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

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)