多发性骨髓瘤M蛋白血清转换型复发的实验室诊断与临床意义

The Laboratory Diagnosis and Clinical Significance of Relapse Manifestingfor M Protein Seroconversion

目的探讨多发性骨髓瘤(multiple myeloma,MM)单克隆免疫球蛋白(monoclonal immunoglobulin,M)血清转换型复发的实验室诊断和预测指标。方法对33例M蛋白血清转换的MM患者的相关实验室检验结果和临床资料进行回顾性分析,以未发生M蛋白血清转换的33例MM患者作为对照组。结果初诊时,血清转换组本周蛋白(Bence-Jones protein,BJP)水平、血清游离轻链(serum free light chain,sFLC)水平显著高于对照组(P值均<0.05),蛋白电泳图谱两组间无明显差异;发生血清转换后,患者M蛋白和血红蛋白(hemoglobin,Hb)水平显著下降(P值均<0.01),BJP、血清肌酐(creatinine,Cr)、β2微球蛋白(β2-microglobulin,β2-MG)、sFLC的水平显著升高(P值均<0.01),骨髓瘤浆细胞形态明显变化;血清转换组sFLC先于BJP变化61.37±19.26 d,严重肾功能受损时,BJP水平可不再上升,甚至下降,而sFLC水平变化与病情相一致;血清转换组与对照组中位生存期分别是24个月和43个月,两组生存率差异有统计学意义(χ^2=6.744,P<0.01)。结论初诊时,BJP或sFLC水平显著升高的MM患者,治疗过程中易发生M蛋白血清转换型复发,并且预后往往不良,监测sFLC可早期预测M蛋白血清转换型复发。

Objective To explore the laboratory diagnosis and clinical significance of relapse for multiple myeloma with M protein seroconversion.Methods The laboratory data of 33 cases of MM patients with M protein seroconversion were collected retrospectively from January,2002 to October,2019,while 33 cases of MM patients without M protein seroconversion were enrolled as the control group.Results At the initial diagnosis,both FLC and BJP levels were significantly different between the groups(all P<0.05).When M protein seroconversion occurred,the levels of M protein and Hb were decreased significantly,while BJP,Cr,β2-MG and sFLC levels significantly increased(all P<0.05).Another major feature accompanying the presentation of M protein seroconversion was the conversion of plasma cell morphology.Monitoring sFLC was more efficient in the early diagnosis of M protein seroconversion than BJP,and sFLC level was consistent with the injuries of kidney.The median survival time were 24 months and 43 months for the case and control groups,respectively,Log-rank test demonstrated a significant difference between the survival rates of these two groups(χ^2=6.744,P<0.01).Conclusion MM patients with significantly elevated levels of BJP and sFLC are prone to develop M protein seroconversion.Monitoring the level of sFLC could be used for the early diagnosis of M protein seroconversion,and the M protein seroconversion is useful for the prediction of a poor prognosis of MM.