Clinicopathological and immunohistological features in childhood IgA nephropathy: a single-centre experience

The role of mononuclear phagocyte system in IgA nephropathy: pathogenesis and prognosis

Although the "multiple hits" theory is a widely accepted pathogenesis in IgA nephropathy (IgAN), increasing evidence suggests that the mononuclear/macrophage system plays important roles in the progression of IgAN; however, the exact mechanism is unclear. In the present study, we explored 1,067 patients in 15 studies and found that the number of macrophages per glomerulus was positively related with the degree of hematuria, and the macrophages in the glomeruli were mainly related to mesangial proliferation (M) in renal biopsy. In the tubulointerstitium, macrophages were significantly paralleled to tubulointerstitial α-SMA and NF-kB expression, tubulointerstitial lesion, tubule atrophy/interstitial fibrosis (T), and segmental glomerulosclerosis (S). In the glomeruli and tubulointerstitium, M1 accounted for 85.41% in the M classification according to the Oxford MEST-C, while in the blood, M1 accounted for 100%, and the patients with low CD89⁺ monocyte mean fluorescence intensity displayed more severe pathological characteristics (S1 and T1-2) and clinical symptoms. M1 (CD80⁺) macrophages were associated with proinflammation in the acute phase; however, M2 (CD163⁺) macrophages participated in tissue repair and remodeling, which correlated with chronic inflammation. In the glomeruli, M2 macrophages activated glomerular matrix expansion by secreting cytokines such as IL-10 and tumor necrosis factor-β (TGF-β), and M0 (CD68⁺) macrophages stimulated glomerular hypercellularity. In the tubulointerstitium, M2 macrophages played pivotal roles in renal fibrosis and sclerosis. It is assumed that macrophages acted as antigen-presenting cells to activate T cells and released diverse cytokines to stimulate an inflammatory response. Macrophages infiltrating glomeruli destroy the integrity of podocytes through the mesangio-podocytic-tubular crosstalk as well as the injury of the tubule.

An evaluation of the roles of hematuria and uric acid in defining the prognosis of patients with IgA nephropathy

In recent years, many significant advances have been made in determining which clinical manifestations and pathologic lesions can provide prognostic information for patients with IgA nephropathy (IgAN). However, some important questions remain, including the long-term consequences of hematuria, both macroscopic (MH) and microscopic (mH), in patients with IgAN. The importance of distinguishing patients who have a single episode of MH of long duration from those with recurrent episodes of short duration and the prognostic importance of the episodes of acute kidney injury (AKI) that sometimes accompany episodic MH will be discussed. Studies that have evaluated the mechanisms that may be responsible for recurrent MH and the toxic effects of red blood cells (RBCs), or their constituents, on kidney tubules will also be addressed. In the last section, I will review the evidence that hyperuricemia (HU) may be a significant independent risk factor for progressive kidney disease in patients with IgAN.

Intensity of Macrophage Infiltration in Glomeruli Predicts Response to Immunosuppressive Therapy in Patients with IgA Nephropathy

BACKGROUND

The lack of a tool for predicting the response to immunosuppressive therapy in IgA nephropathy (IgAN) limits patient-specific risk stratification and early treatment decision making. Models for predicting response to immunosuppression in IgAN that can be applied at the time of kidney biopsy are needed.

METHODS

This prospective cohort study involved 621 Chinese patients with IgAN who were at high risk for disease progression and had persistent proteinuria ≥1 g/d, despite 3 months of optimized supportive care with renin-angiotensin system inhibitors. Participants received immunosuppressive therapy for a median of 18 months. We used immunochemistry to identify macrophage and lymphocyte infiltrates in biopsy specimens and digital image analysis to quantify them. The outcome was response to immunosuppression, defined as complete or partial remission within 12 months of immunosuppression.

RESULTS

Kidney infiltration of CD68 + and CD206 + macrophages increased in patients with IgAN. Having higher levels of glomerular CD206 + macrophage infiltration was associated with a 40-fold increased probability of response to immunosuppression in adjusted analysis compared with having lower levels. Patients with a higher intensity of glomerular CD68 + infiltrates had a 13-fold increase in probability of responding to immunosuppression. Intensity of glomerular CD206 + and CD68 + macrophage infiltration predicted the response to immunosuppression (area under the curve [AUC], 0.84; 95% CI, 0.81 to 0.88). The AUC increased to 0.87 (95% CI, 0.84 to 0.91) in a model combining the infiltration score of CD206 + and CD68 + infiltrates with the MEST-C score and clinical data at biopsy.

CONCLUSIONS

Intensity of glomerular macrophage infiltration predicted response to immunosuppressive therapy in patients with IgAN who were at high risk of progression, and may help physicians identify patients who will benefit from such treatment.

The role of transcriptional factor D-site-binding protein in circadian CCL2 gene expression in anti-Thy1 nephritis

Mesangial proliferative glomerulonephritis (MsPGN) is an inflammatory disease, but both the nature of disease progression and its regulation remain unclear. In the present study, we monitored the course of anti-Thy1 nephritis from days 1 to 5 and established gene expression profiles at each time point using microarrays to explore the development of inflammation. According to the gene expression profiles, macrophage infiltration (triggered by CCL2 activation) was evident on day 1 and enhanced inflammation over the next few days. We screened for genes with expression levels similar to CCL2 and found that the upregulation of the circadian gene albumin D-site-binding protein (DBP) was involved in CCL2 activation in mesangial cells. More importantly, CCL2 expression showed oscillatory changes similar to DBP, and DBP induced peak CCL2 expression at 16:00 a clock on day 1 in the anti-Thy1 nephritis model. We knocked down DBP through transfection with a small interfering RNA (siRNA) and used RNA sequencing to identify the DBP-regulated TNF-α-CCL2 pathway. We performed chromatin immunoprecipitation sequencing (ChIP-Seq) and the dual luciferase assay to show that DBP bound to the TRIM55 promoter, regulating gene expression and in turn controlling the TNF-α-CCL2 pathway. In conclusion, DBP-regulated circadian CCL2 expression by the TRIM55-TNF pathway in injured mesangial cells at an early stage, which promoted macrophage recruitment and in turn triggered infiltration and inflammation in a model of anti-Thy1 nephritis.

Crianças com doenças renais: associação entre diagnósticos de enfermagem e seus componentes

Resumo Objetivo Identificar os diagnósticos de enfermagem em crianças com doenças renais e analisar a associação entre esses diagnósticos, suas características definidoras e os fatores relacionados ou de risco. Métodos Estudo transversal, quantitativo, realizado com 68 crianças internadas em um Hospital Universitário no Nordeste do Brasil. Para a coleta de dados foi utilizado um roteiro de entrevista e exame físico. A elaboração dos diagnósticos foi processual e os dados foram analisados por meio da estatística descritiva e inferencial. Resultados Identificaram-se 13 diagnósticos. Os mais frequentes tiveram relação estatisticamente significativa com seus componentes e estavam inseridos nos domínios promoção da saúde, eliminação/troca, nutrição, segurança/proteção e atividade/repouso. Conclusão Os diagnósticos de enfermagem mais prevalentes foram volume de líquidos excessivo, risco de infecção, eliminação urinária prejudicada, fadiga e proteção ineficaz. Em geral, as características definidoras e os fatores dos diagnósticos apresentaram associação significante.

Expression of prorenin receptor in renal biopsies from patients with IgA nephropathy

Prorenin receptor (PRR) has been implicated in the onset and progression of various renal diseases, though its possible association with immunoglobulin A (IgA) nephropathy remains unclear. In the present study, we tried to clarify expression and pathophysiological significance of PRR in IgA nephropathy. We immunohistochemically assessed PRR levels in renal biopsy specimens from 48 patients with IgA nephropathy and evaluated its relevance to the clinical and pathological features of the disease. PRR was detected mainly in renal tubular cells, which was confirmed at the subcellular level using immunoelectron microscopy. The PRR-positive area (%PRR area) correlated with daily urinary protein, which is known to reflect disease severity (r=0.286, P=0.049). PRR levels were weaker in tubular cells bordering areas of severe interstitial fibrosis, where α-smooth muscle actin-positive myofibroblasts were present. We also used immunohistochemical detection of microtubule-associated protein-1 light chain 3 (LC3) and electron microscopy to assess autophagy, a cytoprotective mechanism downstream of PRR. We noted an apparent coincidence between autophagy activation in tubular cells and PRR expression in the same cells. Taken together, our findings suggest that renal expression of PRR in IgA nephropathy may be a compensatory response slowing disease progression by preventing tubular cell death and subsequent fibrosis through activation of cytoprotective autophagic machinery. Further studies using different type of kidney diseases could draw conclusion if the present finding is a generalized observation beyond IgA nephropathy.