| Budget Amount *help |
¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥3,700,000 (Direct Cost: ¥3,700,000)
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| Research Abstract |
Thymectomy was recommended for myasthenic patients who did not respond to conservative treatments, thymomotous patients especially with malignancy, However, not all myasthenic patients are benefited by thymectomy, Thus, in order to acquire good operative results in the patients, it is important to clalify a pathological role of myasthenic thymus n MG. We previously reported that the myasthenic patients with enhanced l cell-mediated immune reactivity showed dramatic improvement in their symptoms and the remission of their immunological hyperreactivity ofter thymectomy. It is therefore, lymphocyte migration to myasthenic thymus may implicate the pathological role in the thymus. In this view, we have examined myasthenic thymus, and as a result, we found a potent and specific chemotactic factor for lymphocytes was found in thymic tissue extract form myasthenic patients who received thymectomy. Biological activities and biochemical natures of this factor were examined, and major findings we
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re; 1) The factor form myasthenic thymus was specifically chemotactic for T lymphooytes. Analysis of T lymphocyte subsets revealed that only helper/inducer T cells responded to the factor. A chemotactic activity was also found in normal thymus, but its activity was different from that found in myasthenic thymus.
Interestingly, suppressor/ cytotoxic T cells as well as helper/ inducer T cells exhibited similar weak migration to normal thymic extract. 2) chromatography of the extract by Sephadex G-100 gel filtration, gave three distinct peaks with the activity; molecular sizes were 160,000-100,000, 25,000-15,000 and smaller than 1,350 daltons respectively. 3) The factor was inactivated by heating for 30 min at 56゜C and also destroyed at pH 4 or at pH 10 condition. And the factor was sensitive to the treatment by trypsin, sodium metaperiodate, 8M urea, reduction or alkylation. 4) The chemotactic activity had charactreistics distinct from other known chemotactic factors, including D5a, Interleukin-1 and Interleukin-2. 5) A chemotactic activity for lymphocytes was found in both aqueous extract and culture supernatant of thymic stromal cells, but not in thymocyte extract nor in serum.
The present findings will likely provide a new approach to investigate further the reasons for the beneficial effects of thymectomy. Furthermore, it may be useful to predict postoperative prognosis for ptients by examining the potency of factor in their thymus. Less
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