Fenoglio, Roberta

Immune checkpoint inhibitors (ICIs) have transformed cancer therapy but are associated with immune-related adverse events, including ICI–associated acute kidney injury (ICI-AKI). ICI-AKI presents diagnostic and management challenges and can influence decisions regarding immunosuppression and ICI rechallenge, with important implications for both kidney and cancer outcomes. An international, multidisciplinary panel convened at the 34th Acute Disease Quality Initiative (ADQI) consensus conference in September 2024. Systematic literature searches of PubMed were conducted to identify studies on the epidemiology, mechanisms, diagnosis, management, rechallenge, and outcomes of ICI-AKI. The meeting followed the established ADQI process and used a modified Delphi method to achieve consensus. Evidence was reviewed and appraised by workgroups, and consensus statements were developed through structured discussion and voting. Observational data suggest that AKI occurs in up to 20% of patients receiving ICIs, with ICI-AKI accounting for approximately 2%–5% of cases. Acute tubulointerstitial nephritis is the most common lesion, observed in 80%–90% of biopsies, although glomerular diseases are increasingly recognized. No clinical features reliably distinguish ICI-AKI from other causes of AKI, and kidney biopsy remains the diagnostic gold standard. Emerging urinary, circulating, and imaging biomarkers show promise but are not yet ready for routine clinical use. Early glucocorticoid initiation (within 3 days of ICI-AKI diagnosis versus >3 days after diagnosis) is associated with higher rates of kidney recovery, although optimal dosing and duration remain uncertain. Recurrent ICI-AKI occurs in fewer than 20% of patients undergoing ICI rechallenge. Management of high-risk populations, including kidney transplant recipients and patients with autoimmune disease or advanced CKD, requires individualized, multidisciplinary decision-making. ICI-AKI is an important and potentially reversible complication of cancer immunotherapy; these consensus statements provide a framework for diagnosis and management, support cautious ICI rechallenge in selected patients, and identify priorities for future research.

ABSTRACT Background and hypothesis Podocytopathy associated with likely pathogenic/pathogenic variants of Transient receptor potential cation channel subfamily C member 6 (TRPC6) (TRPC6-AP) has been recognized for about 20 years. As a result of its rarity however, the spectrum of clinical phenotypes and genotype–phenotype correlation of TRPC6-AP remains poorly understood. Here, we characterized clinical, histological and genetic correlates of familial and sporadic patients with TRPC6-AP. Methods In this multicentre observational study, an online questionnaire followed by a systematic literature review was performed to create a cohort with comprehensive data on genetic and clinical outcomes [age of onset, clinical presentation, treatment response, kidney biopsy findings and progression to kidney failure (KF)]. Logistic regression, Cox proportional hazards model and Kaplan–Meier analyses investigated the associations between genetic variants and disease progression. Results Among 87 families (96 familial and 45 sporadic cases), 31 distinct missense TRPC6 variants (including 2 novel) were identified, with c.2683C>T p.(Arg895Cys) and c.523C>T p.(Arg175Trp) the commonest variants. Proteinuric kidney disease/nephrotic syndrome was the most common clinical presentation (83.7%), while focal segmental glomerulosclerosis was the most common histological finding (89.4%). By 33 (interquartile range 17–40) years, 48.9% (69/141) of patients had progressed to KF. Sporadic TRPC6-AP demonstrated an earlier progression to KF than familial cases (P = .001) and were more likely to present with nephrotic syndrome [odds ratio 4.34 (1.85–10.15); P = .001]. Gain-of-function TRPC6 variants were more frequent in familial than sporadic TRPC6-AP (70.8% vs 44.4%; P = .004). Compared with patients with other TRPC6 variants, patients with TRPC6 p.R175W and p.R895C variants progressed to KF earlier [median kidney survival of 21 years, hazard ratio 2.985 (95% confidence interval 1.40–5.79); and 38 years, hazard ratio 1.65 (95% confidence interval 1.01–2.81), respectively, log-rank P = .005]. Conclusion Our study shows unique clinical and genetic correlations of TRPC6-AP, which may enable personalized care and promising novel therapies.

Abstract Light chain cast nephropathy (LCCN) in multiple myeloma often leads to severe and poorly reversible acute kidney injury. Severe renal impairment influences the allocation of chemotherapy and its tolerability; it also affects patient survival. Whether renal biopsy findings add to the clinical assessment in predicting renal and patient outcomes in LCCN is uncertain. We retrospectively reviewed clinical presentation, chemotherapy regimens, hematologic response, and renal and patient outcomes in 178 patients with biopsy-proven LCCN from 10 centers in Europe and North America. A detailed pathology review, including assessment of the extent of cast formation, was performed to study correlations with initial presentation and outcomes. Patients presented with a mean estimated glomerular filtration rate (eGFR) of 13 ± 11 mL/min/1.73 m2, and 82% had stage 3 acute kidney injury. The mean number of casts was 3.2/mm2 in the cortex. Tubulointerstitial lesions were frequent: acute tubular injury (94%), tubulitis (82%), tubular rupture (62%), giant cell reaction (60%), and cortical and medullary inflammation (95% and 75%, respectively). Medullary inflammation, giant cell reaction, and the extent of cast formation correlated with eGFR value at LCCN diagnosis. During a median follow-up of 22 months, mean eGFR increased to 43 ± 30 mL/min/1.73 m2. Age, β2-microglobulin, best hematologic response, number of cortical casts per square millimeter, and degree of interstitial fibrosis/tubular atrophy (IFTA) were independently associated with a higher eGFR during follow-up. This eGFR value correlated with overall survival, independently of the hematologic response. This study shows that extent of cast formation and IFTA in LCCN predicts the quality of renal response, which, in turn, is associated with overall survival.