Natural history of "silent" lupus nephritis

Does kidney biopsy in pediatric lupus patients "complement" the management and outcomes of silent lupus nephritis? Lessons learned from a pediatric cohort

BACKGROUND

Silent lupus nephritis (SLN) is systemic lupus erythematosus (SLE) without clinical and laboratory features of kidney involvement but with biopsy-proven nephritis. This study aims to describe and compare the baseline characteristics and outcomes of pediatric SLN with overt LN (OLN) and to identify associated risk factors and biochemical markers.

METHODS

In this retrospective, observational study, multivariate logistic regression and receiver operating characteristic (ROC) analyses studied age, sex, race, serum complements, anti-double-stranded-DNA antibody, anti-Smith antibody, eGFR, and proliferative nephritis.

RESULTS

In our cohort of 69 patients, 47 were OLN, and 22 were SLN. OLN (OR = 4.9, p = 0.03) and non-African Americans (AA) (OR = 13.0, p < 0.01) had higher odds, and increasing C3 and C4 were associated with lower odds of proliferative nephritis (OR 0.95 and 0.65 per one unit increase in C3 and C4, respectively, p < 0.01). They demonstrated a good discriminative ability to detect proliferative nephritis as assessed by the area under the ROC curve (C3 = 0.78, C4 = 0.78). C3 and C4 in proliferative SLN and OLN were comparable and significantly lower than their non-proliferative counterparts. No association was observed between age, sex, anti-double-stranded-DNA antibody, anti-Smith antibody, eGFR, and proliferative nephritis. Proliferative SLN and OLN patients received similar treatments. Adverse events were identified in the proliferative OLN only.

CONCLUSIONS

Lower complement levels are associated with proliferative lesions in pediatric LN-both SLN and OLN. The non-AA population had higher odds of having proliferative nephritis than the AA. Prospective, randomized, long-term follow-up of proliferative SLN patients is needed to ascertain the beneficial effect of early diagnosis and treatment. A higher resolution version of the Graphical abstract is available as Supplementary information.

High incidence of proliferative and membranous nephritis in SLE patients with low proteinuria in the Accelerating Medicines Partnership

OBJECTIVE

Delayed detection of LN associates with worse outcomes. There are conflicting recommendations regarding a threshold level of proteinuria at which biopsy will likely yield actionable management. This study addressed the association of urine protein:creatinine ratios (UPCR) with clinical characteristics and investigated the incidence of proliferative and membranous histology in patients with a UPCR between 0.5 and 1.

METHODS

A total of 275 SLE patients (113 first biopsy, 162 repeat) were enrolled in the multicentre multi-ethnic/racial Accelerating Medicines Partnership across 15 US sites at the time of a clinically indicated renal biopsy. Patients were followed for 1 year.

RESULTS

At biopsy, 54 patients had UPCR <1 and 221 had UPCR ≥1. Independent of UPCR or biopsy number, a majority (92%) of patients had class III, IV, V or mixed histology. Moreover, patients with UPCR <1 and class III, IV, V, or mixed had a median activity index of 4.5 and chronicity index of 3, yet 39% of these patients had an inactive sediment. Neither anti-dsDNA nor low complement distinguished class I or II from III, IV, V or mixed in patients with UPCR <1. Of 29 patients with baseline UPCR <1 and class III, IV, V or mixed, 23 (79%) had a UPCR <0.5 at 1 year.

CONCLUSION

In this prospective study, three-quarters of patients with UPCR <1 had histology showing class III, IV, V or mixed with accompanying activity and chronicity despite an inactive sediment or normal serologies. These data support renal biopsy at thresholds lower than a UPCR of 1.

Retrospective review of the clinical and laboratory data in silent lupus nephritis

PURPOSE

To determine the ratio of renal disease necessitating immunosuppressive treatment in lupus patients who are clinically asymptomatic by means of renal disease. It was also examined whether silent lupus nephritis is associated with any of the non-renal clinical findings.

METHODS

All kidney biopsies performed in lupus patients between 1990 and 2009 at the Rheumatology Department of Ege University Faculty of Medicine were retrospectively screened. Among the 258 kidney biopsies screened, 54 had no clinical renal findings but had active disease together with anti-dsDNA positivity and/or hypocomplementemia. Patients were classified into two groups who require and do not require immunosuppressive therapy according to their final pathological results at biopsy. The frequency of serious renal involvement in the sample was calculated. Then subgroups were compared with each other in terms of the clinical and laboratory features using Statistical Package for Social Sciences version 13 software.

RESULTS

Thirteen of the 54 patients (24%) had severe renal involvement requiring immunosuppressant therapy. When the groups were compared to each other, it was found that serositis and hematologic involvement were significantly more frequent in patients who needed immunosuppressive treatment (42.9% versus 10.0%; p = 0.003 and 64.3% versus 37.5; p = 0.039).

CONCLUSION

Even in the absence of clinical renal manifestations, active patients at high risk of renal disease such as hypocomplementemia, anti-ds DNA positivity may have severe renal disease requiring immunosuppressive treatment. Thus, renal biopsy indications in lupus patients should better be revaluated.

Low-Level Proteinuria in Systemic Lupus Erythematosus

Introduction

In patients with systemic lupus erythematosus (SLE) without concurrent active urinary sediment or unexplained acute kidney injury (AKI), current guidelines recommend performing a kidney biopsy in those with at least 500 mg/24-hour (European League Against Rheumatism/European Renal Association-European Dialysis and Transplant Association [EULAR/ERA-EDTA]) or 1000 mg/24-hour (American College of Rheumatology [ACR]) proteinuria. To evaluate the relevance of these indications, we studied histopathologic findings in patients with SLE with proteinuria below these cutoffs.

Methods

We retrospectively reviewed the clinical, laboratory and histological characteristics of patients with SLE with <1000 mg/24-hour proteinuria (or mg/g urinary protein-to-creatinine ratio [UPCR]) who underwent their first kidney biopsy between 2003 and 2018.

Results

We identified 87 patients with SLE with proteinuria less than 1000 mg/24-hour (or mg/g UPCR); 52 of 87 (60%) with isolated proteinuria, that is, without AKI or active urinary sediment (hematuria). Histologic evidence of lupus nephritis (LN) was present in 40 of 52 (76%). Of the 40 patients with LN, 12 had class I or II, 14 had class III or IV, 8 had class V, 6 had a combined proliferative and membranous LN. Non-lupus diagnoses included focal segmental glomerulosclerosis, acute interstitial nephritis, and others. Patient’s age, low C3, low C4, and positivity for anti-double-stranded DNA (anti-dsDNA) antibodies predicted the histological diagnosis of LN on univariate logistic regression; however, a multivariate model including these parameters as independent covariates failed to predict LN.

Conclusions

Patients with SLE with low-level proteinuria may have significant lupus- or non–lupus-related kidney disease with management implications. There was a significant burden of severe forms of LN. The presence of LN was not predicted by laboratory abnormalities. Based on our findings, we suggest current guidelines be revised to expand kidney biopsy indications to include isolated proteinuria of any grade.

Non-histologic factors discriminating proliferative lupus nephritis from membranous lupus nephritis

BACKGROUND

To investigate non-histologic factors that can discriminate proliferative lupus nephritis (LN) from membranous LN in patients with systemic lupus erythematosus with renal manifestations.

METHODS

Patients with biopsy-proven proliferative LN (class III ± V and class IV ± V) and membranous LN (class V) were included. Non-histologic factors were compared between the two groups. A logistic regression analysis was performed to identify the factors associated with proliferative LN. To assess the accuracy of these factors in discriminating between proliferative LN and membranous LN, we performed a receiver-operating characteristic analysis.

RESULTS

Of the total 168 patients with biopsy-proven LN, 150 patients (89.3%) had proliferative LN, and 18 patients (10.7%) had membranous LN. In the multivariable logistic regression analysis, positive anti-double-stranded DNA (anti-dsDNA) antibody (adjusted OR = 11.200, 95% CI = 2.202-56.957, p = 0.004) was associated with proliferative LN, while positive anti-U1RNP antibody (adjusted OR = 0.176, 95% CI = 0.040-0.769, p = 0.021) and higher glomerular filtration rate (GFR) (adjusted OR = 0.973, 95% CI = 0.951-0.994, p = 0.013) were inversely associated with proliferative LN. Among these covariates, the anti-dsDNA antibody (area under the curve = 0.806, 95% CI = 0.695-0.916) had the highest accuracy in discriminating between proliferative LN and membranous LN.

CONCLUSION

The positivity of anti-dsDNA antibody was associated with proliferative LN, while the positivity of anti-U1RNP antibody and GFR were inversely associated with proliferative LN. The anti-dsDNA antibody had a good accuracy in discriminating proliferative LN from membranous LN.

The potential diagnostic utility of coexpression of Ki-67 and P53 in the renal biopsy in pediatric lupus nephritis

Background

The proliferative activity as well as apoptosis has been suggested to play a role in the pathogenesis of lupus nephritis (LN). The aim of the study was to investigate the coexpression of Ki-67-triggered marked proliferation and P53-induced apoptosis in renal biopsy of childhood lupus nephritis (cLN) and to compare the coexpression of proliferative and apoptotic indices between different subgroups and clinicopathologic patterns of renal disease.

Methods

Renal biopsy specimens of 33 children with lupus nephritis (LN) and 10 healthy subjects were retrospectively evaluated. The type of LN and activity and chronicity indices were determined. Ki-67 and P53 immunostaining were performed. The coexpression of Ki-67 and P53 was compared among different subgroups of LN and correlated with disease activity index, serum creatinine, proteinuria, anticardiolipin antibodies, and complement levels. Histopathological examination of LN was classified based on the International Society of Nephrology/Renal Pathology. Histological LN activity was measured by the National Institutes of Health activity index (NIH-AI).

Results

In comparison with the healthy control group, the coexpression of Ki-67and P53 was greater in cLN (particularly in classes II, III, and IV) than in normal renal tissue. The coexpression of Ki-67and P53 shows a positive correlation with subclasses II, III, and IV of LN (P<0.02) and LN activity index (P<0.03). Moreover, the positive correlation was found between the coexpression of Ki-67 and P53 with erythrocyte sedimentation rate (P<0.02), D-dimer (P<0.03), serum creatinine (P<0.03), proteinuria (P<0.04), and anticardiolipin antibodies (P<0.05) significantly. Unexpectedly, adverse correlation between the coexpression of Ki-67 and P53 with serum C3 (P<0.02) and C4 complement (P<0.03) was significant.

Conclusion

Our data showed that the coexpression of Ki-67-induced marked proliferation and P53-induced apoptosis in proliferative and active phases of cLN could reflect a valuable marker for treatment and remission in cLN patients before reaching the end stage of renal disease.

Further description of early clinically silent lupus nephritis

Thirty silent lupus nephritis (SLN) patients were compared to 16 individuals bearing overt lupus nephritis (OLN). Results included: years of systemic lupus erythematosus (SLE) diagnosis were significantly earlier (4.6 ± 2.8 years) in SLN than in OLN (7.18 ± 3.61) ( P < 0.05). Neurological compromise, hypertension, normocitic anemia and lymphopenia were significantly prevalent in OLN than in SLN ( P < 0.05). Beside normal urinary sediment and renal function tests, the SLN group showed a moderate increase of both activity (AI) and chronicity (CI) renal pathology index when compared to highly increased AI and CI in OLN ( P < 0.05). Seventy percent of SLN patients were ISN/RPS Classes I (6.6%) and II (63.3%) while 81% of OLN cases were Classes III, IV (37.5%) and V. IgG, IgA, IgM, λchain, C3 and fibrinogen immune deposits were found in 90% or over in both SLN and OLN individuals while in 60% or over, both groups also showed K chain, C1q and C4 deposits. While prevalence of ANA, anti-dsDNA and anti-C1q antibodies were similar in both groups, anti-histone, anti-RNP, CIC and CH50 serum levels were significantly different in OLN versus SLN ( P < 0.05). We strongly suggest that indeed SLN is the earliest stage in the natural history of lupus nephritis.

The role of kidney biopsy in the management of lupus nephritis

PURPOSE OF REVIEW

This review evaluates the role of kidney biopsy as a tool in the diagnosis, prognostication and therapeutic management of lupus nephritis. The renal biopsy is the only method available for diagnosing and classifying lupus nephritis. However, disagreements persist regarding the appropriate role of a renal biopsy in the management and identification of predictors of short and long-term outcomes.

RECENT FINDINGS

Recent modifications to the classification of lupus nephritis, the emergence of newer scoring indices, and the availability of a variety of therapeutic options predicate a reassessment of the role of the renal biopsy in the management of lupus nephritis, especially for high-risk patients.

SUMMARY

Despite some controversy, the renal biopsy has been shown to provide information over and above that provided by the clinical variables, and remains a pivotal element in optimizing therapy and the rational management of lupus nephritis.

Renal Outcome and Predictors of Clinical Renal Involvement in Patients with Silent Lupus Nephritis

OBJECTIVES

We investigated the development of clinically overt nephritis in patients with silent lupus nephritis in an effort to determine predictors of onset.

METHODS

We selected 31 patients with systemic lupus erythematosus (SLE) who were diagnosed as having silent lupus nephritis between 1985 and 1995. Urinalysis, blood cell count, serum creatinine, complement levels, and anti-double-stranded DNA antibody (anti-dsDNA antibody) levels were followed retrospectively for at least 60 months in each patient.

RESULTS

During the follow-up period, 8 patients developed clinical renal disease and 23 had no renal impairment. The mean time of overt nephritis onset was 58 months and renal function deteriorated mildly in 3 patients. Although clinical and laboratory findings were not significantly different at SLE onset, patients with overt nephritis showed both persistent elevation of anti-dsDNA antibodies and persistently low levels of serum C3 and CH50 for at least 24 months before the onset of overt nephritis.

CONCLUSIONS

Although the renal prognosis was relatively favorable, 25.8% of patients developed overt nephritis during the follow-up period. Elevation of anti-dsDNA antibodies with hypocomplementemia was persisted in these patients, suggesting the utility of these factors as predictors of clinical renal involvement in silent lupus nephritis.

Prediction of lupus nephritis in patients with systemic lupus erythematosus using artificial neural networks

Artificial neural networks are intelligent systems that have been successfully used for prediction in different medical fields. In this study, efficiency of neural networks for prediction of lupus nephritis in patients with systemic lupus erythematosus (SLE) was compared with a logistic regression model and clinicians' diagnosis. Overall accuracy, sensitivity and specificity of the optimal neural network were 68.69, 73.77 and 62.96%, respectively. Overall accuracy of neural network was greater than the other two methods (P-value < 0.05). The neural network was more specific in predicting lupus nephritis (P-value < 0.01), but there was no significant difference between sensitivities of the three methods. Sensitivities of all three methods were greater than their specificities. We concluded that neural networks are efficient in predicting lupus nephritis in SLE patients.

Outcome of silent lupus nephritis

To analyze the long-term outcome in patients with silent lupus nephritis, we retrospectively studied 20 patients with systemic lupus erythematosus without clinical renal involvement who had renal biopsies in our unit between 1978 and 1986 and reviewed 193 cases reported between 1957 and 1995. Two patients of the current series were lost to follow-up. Mean follow-up in the other 18 was 13 +/- 3 years (range, 2 to 17). On kidney biopsy, nine had class I, six class II, one class IV, and two class V disease (WHO classification). Three patients with prior normal renal function died of nonrenal causes. During the study, the remaining 15 patients had normal renal function and urinalysis. Most patients from the literature had "mild" histologic lesions, but 30 had diffuse proliferative glomerulonephritis. Over an average of 46 months of follow-up from biopsy, renal survival rate and patient survival rate were 98% and 91%, respectively. Three patients died of end-stage renal failure. In conclusion, end-stage renal failure in patients with silent lupus nephritis is rare regardless of the histopathological renal lesions. Patients survival depends on nonrenal causes.

Accuracy of creatinine clearance in measuring glomerular filtration rate in patients with systemic lupus erythematosus without clinical evidence of renal disease

We sought to determine whether creatinine clearance (Ccr) gives an accurate measurement of the glomerular filtration rate in patients with systemic lupus erythematosus (SLE) with no clinical evidence of renal disease. Eighteen such SLE patients underwent measurement of Ccr and 99mtechnetium-DTPA clearance (CDTPA). The mean +/- SD Ccr:CDTPA ratio was 1.12 +/- 0.15 (95% confidence interval 1.04-1.20). These results indicate that Ccr gives an accurate measurement of the glomerular filtration rate in the majority of SLE patients who do not have clinical evidence of renal disease.