Diagnosis of COVID-19 by serology in admitted patients with negative RT-PCR assay

Considering the increasing prevalence and burden of coronavirus disease 2019 (COVID-19) disease and false-negative results in routine reverse transcription-polymerase chain reaction (RT-PCR) tests, additional diagnostic methods are needed to diagnose active cases of this disease. This prospective study was conducted on patients, in whom clinical and radiological symptoms/signs were in favor of COVID-19 while their first PCR test was negative. Later on, a second RT-PCR was performed and serological evaluation was carried out and results were compared with each other. Out of 707 patients who had been referred to the hospital and were clinically and radiologically suspicious of disease, 137 patients with negative RT-PCR tests entered the study. RT-PCR assay became positive for the second time in 45 (32.8%). Anti-COVID-19 IgM and IgG antibodies were positive in 83 (60.6%) and 86 (62.8%) patients, respectively. Finally, it was determined that serological test was diagnostic in 73% of patients and the diagnostic yield of serology was significantly higher after the first week of illness (54.8% in the first week and 88% after that). Taking advantage of both serological tests and RT-PCR helps in diagnosing 83.9% of cases. Based on the present study, the serology may be useful as a complementary test and in parallel to RT-PCR assay for diagnosis of COVID-19 among admitted symptomatic cases.

Trisomy 21 as a risk factor for severe illness in COVID-19: Report of two cases

COVID-19 leads to mild symptoms within the majority of infected patients, but can cause severe multiple organ failure and death. There is only limited information regarding the consequences of this new emerging infection with congenital disorders. According to the previous studies, many people with Down syndrome are considered high risk for complications related to respiratory diseases. We report two trisomy 21 patients who suffered from COVID-19 and summarize the early experience with COVID-19 and Down syndrome. The course of the disease was severe in these two cases, and our concern is close monitoring of the patients with Down syndrome for early signs of COVID-19. © 2020 NRITLD, National Research Institute of Tuberculosis and Lung Disease, Iran.

A novel coronavirus disease (COVID-19): a review of host cell signaling pathways

Coronaviruses (CoVs) are the largest group of positive-sense RNA viruses. By increasing our understanding of the interactions between CoVs and the host innate immune system, we can evaluate the development and persistence of inflammation in the lungs and reduce the risk of CoV-induced lung inflammation with a new group of genetic variants. Here, we aim to discuss some recent changes in host cell factors that may be used by CoV to promote the proliferation cycle. We also discuss different host cell signaling pathways that can be considered in the host-pathogen interactions at the molecular level. The pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has created new challenges for the cultural, economic, and health infrastructures. Therefore, it is important that healthcare systems and physicians recognize a global integrated framework for monitoring the progression of COVID-19 to develop targeted therapies that can potentially save human lives.