No abstract

Primary glomerulopathy can be classified into seven essential patterns based on histopathological studies. The pathogenesis of membranoproliferative glomerulonephritis (MPGN), and membranous nephropathy (MN), which show glomerular IgG deposition and induce mainly nephrotic syndrome, is not known. To clarify the role of IgG subclass in glomerulonephritis, we compared serum concentrations of IgG subclasses, the ratio of serum IgG subclasses to total IgG (%IgG subclass), and glomerular deposition of IgG subclasses between 7 MPGN patients, 21 MN patients, and 9 lupus nephritis (LN) patients. Serum IgG subclasses and %IgG in all groups were almost within normal range based on the values in Japanese healthy adults. In the MPGN and MN groups, the IgG1 concentration was significant lower than that of the LN group (P < 0.001, P < 0.0001, respectively). The IgG2 concentration in the MPGN group decreased significantly compared with that in the LN group (P < 0.05). The %IgG2 of the LN group decreased significantly compared with that of the MN group (P < 0.05). The %IgG3 of the MPGN group was significantly higher that that of the MN group (P < 0.05). The glomerular immunofluorescent intensity of IgG1 and IgG2 were significantly stronger in the LN group than in the MPGN and MN groups (IgG1, P < 0.001, P < 0.01, respectively; IgG2, P < 0.0001, P < 0.0001, respectively). IgG3 in the MPGN and LN groups deposited significantly compared with that in the MN group (P < 0.0001, P < 0.01, respectively). The intensity of IgG4 in the MN group showed a significant difference compared with that in the MPGN and LN groups (P < 0.0001, P < 0.01, respectively). IgG3 is an important factor in the pathogenesis of primary MPGN, while IgG4 relates to glomerular IgG deposition in MN.

BackgroundThe study aim was, for the first time, to conduct a multicenter randomized controlled trial to evaluate the effect of tonsillectomy in patients with IgA nephropathy (IgAN).MethodsPatients with biopsy-proven IgAN, proteinuria and low serum creatinine were randomly allocated to receive tonsillectomy combined with steroid pulses (Group A; n = 33) or steroid pulses alone (Group B; n = 39). The primary end points were urinary protein excretion and the disappearance of proteinuria and/or hematuria.ResultsDuring 12 months from baseline, the percentage decrease in urinary protein excretion was significantly larger in Group A than that in Group B (P < 0.05). However, the frequency of the disappearance of proteinuria, hematuria, or both (clinical remission) at 12 months was not statistically different between the groups. Logistic regression analyses revealed the assigned treatment was a significant, independent factor contributing to the disappearance of proteinuria (odds ratio 2.98, 95% CI 1.01–8.83, P = 0.049), but did not identify an independent factor in achieving the disappearance of hematuria or clinical remission.ConclusionsThe results indicate tonsillectomy combined with steroid pulse therapy has no beneficial effect over steroid pulses alone to attenuate hematuria and to increase the incidence of clinical remission. Although the antiproteinuric effect was significantly greater in combined therapy, the difference was marginal, and its impact on the renal functional outcome remains to be clarified.

Our findings suggest that the distribution patterns of glomerular IgG subclass deposits are different in idiopathic MN and M-MN. The strong IF intensity of glomerular IgG1 and IgG2 in M-MN may provide a possible predictor for this condition.

There are racial differences in primary renal diseases for end-stage renal disease (ESRD) and the incidence and prevalence of cardiovascular disease (CVD). To reduce the number of patients with both ESRD and CVD, an effective screening method for CKD should be established. In Japan, screening with the urine dip-stick test for proteinuria has been used since 1972 targeting every child and worker and since 1983 for every resident over 40 years old. There are several reasons for continuing this screening program. First, the positive rate of proteinuria is high in the Japanese general population, especially subjects with neither hypertension nor diabetes. Most of these subjects have no symptoms, and the only sign of renal disease is asymptomatic urinary abnormalities. Second, the prevalence and incidence of glomerulonephritis, especially IgA nephropathy, are high in the Japanese and Asian races, and urinalysis is the only method for early detection of chronic glomerulonephritis. Third, 10-year survival of the ESRD patients due to glomerulonephritis was approximately twice that of ESRD patients due to diabetes and nephrosclerosis. Consequently, reducing the incidence of ESRD due to glomerulonephritis is one of the best ways to reduce the prevalence of ESRD. Furthermore, higher incidence of ESRD in Asian races than in Caucasians was reported. Proteinuria is known to be the best predictor for reducing renal function, and the urine dip-stick test for proteinuria is less expensive and is cost-effective. For an effective screening strategy to reduce the ESRD population in Japanese and Asians, universal screening with the urine dip-stick test for proteinuria could be one solution.

It was found that ddY mice derived from non-inbred dd-stock mice brought from Germany before 1920 and then raised in Japan developed spontaneously IgA dominant deposition in the glomerular mesangium. In this report we give a detailed natural history of the renal pathology of those mice. The animals were fed rodent laboratory chow and sacrificed in groups of 9 to 10 at 6, 10, 16, 24, 28, 40, and 59 weeks of age. The bladder urine was analyzed, serum immunoglobulins were measured, and the kidney specimens were evaluated with light, fluorescent, and electron microscopy. Proteinuria was (plus) to (2 plus) after 28 weeks and (2 plus) to (3 plus) at 59 weeks with negative hematuria. Mesangial cell proliferation began to appear at 16 weeks, then progressed to a definite proliferative glomerulonephritis. At 59 weeks an additional increase of the mesangial matrix occurred. By immunofluorescence, there were IgG of (2 plus), IgM (plus) to (2 plus), IgA (plus) and C3 (plus) in the glomeruli until 28 weeks. However, IgA started to be dominant at 40 weeks and the glomerular pattern was IgA (2 plus) to (3 plus), IgG (plus) to (2 plus), IgM (+/-) to (plus) and C3 (plus) to (2 plus) at 59 weeks. Polyclonal IgA and IgG2a among immunoglobulins steeply rose at 40 weeks, and at 59 weeks IgA increased by 850%, IgG2a by 280%, IgG1 by 170%, IgG2b by 90%, and IgM by 60%, as compared with their level at 6 weeks. There was no anti-nuclear antibody. Thus, ddY mice, at least after the age of 40 weeks, can be used as a new animal model for spontaneous IgA nephritis. The probable origin of IgA is also discussed.

POEMS nephropathy can be one cause of end-stage renal disease with variable intrarenal pathological changes of a microangiopathic nature which have differential influences on renal function. A pathogenic role for VEGF in POEMS syndrome appears to be likely, but its causal relation to the nephropathy awaits further investigation.

There are few reports concerning the sorting mechanisms of mammalian HSP60 into the mitochondria from the cytoplasm. In the present study we investigated the protein import system. Based on immunoblotting and immunohistochemistry, HSP60 was detected in both the cytoplasm and mitochondria. The purified cytoplasmic HSP60 showed chaperone activity, and the protein was imported into the mitochondria in vitro by a mitochondrial import assay. HSP60 mRNA was increased in the kidney papilla of rats that had been water restricted for three and five days, but no changes in HSP60 mRNA were detected in the cortex or the medulla of the rat kidneys. Upon immunoblotting, HSP60 was detected in both the cytoplasm and the mitochondria of normal rat kidney cortex, medulla, and papilla in almost the same quantity. HSP60 was remarkably decreased in the kidney papilla of rats that were water restricted but the protein was increased in the mitochondria of the rat kidney papilla. We also analysed binding of the protein to the signal sequence of HSP60 using signal sequence-affinity column chromatography. We identified only one protein band with a molecular mass of 70 kDa on SDS/PAGE. The protein was eluted from the affinity column by an excess of signal peptide or by 5 mM ATP. Upon immunoblotting, the 70-kDa protein cross-reacted with an antibody against HSP70. These results suggested that mammalian HSP60 is located both in the cytoplasm as a stable cytoplasmic HSP60 and also in the mitochondria under normal conditions. The cytoplasmic HSP60 is quickly imported into the mitochondria under severe conditions by cytoplasmic HSP70.