Impaired basophil histamine release from allergic patients

Area of Science:

• Immunology
• Allergy Research

Background:

• A subset of patients with verified type I allergic reactions show no histamine release from basophils upon specific antigen challenge.
• This phenomenon, termed non-responding basophils, occurs in 6-7% of allergic patients.

Purpose of the Study:

• To investigate the underlying mechanisms of non-responding basophils in allergic patients.
• To determine if impaired basophil function or a lack of specific IgE contributes to the unresponsiveness.

Main Methods:

• Sera from non-responding allergic patients were used to passively sensitize basophils from healthy controls.
• The effect of enhanced IgE receptor stimulation, using phorbol 12-myristate 13-acetate to stimulate protein kinase C, on histamine release from non-responding basophils was examined.

Main Results:

• Passive sensitization with sera from non-responding patients induced histamine release in healthy basophils upon antigen challenge, confirming the presence of circulating antigen-specific IgE.
• Stimulation with phorbol 12-myristate 13-acetate enabled non-responding basophils to release histamine when challenged with anti-IgE or specific antigen.

Conclusions:

• The unresponsiveness of basophils in some allergic patients is not due to a lack of cell-bound IgE.
• Findings support the hypothesis that impaired IgE receptor complex activation or subcellular functioning is responsible for non-responding basophils in allergic individuals.