5. History of or an ongoing opportunistic infection (e.g. systemic fungal infection, parasites) or any other serious infection. This includes diagnoses that required more than 2 weeks of therapy, such as endocarditis and osteomyelitis, that have been treated in the past 6 months. In addition, if the subject is currently receiving antibiotics, antivirals, or antifungals for an infection or for suppression or prophylaxis for any diagnosis, the subject will be excluded.