Unexpected and persistent depletion of B lymphocytes CD20 following a minimum dose of anti-CD20 antibody (Rituximab).

This study describes a woman patient suffering from rheumatoid arthritis which was resistant to treatment with the most commonly used DMARDs and anti-TNF alfa drugs, however following the administration of a minimum dose of Rituximab the patient showed a persistent and complete depletion of CD 20 lymphocytes. The dose of Rituximab administered to the patient was halted at 50 mg due to the onset of an allergic reaction. Based on these observations, a number of important speculations are possible, which however would require a larger number of case histories for their confirmation.