[Clinical study of immunotherapy for bronchial asthma using purified mite feces antigen].

For many years, hyposensitization therapy was considered to be a radical therapy for allergic diseases such as bronchial asthma. Adverse effects including the inducement of asthma attacks or anaphylactic shock were attributed to the use of crude antigen solution during treatment. To contribute to the establishment of safer and more effective approaches, we conducted immunotherapy trials using purified mite feces antigen. Among the antigen fractions that were separated and purified for this purpose, the HM 2 antigen fraction with a molecular weight in the 30-40 kD range was found to be the most suitable for use. Treatment utilizing this fraction achieved favorable outcomes. Of 25 patients with nonseasonal asthma, the clinical outcome of treatment was "markedly improved" in 7, "moderately improved" in 11, "slightly improved" in 3, "unchanged" in 4, and "worsened" in none. Also, 4 of 5 patients with seasonal asthma experienced a cessation of seasonal attacks. Among factors that affect therapeutic efficacy, high Df-RAST scores and a history of childhood asthma were considered to be particularly important.

[Desensitization immunotherapy on patients with mite-positive bronchial asthma using purified mite feces antigen fractions].

At present, we are performing desensitization immunotherapy on patients with mite-positive bronchial asthma using purified mite feces antigen fractions. We obtained the following results in 13 patients 4 to 12 months after the start of treatment. 1) The fraction showing the maximum reaction in the skin test was HM1-2 (molecular weight: 150-155 kD) in two patients, HM2 (30-40 kD) in nine patients and HM3 (10-20 kD) in two patients, and immunotherapy was performed using these fractions. None of the patients showed the maximum skin reactions or was treated with HM4 (less than 10 kD). 2) In nine patients with perennial asthma, the effects of treatment were excellent in four and moderate in three, while two cases remained unchanged. In four patients with seasonal asthma, the treatment was effective in all cases. 3) In patients in whom immunotherapy was effective, specific IgG antibody increased after the treatment, but it did not increase in the unchanged cases. Among the subclasses of specific IgG antibody increased by the treatment, no clear changes were seen in IgG4 antibody and no conclusion has been reached at present. 4) None of the patients had definite adverse reactions such as the occurrence of asthma attacks or anaphylaxis. These results suggested that purified mite feces antigens are safe and effective. We plan to continue this study with more patients in the future.