Clinical efficacy of intravenous immunoglobulin for patients with MPO-ANCA-associated rapidly progressive glomerulonephritis.

BACKGROUND: To determine whether intravenous immunoglobulin (IVIg) can control disease activity in patients with myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-associated rapidly progressive glomerulonephritis (RPGN). METHODS: Twelve patients with serologically and histologically confirmed MPO-ANCA-associated RPGN (7 men, 5 women; mean age 71 +/- 3 years) received IVIg (400 mg/kg/day) alone for 5 days. The effects of IVIg were evaluated by white blood cell counts, serum C-reactive protein levels, Birmingham Vasculitis Activity Score, rate of change in reciprocal creatinine (1/Cre), and plasma tumor necrosis factor-alpha levels after IVIg administration. Corticosteroids with or without cyclophosphamide were commenced after IVIg. RESULTS: After IVIg treatment, a significant decrease was observed in white blood cell count (p < 0.05), C-reactive protein values (p < 0.001), and Birmingham Vasculitis Activity Score (p < 0.001) concomitant with the amelioration of systemic symptoms. The rate of change in 1/Cre significantly improved (p < 0.05). Plasma tumor necrosis factor-alpha levels that were significantly elevated in patients before IVIg compared with normal controls (p < 0.0001), rapidly declined after IVIg with a significant reduction (p < 0.05). Three months post-treatment with IVIg, all patients showed improvement of disease without serious infectious complications. CONCLUSION: IVIg is a potential component of remission induction therapy for patients with MPO-ANCA-associated RPGN.

Chromosomal mapping of hyperserum IgA and glomerular IgA deposition in a high IgA (HIGA) strain of DdY mice.

BACKGROUND: The high IgA (HIGA) strain of ddY mice is an inbred model of IgA nephropathy (IgAN), established by selective mating of outbred ddY mice. HIGA mice show high levels of serum IgA and glomerulonephritis with mesangial IgA deposition. To identify the genetic loci responsible for hyperserum IgA and glomerular IgA deposition in this strain, quantitative trait loci analysis was carried out. METHODS: By crossing HIGA with BALB/c mice, 244 F2 generations were produced. Serum IgA levels and glomerular IgA deposition were examined at 40 weeks of age. Genetic markers were typed at 105 microsatellites and the quantitative trait loci of hyperserum IgA and glomerular IgA deposition were confirmed using Map Manager QTX software. RESULTS: Two significant quantitative trait loci of hyperserum IgA were identified on chromosome 2 [logarithm of odds (LOD) = 5.01] and chromsome 4 (LOD = 4.45), and a suggestive quantitative trait locus of hyperserum IgA was located on chromosome 1 (LOD = 3.49). On chromosome 15, a significant quantitative trait locus of glomerular IgA deposition was identified (LOD = 4.40) without the hyperserum IgA locus. Serum IgA level was weakly correlated with the intensity of glomerular IgA in 244 F2 mice; however, the quantitative trait loci of hyperserum IgA were not significantly associated with glomerular IgA deposition. CONCLUSION: These findings indicate that, in HIGA mice, glomerular IgA deposition is mainly regulated by a quantitative trait locus on chromosome 15, and hyperserum IgA synergistically but weakly affect glomerular IgA deposition. The immune disturbance similar to IgAN was revealed to be under multigenic control in HIGA mice.

Coagulation in the mesangial area promotes ECM accumulation through factor V expression in MsPGN in rats.

It is well known that tissue factor starts the extrinsic coagulation pathway, which activates factor X to Xa, and factor V is a membrane-bound potent cofactor for the terminating stage of prothrombin activation by factor Xa. In a previous in vitro study, factor V was induced in cultured mesangial cells by inflammatory stimulation and increased expression of factor V promoted fibrin generation on the cultured mesangial cell surface. We report that extracellular matrix (ECM) accumulation is increased in association with coagulation in the mesangial area through factor V expression in mesangioproliferative glomerulonephritis (MsPGN). Wistar rats were intravenously injected with rabbit anti-rat thymocyte serum accompanied with or without simultaneous injection of rabbit anti-factor V antibody. Time course study in immunohistochemistry revealed that factor V expression was prominent on day 3 and fibrin-related antigen (FRA) deposition, then ECM accumulation, followed from day 3 to day 8. Massive fibronectin depositions and transforming growth factor (TGF)-beta expression were also noted in glomeruli from the disease control group, markedly higher than those in the normal group, and these depositions and expressions were significantly decreased in the anti-factor V neutralizing antibody-injected group. Northern blot analysis revealed that factor V mRNA expression was prominent on day 3 and was weak on day 8. Double-labeling experiments revealed the frequent colocalization of alpha-smooth muscle actin with factor V, FRA, and fibronectin in the same mesangial areas of glomeruli. TGF-beta, connective tissue growth factor (CTGF), collagen type IV, and fibronectin mRNA were upregulated in the disease control group, and anti-factor V-neutralizing antibody injection suppressed these mRNA expressions in glomeruli. The present results suggest that ECM components accumulation may progress in accordance with coagulation in the mesangial area through mesangial factor V expression and upregulated expression of TGF-beta and CTGF in MsPGN.