid protein antigens persist in BAL fluid from patients with post-COVID lung disease following severe infection up to two years after acute infection, with demonstrated persistence of non-circulating virus over one year after acute infection. Many patients with newly diagnosed ILD after 2022 with no documented COVID infection history demonstrate the presence of SARS-CoV-2 proteins within collected BAL fluid significantly above COVID negative controls. We are currently exploring whether these persistent spike and nucleocapsid proteins may serve as chronic antigens, driving the development of chronic pulmonary diseases prevalent in both patients with severe infection leading to post-COVID lung disease and newly diagnosed ILD with no documented history of COVID infection.

This abstract is funded by: NIH