A 24-Year-Old Woman Comes to the Office Due to 3

A 24-year-old woman comes to the office due to 3 weeks of worsening throat pain and difficulty swallowing.  She has no chronic medical problems but has had recurrent vulvovaginal candidiasis and bacterial folliculitis over the past year.  The patient has also had an unintentional weight loss of 4.5-kg (10-lb) over the past 3 months.  She is an exchange student from Senegal.  Physical examination shows generalized lymphadenopathy and oropharyngeal thrush.  Upper endoscopy confirms Candida esophagitis.  HIV antigen/antibody immunoassay returns positive.  Further testing shows a CD4 count of 180/mm³ but there is no detectable plasma HIV-1 RNA.  Which of the following best explains the observed laboratory findings in this patient?

A) False-positive serology from cross-reactive antibodies
B) Homozygous CCR5 deletion
C) Infection with CXCR4 tropic strain
D) Infection with HIV-2
E) Window period of HIV infection