Sources of variability in repeated T-helper lymphocyte counts from human immunodeficiency virus type 1-infected patients: total lymphocyte count fluctuations and diurnal cycle are important

Abstract

The study objective was to determine the causes and magnitude of absolute CD4 (T4) count variation in human immunodeficiency virus type 1 (HIV-1)-infected (+) adult males. We conducted a prospective, blinded, and controlled study of 22 adult military male outpatients, including 16 HIV(+) [12 in Walter Reed stage (WR-) 1 through 5, 4 in WR-6 (AIDS)], and 6 HIV seronegative (-) healthy controls. Ten CD4+ cell counts were drawn within a 3-day interval from each patient at the following times: 0800, 1200, 1600, and 2200 h on day 1; and 0800, 1200, and 1600 h on days 2 and 3. A significant CD4+ cell count diurnal increase of 59 cells/mm3 was detected between 0800 h and 2200 h from the WR-1-5 patients (p = 0.018), although this diurnal change was significantly blunted (p = 0.028) as compared with the 506 cells/mm3 CD4+ cell count diurnal increase observed from the HIV(-) healthy controls. The coefficients of variation [CV = (standard deviation/average) x 100] of the three daily 0800 h CD4 cell counts from each patient were 15 (median) and 19 (average) for the WR-1-5 patient group. Blood leukocyte counts, differential fractions of lymphocytes, and total lymphocyte counts contributed more to the observed CD4+ cell count variability than did the CD4% measurements [CV = 7.5 (median), 11 (average)] obtained from flow cytometry. We conclude that the large fluctuations that we observed in repeated CD4+ cell counts in HIV(+) patients can be explained in part by CD4+ cell count diurnal cycle and in part by high variability in total lymphocyte counts.(ABSTRACT TRUNCATED AT 250 WORDS)