Immunological background in paraneoplastic neurological syndrome and its therapeutic approach

副肿瘤性神经综合征(PNS)被归类为自身免疫性神经系统疾病，在PNS中，癌症免疫和对神经元组织的自身免疫机制都被诱发。由于常规筛查系统发现的肿瘤往往很小，因此至少在PNS的早期阶段可能会加速抗肿瘤免疫。为了验证这一假设，我们分析了PNS患者外周血中富含FOXP3、TGF-pi、CTLA-4和GITR等功能分子的淋巴细胞亚群和调节性T细胞(Treg)mRNA的表达情况。结果表明，与没有神经系统症状的癌症患者相比，PNS患者外周血中FOXP3和CTLA-4的表达减少，提示PNS发生在Treg系统功能障碍的癌症患者中。这些结果为理解PNS的发病机制和构建潜在癌症的治疗策略带来了新的见解。

Paraneoplastic neurological syndrome (PNS) is categorized in autoimmune neurological disease ; in that, cancer immunity and autoimmune mechanisms to neuronal tissue are both elicited in PNS. Because the tumor is often very small to be detected with conventional screening system, anti-tumor immunity might be accelerated at least in early stage of PNS. Furthermore, PNS develops in a small population of patients who have similar tumor pathology, suggesting that PNS patients might have special immunological backgrounds to tune up immunity on tumor and nervous tissue.To inspect this hypothesis, we analyzed prevalence of lymphocyte subpopulation and regulatory T cell (Treg) mRNA expression of functional molecules such as FOXP3, TGF-pi, CTLA-4 and GITR in Treg-rich fraction from peripheral blood of PNS patients.As the results, the expression of FOXP3 and CTLA-4 mRNA were diminished in PNS, group compared to cancer patients without neurological symptom, suggesting PNS develops in those cancer patients having dysfunction in Treg system. These results have brought a new insight in understanding the pathomechanisms of PNS and in constructing a treatment strategy for underlying cancer.