To evaluate the effect of BCG vaccination and T lymphocyte subpopulations
on the reactivity to the tuberculin skin test, 113 asymtomatic HIV+
individuals were tuberculin tested by intradermal injection of 5TU of
purified protein derivative and the levels of circulating lymphocyte (CD3,
CD4 and CD8) subpopulations determined by indirect immunofluorescence.
Ninety-two percent of the subjects included in the study were males. The
mean age of the group was 32.1+/-7.4 years. Sixty-two percent presented a
BCG scar. However, only 22% exhibited positive tuberculin reactions (}5mm)
irrespective of the presence of the BCG scar. Tuberculin positive
individuals exhibited higher CD4+ cell counts (p=0.004) and CD4+/CD8+
ratios (p=0.006) than tuberculin negative ({5mm) HIV+ individuals. The
number of individuals with positive tuberculin reactions was significantly
higher in subjects with more than 500 CD4+ lymphocytes/ml (p=0.02) or
CD4+/CD8+ ratios }1.12 (p=0.002).
These results suggest that a prior BCG vaccination does not influence
the reactivity to the tuberculin skin test in HIV+ asymptomatic individuals
and that the number of CD4+ lymphocytes and the CD4+/CD8+ ratio positively
correlate with the tuberculin reactivity.
