Observational Study of HIV-Infected Subjects With X4-Tropic or Non-Phenotypeable Virus

GSK Investigational Site, New York

GSK Investigational Site, Washington D.C.

GSK Investigational Site, Baltimore

GSK Investigational Site, Hampton

GSK Investigational Site, Charlotte

GSK Investigational Site, Decatur

GSK Investigational Site, Atlanta

GSK Investigational Site, Key West

GSK Investigational Site, Miami

GSK Investigational Site, Plantation

GSK Investigational Site, Fort Myers

GSK Investigational Site, Los Angeles

GSK Investigational Site, Tarzana

GSK Investigational Site, Atlanta

GSK Investigational Site, East Orange