Background. Early identification of COVID-19 patients at risk of critical illness is a challenging endeavor for clinicians. We aimed to establish immunological, virological, and routine laboratory markers, which, in combination with clinical information, may allow identifying such patients. Methods. Blood tests to measure neutrophil/lymphocyte ratio (NLR) and levels of ferritin, CRP, D-dimer, complement components (C3 and C4), cytokines, and lymphocyte subsets, as well as SARS-Cov-2 RT-PCR tests, were performed in COVID-19-confirmed cases within 48 hours of admission. RT-PCR cycle threshold (Ct) values from oropharyngeal or nasopharyngeal swabs were determined on the day of admission. Symptom severity was categorized as mild (grade 1), severe (grade 2), or critical (grade 3). Results. Of 120 patients who were included, 49 had mild, 32 severe, and 39 critical COVID-19. Levels of 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-2rα (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. This association was confirmed in the multivariate age-adjusted analysis only for ferritin, CRP, NLR, IL-10, sIL-2rα, and IL-18. T, B, and NK cells were significantly decreased in critical patients. SARS-CoV-2 was not detected in blood except in 3 patients who had indeterminate results. RT-PCR Ct values from oropharyngeal or nasopharyngeal swabs on admission were not related to symptom severity. Conclusion. Ferritin, D-dimer, CRP, NLR, cytokine (IL-18 and IL-10), and cytokine receptor (IL-6, IL1-Ra, and sCD25) test results combined with clinical data can contribute to the early identification of critical COVID-19 patients.

中文翻译：

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入院时危重 COVID-19 的预测免疫学、病毒学和常规实验室标记


背景。对临床医生来说，早期识别有危重症风险的 COVID-19 患者是一项具有挑战性的工作。我们的目标是建立免疫学、病毒学和常规实验室标志物，结合临床信息，可以识别此类患者。方法。进行了血液检测，以测量中性粒细胞/淋巴细胞比率 (NLR) 和铁蛋白、CRP、D-二聚体、补体成分（C3 和 C4）、细胞因子和淋巴细胞亚群的水平，以及 SARS-Cov-2 RT-PCR 检测。在 COVID-19 确诊病例入院 48 小时内进行。入院当天确定口咽或鼻咽拭子的 RT-PCR 循环阈值 (Ct)。症状严重程度分为轻度（1 级）、重度（2 级）或严重（3 级）。结果。在纳入的 120 名患者中，49 名患者患有轻度、32 名重症和 39 名重症 COVID-19。铁蛋白水平 >370 ng/mL（OR 16.4，95% CI 5.3–50.8），D-二聚体 >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（或 16.45，95% CI 5.32–50.81），sIL-2r α (sCD25) >804.5 pg/mL（或 14.06，95% CI 4.56–43.28），IL-1Ra >88.4 pg/mL（或 4.54，95）在单变量年龄调整分析中，% CI 2.03–10.17）和 IL-18 >144 pg/mL（OR 17.85，95% CI 6.54–48.78）与危重 COVID-19 相关。这种关联仅在铁蛋白、CRP、NLR、IL-10、sIL-2r α和 IL-18 的多变量年龄调整分析中得到证实。危重患者的T、B和NK细胞显着减少。除了 3 名结果不确定的患者外，血液中未检测到 SARS-CoV-2。 入院时口咽或鼻咽拭子的 RT-PCR Ct 值与症状严重程度无关。结论。铁蛋白、D-二聚体、CRP、NLR、细胞因子（IL-18 和 IL-10）和细胞因子受体（IL-6、IL1-Ra 和 sCD25）检测结果与临床数据相结合，有助于早期识别关键疾病COVID-19 患者。