Study On The Role Of Serum Free Light Chain And MiR-21 In The Early Diagnosis Of Multiple Myeloma Complicated With Renal Injury

Objective:The purpose of this study is to explore the role of serum free light chain and miR-21 in the diagnosis of multiple myeloma renal damage by analyzing the laboratory indexes of patients with multiple myeloma(MM).The purpose of this study is to find the detection index of early detection of multiple myeloma renal damage,and to explore the independent risk factors of myeloma renal damage.Finally,the goal of improving the prognosis and prolonging the survival time of patients with myeloma was achieved.Methods:Twenty patients with untreated multiple myeloma were divided into renal damage group(n=10)and normal renal function protein group(n=10)according to renal function and urinary protein.The expression of miR-21 in plasma was detected by fluorescence quantitative PCR,and the sensitivity and specificity were analyzed.At the same time,the difference of serum light chain among multiple myeloma patients was compared,and the sensitivity and specificity were analyzed.Combine the two methods to predict multiple myeloma renal damage,and study the correlation with the existing clinical indicators,and further explore the risk factors of renal damage in myeloma.Results:The relative expression of miR-21 in kidney damage group,protein group and control group was 2.32±0.63,1.56±0.22,1.06±0.37.All of them have statistical differences.In the analysis of serum light chain,κ light chain,κ/λ,|κ-λ|,there was significant difference.While the difference of λ light chain was weak and had no statistical significance.The AUC=0.780,95% confidence interval of κ light chain to distinguish the area under the curve between multiple myeloma kidney damage group and protein group:0.541 to 0.931,the diagnostic threshold is 2.6,the sensitivity is 70%,and the specificity is 90%.The AUC=0.830,95% confidence interval of κ/λ to distinguish the area under the curve between multiple myeloma kidney damage group and protein group is 0.598～0.958,the diagnostic threshold is 1.675,the sensitivity is70%,and the specificity is 90%.|κ-λ| the area under the curve to distinguish between MM kidney damage group and protein group AUC=0.850,95% confidence interval:0.621～0.968,diagnostic cutoff value is 2.04,sensitivity is 70%,specificity is 90%.Analysis of sensitivity and specificity of miR-21 as a diagnostic marker for renal damage in multiple myeloma:AUC=0.900,95% confidence interval:0.683～0.988,score=0.002< 0.05,diagnostic cutoff value is 1.777,sensitivity is 90%,specificity is90%.The sensitivity and specificity of miR-21 combined with κ/λ in the diagnosis of myeloma renal damage are both 90% and 90%.The sensitivity and specificity of combination of κ/λ and κ/λ are close to100% and 90%,respectively.The sensitivity and specificity of combined diagnosis of κ/λ and |κ-λ| are close to 100% and90%,respectively.Crrelation analysis of serum light chain κ/λ the expression level of serum light chain κ/λ was positively correlated with κlight chain and |κ-λ|,but not with blood urea nitrogen,serum uric acid,serum β 2 microglobulin,serum calcium and λ light chain.Light chain|κ-λ| correlation analysis light chain |κ-λ| positively correlated with κ light chain and κ/λ,but not with blood urea nitrogen,serum calcium,serum uric acid,serum β2-microglobulin and λ light chain.The expression level of serum miR-21 in patients with multiple myeloma was positively correlated with κ light chain and κ/λ,and the correlation was strong.It has no correlation with serum uric acid,serum β 2-microglobulin,blood urea nitrogen,λ light chain,|κ-λ|,serum calcium.Univariate Logistic regression analysis showed that serum creatinine,Blood urea nitrogen,kappa light chain,κ/λ and |κ-λ| were the risk factors of renal damage,but the independent risk factors could not be found.Conclusion:This study suggests that serum miR-21 may be a new marker for early diagnosis of renal damage in multiple myeloma.At the same time,it is proved that serum free light chain,especially κ/λ,|κ-λ| also has diagnostic value for diseases.The combination of miR-21 and serum light chain has higher diagnostic value,while serum creatinine.At the same time,it was also proved that the effect of urinary protein on renal damage of myeloma was earlier than that of serum creatinine.blood urea nitrogen and κ light chain are risk factors to promote the development of the disease.