不同性别成人IgA肾病患者临床特征

目的了解不同性别成人原发性IgA肾病（IgAnephropathy,IgAN）患者的临床特征。方法选择我科1996年3月至2009年11月经肾活检确诊为kAN的成人患者192例,对比分析男性和女性患者各临床表现和病理积分特点。结果成人IgAN患者中,不同性别患者的病程、发病年龄、血胆固醇、清蛋白、血IgA、血C3、尿红细胞计数和估算肾小球滤过率值的差异无统计学意义,但男性收缩压、舒张压、血肌酐、尿素氮、血尿酸及24h尿蛋白定量明显高于女性,差异显著。男性高血压、高尿酸血症、高三酰甘油血症、24h尿蛋白定量〉1g的比例显著高于女性。男女患者的肾小球积分、肾小管间质积分、血管积分及慢性病变、活动性病变积分差异均无统计学意义。肾功能中度损伤的独立危险因素为高尿酸血症（r=9．146,95．0％CI：2．322-36．026,P〈0．01）、总积分（r=2．772,95．0％CI：1．709～4．496,P〈0．01）、肾小球积分（r=0．522,95．0％CI：0．287-0．952,P〈0．05）。结论成人IgAN患者肾活检时男女患者间的肾功能及。肾脏病理改变并无明显差异,但男性患者相关临床病变重,血压、血肌酐、血尿酸及24h尿蛋白定量高,需积极干预延缓其进展。     

Histological differences in new-onset IgA nephropathy between children and adults.

BACKGROUND: It is suggested that IgA nephropathy (IgAN) manifests differently in children vs adults on the basis of biopsy findings. However, this has been difficult to establish owing to the uncertainty of the timing of disease onset in adult IgAN. We addressed this question by comparing both histology and leucocyte accumulation in biopsies of recently diagnosed childhood and adult IgAN. METHODS: Biopsies taken within 2 years from the onset of renal abnormalities in 33 childhood (10 +/- 3 years of age) and 38 adult (35 +/- 6 years) cases of IgAN were examined for histological changes (cellularity in mesangial, endocapillary and extracapillary areas, matrix expansion, adhesions/crescents and interstitial damage), glomerular deposition of immunoglobulin and complement, and the presence of macrophages, activated macrophages and T cells by immunohistochemistry. RESULTS: Glomerular hypercellularity owing to increased cells in mesangial area was prominent in paediatric IgAN and significantly greater than in adult IgAN. In contrast, glomerular matrix expansion, crescent formation and interstitial damage were more severe in adults compared to paediatric IgAN. Indeed, glomerular hypercellularity correlated with proteinuria in paediatric but not in adult IgAN, whereas glomerular matrix correlated with proteinuria and renal function in adult but not in paediatric IgAN. The degree of C3c deposition was significantly greater in paediatric IgAN, while deposition of fibrinogen was greater in adult IgAN. Glomerular and interstitial CD68+ macrophages and a subset of sialoadhesin (Sn)+ activated macrophages were identified in both paediatric and adult IgAN, being significantly greater in number in adult IgAN. Glomerular leucocyte infiltration correlated with proteinuria while interstitial leucocyte infiltration correlated with interstitial damage in both groups. However, only the subset of Sn+ macrophages gave a significant correlation with renal function, glomerular hypercellularity and glomerular matrix. CONCLUSIONS: This study has demonstrated significant differences in the early glomerular lesions of IgAN in children vs adults. Furthermore, Sn+ activated macrophages are implicated in the pathogenesis of IgAN in both patient groups. The prognostic significance of these findings warrants further study.     

Proteinuria in IgA nephropathy

Clinicopathological data in 74 patients with IgA nephropathy were analyzed with special attention to level of proteinuria and its prognostic significance in this disease. Excretion rates exceeding 3 g per day (heavy), in the range of 1 to 2.9 g (moderate) and under 1 g per day (mild) each occurred in approximately equal proportions of patients. One-sixth of those with more than 1 g developed end-stage renal failure, while serum creatinine never exceeded 2 mg/dl in any with mild proteinuria. "Renal survival" (serum creatinine of 2 mg/dl or less) at five years after presentation was 100% in patients with persistently mild proteinuria, 87% in those whose protein excretion reached the moderate range, and 69% when heavy or nephrotic range proteinuria developed. Of significance, only rarely did mild proteinuria at presentation increase to higher levels. A correlation existed between level of protein excretion and severity of mesangial, segmental or global proliferation, glomerulosclerosis, podocyte effacement, interstitial infiltration, tubular atrophy and vascular sclerosis, even in patients with unimpaired renal function. Moderate or heavy proteinuria typically preceded the onset of hypertension and occurred prior to the development of renal insufficiency. Our results underscore magnitude of proteinuria as an early marker of glomerular damage in the prognosis of IgA nephropathy.     

Immunotherapy in IgA nephropathy

Summary: The purpose of this presentation was to review the recent results of immunotherapy (i.e. corticosteroids, cyclosporine A and mizoribine), in patients with IgA nephropathy. We summarized the effects of corticosteroid therapy in patients with advanced stage of IgA nephropathy in our division. These patients were divided into steroid or non-steroid (anti-platelet and/or anti-coagulation drug) therapy group. The clinical findings, 6 years after renal biopsy, were observed in this study. Mean levels of urinary protein excretion in the steroid therapy group (11 patients; 3.42 g/day) were higher than those in the non-steroid therapy group (nine patients; 1.64 g/day) at the time of renal biopsy. The mean levels of creatinine clearance (CCr) in the steroid or non-steroid therapy group were 61.2 and 78.6 mL/min, respectively. Efficacy of steroid or non-steroid therapy was similar in patients with the advanced stage of IgA nephropathy, and it appeared that the steroid therapy was not effective for patients in the advanced stage of this disease. Cyclosporine A is a fungal peptide with immunoregulatory properties inhibiting activation of both T and B cells. Recently, a new immunosuppressive agent, mizoribine has been developed in Japan. Mizoribine has a suppressive effect on antibody formation via the direct inhibition of B cell function. Koshikawa et al. reported the effect of this drug in 158 patients with steroid-resistant nephrotic syndrome in multi-center studies in Japan. Mizoribine was administered orally at 150 mg/day for 24 weeks. Efficacy of treatment with mizoribine was marked compared with that with placebo in patients with IgA nephropathy and membranous nephropathy. At present, the authors are determining the clinicopathological effects of mizoribine in ddY mice, a spontaneous animal model of IgA nephropathy.     

Role of macromolecular IgA in IgA nephropathy

Primary IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis, leading to progressive renal failure in almost one third of the patients. The disease is characterized by mesangial deposits of IgA. The pathogenesis of IgAN remains incompletely understood. The basic abnormality of this disorder lies within the IgA immune system rather than in the kidney. Elevated levels of IgA and IgA-containing complexes are found in sera of most patients with IgAN, but increased levels alone are not sufficient to develop IgAN. Therefore abnormal physicochemical properties of circulating IgA, such as size, charge, and glycosylation may play a role. This is supported by the presence of altered glycosylation of serum and mesangial IgA in patients with IgAN. Although the precise origin and nature of the mesangial IgA deposits are still uncertain, they contain at least in part macromolecular IgA, which may be derived from circulating IgA-containing complexes. Recently, novel insights have been obtained in the molecular composition of circulating high-molecular-weight IgA, which might include complexes with underglycosylated IgA1 and IgA-CD89 complexes. In this review various aspects of macromolecular IgA in relation to IgAN will be discussed.     

MicroRNAs in IgA nephropathy

IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. It is considered that the pathogenesis of IgAN involves the ‘multiple hit theory’ and the immune-inflammatory mechanism; however, these theories have certain limitations. The gold standard for diagnosing IgAN is still renal biopsy. Although renal biopsy is accurate, it is traumatic and is associated with some risks and limitations, so there is a need for non-invasive diagnostic methods. According to recent studies, microRNAs (miRNAs) play important roles in the occurrence and development of IgAN; thus, they provide the possibility of the noninvasive diagnosis of IgAN and also have some value in predicting prognosis. This review summarizes the current research status of miRNAs in the occurrence, development, diagnosis, and prognosis of IgAN. We also highlight some interesting and challenging points that require further study.     

Polymorphism in IgA nephropathy

Summary: IgA nephropathy (IgAN) is polyphormic in its clinical manifestation, course and prognosis. Patients with isolated IgA deposit in glomeruli tend to have a high incidence of macroscopic haematuria and carry a better prognosis. In contrast, patients with deposits of IgA and IgG and IgM have a higher incidence of nephrotic syndrome and hypertension. In parallel, patients with IgA and IgG and IgM tend to have more glomerulosclerosis and tubulointestitial lesions. Recently, the angiotensin converting enzyme (ACE) gene polymorphism and its association in disease risk provided interesting exploration leading us to speculate about a possible mechanism to explain the variation in the rate of progression of IgAN; although, the results are still controversial. The variability of plasma ACE concentration has been shown to be associated with an insertion/deletion polymorphism. The frequencies of ACE genotype in 177 Chinese patients with IgAN has been observed. We found that patients with IgAN showed a higher frequency of DD genotype than normal population. In contrast to the previous reports, we did not find any association between ACE genotype and the rate of progression of IgAN. As different genotypes of IL-1 receptor antagonist (IL-1 ra) are also responsible for the circulating levels of IL-1 ra, the polymorphism of IL-1 ra gene has been analyzed in 100 IgAN patients. There was no significant difference in the frequency of IL1RN*2 allele between normal subjects and IgAN. However, patients with recurrent macroscopic haematuria showed a higher carriage rate of IL1RN*2. Hereditable factors, in combination with a number of recognized environmental risk factors, are important determinants of the pathogenesis and natural history of IgAN. The notion that the gene polymorphism might be responsible for the clinical features and progression of IgAN is both intriguing and provocative. The lessons from previous multiple small size studies have produced conflicting results illustrating the need for observation of large numbers of cases in further studies to verify these observed associations.     

Prognosis in IgA nephropathy

Summary: IgA nephropathy it is now widely recognized as the most common glomerulonephritis causing end-stage renal failure (ESRF) in many parts of the world. Large series of patients have been analysed in an attempt to identify prognostic clinical and histological features. Increasingly the importance of stage specific analysis of such factors has been reflected in the literature. Such analysis suggests that if therapeutic trials are to be conducted in an attempt to improve prognosis in IgA nephropathy these will need to be organized on a multicentre basis under the auspices of an international organization.     

Neutrophils in IgA nephropathy

Summary: Neutrophil participation is prominent in proliferative forms of glomerulonephritis. They are recruited by antibody-mediated chemoattractant complement fragments. Monocyte and endothelial derived cytokines or adhesion molecules may also recruit these cells. In most situations of inflammation, neutrophils induce injury by the release of reactive oxygen radicals and their production of lysosomal proteolytic enzymes. the clinical importance of neutrophils in mediating glomerular injury in IgA nephropathy (IgAN) has often been downplayed, although it has been recognized that IgA is involved in the initiation of intracellular oxidative metabolism in normal neutrophils. That disordered neutrophil activation could be relevant to the pathogenesis of IgAN seems likely from their prominent infiltration in glomerular capillaries in the acute phase of primary IgAN, increased expression of complement 3 receptors on neutrophils from patients with IgAN, and increased oxidative metabolism of neutrophils in these patients. Furthermore, recent data revealed heat-aggregated forms of IgA prepared from patients with IgAN exert an up-regulatory effect on calcium mobilization, inositol triphosphate production, and oxidative metabolism in human neutrophils. Interestingly, the plasma level of E-selectin, mainly derived from activated vascular endothelial cells upon interaction with neutrophil, was elevated following synpharyngitic macrohaematuria in patients with IgAN. There was also a significant stepwise increase in circulating E-selectin associated with increased histopathologic severity in these patients. These data tend to support the notion that neutrophils could be activated in IgAN despite lack of acute clinical exacerbation and may potentially be participating in the inflammatory process of glomerular and interstitial injury.