Soluble factors released by both T and B cells are involved in the class-specific regulation of IgE antibody formation; some factors have affinity for IgE, whereas others do not. The induction phase of the primary and secondary IgE antibody response is highly sensitive to treatment with such factors or some drugs. In contrast, persistent IgE antibody formation is mostly insensitive to the same treatments, indicating that this phase differs apparently from the induction phase. Thus, it is very important to note the marked differences between the regulatory mechanisms of these two phases when drugs responsible for the suppression of IgE antibody response are developed. In the present review, the recent advances pertaining to the regulation of IgE antibody formation in animals and humans are described in view of immunopharmacology.