Studies on Mechanism of Proliferation of Lymphocytis to Produce Platelet Associated Immunoglobulin.

1)分泌PAIgG的淋巴细胞的增殖机制我们建立了一种新的改良ELISA空斑试验方法，用于鉴定和计数人血小板致敏小鼠脾细胞中分泌血小板相关IgG（PAIgG）的淋巴细胞。环磷酰胺、大剂量泼尼松龙和长期泼尼松龙均能抑制分泌PAIgG的小鼠脾细胞的增殖。但在慢性ITP患儿的脾细胞和经异源血小板输注致敏的患儿外周血淋巴细胞中均未检测到分泌PAIgG的淋巴细胞，另一方面，我们用含血小板结合IgG的患儿血清的IgG组分免疫小鼠，制备了抗人IgG的多克隆抗体。用该抗体检测慢性ITP、Evans综合征和溃疡性结肠炎患儿外周血中与IgG结合的淋巴细胞（LAIgG），发现其数量明显增加。然后，显示具有LAIgG的淋巴细胞是T细胞。2）血小板膜抗原结合自身抗体位点的检测我们检测了慢性ITP、Evans综合征和血栓性贫血患儿血小板膜上结合的单克隆抗体的数量。22例慢性ITP患儿中5例单克隆抗体与血小板膜结合量减少。提示在GPIIb/IIIa表位附近存在与自身免疫血小板抗体结合的抗原位点联合收割机。

1) Mechanism of proliferation of PAIgG-secreting lymphocytes.We developed the new modified methods of ELIZA-plaque assay which could identify and count the lymphocytes to secrete platelet associated IgG (PAIgG) in mouse spleen cells sensitized with human platelets. The proliferation of PAIgG secreting spleen cells of mouse were suppressed with such drugs as cyclophosphamide, bolus prednisolone and prednisolone of long period. However, we could not detect PAIgG-secreting lymphocytes in spleen cells of children with chronic ITP and the peripheral lymphocytes of the patient sensitized with isologous platelets transfusion.On the other hand, we immunized mouse with IgG fraction of the children whose sera contained platelet bound IgG and produced the polyclonal antibody for antihuman IgG. Using this antibody, we could found incresed number of the lymphocytes combined with IgG (LAIgG) in the peripheral blood of children with chronic ITP, Evans syndrome and ulcerative colitis. Then, the lymphocytes with LAIgG were shown to be T-cells. The student are going to make clear the significance of the increase of lymphocytes with LAIgG in those children.2) Detection of antigen site on the palatelet membrane combined with autoantibody.We measured the amount of monoclonal antibodies to conbine with platelet membrane as for platelets of children with chronic ITP, Evans syndrome and thromboasthenia. Five of 22 children with chronic ITP showed decreased amount of monoclonal antibodies combined with platelet membrane. This phenomenon suggested that there were the antigen site to combine with autoimmune platelet antibodies near the epitope of GPIIb/IIIa.