A preliminary study of circulating immune complexes during allergen immunotherapy in Thai patients.

Circulating immune complexes are suspected as a potentially serious adverse effect after prolonged allergen immunotherapy. This study was undertaken to determine whether there were any significant immunological differences between 32 subjects with allergic rhinitis/asthma treated with immunotherapy of various durations and 13 subjects with similar diagnosis who had never been treated by immunotherapy. All patients were carefully examined for symptoms and signs of immune-complex diseases with negative results. The presence of circulating immune complexes was evaluated by the modified 125I-C1q binding test, the solid phase conglutinin (K) binding test and determination of C3, C4 and C3d levels. In addition, urinalysis, and quantitative determination of serum IgG, IgA, IgM and IgE were also performed. The overall results suggested that prolonged allergen immunotherapy did not result in an increase of circulating immune complexes or other adverse immunological consequences.