CD163 and calprotectin have been proposed as biomarkers of active renal vasculitis. This study aimed to determine whether the combination of serum/urine calprotectin (s/uCalprotectin) and urinary soluble CD163 (suCD163) increases their individual performance as activity biomarkers. We included 138 patients diagnosed with ANCA vasculitis (n = 52 diagnostic phase, n = 86 remission). The study population was divided into the inception (n = 101) and the validation cohort (n = 37). We determined the s/uCalprotectin and suCD163 concentration using ELISA at the diagnostic or at the remission phase. ROC curves were conducted to assess the biomarkers’ classificatory values. We elaborated a combinatorial biomarker model in the inception cohort. The ideal cutoffs were used in the validation cohort to confirm the model's accuracy in the distinction between active disease and remission. We added the classical ANCA vasculitis activity biomarkers to the model to increase the classificatory performance. sCalprotectin and suCD163’s concentration was higher in the diagnostic compared to the remission phase, P = 0 013 and P < 0,0001. According to the ROC curves, sCalprotectin and suCD163 were accurate biomarkers to discern activity [AUC 0,73 (0,59–0 806), P = 0 015 and 0,88 (0,79–0,97), P < 0,0001]. The combinatory model with the best performance in terms of sensitivity, specificity, and likelihood ratio included sCalprotectin, suCD163, and haematuria. Regarding the inception and the validation cohort, we obtained a sensibility, specificity, and a likelihood ratio of 97%, 90%, and 9,7 and 78%, 94%, and 13, respectively. In patients with ANCA vasculitis, a predictive model combining sCalprotectin, suCD163, and haematuria could be useful in detecting active kidney disease.

Acute interstitial nephritis (AIN) related to immune checkpoint inhibitors (ICI-AIN) has a not completely understood pathophysiology. Our objectives were to analyze possible biomarkers for the differentiation between acute tubular necrosis (ATN) and AIN, especially in cancer patients, and to study the participation of the immune checkpoint pathway in ICI-AIN. We performed an observational study. We recruited patients with incident diagnosis of ICI-AIN (n = 19). We measured soluble PD-1 (sPD-1), sPD-L1, and sPD-L2 in serum and urine at diagnosis and compared to it patients with non-ICI-related AIN (non-ICI-AIN) (n = 18) and ATN (n = 21). The findings were validated in an independent cohort from another institution (n = 30). Also, we performed PD-L1 and PD-L2 immunostaining of kidney biopsies from patients with ICI-AIN and compared to patients with non-ICI-AIN. Urinary sPD-1 (usPD-1) was higher in patients with AIN compared to ATN (P = .03). Patients with AIN also showed higher serum sPD-1 (ssPD-1) than patients with ATN (P = .021). In cancer patients, usPD-1 2.64/mm² PD-L2 positive tubules was higher among patients with ICI-AIN compared to non-ICI-AIN (P = .034). There was a positive correlation (P = .009, r = 0.72) between usPD-1 and the number of PD-L1 positive tubules. UsPD-1 and ssPD-1 are higher in AIN than ATN. Moreover, there was a strong correlation between usPD-1 and renal tubular PD-L1 expression. Our findings suggest a role of usPD-1 as non-invasive biomarker to differentiate ICI-AIN from ATN, especially in cancer patients, which has been confirmed in an external validation cohort.

Diabetes mellitus (DM) in kidney transplant recipients (KTR) is a risk factor for mortality, increases the risk of infections and, in the long term, can lead to graft loss due to diabetic kidney disease. A preventive approach applied to those on the waiting list could decrease the incidence of post-transplant DM (PTDM) by detecting those patients at risk, thus allowing strategies to minimize the probability of developing a New Onset Diabetes After Transplant (NODAT). On the other hand, modifications of immunosuppressive therapy may improve glucose control in patients with KTR. In recent years, two new classes of antidiabetic drugs and non-steroidal mineralocorticoid receptor antagonists have demonstrated cardiovascular and renal benefits in randomized clinical trials where the transplant population has not been represented. Because of the potential benefit expected in this population, the clinical use of glucagon-like peptide-1 receptor agonists (GLP-1RA), sodium-glucose cotransporter 2 inhibitors (SGLT2i) and finerenone is increasing in the kidney transplant setting. This review focuses on comprehensive pharmacological interventions in KTR with glucose metabolism disorders. In-depth knowledge in this area will allow prevention and identification of potential adverse effects or drug interactions in the clinical course of KTR with DM.

Objective The PD-1 axis promotes protection against autoimmunity. Immune checkpoint (IC) molecules performance in anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) remains unknown. This study aims to assess the IC pathway’s role in the AAV’s pathophysiology. Methods We recruited 88 AAV from our centre as a discovery cohort (acute=42, remission=46) and 30 patients from another institution for external validation (acute=16, remission=14). Serum, urine and peripheral blood mononuclear cells (PBMCs) were collected. In vitro IC molecules production by lymphocytes was studied with and without MPO/PR3 antigen stimulus. Cell culture supernatant (SN) was obtained by centrifugation. PD-1, PD-L1 and PD-L2 concentrations were assessed in serum (s), urine (u) and SN of AAV and healthy controls (HC) using a multiplex assay. PD-1 and PD-L1’s expression was analysed in six diagnostic kidney biopsies. Results uPD-1 and uPD-L2’s concentration was lower in AAV than HC (p<0.0001, p=0.0075). Acute patients exhibited lower uPD-L2 levels compared with those in remission (p=0.036). Similarly, PBMCs showed reduced PD-1 production than HC (stimulated group p=0.04, unstimulated p=0.0074). Furthermore, patients with inflammatory renal lesions had fewer PD-1-positive interstitial cells/staining intensity compared with those with sclerotic lesions. Contradictorily, sPD-1 and sPD-L1’s concentration was higher in AAV than HC (p=0.007, p<0.0001) with acute patients exhibiting elevated sPD-1 levels compared with those in remission (p=0.0051). Serum and urine findings were confirmed in the validation cohort. Conclusions Results in urine, SN and histology suggest IC pathway abolition during acute disease restored in remission and contribute to understand PD-1 axis’s role in AAV proposing it as a new biomarker of disease activity.

Immune checkpoint inhibitors are essential treatments for many oncologic diseases, but with well-known immune-related adverse events, such as acute interstitial nephritis (ICI-AIN). We investigated novel potential biomarkers that could assist in the diagnosis and follow-up of this condition and that are related to the active pathogenic pathways involved. We measured urinary soluble PD-1, PD-L1 and PD-L2, as well as chemokines CXCL5, CXCL9, CXCL10, CXCL11, CCL2, CCL3, CCL5 and cytokines IL-6 and IL-12p70 performing a Luminex assay in urine from patients with ICI-AIN (n = 35) and compared them with patients with AIN from other causes (non-ICI AIN) (n = 29) and ATN (n = 26). We found that CXCL5, CXCL9, CXCL10, CXCL11, CCL5 and IL-6 were higher in patients with ICI-AIN than in those with ATN, and all of them but CXCL9 and IL-6 were also higher in patients with ICI-AIN compared with non-ICI AIN. We also determined these molecules at follow-up for ICI-AIN patients (40 samples from 22 patients) and found that concentrations of CXCL9, CXCL10, CXCL11 and CCL2 decreased after treatment. The decrease of CXCL9 and CXCL10 correlated with greater kidney function recovery at one-year follow-up. These molecules could serve as noninvasive biomarkers and may aid fine patient monitoring.

The inflammasome regulates the innate inflammatory response and is involved in autoimmune diseases. In this study, we explored the levels of IL-18 and IL-1β in serum and urine and the influence of various single-nucleotide polymorphisms (SNPs) on kidney lesions at diagnosis in patients with ANCA-associated vasculitis (AAV) and their clinical outcomes. Ninety-two patients with renal AAV were recruited, and blood and urine were collected at diagnosis. Serum and urine cytokine levels were measured by ELISA. DNA was extracted and genotyped using TaqMan assays for SNPs in several inflammasome genes. Lower serum IL-18 (p = 0.049) and the IL-18 rs187238 G-carrier genotype (p = 0.042) were associated with severe fibrosis. The IL-18 rs1946518 TT genotype was associated with an increased risk of relapse (p = 0.05), whereas GG was related to better renal outcomes (p = 0.031). The rs187238 GG genotype was identified as a risk factor for mortality within the first year after AAV diagnosis, independent of the requirement for dialysis or lung involvement (p = 0.013). We suggest that decreased cytokine levels could be a surrogate marker of scarring and chronicity of the renal lesions, together with the rs187238 GG genotype. If our results are validated, the rs1946518 TT genotype predicts the risk of relapse and renal outcomes during follow-up.