The correlation between renal histology and class specific (IgG and IgM) antibodies to double stranded DNA (dsDNA) and single stranded DNA (ssDNA) was studied by enzyme linked immunosorbent assay (ELISA) in 40 untreated patients with systemic lupus erythematosus (SLE). The levels of IgG antibodies to dsDNA were significantly higher in patients with World Health Organisation class IV nephritis than in those with class I, class II, or class III nephritis. IgG antibodies to ssDNA were higher in patients with class IV than in those with class II nephritis. IgG antibodies to dsDNA showed a close correlation with the histological activity score and the amount of electron dense deposit. IgG antibodies to ssDNA showed only a weak correlation with the renal histological activity score. IgM antibodies to dsDNA and IgM antibodies to ssDNA were not correlated with renal histological features. Patients with moderate to severe nephritis had a lower ratio of IgM antibodies to dsDNA to IgG antibodies to dsDNA than those with mild nephritis. These results indicate that the measurement of IgG antibodies to dsDNA is predictive in evaluating renal histological activity in patients with SLE.

Abstract. To elucidate the molecular mechanism of glomerular events in lupus nephritis, we performed genome-wide mRNA expression analysis of glomeruli microdissected from lupus mice. MRL / lpr mice (12-week-old) were orally given vehicle or prednisolone (10 mg / kg per day) for 4 weeks. Renal histology of MRL / lpr mice revealed mesangial proliferative glomerulonephritis with cellular infiltration of macrophages, T cells, and neutrophils. We identified 567 upregulated genes in MRL / lpr glomeruli compared to control congenic mice. Those included complement components, adhesion molecules, chemokines and their receptors, and molecules related to antigen presentation. Over 130 genes were considered preferentially or exclusively expressed in hematopoietic cell lineages possibly reflecting leukocytes accumulation. Of note is the finding that chemokines and chemokine receptors (CCL3, CCL4, CCL5, CXCL9, CXCL10, CXCL11, CXCL16, CCR5, CXCR3, and CXCR6) that are related to T helper 1 (Th1) cells accumulation were up-regulated concomitantly with increased expression of Ebi3, a subunit of IL-27 that plays a role in Th1 predominance. These changes were accompanied by increased mRNA expression of many genes that were inducible by Th1 cytokine interferon-γ. Prednisolone markedly attenuated glomerular lesion and leukocyte influx parallel with the reduction of enhanced gene expression. The present study shows additional evidence supporting glomerular Th1 cells accumulation and their role. Our data also provide an important resource in seeking new therapeutic targets to lupus nephritis.Supplemental table: available only at http://dx.doi.org / 10.1254 / jphs.FP0071337

Activation of alternative complement pathway is presumed to be important pathogenically in IgA nephropathy since renal biopsies usually exhibit glomerular deposition of C3 and P (properdin). Surprisingly, little is known about plasma complement activation in this disease, and the plasma C3 and C4 concentrations are usually normal or increased. We quantitated C3 activation in 202 plasmas from 81 patients with IgA nephropathy using a sensitive new assay that detects a neoantigen [iC3b-C3d neoantigen) which appears when C3b is inactivated to iC3b, C3dg, or C3d. This assay accurately quantitates small amounts of in vivo C3 activation. The concentration of iC3b-C3d neoantigen in plasma was significantly increased, indicating C3 activation in 37% of the pediatric and 57% of the adult plasmas assayed. When data from serial determinations in the patients were analyzed, 75% of the adult and 57% of the pediatric patients had C3 activation on at least one occasion. Classical pathway activation, quantitated by C4 activation was found in 20% of the adult and 5% of the pediatric plasmas. No association was found between elevated iC3b-C3d neoantigen concentration and history of macroscopic hematuria, chronic renal insufficiency or degree of proteinuria. These studies show that complement activation can frequently be detected in the plasma of IgA nephropathy patients. However, the pathophysiologic significance of this complement activation remains to be determined.

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To clarify the role of PDGF A-chain in hypertensive vascular hypertrophy of spontaneously hypertensive rats (SHRs), we studied levels of PDGF A-chain gene expression and transcription factors related to the gene in vascular smooth muscle cells (VSMCs) of SHRs in vivo. RNase protection assay and in situ hybridization showed that PDGF A-chain mRNA levels in VSMCs of SHRs were twofold higher than in those of normotensive Wistar-Kyoto rats. Gel retardation assays showed that levels of Spl and AP-2 in VSMCs of SHRs were twofold more abundant than in those of WistarKyoto rats. Treatment with four pharmacologically different species of antihypertensive drugs for 2 wk decreased the levels of both PDGF A-chain mRNA and Spl, but not AP-2 level in VSMCs of SHRs with regression of aortic hypertrophy, indicating that increases in levels of both PDGF Achain mRNA and Spl in VSMCs of SHRs were associated with high blood pressure. These results suggest that high blood pressure is a stimulus which upregulates PDGF Achain gene expression in VSMCs of SHRs, resulting in an autocrine enhancement in hypertensive vascular hypertrophy, and that the activation of the gene may be mediated through increases in Spl in these cells. (J. Clin. Invest. 1995Invest. . 95:1140Invest. -1150