Denic, Aleksandar; Bogojevic, Marija; Mullan, Aidan F.; Sabov, Moldovan; Asghar, Muhammad S.; Sethi, Sanjeev; Smith, Maxwell L.; Fervenza, Fernando C.; Glassock, Richard J.; Hommos, Musab S.; Rule, Andrew D.

JASN October 2022, 33 (10) 1927-1941; DOI: https://doi.org/10.1681/ASN.2022030234

Chronic damage as assessed in the kidney biopsy is an independent predictor of renal function decline (doi: 10.1681/ASN.2017121260, doi: 10.1681/ASN.2021010044). Different grading systems for chronicity have been published: some are diagnosis-specific, others can be used regardless of disease etiology.

The success of histologic grading schemes partly depends on ease-of-use; too detailed or time-intensive systems generally do not make it to diagnostic practice. In a recent study published in JASN, the authors examine a morphometry-based approach (with quantification of chronicity parameters assisted by software) to a standard, commonly used ‘eyeballing’ or visual estimation approach based on glomerulosclerosis, interstitial fibrosis/ tubular atrophy (IFTA) and arteriosclerosis (DOI: 10.1016/j.kint.2017.01.002). The study population consisted of a historical cohort of 353 biopsies with follow-up data, making evaluation on hard end points possible (namely, evolution to end-stage kidney disease or progressive chronic kidney disease, respectively emerging in 21% and 44% of patients, over a median follow-up of 7.5 years). Interestingly, morphometry for the above-described features did not substantially differ in predicting outcomes compared to eyeballing.

Additionally, the authors took the opportunity to examine less ‘classical’ measures of chronicity such as IFTA foci density and arteriolar hyalinosis by morphometry. A ten-point score using percentage of glomerulosclerosis, percentage of IFTA, IFTA foci density and arteriolar hyalinosis showed a superior performance. In the discussion, the authors hypothesize that this actually reflects pathogenesis of chronic damage better. The authors also claim they will work on translating this into a new visual estimation approach and as such, close the circle.

Blogged by Amélie Dendooven

Andrew J.B. Watts, Keith H. Keller, Gabriel Lerner, Ivy Rosales, A. Bernard Collins, Miroslav Sekulic, Sushrut S. Waikar, Anil Chandraker, Leonardo V. Riella, Mariam P. Alexander, Jonathan P. Troost, Junbo Chen, Damian Fermin, Jennifer L. Yee, Matthew G. Sampson, Laurence H. Beck, Joel M. Henderson, Anna Greka, Helmut G. Rennke and Astrid Weins. 

JASN January 2022, 33 (1) 238-252; DOI: https://doi.org/10.1681/ASN.2021060794

Blogged by Amélie Dendooven

Minimal change disease (MCD) is a common diagnosis in children and adults, and can be sparked by triggers such as infections or vaccination.  While a B-cell etiology was already suspected, a recent paper goes a step further. The authors show that nephrin autoantibodies are present in a subset of patients with active MCD, correlate with disease activity and associate with the presence of punctate IgG in the biopsy (colocalizing with nephrin) as evaluated by IF studies. Moreover, a case report of a 27-year old patient known with MCD is presented where pretransplant nephrin antibodies associate with massive proteinuria recurrence after transplantation. Although many questions remain, this is an exciting paper on disease mechanism in one of the most common proteinuric diseases and it invites us all to look more closely at IF in MCD.

Gurmukteshwar Singh, Mark Massak, Michael Czaplicki, Evan Young, Shree Sharma, Alex Chang, Ashok Bhanushali and Prince Anand.
JASN September 2021, https://doi.org/10.1681/ASN.2021070898

Blogged by Amélie Dendooven

Pathology diagnostics is dependent on adequate tissue sampling. Generally speaking, a kidney biopsy should contain at least 10 glomeruli for being considered representative. A large proportion of kidney biopsies now are performed by radiologists. Also, smaller biopsy needles are being used. In this setting, it is especially important to have good bedside evaluation of tissue adequacy, so that, when needed, an extra biopsy core can be immediately obtained to ensure biopsy adequacy.
In a recent study from Singh et al., smartphones were used as a means to assess adequacy of kidney biopsy samples at the bedside. A picture of the biopsy core – taken by a smartphone camera- is put on a larger pc screen and zoomed in. In this fashion, one easily obtains a zoomed-in image where glomeruli can be readily identified without the need for additional (microscopy) equipment. The study shows a good correlation between this bedside smartphone approach and the microscopic evaluation of biopsy adequacy by trained staff in the pathology laboratory. However, the study is limited in sample size and should be followed by larger studies for validation. Also, as pathologists we would like to add a warning to prevent the biopsy from drying out while doing this bedside assessment (e.g. by keeping it moist).