PREDICTIVE IMMUNOLOGICAL, VIROLOGICAL, AND ROUTINE LABORATORY MARKERS FOR CRITICAL COVID-19 ON ADMISSION.Immunocovid study

Gasalla, M. G.; Ferrer, J. M.; Fraile-Ribot, P. A.; Ferre-Beltran, A.; Rodriguez, A.; Martinez-Pomar, N.; Ramon-Clar, L.; Iglesias, A.; Fanjul, F.; Pou, J. A.; LLompart, I.; Losada, I.; Toledo, N.; Pons, J.; Oliver, A.; Riera, M.; Murillas, J.

Introduction: Early identification of COVID-19 patients at risk of critical illness is challenging for clinicians. Immunological, virological, and routine laboratory markers to be used in addition to clinical data are needed. Aim and methods: Blood tests to measure neutrophil/lymphocyte ratio (NLR), levels of ferritin, CRP, D-dimer, complement components (C3, C4), lymphocyte subsets, and cytokines, and SARS-Cov2 RT-PCR tests were performed in COVID-19 confirmed cases within 48 hours of admission. Cycle threshold (Ct) values were determined by RT-PCR from oral or nasopharyngeal swabs on the day of admission. Severity of symptoms was categorized as mild (grade 1), severe (grade 2), and critical (grade 3). Results: 120 patients were included. COVID-19 was mild in 49, severe in 32, and critical in 39. Ferritin >370 ng/mL (OR 16.4, 95% CI 5.3-50.8), D-dimer >440 ng/mL (OR 5.45, 95% CI 2.36-12.61), CRP >7.65 mg/dL (OR 11.54, 95% CI 4.3-30.8), NLR >3.77 (OR 13.4, 95% CI 4.3-41.1), IL-6 >142.5 pg/mL (OR 8.76, 95% CI 3.56-21.54), IL-10 >10.8 pg/mL (OR 16.45, 95% CI 5.32-50.81), sIL-2r (sCD25) >804.5 pg/mL (OR 14.06, 95% CI 4.56-43.28), IL-1Ra >88.4 pg/mL (OR 4.54, 95% CI 2.03-10.17), and IL-18 >144 pg/mL (OR 17.85, 95% CI 6.54-48.78) were associated with critical COVID-19 in the univariate age-adjusted analysis. In the multivariate age-adjusted analysis, this association was confirmed only for ferritin, CRP,NLR, IL-10, sIL-2r, and IL-18. T, B, and NK cells were significantly decreased in critical patients. SARS-CoV-2 was undetected in blood except in 3 patients with indeterminate results. Ct values determined by RT-PCR from oral/nasopharyngeal swabs on admission were not related to symptom severity. Conclusion: levels of ferritin, D-dimer, CRP, NLR, and cytokines and cytokine receptors IL-6, IL1-Ra, sCD25, IL-18, and IL-10, taken together with clinical data, can contribute to the early identification of critical COVID-19 patients.