Splenectomy History of splenectomy or planning to undergo splenectomy Splenectomy Prior splenectomy Patients with history of splenectomy Patients who have undergone splenectomy Splenectomy ? 90 days prior to the first dose of PRTX-100 Patients having previously undergone splenectomy. Previous history of splenectomy or whole spleen radiation History of splenectomy Prior splenectomy Prior splenectomy Subjects with splenectomy. History of splenectomy Prior splenectomy Prior splenectomy Patients having previously undergone splenectomy. Prior splenectomy Patients having undergone splenectomy. Patients who have undergone splenectomy Splenectomy (Phase 2 portion of the study only) Patients with a prior history of a splenectomy and/or sickle cell trait/disease Prior splenectomy unless Howell-Jolly bodies are absent. History of splenectomy Prior splenectomy Patient is immunocompromised (patients with splenectomy are allowed). Immunocompromised patient (Note: patients with splenectomy are allowed) Immunocompromised patient (Note: patients with splenectomy are allowed) Previous splenectomy Immunodeficiency or splenectomy Prior splenectomy