Study of immunological changes after hyposensitization in house dust sensitive asthmatic children.

The working mechanisms of hyposensitization were studied in 22 asthmatic children who had completed an one-year course of immunotherapy with house dust. Several immunological parameters were followed every four months during the study period. The results showed: (1) There was no significant change in the distribution of total T, active T and B lymphocytes. (2) While the numbers of Tmu and Tgamma cells remained unchanged, their capability to increase after allergen challenge was lost four months after immunotherapy. (3) No change could be found in the total serum IgE, specific IgE and IgG antibodies. Surprisingly enough, the specific IgG antibody, and thus the specific IgG/IgE antibody ratio, decreased in patients who often developed immediate-type asthmatic reactions after allergen shots. (4) The lymphoproliferative response to house dust started to decrease four months after treatment while the mitogenic response to phytohemagglutinin remained the same. (5) The mean percentages of polymorphonuclear leukocytes with Fc and complement receptors were lower than those for normals throughout the study period but the sensitivity of receptor functions to allergen challenge began to decline four months after immunotherapy. Thus this study shows that hyposensitization is able to specifically correct some of the immunological aberrations of the atopic individuals and provides the rationale for the hyposensitization in the treatment of allergic diseases.