Outpatient biopsies of the palatine tonsil: Access to lymphoid tissue for assessment of human immunodeficiency virus RNA titers

OBJECTIVES: Our objective was to assess the feasibility of using tonsillar lymphoid biopsy specimens obtained on an outpatient basis to quantitate a patient's lymphoid human immunodeficiency virus (HIV) RNA titers. DESIGN: A pilot cohort study was performed. PARENTS: We evaluated ten HIV-seropositive patients who ranged in age from 26 to 48 years and had CD4+ cell counts ranging from 110 to 833 at enrollment. MAIN OUTCOME MEASURES: The main outcome measures were tolerance and safety of outpatient tonsil biopsies and quantitation of HIV RNA titers in tonsillar lymphoid biopsy specimens, plasma, and peripheral blood mononuclear cells determined by a new method of HIV RNA signal amplification with branched DNA probes. RESULTS: Outpatient tonsil biopsies were well tolerated and were performed without complications. Nine of 10 tonsil biopsies from the HIV-seropositive patients examined were positive for significant concentrations of HIV RNA, ranging from 10⁶ to 10⁹ HIV RNA equivalents per gram of tissue. All of the HIV RNA-positive tonsillar lymphoid specimens had HIV RNA titers that were 10² to 10⁴ times greater than those recovered from plasma (per milliliter) of the same patient obtained at the time of biopsy. CONCLUSIONS: Sufficient tonsillar tissue can be obtained in an outpatient clinic setting to quantitate lymphoid HIV titers by the new branched-DNA signal amplification method with relative ease and without complication. The biopsy method described here affords ready access to the lymphoreticular system, which may help to advance our understanding of the pathogenesis of myriad immune diseases without the need for excisional node biopsies.