Huo Y, Deng R, Liu Q, Fogo AB, Yang H. AI applications in renal pathology. Kidney Int. 2021 Jun;99(6):1309-1320. [PubMed link]
The authors provide an integrated review on current and possible future applications in AI-assisted renal pathology, by including perspectives from computer scientists and renal pathologists.
Demir E, Turkmen A, Sever MS. Risk factors, pathogenesis, presentation and management of BK virus infection in kidney transplantation. Nephrol Dial Transplant. 2021 May 27;36(6):985-987. [PubMed link]
"Although BKVN can potentially result in graft loss, it may be prevented or at least the risk for BKVN can be minimized by a careful screening approach". A review.
Bu L, Mirocha J, Haas M. Immunoglobulin G/albumin staining in tubular protein reabsorption droplets in minimal change disease and focal segmental glomerulosclerosis. Nephrol Dial Transplant. 2021 May 27;36(6):1016-1022. [PubMed link]
As protein excretion in MCD has been described as being albumin-selective, the authors examined whether the ratio of immunoglobulin G (IgG)/albumin staining in protein reabsorption droplets (tPRD) might help distinguish MCD from FSGS. They concluded that: "A ratio of ≤0.33 was associated with MCD, whereas a ratio of 1.0 was most often seen with FSGS-NOS."
Helgeson ES, Mannon R, Grande J, Gaston RS, Cecka MJ, Kasiske BL, Rush D, Gourishankar S, Cosio F, Hunsicker L, Connett J, Matas AJ. i-IFTA and chronic active T cell-mediated rejection: A tale of 2 (DeKAF) cohorts. Am J Transplant. 2021 May;21(5):1866-1877. [PubMed link]
In this interesting research, the authors conclude: "the diagnostic category 'chronic active T cell mediated rejection' should be reconsidered".
Caravaca-Fontán F, Trujillo H, Alonso M, et al. Validation of a Histologic Scoring Index for C3 Glomerulopathy. Am J Kidney Dis. 2021 Epub ahead of print. [PubMed link]
With a proposed prognostic Histologic Index that include activity score (mesangial hypercellularity, endocapillary proliferation, MPGN morphology, leukocyte infiltration, crecents, fibrinoid necrosis, and interstitial inflammation) and chronicity score (glomerulosclerosis, interstitial fibrosis, tubulary atrophy, and arteriosclerosis). Only tubular atrophy and interstitial fibrosis were identified as predictors in a model with histological variables. When the Total Activity Score and Total Chronicity Score were added to the model, only the latter (Total Chronicity Score) was identified as an independent predictor of kidney failure.
Vaulet T, Divard G, Thaunat O, Lerut E, Senev A, Aubert O, Van Loon E, Callemeyn J, Emonds MP, Van Craenenbroeck A, De Vusser K, Sprangers B, Rabeyrin M, Dubois V, Kuypers D, De Vos M, Loupy A, De Moor B, Naesens M. Data-driven Derivation and Validation of Novel Phenotypes for Acute Kidney Transplant Rejection using Semi-supervised Clustering. J Am Soc Nephrol. 2021 May 3;32(5):1084-1096. [PubMed link]
The current Banff classification is a purely empiric classification, it was not primarily developed to reflect clinically meaningful outcomes such as graft failure, and allows ambiguous phenotypes to overlap. This paper describes the use of data-driven clustering methods to produce a phenotypic reclassification of kidney transplant rejection that is both histologically and clinically relevant. Six novel cluster phenotypes are validated on external data. Each of these new phenotypes is significantly associated with graft failure and overcomes the current limitations of intermediate and mixed phenotypes. The data-driven phenotypic reclassification of kidney transplant rejection is a proof of concept, opening future research directions.
Vasquez-Rios G, Menon MC. Kidney Transplant Rejection Clusters and Graft Outcomes: Revisiting Banff in the Era of "Big Data". J Am Soc Nephrol. 2021 May 3;32(5):1009-1011. [PubMed link]
An very interesting editorial comment on the previos article.
Lau WL, Zuckerman JE, Gupta A, Kalantar-Zadeh K. The COVID-Kidney Controversy: Can SARS-CoV-2 Cause Direct Renal Infection? Nephron. 2021;145(3):275-279. [PubMed link]
TEM is challenging as numerous ultrastructures (termed viral-like particles) can mimic viruses. For example, multivesicular bodies in podocyte cytoplasm and clathrin-coated endocytosed vesicles in tubular epithelial cells can have the appearance of a viral corona. Several investigations of pre-COVID era biopsies have demonstrated structures morphologically identical to those reported as “SARS-CoV-2 viral particles”. At this time, whether inhibition of viral infection and replication directly modulates kidney damage is inconclusive.
Haas M. Towards harmony in defining and reporting glomerular diseases on kidney biopsy. Curr Opin Nephrol Hypertens. 2021 May 1;30(3):280-286. [PubMed link]
A review of recent efforts to develop uniformity and precision in defining individual glomerular histologic and ultrastructural lesions and proposals for developing greater uniformity in reporting of glomerular diseases.
Moledina DG, Simonov M, Yamamoto Y, Alausa J, Arora T, Biswas A, Cantley LG, Ghazi L, Greenberg JH, Hinchcliff M, Huang C, Mansour SG, Martin M, Peixoto A, Schulz W, Subair L, Testani JM, Ugwuowo U, Young P, Wilson FP. The Association of COVID-19 With Acute Kidney Injury Independent of Severity of Illness: A Multicenter Cohort Study. Am J Kidney Dis. 2021 Apr;77(4):490-499.e1. [PubMed link]
COVID-19 is associated with high rates of AKI not fully explained by adjustment for known risk factors. This suggests the presence of mechanisms of AKI not accounted for in this analysis, which may include a direct effect of COVID-19 on the kidney or other unmeasured mediators.
Alsharhan L, Beck LH Jr. Membranous Nephropathy: Core Curriculum 2021. Am J Kidney Dis. 2021 Mar;77(3):440-453. [PubMed link] [Free full text]
Sethi S. New 'Antigens' in Membranous Nephropathy. J Am Soc Nephrol. 2021 Feb;32(2):268-278. [PubMed link]
Use of laser microdissection and mass spectrometry enabled identification of 4 new targets antigens causing MN: exotosin 1 (EXT1) - exotosin 2 (EXT2), NELL1, Sema3B, and PCDH7. Further studies are required to understand the pathophysiology, response to treatment, and outcomes of these new MNs.
Del Sordo R, Covarelli C, Brugnano R, Sciri R, Bellezza G, Mandarano M, Sidoni A. PLA2R Immunohistochemistry Staining in Membranous Glomerulopathy: A Challenging Stain to Interpret But a Potentially Useful Diagnostic Tool. Appl Immunohistochem Mol Morphol. 2021 Epub ahead of print. [PubMed link]
Detection of PLA2R antigen in renal tissue, with immunohistochemistry (PLA2R IHC), strongly correlates with serum PLA2R-Ab, although in literature has no univocal interpretation.
Akilesh S, Nast CC, Yamashita M, Henriksen K, Charu V, Troxell ML, Kambham N, Bracamonte E, Houghton D, Ahmed NI, Chong CC, Thajudeen B, Rehman S, Khoury F, Zuckerman JE, Gitomer J, Raguram PC, Mujeeb S, Schwarze U, Shannon MB, De Castro I, Alpers CE, Najafian B, Nicosia RF, Andeen NK, Smith KD. Multicenter Clinicopathologic Correlation of Kidney Biopsies Performed in COVID-19 Patients Presenting With Acute Kidney Injury or Proteinuria. Am J Kidney Dis. 2021 Jan;77(1):82-93.e1. [PubMed link]
A case series of 17 patients with SARS-CoV-2 infection confirmed by reverse transcriptase-polymerase chain reaction, only 3 presented with severe COVID-19 symptoms. Acute kidney injury (n=15) and proteinuria (n=11) were the most common indications for biopsy and these symptoms developed concurrently or within 1 week of COVID-19 symptoms in all patients. Acute tubular injury (n=14), collapsing glomerulopathy (n=7), and endothelial injury/thrombotic microangiopathy (n=6) were the most common histologic findings. 2 of 3 transplant recipients developed active antibody-mediated rejection weeks after COVID-19.
Angelotti ML, Antonelli G, Conte C, Romagnani P. Imaging the kidney: from light to super-resolution microscopy. Nephrol Dial Transplant. 2021 Jan 1;36(1):19-28. [PubMed link]
This review provides an overview of available kidney imaging strategies, with a focus on the possible impact of the most recent technical improvements.
Kudose S, Santoriello D, Debiec H, Canetta PA, Bomback AS, Stokes MB, Batal I, Ronco P, D'Agati VD, Markowitz GS. The clinicopathologic spectrum of segmental membranous glomerulopathy. Kidney Int. 2021 Jan;99(1):247-255. [PubMed link]
Loupy A, Haas M, Roufosse C, et al. The Banff 2019 Kidney Meeting Report (I): Updates on and clarification of criteria for T cell- and antibody-mediated rejection. Am J Transplant. 2020;20(9):2318-2331. [PubMed link].
Segmental membranous glomerulopathy (MGN) is a glomerulonephritis with only segmental immune deposits. It is a rare PLA2R-negative variant of MGN with favorable prognosis, even in the absence of immunosuppressive treatment.