CCL13 and COVID-19: Moreover, exposure to traumatic situations leads to changes in inflammatory markers associated with PTSD, including elevations in the CRP and the chemokines CCL13, CCL20, and CXCL6, and lowered levels of TNF-α and interferon-gamma.32 In this review, the PHOSP-COVID Collaborative Group found that 10% of the individuals discharged from the hospital due to COVID-19 presented PTSD diagnoses after 1 year.24