Immune checkpoint inhibitors associated granulomatous small vessel vasculitis accompanied with tubulointerstitial nephritis: a case report

CD163 detection in immune check-point inhibitors-related acute interstitial nephritis

Background

Acute interstitial nephritis (AIN) is the most common renal immune-related adverse event after immune check-point inhibitors (ICI). We hypothesized that alternatively activated macrophages (CD163-M) could be involved in ICI-AIN and wished to evaluate the use of their soluble urinary form (us)CD163 as a non-invasive diagnostic marker.

Methods

CD163-M infiltrates were evaluated by both immune-histochemistry and multiplex immunofluorescence and imaging. usCD163 was detected with ELLA technology and evaluated together with urinary creatinine to be expressed as a ratio to creatinuria in ng/mmol. Clinical data were collected to perform correlations with renal function assessed by estimated glomerular filtration rate (eGFR).

Results

A retrospective cohort of 63 ICI-exposed patients with tubular acute kidney injury profile requiring a biopsy were selected. AIN patients (n = 44) were compared to acute tubular necrosis (ATN) patients (n = 19). CD163-M staining was detectable in all ICI-AIN patients, which was significantly higher than in ATN patients (18.4% vs 3.6% of area, P  = .005). CD163-M staining was restricted to the interstitial compartment. CD163-M infiltrate inversely correlated with initial eGFR (r = -0.6, P  = .003), and was positively correlated with delta eGFR, reflecting a renal improvement outcome (r = 0.48; P  = .02). usCD163 was well detected in urines of patients, but did not allow us to distinguish ATN from AIN patients at diagnosis. No correlation was observed, neither between usCD163 and CD163-M staining nor with renal response after 3 months of glucocorticoid tapering.

Conclusion

CD163-M are detected in ICI-AIN and correlate both with severity at diagnosis and better prognosis at 3 months. CD163-M may help us to distinguish AIN from ATN but, it does not allow us to assess ICI imputability. Although detected in urine, usCD163 is clearly not a surrogate biomarker for AIN diagnosis.

Pathological findings of immunotherapy-induced nephrotoxicity in a humanized immune system mouse model

While immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment, they can elicit organ-related immune-related adverse events (irAEs) such as kidney injury. Here, our study evaluated the ability of a humanized immune system (HIS) tumor-bearing mouse model to investigate ICI-mediated kidney injury. Non-humanized (BRGS) and humanized (HIS-BRGS) mice were implanted with human breast cancer cells and treated with either nivolumab (anti-PD-1) or a combination of nivolumab and ipilimumab (anti-CTLA-4) for four weeks. Histopathological analysis revealed that HIS-BRGS mice treated with ICIs exhibited significant interstitial nephritis and vasculitis/periarteritis, consistent with kidney phenotypes observed in patients. Combination therapy resulted in more extensive kidney pathology than nivolumab alone and exhibited an accumulation of T helper cells in the affected areas. Importantly, our results suggest that HIS-BRGS mice can effectively recapitulate features of ICI-induced kidney injury observed in patients and can be used to study mechanisms and prevention strategies to limit irAEs.

Predominant CD8+ cell infiltration and low accumulation of regulatory T cells in immune checkpoint inhibitor-induced tubulointerstitial nephritis

Immune checkpoint inhibitors (ICIs) can provide survival benefits to cancer patients; however, they sometimes result in the development of renal immune-related adverse events (irAEs). Tubulointerstitial nephritis (TIN) is the most representative pathological feature of renal irAEs. However, the clinicopathological entity and underlying pathogenesis of ICI-induced TIN are unclear. Therefore, we compared the clinical and histological features of this condition with those of non-ICI drug-induced TIN. Age and C-reactive protein levels were significantly higher in ICI-induced TIN, but there were no significant differences in renal function. Immunophenotyping of ICI-induced TIN showed massive T cell and macrophage infiltration with fewer B cells, plasma cells, neutrophils, and eosinophils. Compared with those in non-ICI drug-induced TIN, CD4+ cell numbers were significantly lower in ICI-induced TIN but CD8+ cell numbers were not significantly different. However, CD8/CD3 and CD8/CD4 ratios were higher in ICI-induced TIN. Moreover, CD25+ and FOXP3+ cells, namely regulatory T cells, were less abundant in ICI-induced TIN. In conclusion, T cell, B cell, plasma cell, neutrophil, and eosinophil numbers proved useful for differentiating ICI-induced and non-ICI drug-induced TIN. Furthermore, the predominant distribution of CD8+ cells and low accumulation of regulatory T cells might be associated with ICI-induced TIN development.

The histomorphology of the senescent kidney - the clinical relevance of specimen and biopsy findings in the elderly native kidneys

PURPOSE OF REVIEW

Renal pathology is crucial in diagnosing the ageing kidney. Recent technological advances enabled high-resolution molecular investigations into the complex mechanisms of ageing and senescence.

RECENT FINDINGS

The pathological analysis of large kidney tissue collections coupled with computer-assisted morphometry contributed to the establishment of age-related reference values for glomerular or vascular sclerosis, interstitial fibrosis, and tubular atrophy. Furthermore, new high-throughput proteomic and transcriptomic platforms have entered the field of pathology. When coupled with morphology information, these techniques facilitated the study of extracellular matrix modifications and the senescent immune system in the ageing kidney. Finally, iatrogenic complications are now frequent indications for diagnostic kidney biopsies in older patients, potentially accelerating kidney senescence.

SUMMARY

Recent pathology literature supports identifying and prognosticating sclerosing processes in ageing kidneys.

The Utility of Laboratory Investigations for the Assessment and Management of Rheumatic Immune Related Adverse Events

Immune checkpoint inhibitors (ICIs) have greatly improved survival of several cancers with historically very poor prognosis. ICIs act by stimulating the patient's own immune system to fight cancer. Simultaneously, this immune activation can lead to immune-related adverse events (irAEs), including rheumatic manifestations (Rh-irAEs). Rh-irAEs mimic primary rheumatic diseases including arthritis, polymyalgia rheumatica, myositis, vasculitis, sarcoidosis, and sicca. This article summarizes the latest evidence regarding the utility of laboratory investigations in Rh-irAEs.

PD-1/PD-L1 axis in organ fibrosis

Fibrosis is a pathological tissue repair activity in which many myofibroblasts are activated and extracellular matrix are excessively accumulated, leading to the formation of permanent scars and finally organ failure. A variety of organs, including the lung, liver, kidney, heart, and skin, can undergo fibrosis under the stimulation of various exogenous or endogenous pathogenic factors. At present, the pathogenesis of fibrosis is still not fully elucidated, but it is known that the immune system plays a key role in the initiation and progression of fibrosis. Immune checkpoint molecules are key regulators to maintain immune tolerance and homeostasis, among which the programmed cell death protein 1/programmed death ligand 1 (PD-1/PD-L1) axis has attracted much attention. The exciting achievements of tumor immunotherapy targeting PD-1/PD-L1 provide new insights into its use as a therapeutic target for other diseases. In recent years, the role of PD-1/PD-L1 axis in fibrosis has been preliminarily explored, further confirming the close relationship among PD-1/PD-L1 signaling, immune regulation, and fibrosis. This review discusses the structure, expression, function, and regulatory mechanism of PD-1 and PD-L1, and summarizes the research progress of PD-1/PD-L1 signaling in fibrotic diseases.