Analysis Of Clinical And Pathological Characteristics Of Monoclonal Gammopathy Of Renal Significance

Background and Objective:In recent years,the concepts of monoclonal gammopathy(MG),monoclonal gammopathy of renal significance(MGRS),and monoclonal gammopathy of undetermined significance(MGUS)have attracted more and more attention,especially MGRS.Nephrologists are worried about its long-term renal outcome.In this article,We subsequently reviewed electronic medical records of patients who were monoclonal gammopathy and summarize their clinical and pathological characteristics to explore predictors of finding lesions of MGRS on kidney biopsy specimens among patients with MGMethods:We identified all patients that had a positive serum immunofixation electrophoresis(IFE)and/or blood/urinary light chain ratio within Qilu Hospital of Shandong University from 2016 to 2019.We collected their general clinical information,laboratory tests,pathological results and exclude patients who had not undergone a kidney biopsy or patients with multiple myeloma.The patients were divided into MGRS group,MGUS group.Univariate and multivariate logistic regression analysis were used to explore predictors of finding lesions of MGRS with MG.Result:1.The study included 38 MG patients with an average age of(57.91 ± 10.97)years old,23(60.5%)of whom are male;Of the 38 patients,12(31.6%)patients had an MGRS lesion,with an average age of(58.58± 10.38)years old,the percentage of male is 41.7%;The MGUS group includes 26 patients,with an average age of(56.81±11.92)years old,18 of whom are male.There were no significant differences in age and the proportion of male.The MG group has high BMI,and there was no significant difference between three groups.Besides,there were statistically significant differences in systolic blood pressure levels at admission between the two groups,and blood pressure in MGRS group was lower than that in MGUS group.In addition,the MGRS group had higher lactate dehydrogenase(LDH)and hemoglobin(HB)compared with the MGUS group.19 cases(50.0%)had increased serum creatinine at admission,including 5 cases(41.7%)in MGRS group,14 cases(53.8%)in MGUS group.There were no significant differences in serum creatinine,eGFR,urinary albumin creatinine ratio(UACR)between the two groups.2.Of the 38 patients who had a kidney biopsy,12 patients(31.6%)had an MGRS lesion,whereas 26 patients(68.4%)had a kidney lesion that was unrelated to the monoclonal immunoglobulin.The second most common lesion are membranous nephropathy and mild lesions(n=9,20.5%)and we also find crescentic glomerulonephritis,focal segmental glomerulosclerosis,IgA nephropathy,etc.In MGRS group,AL-amyloidosis was the only finding.We have observed amyloid deposition on light microscopy.3.Univariate analysis indicated that systolic blood pressure,BMI,,LDH,,blood light chain ? and the percentage of patients who have body weight loss between MGRS group and MGUS group were statistically significant.In the multivariate model which took into account bodyweight loss,LDH,SBP,and blood light chain ?,the strongest predictor of finding an MGRS lesion was SBP(OR=0.935,95%CI:0.881-0.994,P=0.030)4.Divide the MGRS group into two groups based on eGFR to explore the risk factors of MGRS.Multiple linear regression analysis did not find risk factors for MG patients with renal dysfuction.Besides,there was no significant difference between the amyloid deposition site and eGFR as well.Conclusion:1.Monoclonal gammopathy is common in middle-aged and elderly people.The rate of MG patients who recieved renal biopsy was 21.1%,among which 31.6%were diagnosed as MGRS and 68.4%were diagnosed as MGUS with other renal lesions.2.Of the 38 patients who had a kidney biopsy,12 patients(31.6%)had an MGRS lesion.In the MGRS group,AL-amyloidosis was the only finding.We have observed amyloid fibril deposits on light microscopy in glomeruli,interstitial,or vascular.Glomerular deposition of fibrils is the most common location within the kidney.3.Univariate and multivariate logistic regression analysis showed that SBP was negatively correlated with finding a MGRS lesion.4.No correlation between the deposition sites of fibrils and eGFR was found in this study.Multiple linear regression analysis found no risk factors for renal insufficiency in MGRS.