We registered 180 infusions of rituximab with a median (range) administered dose of 500 mg (41.5–1000) and collected 281 measurements of CD19+ lymphocyte counts (52% reported as BLQ) from patients with neurologic diseases (n = 36) and immune-haemato-rheumatologic (IHR) diseases (n = 27). The gene discussed is CD19; the disease is nervous system disorder.