Longitudinal clinical and radiographic evaluation reveals interleukin-6 as an indicator of persistent pulmonary injury in COVID-19

Authors：Liao, Baolin; Liu, Zhipeng; Tang, Libo; Li, Linghua; Gan, Qingxin; Shi, Haiyan; Jiao, Qian; Guan, Yujuan; Xie, Min; He, Xi; Zhao, Han; Chen, Weilie; Liu, Yanxia; Li, Liya; Wang, Yaping; Cao, Yi; Shi, Yaling^*; Li, Yongyin^*; Lei, Chunliang^*

Source：International Journal of Medical Sciences, 2021, 18(1): 29-41.

DOI：10.7150/ijms.49728

• COVID-19
• interleukin-6
• pulmonary injury
• chest CT
• sequential monitoring

Rationale: Previous studies of coronavirus disease 2019 (COVID-19) were mainly focused on cross-sectional analysis. In this study, we sought to evaluate the dynamic changes of immunological and radiographic features, and the association with the outcome of pulmonary lesions in COVID-19 patients. @@@ Methods: Peripheral blood samples and radiographic data were collected longitudinally for up to 8 weeks from 158 laboratory-confirmed COVID-19 patients. The chest computed tomography (CT) scans were scored based on a semi-quantification assessment according to the extent of pulmonary abnormalities; the temporal change of the immunological and radiographic features was analyzed. @@@ Results: Compared with mild and moderate patients, severe patients had significantly decreased counts of lymphocytes, CD4+ T cells, CD8+ T cells, and CD19+ B cells but dramatically elevated counts of neutrophils and levels of interleukin (IL)-6. Sequential monitoring showed a sustained increase in lymphocytes counts and significantly decreased levels of IL-6 in severe patients during the disease course. Notably, patients with persistent pulmonary lesions (CT score 5 in week 8) showed high levels of IL-6 during the follow-up period, compared with those with recovery lesions (CT score < 5 in week 8). More importantly, the peak expression of IL-6 prior to the aggravated lung injury was mainly found in patients with persistent lesions, and multivariate analysis showed that IL-6 level upon admission was an independent factor associated with the persistent pulmonary injury. @@@ Conclusion: Prolonged elevation of IL-6 is associated with persistent pulmonary lesions in COVID-19 patients. Sequential monitoring and timely intervention of IL-6 may favor the clinical management of COVID-19.

• Institution
  南方医科大学; 广州医学院