This report focuses on the clinical and radiological characteristics of 6 patients with severe 2019 novel coronavirus (SARS-Cov-2)-infected pneumonia (NCIP). Huang et al first reported 41 patients with NCIP, in which most patients had a history of exposure to Huanan Seafood Wholesale Market. Subsequently, Wang et al reported 138 Hospitalized Patients with NCIP in Wuhan. In this report, the 6 patients were in critical condition at the time of admission, but they all improved significantly, without deterioration after treatments. As resent study reported, the most common symptoms at onset of illness were dry cough and fever.
The rapid person-to-person transmission of SARS-Cov-2 has occurred in China. The present study showed that the basic reproductive number (R0) is 2.2, which means that, on average, each patient has been spreading infection to 2.2 other people. Two of the six patients in this report had a history of exposure to Wuhan. The other four cases were infected by close contact with patients with a history of exposure to Wuhan. As a result, Guizhou province immediately initiated strict quarantine measures to prevent the spread of SARS-Cov-2.
A present study found that about half of patients infected by 2019nCoV had chronic underlying diseases, mainly cardiovascular disease and diabetes. This found is similar to MERS-CoV. Four of the six patients in our study were older than 65 years, and four patients had comorbidities. Therefore, 2019nCoV appears to infect older adults with chronic comorbidities as a result of the weaker immune functions of patients [3, 8].
The most common laboratory abnormalities observed in this study were depressed total lymphocytes and elevated CRP. The decrease of total lymphocytes may be associated with cellular immune deficiency caused by SARS-Cov-2 infection. Some studies showed that a decrease in total lymphocytes indicates that SARS-Cov-2 consumes many immune cells and inhibits the patient’s cellular immune function. We further examined changes in T cell subsets, and the results showed that T lymphocytes counts, T helper cells and T suppressor cells counts all decreased. Hence, damage to T lymphocytes may be an important factor leading to exacerbations of patients. Few studies have been reported the changes in T cells caused by SARS-Cov-2, so the mechanism for the reduction in T lymphocytes remains unknown.
In Wang’s study, CK and CK-MB levels were higher in ICU patients than that in non-ICU patients3. In our study, CK and CK-MB were not significantly increased, and only 1 patient was higher than normal when admitted to hospital, and returned to normal levels after treatments. We speculate that this may be related to the timely and standardized treatments of these patients. The urea nitrogen of ICU patients was higher than that of non-ICU patients, and patients with persistently elevated urea nitrogen have a higher mortality rate3. Although all of the six patients had increased urea nitrogen, it returned to normal level after treatment. We believe that blood purification may play a certain role.
The leukocyte count and neutrophil count increased in 4 patients, and CPR increased in 6 patients. CRP is a superior biomarker for more complex acute-phase characteristics, e.g., leukocytosis and fever. These changes may be related to cytokine storm induced by virus invasion. However, a single elevated CRP is not very informative. For this reason, CRP is not specific enough to diagnose nosocomial pneumonia. Therefore, we further examined the levels of plasma inflammatory cytokines. Our results showed that IL-6, IL-10 and TNF-α were significantly elevated. IL-6 is a pro-inflammatory cytokine and is involved in a variety of immune and inflammatory responses by enhancing T-cell differentiation through the induction of IL-2. The response time of IL-6 to infection is better than CRP. IL-10 is an anti-inflammatory cytokine, which plays a crucial role in maintaining immune homeostasis, preventing immune mediated inflammatory diseases and exuberant immune responses to pathogens[14, 15]. Therefore, the pro-inflammatory and anti-inflammatory systems of these patients coexist and co-regulate immunity.
Although the six patients were seriously ill at admission, the therapeutic effect was satisfactory after timely treatments. The recovery rate of 2 young patients was significantly faster than 4 old patients. In addition, lesions in chest CTs were absorbed more quickly in two young patients. Therefore, the patient's autoimmunity may be a key factor affecting the patient's outcome. At present, there is no specific medicine for SARS-Cov-2 infection, and the clinical effect of blood purification is not clear. In our study, we performed blood purification for all patients. The Oxygenation improved significantly in all patients and none of them experienced deterioration. Therefore, blood purification can be tried for severe and critically ill patients.