单纯性肾病综合征低ＩｇＧ血症的发生机制至今尚不清楚。研究表明与Ｔ细胞功能紊乱致Ｉｇ同种型转换障碍有关［１］。近年发现ＣＤ４０Ｌ信号在同种型转换中发挥了重要作用，其表达缺失或减少是Ｘ连锁高ＩｇＭ血症（ＸＨＩＭ）血清Ｉｇ水平异常的原因［２］。我们检测了单纯 The pathogenesis of low nephrotic syndrome with low IgG blood syndrome is still unclear. Studies have shown that T cell dysfunction caused by Ig isotype conversion disorders [1]. In recent years, CD40L signaling has been found to play an important role in isotype switching. The loss or loss of CD40L is the reason for the abnormality of serum Ig levels in X-linked hyper IgMmia (X-HIM) [2]. We tested the simple