The ongoing spread of coronavirus disease 2019 (COVID-19) constitutes an international concern on an unprecedented scale. To date, over 23 million people have been diagnosed with COVID-19 worldwide, and this disease has caused more than 800,000 deaths. Hyperinflammation elicited by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been reported to contribute to illness severity and death.1,2 Humoral immune responses play important roles in therapy and prophylaxis for SARS-CoV-2 infection. Since the receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) glycoprotein binds to angiotensin-converting enzyme 2 to trigger virion endocytosis, antibodies against this domain may be able to neutralize SARS-CoV-2 and possibly provide protective immunity in COVID-19 patients.3 Clinical trials investigating the administration of convalescent plasma and the interleukin (IL)-6 antagonist tocilizumab to treat COVID-19 patients are currently underway,4 but the overly robust expansion of antibody-secreting cells (ASCs) could play a major role in the pathogenicity of SARS-CoV-2 in COVID-19 patients.5 Thus, a detailed characterization of the associations between humoral immune responses and inflammatory factors could result in a better understanding of SARS-CoV-2-host interactions in COVID-19 patients.