Hydroxychloroquine can potentially interfere with immune function in COVID-19 patients: Mechanisms and insights

The recent global pandemic due to COVID-19 is caused by a type of coronavirus, SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2). Despite rigorous efforts worldwide to control the spread and human to human transmission of this virus, incidence and death due to COVID-19 continue to rise. Several drugs have been tested for treatment of COVID-19, including hydroxychloroquine. While a number of studies have shown that hydroxychloroquine can prolong QT interval, potentially increasing risk of ventricular arrhythmias and Torsade de Pointes, its effects on immune cell function have not been extensively examined. In the current review, an overview of coronaviruses, viral entry and pathogenicity, immunity upon coronavirus infection, and current therapy options for COVID-19 are briefly discussed. Further based on preclinical studies, we provide evidences that i) hydroxychloroquine impairs autophagy, which leads to accumulation of damaged/oxidized cytoplasmic constituents and interferes with cellular homeostasis, ii) this impaired autophagy in part reduces antigen processing and presentation to immune cells and iii) inhibition of endosome-lysosome system acidification by hydroxychloroquine not only impairs the phagocytosis process, but also potentially alters pulmonary surfactant in the lungs. Therefore, it is likely that hydroxychloroquine treatment may in fact impair host immunity in response to SARS-CoV-2, especially in elderly patients or those with co-morbidities. Further, this review provides a rationale for developing and selecting antiviral drugs and includes a brief review of traditional strategies combined with new drugs to combat COVID-19.