Transformation of diffuse proliferative glomerulonephritis to membranous nephritis in a patient with systemic lupus erythematosus

Role of MHC-linked genes in autoantigen selection and renal disease in a murine model of systemic lupus erythematosus

We previously described a renal protective effect of factor B deficiency in MRL/lpr mice. Factor B is in the MHC cluster; thus, the deficient mice were H2b, the haplotype on which the knockout was derived, whereas the wild-type littermates were H2k, the H2 of MRL/lpr mice. To determine which protective effects were due to H2 vs factor B deficiency, we derived H2b congenic MRL/lpr mice from the 129/Sv (H2b) strain. Autoantibody profiling using autoantigen microarrays revealed that serum anti-Smith and anti-small nuclear ribonucleoprotein complex autoantibodies, while present in the majority of H2k/k MRL/lpr mice, were absent in the H2b/b MRL/lpr mice. Surprisingly, 70% of MRL/lpr H2b/b mice were found to be serum IgG3 deficient (with few to no IgG3-producing B cells). In addition, H2b/b IgG3-deficient MRL/lpr mice had significantly less proteinuria, decreased glomerular immune complex deposition, and absence of glomerular subepithelial deposits compared with MRL/lpr mice of any H2 type with detectable serum IgG3. Despite these differences, total histopathologic renal scores and survival were similar among the groups. These results indicate that genes encoded within or closely linked to the MHC region regulate autoantigen selection and isotype switching to IgG3 but have minimal effect on end-organ damage or survival in MRL/lpr mice.

A renal biopsy study of lupus nephropathy in the United States and Korea

A comparative study was made using renal biopsy specimens obtained from US and Korean patients with lupus nephropathy. Significant differences were observed in the morphologic distribution and activity of the disease. Korean patients exhibited a higher frequency of World Health Organization class IV lupus nephropathy (77.8%) than black (47.2%) or white (42.1%) US patients (P less than 0.025, P less than 0.05, respectively), and a higher inflammatory intensity index (P less than 0.045) than US patients. Korean patients also showed a significantly lower frequency of WHO class III nephropathy (P less than 0.05). No significant morphologic differences were seen between the US white and black patient populations. These data suggest that the Korean patients had a more active and potentially more fulminating disease than the US patients. Whether differences in genetic and external causative factors play a role in the observed differences in renal histopathology among these groups remains to be clarified.

Course of renal pathology in patients with systemic lupus erythematosus

Evaluation of the course of lupus nephropathy by serial kidney biopsy in 50 patients revealed a complex pattern of transitions from one histologic class to another. A high rate of transformations (56 percent) was observed, with fewer than half the patients remaining in the original category. Although the general trend was towards transformation to a less severe lesion (WHO classes III and IV transforming into classes II and V), this was certainly not the rule for all individual classes. These transformations were rarely predictable on the basis of available clinical, laboratory, or pathologic information, and were less common in younger patients. These results help clarify the pathologic behavior of lupus nephropathy in the modern therapeutic era and highlight the value of pathologic examination for the planning and evaluation of therapy in selected patients.