This study evaluated whether decrements in peripheral leukocyte counts
induced by cyclophosphamide can be conditioned in humans. Ten subjects
being treated for multiple sclerosis received four intravenous treatments
with cyclophosphamide (unconditioned stimulus) paired with a conditioned
stimulus. Subjects received conditioned stimulus plus 10 mg of
cyclophosphamide during one of the next two treatments in a double- blind
manner. Eight of 10 subjects (P = 0.044) displayed decreased peripheral
leukocyte counts following conditioned stimulus. This change may have
resulted from classical conditioning processes.Abstract Teaser