Patients are admitted to the hospital for insertion of an angiocath to collect blood samples periodically over 48 hours on the day study medication from the parent study is initiated. After discharge, additional blood samples are obtained over a 6-month period. Within 7 days prior to a scheduled biopsy, patients have physical examinations and laboratory evaluations done. All patients undergo some combination of the following during the 2-week prestudy evaluation period and at Weeks 4 and 24: a) superficial lymph node biopsy from cervical, axillary, or inguinal area; b) rectal biopsy; and/or c) tonsillar biopsy. The tissue samples provide an assessment of viral and cellular dynamics.