In this study, we used an in vitro experimental model with peripheral
mononuclear cells (PBMCs) capable of synthesizing IgE to study the pos
sible parallelism between in vitro IgE synthesis and the findings obta
ined in vivo showing changes in serum IgE values during immunotherapy
(IT). Blood samples were extracted from 10 healthy subjects and 39 all
ergic patients for lymphocyte culture. Allergic patients were classifi
ed into five groups according to the time of IT. After incubation for
7 days at 37-degrees-C, IgE values were assessed by means of a radioim
munoassay technique modified for low values. Likewise, total serum IgE
was assessed. Spontaneous in vitro production of IgE in control indiv
iduals (GO) was significantly lower (p < 0.001) than the mean producti
on in allergic patients (GA). When patients were grouped according to
the time of IT, we observed that IgE values decreased during the cours
e of IT. The significant differences found between allergic patients a
nd control individuals eventually disappeared from the third year of t
reatment. We found a statistically significant positive correlation (r
=0.575, p < 0.001) between total serum IgE values and in vitro IgE pro
duction in all subjects. We conclude that IT induces a series of varia
tions in lymphocyte IgE production in vitro, which consists of a signi
ficant decrease in IgE production from the second year of IT compared
with that of patients without IT. IgE production eventually reaches le
vels similar to those in healthy subjects. The symptomatic recovery sh
own by all patients was associated with evident immunological changes,
which confirms the clinical utility of this treatment in allergic dis
eases and the importance of its long-term effects.