Clinicopathologic correlations in lupus nephritis in Lima, Peru

Association of explanatory histological findings and urinary protein and serum creatinine levels at renal biopsy in lupus nephritis: a cross-sectional study

Background

The aim of the present study was to evaluate the association between the histology of active and chronic lesions and urinary protein and serum creatinine (SCr) levels, as common clinical endpoints in clinical trials for lupus nephritis (LN).

Methods

In total, 119 patients diagnosed with LN class III, IV, and V, as defined by the International Society of Nephrology/Renal Pathology Society, between 1990 and 2015, were enrolled in the present study. Multiple regression analysis was performed to explore semi-quantitative histological variables associated with urinary protein and SCr levels.

Results

The mean age of the enrolled patients was 45 years, and 79% were female. The mean SCr and mean urinary protein levels at the time of renal biopsy were 0.87 mg/dl and 3.00 g/gCr, respectively. Class IV (71%) was the most common type of LN followed by class III (17%), and class V (13%). Multicollinearity was confirmed between monocellular infiltration (variance inflation factor [VIF] = 10.22) and interstitial fibrosis (VIF = 10.29), and between karyorrhexis (VIF = 4.14) and fibrinoid necrosis (VIF = 4.29). Fibrinoid necrosis and monocellular infiltration were subsequently excluded, and multiple regression analysis revealed that only the urinary protein level was correlated with wire loop lesions (β-coefficient [β]: 1.09 and confidence interval [CI]: 0.35 to 1.83), and that the SCr level was correlated with glomerular sclerosis (β: 1.08 and CI: 0.43 to 1.74).

Conclusion

As urinary protein and SCr levels were not quantitatively associated with active lesions, they may not accurately reflect the response to remission induction therapy in patients with LN.

Clinical and laboratory predictors of distinct histopathogical features of lupus nephritis

The authors aimed to explore whether distinct clinical, serological, and urinalysis findings are associated with specific histological classes of lupus nephritis. Clinical and laboratory features were recorded at the time of clinical diagnosis from 297 consecutive patients with biopsy-confirmed lupus nephritis. Univariate and logistic regression analyses were performed and a risk score was developed to estimate the risk for developing different classes of lupus nephritis. Variables independently associated with class II included absence of malar rash, negative anti-dsDNA, and ≤5 urine leucocytes/high power field (hpf); with III/IV: age at nephritis diagnosis ≤32 years old, presence of musculoskeletal features, new-onset hypertension, positive anti-dsDNA, >5 urine leucocytes/hpf, creatinine >1.2 mg/dL, cellular casts >1/hpf, and absence of nephrotic range proteinuria; with V: age at nephritis diagnosis >32 years, malar rash, absence of musculoskeletal complaints or serum C3 hypocomplementemia, nephrotic range proteinuria, and ≤9 urine erythrocytes/hpf. A risk predictive score of specific histological classes was calculated for each patient. Associations between 2, 3 or more risk factors with specific histological classes were also revealed [Odds ratios (95% confidence interval) (≥2 risk factors) was 6.7 (2.8-17.4) for class II nephritis, 15.6 (5.1-47.8), and 8.2 (3.6-19.0) for classes III/IV and for class V, respectively (≥3 risk factors)]. The identification of independent factors associated with specific classes of lupus nephritis can provide guidance in selecting specific therapeutic modalities, particularly in cases in which renal biopsy is contraindicated.

Alpha-melanocyte stimulating hormone ameliorates disease activity in an induced murine lupus-like model

Alpha-melanocyte stimulating hormone (α-MSH) is a neuropeptide exhibiting anti-inflammatory activity in experimental models of autoimmune diseases. However, no studies thus far have examined the effects of α-MSH on systemic lupus erythematosus (SLE). This study aimed to determine the effects of an α-MSH agonist in induced murine lupus. Here we employed female Balb/cAn mice in which lupus was induced by pristane. Groups of lupus animals were treated daily with the α-MSH analogue [Nle4, DPhe7]-α-MSH (NDP-MSH) (1·25 mg/kg) injected intraperitoneally or saline for 180 days. Normal animals comprised the control group. Arthritis incidence, plasma immunoglobulin (Ig)G isotypes, anti-nuclear antibodies (ANA) and plasma cytokines were evaluated. Renal function was assessed by proteinuria and histopathological lesion. Glomerular levels of IgG, α-smooth muscle actin (α-SMA), inducible nitric oxide synthase (iNOS), C3, CD3, melanocortin receptors (MCR)1, corticotrophin-releasing factor (CRF) and α-MSH was estimated by immunohistochemistry. When compared with normal controls, lupus animals exhibited increased arthritis, IgG levels, ANA, interleukin (IL)-6, IL-10, proteinuria and mesangial cell proliferation together with glomerular expression of α-SMA and iNOS. Glomerular expression of MCR1 was reduced in lupus animals. NDP-MSH treatment reduced arthritis scores by 70% and also diminished IgG1 and IgG2a levels and ANA incidence. In the glomerulus, NDP-MSH treatment reduced cellularity by 50% together with reducing IgG deposits, and expression levels of α-SMA, iNOS and CRF were also all decreased. Taken together, our results suggest for the first time that α-MSH treatment improves several parameters of SLE disease activity in mice, and indicate that this hormone is an interesting potential future treatment option.

Analysis of clinicopathologic correlations in Iranian patients with lupus nephritis

OBJECTIVE

To determine clinical features of different histopathological presentations in patients with lupus nephritis (LN).

METHODS

Clinical and pathological features of 71 biopsy-proven LN patients were analyzed in a cross-sectional study during 2005-2011.

RESULTS

Sixty-five women (91.5%) and six men (8.5%) were studied. The mean Activity Index (AI) and Chronicity Index (CI) were 6.2 ± 3.1 and 1.7 ± 1.5, respectively. The most common histopathologic presentation of kidneys was class IV (52.1%). Patients with more advanced International Society of Nephrology and the Renal Pathology Society (ISN/RPS) classes, had longer disease duration (P = 0.007), higher levels of blood urea nitrogen (P = 0.004) and serum creatinine (P = 0.035). The most frequent active lesion seen in renal biopsies was endocapillary hypercellularity (83.1%) while glomerular sclerosis was the most common chronic lesion (52.1%). Patients with chronic lesions, including glomerular sclerosis (P = 0.032), fibrous crescent (P = 0.001), interstitial fibrosis (P = 0.025) and tubular atrophy (P = 0.049) had higher serum creatinine levels. Hypertension was mainly seen in patients who had interstitial fibrosis and tubular atrophy (P = 0.026, 0.002 respectively). Moreover, subjects with renal failure had been more frequently involved with fibrinoid necrosis/karyorrhexis (P = 0.003), interstitial inflammation (P = 0.009), fibrous crescents (P = 0.041), tubular atrophy (P = 0.008) and interstitial fibrosis (P < 0.001).

CONCLUSION

We found that both histopathologic classification (ISN/RPS criteria) and histopathologic grading (US National Institutes of Health activity and chronicity indices) correlate to some clinical manifestations of LN. Considering these correlations may help to determine the patients' clinicopathologic status, prognosis and the need to immediate treatment. Nevertheless, it is necessary to clarify the accuracy of these findings in larger-scale prospective studies.

Tubulointerstitial lesions of patients with lupus nephritis classified by the 2003 International Society of Nephrology and Renal Pathology Society system

The 2003 International Society of Nephrology/Renal Pathology Society (ISN/RPS) system for classifying patients with lupus nephritis was based on glomerular lesions exclusively, despite the fact that lupus nephritis affects all compartments of the kidney. Hence, we analyzed the tubulointerstitial lesions in patients with lupus nephritis within the different classes and subclasses of the 2003 ISN/RPS system. Among 313 patients from five centers in northern China with lupus nephritis, interstitial inflammatory cell infiltration, tubular atrophy, and interstitial fibrosis were severe in 170 patients with class IV, moderate in 55 with class III, and mild in 19 with class II and in 69 with class V disease, each with significance. The severity of tubulointerstitial lesions in classes IV-segmental and III was similar, whereas the score of interstitial inflammatory cell infiltration in patients with subclass IV-global was significantly higher than that in those with subclass IV-segmental. Interstitial fibrosis and tubular atrophy were each significantly more prominent in patients with both active and chronic lesions than in those with active lesions alone. The correlation coefficient ranged from 0.222 to 0.811 comparing glomerular and tubulointerstitial indices. In multivariate Cox hazard analysis of tubulointerstitial lesions, indices of interstitial infiltration, tubular atrophy, and interstitial fibrosis were confirmed as significant independent risk factors for renal outcome. Thus, we found that the 2003 ISN/RPS classification system of lupus nephritis, based on glomerular lesions, could also reflect related tubulointerstitial lesions. Hence, we suggest that the extent of tubulointerstitial lesions may be helpful in predicting renal outcome in patients with lupus nephritis.

An unusual case of loin pain and nephritis

We report a 14-year-old girl with nephrotic syndrome and renal vein thrombosis (RVT) on initial presentation. The patient tested positive for antinuclear antibodies but only weakly positive for anti-double-stranded DNA (anti-dsDNA). Her C3 level was normal. Treatment with low molecular weight heparin resulted in resolution of RVT. Renal biopsy showed membranous glomerulonephritis with segmental sclerosis. Tissue immunostaining showed diffuse granular C3 and immunoglobulin (Ig)G staining along the capillary wall with focal segmental IgM staining deposits in the mesangium. No C1q, IgA, or fibrinogen was noted on immunofluorescence assay. With cyclosporin A and prednisolone, the patient went into remission and corticosteroids were tapered off gradually. Two years later, she had a relapse of proteinuria, hypocomplementemia, and extremely high anti-dsDNA. Systemic lupus erythematosus (SLE) was diagnosed, and she was promptly started on steroid and immunosuppressive agents, which resulted in reduction of proteinuria. Her renal function has been normal all along. Membranous nephropathy is uncommon in Chinese children and could be a possible early presentation of SLE.

Treatment for lupus nephritis: a revisit

The optimal treatment of severe lupus nephritis remains unclear. Regimens consisting of steroid and cyclophosphamide (CYC) appear to be most effective. Infection and gonadal toxicity is a major concern of CYC use in patients of reproductive age. In addition, failure to respond or refractory to CYC treatment may lead to the development of end-stage renal disease. Mycophenolate mofetil (MMF) is a new immunosuppressive agent that selectively inhibits activated lymphocytes and renal mesangial cells. Data from experimental lupus nephritis and controlled studies, albeit small and lacking statistical power, have revealed that MMF is as effective in lupus patients as CYC in the induction of renal remission or as maintenance therapy to reduce renal flare in the short term. The significantly less ovarian toxicity and infection when compared to CYC are particularly attractive for the consideration of MMF in lupus nephritis. The potential of other new therapeutic agents is discussed together with the need for patient recruitment in future trials of lupus nephritis to address the importance of ethnicity as well as histological grading.

Renal tubular dysfunction in children with systemic lupus erythematosus

Renal tubular and glomerular function was studied in patients under 18 years of age with childhood-onset systemic lupus erythematosus (SLE) in relation to disease activity in two groups: patients with clinical or laboratory evidence of lupus nephritis and those without (lupus non-nephritis). We reviewed 11 patients with lupus non-nephritis and 10 patients with lupus nephritis over a 12-month period. The measured glomerular filtration rates had a tendency to be lower in the lupus nephritis group. Glomerular dysfunction was manifest in the lupus nephritis group with elevated urinary albumin/creatinine ratios (P <0.001). Markers of tubular function were measured and compared with data from 94 controls. The lupus nephritis group had elevated urinary NAG [N-acetyl-beta-D-glucosaminidase (P =0.001)] and RBP [retinol-binding protein (P =0.03)] levels. Tubular dysfunction with elevated urinary NAG levels was present in 2 lupus non-nephritis patients with no evidence of glomerular disease. The cohort of patients in this study was followed and 2 lupus non-nephritis patients with the highest urinary RBP levels developed evidence of glomerular dysfunction and biopsy-proven lupus nephritis. Evidence of tubular dysfunction in lupus non-nephritis patients may help to identify lupus nephritis prior to the onset of albuminuria.

Adoptive transfer studies demonstrate that macrophages can induce proteinuria and mesangial cell proliferation

BACKGROUND

Glomerular macrophage accumulation is a feature of proliferative human and experimental glomerulonephritis. However, our understanding of the role of macrophages in the induction of renal injury is based upon indirect evidence from depletion studies, most of which lack specificity for this cell type. Therefore, an adoptive transfer approach was used to directly assess the potential of macrophages to induce renal injury.

METHODS

Accelerated anti-glomerular basement membrane (anti-GBM) disease was induced in rats by immunization with sheep IgG (day -5), followed by administration of sheep anti-rat GBM serum (day 0), with animals killed on day 2. To facilitate the adoptive transfer studies, immunized animals were made leukopenic by cyclophosphamide (CyPh) given on day -2. Bone marrow-derived (BM) or NR8383 macrophages were transferred by tail vein injection 24 hours after injection of anti-GBM serum, with animals killed 3 or 24 hours after transfer.

RESULTS

Pretreatment with CyPh prevented glomerular leukocyte accumulation and completely inhibited proteinuria, glomerular cell proliferation and hypercellularity in accelerated anti-GBM disease. Adoptive transfer led to significant glomerular accumulation of BM or NR8383 macrophages within 3 hours of injection, and this was still evident 24 hours later. Adoptive transfer of BM or NR8383 macrophages induced proteinuria (63 +/- 16 BM vs. 5 +/- 2 mg/24 h CyPh control; P < 0.001), glomerular cell proliferation (5.1 +/- 1.2 BM vs. 0.5 +/- 0.1 PCNA+ cells/gcs CyPh; P < 0.001) and glomerular hypercellularity (51.2 +/- 2.0 BM vs. 41.9 +/- 0.9 nuclei/gcs CyPh; P < 0.001). The degree of renal injury correlated with the number of transferred glomerular macrophages. Two-color immunostaining demonstrated that most glomerular proliferative cell nuclear antigen+ (PCNA+) proliferating cells were OX-7+ mesangial cells. CyPh treatment did not prevent up-regulation of glomerular intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule (VCAM-1) expression or an increase in urinary monocyte chemoattractant protein-1 (MCP-1) excretion.

CONCLUSION

This study provides the first direct evidence that macrophages can induce renal injury in terms of proteinuria and mesangial cell proliferation.

Classes, activity and chronicity indices, and alpha-smooth muscle actin expression as prognostic parameters in lupus nephritis outcome

Renal biopsies of 86 patients with lupus nephritis were assessed according to the WHO classification, and according to activity and chronicity indices. The aim of the present study was to correlate clinical, and histological features (WHO class, activity and chronicity indices, and alpha-SM actin expression) with the progression of lupus nephritis, and identify the pathological role of alpha-SM actin in lupus nephritis. The median follow-up time was 75.5 +/- 57.3 months. Two patients were grouped as WHO class IIa lupus nephritis, eight patients as class IIb, 16 patients as class III, 25 patients as class IV, 15 patients as class V, and 19 patients as mixed pattern lupus nephritis. Sex, age, race, and the alpha-SM actin expression in glomeruli and tubulo-interstitial area in WHO class III and IV showed no correlation with clinical follow-up outcome of lupus nephritis. Unfavorable clinical outcome of lupus nephritis was correlated with WHO class IV compared to the other classes, and with the chronicity index in WHO class III patients.