Severe Coronavirus Disease 2019 That Recovered from Respiratory Failure by Treatment That Included High-dose Intravenous Immunoglobulin.

We herein report a case of severe coronavirus disease 2019 (COVID-19) in which high-dose intravenous immunoglobulin (IVIg) treatment achieved significant clinical improvement of deterioration of pulmonary inflammation after temporary clinical improvement. In the present case, clinical and radiological deterioration occurred despite a decrease in viral load, suggesting that deterioration was caused by reactivation of proinflammatory factors, such as tumor necrosis factor-α and interleukin-6, rather than direct viral effects. IVIg treatment may provide not only immunosuppressive effects but also inhibition of proinflammatory cytokines, indicating that treatment including IVIg may be effective by inhibiting cytokine storm in severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection.

Severe epidemic myalgia with an elevated level of serum interleukin-6 caused by human parechovirus type 3: a case report and brief review of the literature.

BACKGROUND: Human parechovirus type 3 (HPeV-3) is known to cause cold-like symptoms, diarrhea, or severe infections such as sepsis in infants and children. In adults, HPeV-3 infection is rarely diagnosed because the symptoms are generally mild and self-limiting; however, this infection has been linked to epidemic myalgia, regardless of the presence of underlying diseases, immunosuppression, or sex. CASE PRESENTATION: We describe an adult case of severe systemic myalgia and orchiodynia after infection with HPeV-3, which was transmitted from the child of the patient. Interleukin-6 (IL-6) level was found to be elevated in the patient's serum. CONCLUSION: Severe myalgia associated with HPeV-3 infection is potentially caused by an elevated serum level of IL-6.