SARS-CoV-2-reactive IFN-γ CD4 + and CD8 + T cells, clinical severity biomarkers and mortality in unvaccinated critically ill COVID-19 patients (preprint)

Objectives: We examined the relationship between peripheral blood levels of SARS-CoV-2 S1/M-reactive IFN-γ-producing CD4+ and CD8+ T cells, serum levels of biomarkers of clinical severity and mortality in critically ill COVID-19 patients.  Methods: Immune responses were monitored in 71 non-consecutive patients (49 male and 22 female; median age, 65 years) by whole-blood flow cytometry (326 specimens). SARS-CoV-2 RNA loads in paired tracheal aspirates [TA] (n=147) were available from 54 patients. Serum levels of interleukin-6, ferritin, D-Dimer, lactose dehydrogenase and C-reactive protein in paired sera were known. Results: SARS-CoV-2 T cells (either CD4+, CD8+ or both) were detectable in 70 patients. SARS-CoV-2 IFN-γ CD4+ T-cell responses were documented more frequently than their CD8+ counterparts (62 vs. 56 patients) and were of greater magnitude overall. Detectable SARS-CoV-2 S1/M-reactive CD8+ and CD4+ T-cell responses were associated with higher SARS-CoV-2 RNA loads in TA. SARS-CoV-2 RNA load in TA decreased over time, irrespective of the dynamics of SARS-CoV-2-reactive CD8+ and CD4+ T cells. Conclusion: Enumeration of peripheral blood levels of SARS-CoV-2-S1/M-reactive IFN-γ CD4+ and CD8+ T cells does not predict viral clearance from the lower respiratory tract or poor clinical outcomes in critically ill COVID-19 patients.

ICU-Acquired Pneumonia is a Risk Factor of a Poor Health Post-Covid-19 Syndrome (preprint)

Background: . Some patients who had previously presented with COVID-19 have been reported to develop persistent COVID-19 symptoms. Whilst this information has been adequately recognised and extensively published with respect to non-critically ill patients, less is known about the prevalence and risk factors and characteristics of persistent COVID_19 . On other hand these patients have very often intensive care unit-acquired pneumonia (ICUAP). A second infectious hit after COVID increases the length of ICU stay and mechanical ventilation and could have an influence in the poor health post-Covid 19 syndrome in ICU discharged patients Methods: This prospective, multicentre and observational study was done across 40 selected ICUs in Spain. Consecutive patients with COVID-19 requiring ICU admission were recruited and evaluated three months after hospital discharge. Results: A total of 1,255 ICU patients were scheduled to be followed up at 3 months; however, the final cohort comprised 991 (78.9%) patients. A total of 315 patients developed ICUAP (97% of them had ventilated ICUAP) Patients requiring invasive mechanical ventilation had persistent, post-COVID-19 symptoms than those who did not require mechanical ventilation. Female sex, duration of ICU stay, and development of ICUAP were independent risk factors for persistent poor health post-COVID-19. Conclusions: : Persistent, post-COVID-19 symptoms occurred in more than two-thirds of patients. Female sex, duration of ICU stay and the onset of ICUAP comprised all independent risk factors for persistent poor health post-COVID-19. Prevention of ICUAP could have beneficial effects in poor health post-Covid 19