Ying Tan

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.

Clinicopathological characteristics and outcomes of patients with crescentic lupus nephritis

There are few clinicopathologic and outcome data on patients with crescentic lupus nephritis, therefore, we determined factors of the disease by retrospectively reviewing the records of 327 patients diagnosed with lupus nephritis. Of these, 152 cases were regrouped as class IV-G, including 33 patients with crescentic glomerulonephritis. Significantly, all patients with crescentic glomerulonephritis had acute kidney injury as compared with only about a quarter of the patients without the disease. On pathological evaluation, activity scores, chronicity indexes, relapse rates, and the frequency of positive serum anti-neutrophil cytoplasmic antibody (ANCA) were each significantly higher, whereas complete remission rates and renal outcomes, over a mean follow-up of 4 years, were significantly poorer in patients with crescentic glomerulonephritis. Our study shows that crescentic glomerulonephritis was not rare in patients with lupus nephritis and that their long-term outcome was poor. The precise role of ANCA in the pathologic course of crescentic lupus nephritis remains to be determined.

Inclusion of renal vascular lesions in the 2003 ISN/RPS system for classifying lupus nephritis improves renal outcome predictions

The 2003 International Society of Nephrology/Renal Pathology Society (ISN/RPS) pathological classification system of lupus nephritis specified the importance of vascular damage and indicated this should be included in the diagnostic summary. Few pathological studies of lupus nephritis, however, focus on the patterns of renal vascular involvement. Here we assessed renal vascular lesions in lupus nephritis based on the 2003 ISN/RPS classification system and evaluated their association with clinical and pathological data in a large cohort from a single center in China. Among 341 patients with lupus nephritis, 279 were diagnosed with single or multiple renal vascular lesions that included 253 with vascular immune complex deposits, 82 with atherosclerosis, 60 with thrombotic microangiopathy, 13 with noninflammatory necrotizing vasculopathy, and 2 with true renal vasculitis. Patients with thrombotic microangiopathy had the poorest renal outcome. In multivariate Cox hazard analysis after inclusion of renal vascular lesions, the new chronicity index score became a significantly better independent risk factor for renal outcome (hazard ratio 2.32). Thus, renal vascular lesions are common in lupus nephritis and closely correlate with clinical disease activity and renal outcome. Inclusion of a detailed description of renal vascular lesions in the ISN/RPS classification of lupus nephritis may strengthen its predictive value for renal outcome.

Modified C-Reactive Protein Might be a Target Autoantigen of TINU Syndrome

BACKGROUND AND OBJECTIVESnThe cross-reactive antigen(s) of tubulointerstitial nephritis and uveitis (TINU) syndrome from renal tubulointerstitia and ocular tissue remain unidentified. The authors recent study demonstrated that the presence of serum IgG autoantibodies against modified C-reactive protein (mCRP) was closely associated with the intensity of tubulointerstitial lesions in lupus nephritis. The study presented here investigates the possible role of IgG autoantibodies against mCRP in patients with TINU syndrome.nnnDESIGN, SETTING, PARTICIPANTS, & MEASUREMENTSnmCRP autoantibodies were screened by ELISA with purified human C-reactive protein in 9 patients with TINU syndrome, 11 with drug-associated acute interstitial nephritis, 20 with IgA nephropathy, 19 with minimal change disease, 20 with ANCA-associated vasculitis, 6 with Sjogrens syndrome, and 12 with amyloidosis. mCRP expression was analyzed by immunohistochemistry in renal biopsy specimens from the 9 patients with TINU syndrome and 40 from disease controls. Frozen normal human kidney and iris were used to demonstrate co-localization of human IgG and mCRP from patients with TINU syndrome with laser scanning confocal microscopy.nnnRESULTSnThe mCRP autoantibodies were detected in all nine patients with TINU syndrome, significantly higher than that of those with disease controls (P < 0.05). The renal histologic score of mCRP in TINU syndrome was significantly higher than that in disease controls (P < 0.05). The staining of mCRP and human IgG were co-localized in renal and ocular tissues.nnnCONCLUSIONSnIt is concluded that mCRP might be a target autoantigen in TINU syndrome.

Clinical InvestigationInclusion of renal vascular lesions in the 2003 ISN/RPS system for classifying lupus nephritis improves renal outcome predictions

The 2003 International Society of Nephrology/Renal Pathology Society (ISN/RPS) pathological classification system of lupus nephritis specified the importance of vascular damage and indicated this should be included in the diagnostic summary. Few pathological studies of lupus nephritis, however, focus on the patterns of renal vascular involvement. Here we assessed renal vascular lesions in lupus nephritis based on the 2003 ISN/RPS classification system and evaluated their association with clinical and pathological data in a large cohort from a single center in China. Among 341 patients with lupus nephritis, 279 were diagnosed with single or multiple renal vascular lesions that included 253 with vascular immune complex deposits, 82 with atherosclerosis, 60 with thrombotic microangiopathy, 13 with noninflammatory necrotizing vasculopathy, and 2 with true renal vasculitis. Patients with thrombotic microangiopathy had the poorest renal outcome. In multivariate Cox hazard analysis after inclusion of renal vascular lesions, the new chronicity index score became a significantly better independent risk factor for renal outcome (hazard ratio 2.32). Thus, renal vascular lesions are common in lupus nephritis and closely correlate with clinical disease activity and renal outcome. Inclusion of a detailed description of renal vascular lesions in the ISN/RPS classification of lupus nephritis may strengthen its predictive value for renal outcome.

Anti-C1q antibodies and IgG subclass distribution in sera from Chinese patients with lupus nephritis

UNLABELLEDnObjective. Anti-C1q antibodies are common in sera from patients with lupus nephritis (LN) and are associated with disease activity. The current study aimed to further investigate the prevalence of serum IgG anti-C1q antibody, its subclass distribution and their clinical and pathological association in patients with LN.nnnMETHODSnSera were collected from 150 patients with renal biopsy-proven LN, diagnosed from 2000 to 2006 in our hospital, 30 patients with systemic lupus erythematosus (SLE) without clinical evidence of renal involvement (non-renal SLE, NR-SLE) and 63 healthy donors. ELISA was used to detect serum IgG anti-C1q antibody and its subclass. Their clinical and pathological associations were further analysed.nnnRESULTSnThe prevalence of IgG anti-C1q antibody in LN (84/150, 56%) was significantly higher than that in NR-SLE (6/30, 20%) and healthy controls (3/63, 4.8%) (P < 0.005, P < 0.001, respectively). The prevalence of anti-C1q antibody in patients with diffuse proliferative renal lesions (class IV) (59/82, 71.95%) was significantly higher than that in those with non-diffuse proliferative renal lesions (class II + III) (12/26, 46.15%, P = 0.016) and class V (13/42, 30.95%, P < 0.001). The prevalence of IgG2 (60/135, 44.44%) was significantly higher than that of IgG1 (37/135, 27.41%) and IgG3 (25/135, 18.52%) (P < 0.005, P < 0.001, respectively). IgG2 was associated with the occurrence of arthritis (P < 0.05), higher serum creatinine (P < 0.05) and lower serum C3 (P < 0.05). Of the 38 LN patients with sera both in active phase and in remission, 17 were anti-C1q antibody-positive in active phase and the antibody levels decreased in all and turned to negative in 9 (52.94%) in remission. Meanwhile, the ratio of turning negative of IgG1, IgG2 and IgG3 anti-C1q was 33%(2/6), 53.85% (7/13) and 100% (7/7), respectively.nnnCONCLUSIONSnAnti-C1q antibodies are prevalent in LN and are closely associated with diffuse proliferative lesions. IgG2 anti-C1q might be pathogenic and IgG3 anti-C1q might be a more specific biomarker for monitoring disease activity.

Absence of glomerular IgG4 deposition in patients with membranous nephropathy may indicate malignancy

BACKGROUNDnThe renal pathological manifestations of malignancy-associated membranous nephropathy (M-MN) and idiopathic membranous nephropathy (I-MN) are similar. It has been suggested that glomerular IgG4 deposition may play an important role in the pathogenesis of I-MN. In the present study, we compared the IgG subclass of immune complex deposition, clinical data and pathological data of patients with M-MN and I-MN.nnnMETHODSnEight patients with M-MN and 42 patients with I-MN diagnosed between 1997 and 2009 in our hospital were enrolled. The clinical and pathological data were retrospectively collected, and glomerular IgG subclass deposition was detected by immunohistochemistry.nnnRESULTSnPatients with M-MN were older (P = 0.003), with lower serum albumin (P = 0.034) and higher serum C-reactive protein (CRP) level (P = 0.003) than patients with I-MN. The majority of patients with M-MN had earlier pathological stages (P = 0.003) and less IgG deposition in glomeruli (P = 0.029). Absence of IgG4 deposition in glomeruli was notably observed in patients with M-MN (7/8 in M-MN versus 6/42 in I-MN, P < 0.001) and it was an independent predictor for occurrence of malignancy (hazard ratio 0.065, 95% confidence intervals 0.007-0.571, P = 0.014).nnnCONCLUSIONnAbsence of glomerular IgG4 deposition, together with older age, severe hypoalbuminemia and high serum CRP level could be useful clues to differentiate M-MN from I-MN.

Combination of anti-C1q and anti-dsDNA antibodies is associated with higher renal disease activity and predicts renal prognosis of patients with lupus nephritis

BACKGROUNDnAlthough nephritogenic autoantibodies are considered to play a central role in the initiation of lupus nephritis, whether these autoantibodies are associated with renal clinical and pathological activity or renal outcome is still controversial. Here, we investigated the associations of certain serum autoantibodies with renal disease activity and renal outcome in a large cohort of Chinese patients with lupus nephritis.nnnMETHODSnOne hundred and thirty-six Chinese patients with biopsy-proven lupus nephritis and with long-term follow up data were studied. Sera at renal biopsy were tested for a panel of autoantibodies, including anti-nuclear antibodies, anti-double-stranded DNA (anti-dsDNA) antibodies, anti-extractable nuclear antigen antibodies, anti-C-reactive protein antibodies, anti-C1q antibodies, anti-cardiolipin antibodies and anti-β2-glycoprotein I antibodies. Associations of these autoantibodies with clinical features, laboratory findings, histopathological data and renal outcomes were further investigated.nnnRESULTSnAmong the various autoantibodies, anti-dsDNA and anti-C1q antibodies were better than other antibodies to evaluate the renal disease activity. Anti-dsDNA antibodies were correlated with higher incidence of leukocyturia (P< 0.05), total pathological activity index (AI) score (P< 0.05), endocapillary hypercellularity (P< 0.05), subendothelial hyaline deposits (P< 0.05) and leukocyte infiltration (P< 0.05). Anti-C1q antibodies were correlated with leukocyturia (P< 0.01), hematuria (P< 0.003) and the majority of the histopathological AIs including total AI score (P< 0.003), endocapillary hypercellularity (P< 0.003), cellular crescents (P< 0.05), karyorrhexis/fibrinoid necrosis (P< 0.003), subendothelial hyaline deposits (P< 0.003) and leukocyte infiltration (P< 0.01). Patients with both anti-dsDNA and anti-C1q antibodies had higher renal disease activity and poorer renal outcome (log-rank test: P= 0.048) compared with those without the two antibodies. In univariate survival analysis of renal prognosis, neither the presence of anti-C1q nor the presence of anti-dsDNA antibodies was a risk factor of renal survival. However, the combination of the two antibodies predicted renal prognosis (hazard ratio 4.40, 95% confidence interval: 1.268-15.269, P= 0.02).nnnCONCLUSIONSnAnti-C1q antibodies are more closely correlated with renal disease activity than the other autoantibodies. The combination of anti-C1q and anti-dsDNA autoantibodies indicates higher renal disease activity and predicts poor renal outcome.

Serum levels and renal deposition of C1q complement component and its antibodies reflect disease activity of lupus nephritis

BackgroundLupus nephritis is considered to be a principal cause of morbidity and mortality in SLE. Few studies focus on the association between anti-C1q antibodies in circulation and renal C1q deposition in human lupus nephritis. In this study, we detected the serum levels of C1q, presence of anti-C1q antibodies in circulation, renal C1q deposition and further analyzed their associations with clinical and pathological activity in a large cohort of Chinese lupus nephritis patients.MethodsSera and renal biopsies from 218 consecutive patients with lupus nephritis with long-term follow up data were studied. Sera were tested for levels of C1q and anti-C1q autoantibodies. Associations of levels of C1q, anti-C1q autoantibodies with renal deposition of C1q, clinical and histopathological data and renal outcome were further investigated.ResultsThe levels of serum C1q were significantly lower in lupus nephritis than that in normal controls [33.81u2009±u200920.36 v.s. 61.97u2009±u200910.50xa0μg/ml (Pu2009<u20090.001)]. The prevalence of anti-C1q antibodies, ratios of glomerular and vascular deposition of C1q in patients with lupus nephritis were 42.7% (93/218), 71.6% (156/218) and 86.2% (188/218), respectively. The serum C1q levels and anti-C1q antibodies were associated with SLEDAI scores (Pu2009<u20090.001, Pu2009=u20090.012, respectively), renal total activity indices scores (Pu2009<u20090.001, Pu2009<u20090.001, respectively). Granular positive staining of C1q and IgG by immunofluorescence was co-localized almost completely along the glomerular capillary wall and mesangial areas. Patients with anti-C1q antibodies presented with significantly lower serum C1q levels than those without it (23.82 [0.60, 69.62] μg/ml v.s. 37.36 [0.64, 82.83] μg/ml, Pu2009<u20090.001). The presence of anti-C1q antibodies was associated with the presence of glomerular C1q deposition (Pu2009<u20090.001), but not with the presence of renal vascular C1q deposition (Pu2009=u20090.203).ConclusionAnti-C1q autoantibodies were closely associated with serum levels of C1q and glomerular deposition of C1q. Kidney is at least one of the target organs of anti-C1q autoantibodies.

Autoantibodies against monomeric C-reactive protein in sera from patients with lupus nephritis are associated with disease activity and renal tubulointerstitial lesions

Serum levels of C-reactive protein (CRP) often remain low despite high disease activity in systemic lupus erythematosus (SLE). Sera from 96 patients with renal biopsy-proven active lupus nephritis, 24 of 96 patients in remission, and 49 patients with SLE with negative urinalysis (nonrenal SLE) was collected. Immunoglobulin G autoantibodies against monomeric CRP (mCRP) were screened by enzyme-linked immunosorbent assay with purified human CRP. Associations with clinical features, pathological data, and laboratory findings were investigated. The prevalence of mCRP autoantibodies in active lupus nephritis (57/96, 59.4%) was significantly higher than that in patients with SLE without clinical evidence of kidney involvement (20/49, 40.8%, p = 0.034). For the 13 patients with positive mCRP autoantibodies and sequential sera, their positive mCRP autoantibodies in active phase turned negative in remission (13/13, 100%). Patients with mCRP autoantibodies had significantly higher SLEDAI scores than patients without mCRP autoantibodies (18.3 +/- 5.2 vs 15.8 +/- 4.0, p = 0.013), who were more likely to experience acute renal failure (14/55 vs 2/33, p = 0.022), oral ulcer (15/57 vs 3/39, p = 0.022), and delayed activated partial thromboplastin time (18/52 vs 2/38, p = 0.001). Positive correlations between levels of mCRP autoantibodies and semiquantitative scores of renal histologic features were first observed in lupus nephritis as follows: interstitial inflammation (r = 0.328), tubular atrophy(r = 0.276), interstitial fibrosis (r = 0.211), and chronicity index score (r = 0.243). Autoantibodies against mCRP are prevalent in patients with lupus nephritis and are associated with disease activity and renal tubulointerstitial lesions.