To communicate an adverse effect with fatal outcome in a patient treated with Ocrelizumab.

Available data from Ocrelizumab indicate excellent tolerability and low risks for serious opportunistic infections or secondary malignancies.

Rheumatic heart disease continues unabated in poor countries and amongst vulnerable groups in wealthy ones. It results from an abnormal autoimmune response to group A beta-hemolytic streptococcus infection in a genetically susceptible host.

A 48-year-old male, who was diagnosed 9 years before with a primary progressive multiple sclerosis and had an Expanded Disability Status Scale of 6, started treatment with Ocrelizumab on February 2019 (2 infusions of 300 mg each). During the third infusion (600 mg), in August 2019, he developed a fulminant respiratory distress with subsequent cardiac arrest and death.

Amongst his medical history, an ablation due to paroxysmal supraventricular tachycardia was practiced in 2008. At that moment, the transthoracic echocardiography demonstrated no data of interest.

Thenceforth, the patient did not show any signs of heart disease.

An autopsy was performed and it revealed the following findings: a severe rheumatic pancarditis in different stages, involving a fibrotic component, calcified areas and inflammatory infiltrate, along with massive pulmonary edema and hemorrhage.

Heretofore, there are no records of the association between the treatment with Ocrelizumab and the reactivation of an autoimmune process such as rheumatic heart disease. Therefore, the reason for such association is not clear.