- Follow-up: After treatment is completed, patients return to the clinic once a month for several months for physical examinations, a review of side effects, laboratory tests and scans. They may undergo leukapheresis at some visits to look at the effect of treatment on the immune system and check the viability of the infused cells. Patients then return to the National Institute of Health (NIH) clinic once a year for 5 years and then complete a follow-up questionnaire for another 10 years.