Advances in human antiglomerular basement membrane disease

Serum BAFF and APRIL might be associated with disease activity and kidney damage in patients with anti-glomerular basement membrane disease

AIM

B cell activating factor belonging to the tumour necrosis factor family (BAFF) and a proliferation inducing ligand (APRIL) are two tumour necrosis factor (TNF)-like cytokines that were found to be elevated in many autoimmune diseases. Anti-glomerular basement membrane (GBM) disease is a typical severe autoimmune disease characterized by raised serum anti-GBM antibodies. In this study we aimed to detect the serum levels of BAFF and APRIL in patients with anti-GBM disease, and their clinical significance was further analyzed.

METHODS

Forty-seven patients with anti-GBM disease were enrolled in this study. Forty-eight healthy individuals were used as normal controls. The levels of serum BAFF and APRIL were assessed using commercially available enzyme linked immunosorbent assay kits. The association between the levels of serum BAFF and APRIL, and the clinical and pathological parameters were further evaluated.

RESULTS

The serum levels of BAFF and APRIL in patients with anti-GBM disease were significantly higher than that in normal controls (12.3 ± 14.1 ng/mL vs. 0.9 ± 0.3 ng/mL, P < 0.001; 19.1 ± 22.9 ng/mL vs. 1.6 ± 4.6 ng/mL, P < 0.001), respectively. The levels of serum APRIL were correlated with the titres of anti-GBM antibodies (r = 0.347, P = 0.041), and the levels of serum BAFF were associated with the percentage of glomeruli with crescents (r = 0.482, P = 0.015) in patients with anti-GBM disease.

CONCLUSION

The levels of serum BAFF and APRIL were raised in patients with anti-GBM disease and might be associated with disease activity and kidney damage.

Anti-glomerular basement membrane antibody disease is an uncommon cause of end-stage renal disease

There are few reports regarding outcomes of anti-glomerular basement membrane (GBM) disease in patients who underwent renal replacement therapy. To help define this we studied all patients with anti-GBM disease who started renal replacement therapy for end-stage renal disease (ESRD) in Australia and New Zealand (ANZDATA Registry) between 1963 and 2010 encompassing 449 individuals (0.8 percent of all ESRD patients). The median survival on dialysis was 5.93 years with death predicted by older age and a history of pulmonary hemorrhage. Thirteen patients recovered renal function, although 10 subsequently experienced renal death after a median period of 1.05 years. Of the 224 patients who received their first renal allograft, the 10-year median patient and renal allograft survival rates were 86% and 63%, respectively. Six patients experienced anti-GBM disease recurrence in their allograft, which led to graft failure in two. Using multivariable Cox regression analysis, patients with anti-GBM disease had comparable survival on dialysis or following renal transplantation (hazard ratios of 0.86 and 1.03, respectively) compared to those with ESRD due to other causes. Also, renal allograft survival (hazard ratio of 1.03) was not altered compared to other diseases requiring a renal transplant. Thus, anti-GBM disease was an uncommon cause of ESRD, and not associated with altered risks of dialysis, transplant or first renal allograft survival. Death on dialysis was predicted by older age and a history of pulmonary hemorrhage.

Basic and translational concepts of immune-mediated glomerular diseases

Genetically modified immune responses to infections and self-antigens initiate most forms of GN by generating pathogen- and danger-associated molecular patterns that stimulate Toll-like receptors and complement. These innate immune responses activate circulating monocytes and resident glomerular cells to release inflammatory mediators and initiate adaptive, antigen-specific immune responses that collectively damage glomerular structures. CD4 T cells are needed for B cell-driven antibody production that leads to immune complex formation in glomeruli, complement activation, and injury induced by both circulating inflammatory and resident glomerular effector cells. Th17 cells can also induce glomerular injury directly. In this review, information derived from studies in vitro, well characterized experimental models, and humans summarize and update likely pathogenic mechanisms involved in human diseases presenting as nephritis (postinfectious GN, IgA nephropathy, antiglomerular basement membrane and antineutrophil cytoplasmic antibody-mediated crescentic GN, lupus nephritis, type I membranoproliferative GN), and nephrotic syndrome (minimal change/FSGS, membranous nephropathy, and C3 glomerulopathies). Advances in understanding the immunopathogenesis of each of these entities offer many opportunities for future therapeutic interventions.