Rate and Predictors of Finding Monoclonal Gammopathy of Renal Significance (MGRS) Lesions on Kidney Biopsy in Patients with Monoclonal Gammopathy

Nattawat Klomjit; Nelson Leung; Fernando Fervenza; Sanjeev Sethi; Ladan Zand

doi:10.1681/ASN.2020010054

This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.

Visual Abstract

Significance Statement

It is not known how frequently a kidney biopsy specimen reveals monoclonal gammopathy (MG) of renal significance (MGRS) in patients with MG or what factors predict this finding. In a review of medical records of 6300 patients with MG, the authors found that only 160 (2.5%) had a biopsy. Of those, 96 (60%) had lesions unrelated to MG, with arteriosclerosis and diabetic nephropathy accounting for most cases. Among 64 patients with MGRS, amyloid light chain amyloidosis and proliferative GN with monoclonal Ig deposition were the most common lesions. An elevated serum free light chain ratio, proteinuria ≥1.5 g/d, and hematuria were the strongest independent predictors of finding MGRS on biopsy specimens. These findings will assist nephrologists in determining which patients with MG and CKD would be at high risk of having MGRS.

Abstract

Background Little is known about the rate and predictors of finding lesions of monoclonal gammopathy (MG) of renal significance (MGRS) on kidney biopsy specimens among patients with MG.

Methods We reviewed the medical records from 2013 to 2018 at the Mayo Clinic in Rochester, Minnesota, to identify patients with MG and whether they had undergone a kidney biopsy. In a more select group of patients with MG from 2017 to 2018, we conducted a review of records to determine how many had underlying CKD, which of those with CKD had undergone a kidney biopsy, and reasons for deferring a kidney biopsy.

Results Between 2013 and 2018, we identified 6300 patients who had MG, 160 (2.5%) of whom had undergone a kidney biopsy. Of the 160 patients, 64 (40%) had an MGRS lesion; amyloid light chain amyloidosis, the most common finding, accounted for nearly half of these lesions. In the non-MGRS group comprising 96 patients, 23 had arteriosclerosis, the most common finding. In multivariate analysis, strong predictors of finding an MGRS lesion included the presence of an elevated free light chain ratio, proteinuria, and hematuria. Among 596 patients with CKD and MG from 2017 to 2018, 62 (10.4%) underwent a kidney biopsy. Kidney biopsy was deferred for 70 patients (20%); for 62 of the 70, the diagnosis was already known, and eight were not candidates for therapy. Younger age and higher proteinuria and serum creatinine levels increased the likelihood that the patient would undergo a kidney biopsy.

Conclusions Proteinuria ≥1.5 g/d, hematuria, and an elevated free light chain ratio increase the likelihood of finding MGRS, and a kidney biopsy should be highly considered in such patients.

View Full Text

If you are:

an ASN member, select the "ASN Member" login button.
an individual subscriber, login with you User Name and Password.
an Institutional user, select the Institution option where you will be presented with a list of Shibboleth federations. If you do not see your federation, contact publications@asn-online.org.

Log in through your institution

Purchase access

Pay Per Article - You may access this article (from the computer you are currently using) for 1 day for US$32.00

In order to get access to the article, you must have an account. If you have an account, enter your user name and password into the boxes above. If you do not have an account, follow the instructions below to create one. Once you have purchased the article, you will have access to it for 24 hours.

Steps for Creating an Account:

Click the "Purchase Access" button. The page will redisplay with the following message at the top of the screen. In the message, click to create an account.

When you create the account, you will be asked to register a user name, email address and you will need to create a password that is at least eight characters in length. You do not need an ASN Member number to complete the form. As you move through the registration page, you will have to verify you are a person by completing a Captcha request. Lastly, your first and last name will be required.

Once your information is successfully saved, the system will redisplay the home page of the journal. From there, navigate back to the article to purchase. Select the article and at the bottom of the page, use the credentials you just created to login. The article will be added to your shopping cart. You can continue to navigate across JASN and CJASN adding to your cart from both journals. When you are ready to complete your purchse, select the Shopping Cart from the upper right hand corner of the page and follow the onscreen instructions.