多发性骨髓瘤（MM）是一种恶性疾病，其特点是逐渐进行性免疫功能紊乱。PD-1/ PD-L1在MM中的重要性已经在不同人群中有所记录，但研究仅限于中国人群。在本研究中，我们检查了大量中国患者和健康对照组中PD-1/PD-L1的作用，以揭示其与MM的可能关联性。本研究纳入了334名MM患者和202名年龄和性别匹配的健康受试者。我们通过酶联免疫吸附试验法量化了PD-1和PD-L1的血清水平。流式细胞术评估了表达PD-1受体的T细胞（CD4+和CD8+ T细胞）的百分比。通过PCR-RFLP方法对PD-L1基因（rs4143815）和PD-1基因（rs2227981、rs2227982、rs7421861和rs11568821）进行了基因分型。相较于健康对照组，多发性骨髓瘤患者的PD-1和PD-L1水平较高，表明编程细胞死亡蛋白-1及其配体在MM的发病机制中起重要作用。表达PD-1受体的T细胞也明显高于对照组。PD-L1（rs4143815）和PD-1（rs2227982和rs7421861）的突变体在MM中显著更常见。有趣的是，PD-L1（rs4143815）和PD-1（rs2227982和rs7421861）变体分别与较高的sPD-L1和sPD-1水平相关联。PD-1/PD-L1水平在MM患者中显著升高，可能是一种有希望的生物标志物。PD-L1和PD-1的变异与血清可溶性蛋白的产生有关，并与MM的发展相关。

Multiple myeloma (MM) is a malignant disorder characterised by progressive immune dysregulation. The importance of programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) in MM has been documented in various populations, but studies have been limited to the Chinese cohort. In the present study, we examined the role of PD-1/PDL-1 in large cohorts of Chinese patients with MM and healthy controls to reveal a possible association with MM. Three hundred thirty-four MM patients and 202 healthy age-sex-matched subjects were enrolled in the present study. Serum levels of PD-1 and PD-L1 were quantified by ELISA. Percentages of T cells (CD4+ and CD8+ T cells) expressing PD-1 receptor were assessed by flow cytometry. Variants in PD-L1 (rs4143815) and PD-1 gene (rs2227981, rs2227982, rs7421861 and rs11568821) were genotyped by PCR-RFLP method. Patients with multiple myeloma had higher levels of PD-1 and PDL-1 than healthy controls, indicating an important role for programmed cell death protein-1 and its ligand in the pathogenesis of MM. T cells expressing PD-1 receptors were also significantly higher in MM patients than in controls. Mutants for PD-L1 (rs4143815) and PD-1 (rs2227982 and rs7421861) polymorphisms were significantly more common in MM than in HC. Interestingly, PD-L1 (rs4143815) and PD-1 (rs2227982 and rs7421861) variants were linked to higher sPD-L1 and sPD-1 levels, respectively. PD-1/PD-L1 levels are significantly higher in MM patients and could be a promising biomarker for the disease. Variants of PD-L1 and PD-1 are linked to serum-soluble proteins and are associated with the development of MM.