重症肌无力B细胞免疫应答涉及乙酰胆碱受体的全部亚单位

The B Cell Repertoire in Myasthenia Gravis Includes All Four Acetylcholine Receptor Subunits

用酶联免疫斑点（Ｅｌｉｓｐｏｔ）法计数乙酰胆碱受体（ＡＣｈＲ）及其α－、β－、γ－和δ－４种亚单位的特异性ＩｇＧ抗体分泌细胞，评价重症肌无力（ＭＧ）患者外周血Ｂ细胞免疫应答。与其他神经疾病（ＯＮＤ）组相比，ＭＧ组存在显著高水平的ＡＣｈＲ及其４种亚单位的抗体分泌细胞，ＭＧ组４种ＡＣｈＲ亚单位的抗体分泌细胞平均值为１０／１０５～１５／１０５外周血单个核细胞（ＭＮＣ），ＯＮＤ组为０．６／１０５～１．４／１０５ＭＮＣ（Ｐ＜０．０００１）。ＭＧ组ＡＣｈＲ抗体分泌细胞数总是高于任何一种亚单位抗体分泌细胞数，且对α－亚单位的Ｂ细胞免疫应答占有明显优势，这可能是α－亚单位存在主要免疫源区（ＭＩＲ）的间接证据。

By enumerating cells secreting IgG antibodies of particular specificities,the B cell responses to Torpedo acetylcholine receptor (AChR)in blood from patients with myasthenia gravis (MG),and controls were evaluated. Compared to controls,the patients with MG had elevated numbers of B cells secreting antibodies to all subunits (α-,β-,γ-,δ-)in parallel.Mean values of subunit-responsive B cells in MG varied between 10 and 15 per 105 MNC,compared to between 0.6 and l.4 per 10s MNC in controls,the latter probably representing naturally occurring subunit-reactive B cells.Most MG patients (60%) had B cells that predominantly recognized the a-subunit,and this may be considered an indirect argument for the existence of a main immunogenic region (MIR) on the α-subunit. 40% of the B cells predominantly responded to β-and γ- orδ- subunits. It is suggested that all 4 AChR subunits may function as strong immunogen in MG and that theβ-,γ-,orδ- subunits may function as major immunogen in a substantial proportion of patients with MG.