Membranous transformation of lupus nephritis

Long-term renal outcomes of patients with non-proliferative lupus nephritis

BACKGROUND/AIMS

Although non-proliferative lupus nephritis (LN) (class I, II or V) has been considered as a less severe type of LN, data on long-term renal prognosis are limited. We investigated the long-term outcomes and prognostic factors in non-proliferative LN.

METHODS

We retrospectively reviewed patients with systemic lupus erythematosus who were diagnosed with LN class I, II, V, or II + V by kidney biopsy from 1997 to 2021. A poor renal outcome was defined as an estimated glomerular filtration rate (eGFR) of < 60 mL/min/1.73 m2.

RESULTS

We included 71 patients with non-proliferative LN (class I = 4; class II = 17; class V = 48; class II+V = 2), and the overall rate of poor renal outcomes was 29.6% (21/71). The univariate analysis indicated that older age, low eGFR at 6 or 12 months, failure to reach complete remission at 6 months, and LN chronicity score > 4 or activity score > 6 were significantly associated with poor renal outcomes. The multivariate analysis revealed that low eGFR at 6 months (HR 0.971, 95% CI 0.949-0.991; p = 0.014) was significantly associated with poor renal outcomes.

CONCLUSION

Poor renal outcomes occurred in approximately 30% of patients with non-proliferative LN after long-term follow-up. More active management may be needed for non-proliferative LN, especially for patients with eGFR < 60 mL/ min/1.73 m2 at 6 months follow-up after LN diagnosis.

Relapse with transformation of lupus nephritis in a transplant kidney

Lupus nephritis is a constellation of different renal histologies, characterized by an immune complex mediated glomerular disease. Histological transformation in lupus nephritis usually occurs from a mild mesangial proliferative glomerulonephritis to a more aggressive diffuse proliferative lesion. We present a case of relapsed systemic lupus erythematosus (SLE) in a renal transplant recipient in which there was a histological transformation from the original diffuse proliferative lupus nephritis in the native kidneys to a membranous lupus nephritis in the renal transplant.

The development of membranous lupus nephritis during treatment with mycophenolate mofetil for proliferative renal disease

The transformation of lupus nephritis from one histologic pattern to another is well described. We report a case of a patient who initially presented with diffuse proliferative glomerulonephritis and was treated with prednisone and mycophenolate mofetil (MMF). She initially responded well to therapy, but later developed high-grade proteinuria while still on MMF and low-dose steroids. A repeat biopsy performed after the increase in proteinuria demonstrated that she had focal proliferative disease but that she had also developed membranous lupus nephritis. Our case is unique in that we report a patient who developed membranous lupus nephritis while receiving MMF.

[Lupus membranous nephropathy]

The systemic lupus erythematosus associated renal hystopathological complexity and its clinical translation, are still a diagnostic challenge with therapeutical implications which, however, include new options in the last few years within the immunosupression compass. The new insights elicited by research work attempt to give some light on renal biopsy performance, its relationship with the arrogated clinical spectrum, its prognosis and on the lupus nephropathy new treatments currently under ongoing clinical trials, some of them showing encouraging results. The lupus membranous nephropathy, recognized as an anatomopathological entity more than 4 decades ago, means a specific pattern in the whole renal lupus histologycal range and, in many aspects, an etiopathogenic enigma.

Silent nephritis in systemic lupus erythematosus

Silent lupus nephritis (SLN) was investigated in 42 renal asymptomatic patients and compared with 49 untreated patients with overt lupus nephropathy (OLN). Urinary sediment, quantitative proteinuria, creatinine clearance, antinuclear antibodies (ANA), complement, circulating immune complexes (CIC) and renal biopsies were evaluated in all of the patients. Forty-one out of the 42 (97.6%) patients had SLN according to histopathological findings. Results showed that the mean age, female/male ratio and the clinical activity index (SLEDAI) were similar in both groups (P > 0.05). The prevalence of ANA, anti-ds DNA, anti-ENA autoantibodies and C4 serum levels showed no statistical differences between the two groups (P > 0.05). Conversely, in the OLN group, elevated CIC and diminished CH50 and C3 serum levels were significantly different (P < 0.01). WHO class II was the predominant renal lesion in the group with SLN (P < 0.0001), whereas class IV was in the OLN patients (P < 0.0001). We conclude that, in our series, SLN was highly prevalent in renal asymptomatic patients with otherwise systemic lupus erythematosus. Furthermore, abnormal levels of CIC, CH50 and C3 associated with WHO class II suggest a moderate but ongoing activation of immune-mediated renal injury mechanisms.

Renal involvement in systemic lupus erythematosus. A study of 180 patients from a single center

Charts of 180 patients (147 women, 33 men) with systemic lupus erythematosus (SLE) complicated by renal involvement were retrospectively analyzed from a series of 436 patients. Mean age at renal disease onset was 27 years. Thirty-six percent of the patients had renal involvement after diagnosis of lupus, for 30.7% of that group it was more than 5 years later. Renal involvement occurred more frequently in young male patients of non-French non-white origin. Patients with renal involvement suffered more commonly from malar rash, psychosis, myocarditis, pericarditis, lymphadenopathy, and hypertension. Anemia, low serum complement, and raised anti-dsDNA antibodies were more frequent. According to the 1982 World Health Organization classification, histologic examination of initial renal biopsy specimen in 158 patients showed normal kidney in 1.5% of cases, mesangial in 22%, focal proliferative in 22%, diffuse proliferative in 27%, membranous in 20%, chronic sclerosing glomerulonephritis in 1%, and other forms of nephritis in 6.5%. Distribution of initial glomerulonephritis patterns was similar whether renal involvement occurred before or after the diagnosis of lupus. Transformation from 1 histologic pattern to another was observed in more than half of the analyzable patients (those who underwent at least 2 renal biopsies). Nephritis evolved toward end-stage renal disease in 14 patients despite the combined use of steroids and cyclophosphamide in 12. Initial elevated serum creatinine levels, initial hypertension, non-French non-white origin, and proliferative lesions on the initial renal biopsy were indicators of poor renal outcome. Twenty-four patients died after a mean follow-up of 109 months from SLE diagnosis. Among our 436 patients, the 10-year survival rate was not significantly affected by the presence or absence of renal involvement at diagnosis (89% and 92%, respectively).

A transition from proliferative to membranous glomerulonephritis in chronic serum sickness

Chronic serum sickness glomerulonephritis was induced in rats by daily i.v. administration of bovine serum albumin (BSA). Previous studies have shown that the disease progresses through three discrete stages: mild, moderate and severe. The diffuse, proliferative necrotizing glomerulonephritis of severe chronic serum sickness, which is accompanied by a decreased glomerular filtration rate and increased glomerular permeability to macromolecules, has an inevitable fatal outcome. In the experiments reported here, BSA injections were discontinued at the transition from moderate to severe glomerulonephritis, a point which was identified by decreased sodium excretion. Retrospectively, rats could be divided into two categories. Some, called non-survivors, continued to exhibit sodium retention. Those animals progressed rapidly to end-stage renal disease and died within two weeks of the cessation of antigen injections. Others, called survivors, returned to sodium balance and remained alive for many months. The development of progressive membranous glomerulonephritis, with prominent spike formation and disappearance of glomerular hypercellularity, was noted in all survivors. That change in histopathology occurred in the absence of both circulating BSA and precipitating antibodies to BSA. The transition of proliferative to membranous glomerulonephritis was accompanied by partial recovery of glomerular function, although proteinuria persisted. Maintenance of severe proteinuria did not appear to depend on an active immunological process.

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.

Subepithelial electron-dense deposits in proliferative glomerulonephritis of systemic lupus erythematosus

Subepithelial electron-dense deposits (SED) were found in the renal biopsies of 36 of 59 patients with systemic lupus erythematosus (SLE). The SED were divided into two groups based on their ultrastructural appearance and distribution within the glomeruli. Type I SED were regular in size and shape, had a homogeneous electron density and a diffuse distribution within the glomeruli, and involved all of the glomeruli in the biopsy. In contrast, the type II SED were irregular in size and shape, tended to be quite large, and had variable electron density. They were present in reduced numbers in involved capillary loops, and they were absent from other loops within the same glomerulus. Type I SED were seen in cases of membranous SLE glomerulonephritis (GN), and type II SED were associated with severe proliferative SLE GN. Although the patients with proliferative GN had more active urinary sediments at the time of biopsy than did the patients with membranous GN, the mean serum creatinine and urinary protein excretion were not significantly different in the two groups. The mean followup was almost twice as long for the membranous compared to the proliferative lesions (33.70 months +/- SE 7.96 vs. 16.78 +/- 4.21), but at the end of the study, mean renal function was better preserved in patients with proliferative GN (2.13 mg/dl +/- SE 0.49). As a group, patients with type I SED had mild serologic abnormalities compared to patients with type II SED. In contrast the abnormal serologies of the patients with type II SED were not significantly different from patients with proliferative SLE GN in general. The results suggest that the heterogeneous morphology of SED may reflect different pathogenetic mechanisms responsible for their formation. When focal and segmental SED (type II) are seen in proliferative SLE GN, they should be interpreted with caution, for they have very different clinical, prognostic, and therapeutic implications from type I SED.