AUTHOR AND EDITOR INFORMATION

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INTRODUCTION

Section 2 of 11  

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• Introduction
• Clinical
• Differentials
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• Follow-up
• Miscellaneous
• Multimedia
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Background

Idiopathic immunoglobulin A (IgA) nephropathy (IgAN), often termed Berger nephropathy, was first described by Berger and Hinglais in 1968, based on the finding of predominant IgA deposition in the mesangium with a mesangial proliferation and clinical features that spanned the spectrum from asymptomatic hematuria to rapidly progressive glomerulonephritis.

IgAN is an immune-mediated glomerulonephritis involving a heterogeneous group of patients with a variety of different clinical permutations. The natural history of IgAN among patients with hematuria and minimum proteinuria is unknown. Advanced age, hypertension, proteinuria, and impaired renal function at presentation are poor prognostic indicators.

IgAN is now recognized as one of the most common primary glomerulonephritises worldwide. It was initially considered a benign condition, but extended follow-up indicates that as many as 40% of cases progress to end-stage renal failure in 10 years. Spontaneous remission has been reported in children and adults. Secondary IgA nephropathy is also associated with a variety of disease processes.

Pathophysiology

Thirty-five years after its first description, the pathogenesis of IgAN is now becoming more clear. Substantial evidence indicates that it is an immune complex disease. The characteristic pathologic findings by immunofluorescence microscopy of granular deposits of IgA and C3 in the glomerular mesangium and detection of IgA immune complexes from circulation suggests that this disease is the result of the deposition of circulating immune complexes. Many immunologic abnormalities that may lead to formation of immune complexes have been reported in patients with IgAN. Recurrence of IgAN has been reported in allograft, and rapid disappearance of IgA deposits is observed when kidneys with IgA deposits are transplanted in a patient without IgAN.

Immunoglobulin A

Monomeric IgA molecules have a molecular weight of 150,000 d; polymers range in weight up to 350,000 d. Polymer forms of IgA contain the J, or joining chain. Two IgA subclasses (IgA1, IgA2) are identified on the basis of structural differences of the heavy alpha chain. IgA2 molecules are further classified into 2 categories (A2m[1], A2m[2]) on the basis of genetic marker presence.

Secretory IgA

The Ig patterns of external secretions are characterized by secretory IgA in saliva; tears; bile; urine; and nasal, tracheobronchial, intestinal, and cervical fluids. Most IgA molecules in external secretions exist as dimers composed of two 7S IgA monomers plus two other non-Ig proteins, the J chain and secretory component (SC) (molecular weight, 71,000).

IgA is the most abundant immunoglobulin in the body; it is chiefly concerned with mucosal defense. IgA is produced by plasma cells in the mucosa and by bone marrow cells. The mucosal immune system synthesizes polymer IgA (pIgA) and transports it into mucosal fluid. The SC remains attached to the pIgA. Plasma cells only assemble pIgA. Both subclasses of IgA (ie, IgA1, IgA2) are present in mucosa.

The process begins with the accumulation of IgA, predominantly IgA1, in renal mesangial cells. Glycosylation and size of IgA1 are essential for interaction with mesangial receptor in IgA nephropathy. IgA1 contains a J chain but no SC. IgAN is often assumed to be an immune complex disease because similar patterns of mesangial immunoglobulin deposition can be induced by the infusion of preformed antigen-antibody complexes. Deposition of IgA immunoglobulin leads to cytokine release, mesangial cell proliferation, and activation of the complement system via the alternative pathway. Ultimately, the glomerular filtering surface is damaged and reduced, and renal failure ensues.

The fact that polymeric IgA1 is usually derived mainly from the mucosal immune system and the association of some cases of IgA nephropathy with syndromes that affect the respiratory tract or gastrointestinal tract has led to the suggestion that IgA nephropathy is a disease of the mucosal immune system. This concept was supported by the finding of immunoglobulin antibodies to dietary antigens or various infectious agents, both viral and bacterial, in some patients with IgA nephropathy. This concept is also supported by the clinical observation that, in some patients with IgA nephropathy, the hematuria increases acutely at the time of upper respiratory tract or gastrointestinal infection.

Regardless of the mechanism that leads to the increased deposition of IgA or IgA-containing immune complexes in the glomeruli, the mechanisms responsible for the glomerular injury remain poorly understood, especially when one keeps in mind the poor phlogistic nature of IgA and its inability to activate complement. Despite the demonstration of a specific IgA receptor on mesangial cells and in the glomerulus of patients with IgA nephropathy, studies of the expression of Fc alpha R on peripheral blood mononuclear cells and granulocytes led to conflicting results. IgA nephropathy may be linked to the expression of an IgA nephropathy–specific variant of Fc alpha R receptor on monocytes. The role, if any, of Fc alpha R in the pathogenesis of IgA nephropathy remains to be elucidated. Alternatively, IgA-IgG immune aggregates have been hypothesized to activate C3 by the IgG contained in those aggregates.

IgAN and Henoch-Schönlein purpura

IgAN and Henoch-Schönlein purpura (HSP) share many morphologic and immunopathologic features. The most striking similarities between IgAN and HSP nephropathy (HSN) are mesangial IgA deposition, elevated serum IgA level, and IgA circulating immune complexes. The glomerular changes (diffuse or focal mesangial proliferation) in HSN are essentially the same as those in IgAN. An infective episode precedes HSN in 30-50% of patients, and presence of Haemophilus influenza antigen in the glomerular mesangium and the presence of IgA antibody against H Influenza in sera has been reported in the patient with HSN.

The presence of antineutrophil cytoplasm antibodies (ANCA) was proposed as a marker of HSN to distinguish HSN from IgAN. Both have broadly similar geographic distributions and are rare in black persons. Coexistence in different members of the same family has been reported. Despite these similarities, the 2 conditions are clinically different and pathogenesis is not clear. The HSN is an acute condition with a glomerular lesion mostly nonprogressive after the onset, while IgAN is a chronic slowly progressive lesion, which may eventually lead to renal failure. IgAN has a male predominance. HSP occurs mostly is young children and is rare in adults, whereas IgAN occurs mainly in older children and young adults.

Frequency

United States

IgAN accounts for 2-10% of all primary glomerular diseases occurring in the United States. The prevalence of IgA in the general population has been estimated to be 25-50 cases per 100,000, although the fact that almost 5% of all biopsied patients have at least some IgA deposits in their glomeruli should be noted.

International

IgAN has been diagnosed worldwide, but its prevalence in different countries varies. In Pacific countries, particularly in Japan, it accounts for approximately 50% of all primary glomerular diseases. In Europe, it is responsible for 20-30%. The explanation of this apparent variability is uncertain, but it may be related, in part, to differing indications for renal biopsy in different centers. High incidence rates are reported in Asia, France, Italy, Finland, and southern Europe. Genetic and environmental factors may contribute to geographic differences in prevalence. Population studies in Germany and France have calculated an incidence of 2 cases per 10,000, although autopsy studies performed in Singapore suggest that 2-4.8% of the population may have IgA deposition in their glomeruli.

Mortality/Morbidity

• Although IgA nephropathy was thought to carry a relatively benign prognosis, an estimated 1-2% of all patients with IgA nephropathy develop end-stage renal failure each year from the time of diagnosis. In a study of 1900 patients derived from 11 separate series, the long-term renal survival was estimated to be 78-87% within a decade of presentation. Similarly, European studies have suggested that renal insufficiency may occur in 20-30% of patients within 2 decades of the original presentation.
• In a study from Hong Kong, patients with mild IgA nephropathy were followed prospectively. Significant proteinuria or renal insufficiency was found in a number of patients, suggesting that a significant risk of progression exists, even in patients who present with milder forms of disease.
• Several studies have assessed features that predict a poor prognosis. Sustained hypertension, persistent proteinuria (especially proteinuria > 1 g), impaired renal function, and the nephrotic syndrome constitute poor prognostic markers.
• Typically, mortality associated with IgAN is secondary to renal failure or its complications. Morbidity may be subsequent to hypertension, electrolyte abnormalities, or other consequences of reduced renal function.
• Familial IgAN has an increased risk of end-stage renal disease.

Race

The distribution of IgA nephropathy varies in different geographic regions throughout the world. It is the most common form of primary glomerular disease in Asia, accounting for as much as 30-40% of all biopsies, for 20% of biopsies in Europe, and for 10% of all biopsies performed for glomerular disease in North America. The reason for this wide variance in incidence is partly attributable to indications for renal biopsy in Asia compared to those in North America. In the United States, incidence of IgAN is increased in children who are Asian or white; incidence is lowest in blacks.

Sex

Incidence is higher in males than in females. Male-to-female ratios of 2:1 and 6:1 have been reported.

Age

IgA nephropathy occurs in persons of all ages, but it is still most common in the second and third decades of life and is much more common in males than females. IgA nephropathy is uncommon in children younger than 10 years. In fact, 80% of patients are between the ages of 16 and 35 years at the time of renal biopsy.

CLINICAL

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History

IgAN is characterized by recurrent episodes of macroscopic hematuria accompanied by upper respiratory tract infections or persistent asymptomatic microscopic hematuria with or without proteinuria. IgAN is frequently classified as primary (idiopathic) or secondary (associated with some other known condition).

• Although the clinical presentation of IgAN varies from asymptomatic urinary abnormalities to acute renal failure, 5 different clinical syndromes are generally recognized.
• • The most common presentation (~60-80%) of IgAN is asymptomatic microscopic urinary abnormalities with one or more episodes of intermittent gross hematuria. The recurrent macroscopic hematuria often associated with upper respiratory infection (synpharyngitic) is traditionally regarded as the hallmark of childhood IgAN, compared with poststreptococcal glomerulonephritis (PSGN), in which hematuria usually occurs 1-2 weeks after infection. The hematuria is usually painless, but loin pain has been reported. Blood pressure may be within the reference range or elevated. Renal clearance function is within the reference range or reduced.
  • The second most common presentation (~26%) is asymptomatic microscopic hematuria with or without mild proteinuria, hypertension, or reduced renal clearance function.
  • Acute nephritic presentation with heavy proteinuria, normal or low clearance function, and normal or high blood pressure is the third most common presentation (~12%).
  • Nephrotic syndrome may be the initial presentation in as many as 10% of patients.
  • Rarely, IgAN may present as an acute crescentic glomerulonephritis with oliguria, edema, and hypertension.
• When renal mesangial IgA deposition occurs because of another specific clinical condition (secondary IgAN), the history of that disease or signs and symptoms related to the primary condition may be present.

Physical

In the early stages of primary IgAN, no physical signs may be observed. However, the diagnosis mighty be suggested by a screening urinalysis that reveals microscopic hematuria with or without proteinuria.

• Hypertension is infrequent, mild to moderate, and usually a late presentation of disease.
• Nephrotic edema is reported approximately 10% of patients.
• If renal function is reduced by 70% or more, patients may have signs of chronic renal failure (eg, uremic syndrome, anemia, pallor).
• If IgAN is secondary, physical findings include signs and symptoms specific to the primary disease, such as rash in HSP or systemic lupus erythematosus (SLE).

Causes

The cause of primary IgAN is unknown. Conditions producing secondary mesangial IgA deposition include the following:

• HSP
• Celiac disease
• Chronic ulcerative colitis
• Crohn disease
• Dermatitis herpetiformis
• Psoriasis
• Cystic fibrosis
• Sarcoidosis
• Lung cancer
• Colon cancer
• Monoclonal IgA gammopathy
• Non-Hodgkin lymphoma
• Pancreatic cancer
• HIV
• Mycoplasma infection
• Toxoplasmosis
• Cirrhosis
• Pulmonary hemosiderosis
• Cryoglobulinemia
• Polycythemia
• Hepatitis B
• Systemic lupus erythematosus
• Sjögren syndrome
• Rheumatoid arthritis

DIFFERENTIALS

Section 4 of 11  

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WORKUP

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Lab Studies

• On initial evaluation, the following studies are directed at identifying IgAN:
• • Urinalysis (UA) test results should show hematuria, proteinuria, and leukocytes. Microscopy shows dysmorphic RBCs and RBC casts suggestive of glomerular origin of RBC but not specific for IgAN, whereas normal RBC morphology indicates lower urinary tract involvement.
  • Obtain a CBC with differential count.
  • A 24-hour urine collection is used to estimate creatinine clearance (CrCl) and protein excretion. Proteinuria is associated with histologic lesion and a risk for progression.
  • Determine the urine calcium (Ca)–to–creatinine (Cr) ratio to measure hypercalciuria (normal is <0.2) and the protein (Pr)–to–Cr ratio to measure proteinuria (normal is <0.2).
  • Measure serum electrolyte levels.
  • Obtain BUN and Cr levels to estimate renal function.
  • Serum C3 levels are usually normal. C3 is routinely measured to eliminate the diagnosis of postinfectious glomerulonephritis or membranoproliferative glomerulonephritis.
  • Obtain the antistreptolysin-O (ASO) titer or streptozyme test.
  • The serum IgA level is elevated in approximately 30-50% in adults but in only 8-16% of children with IgAN.
• Evaluation from a renal standpoint should include consideration of any condition causing hematuria, proteinuria, hypertension, and/or reduced renal function.

Imaging Studies

• Renal ultrasonography cannot be used to confirm, support, or reject a diagnosis of IgAN. However, it is an excellent diagnostic tool to detect other structural abnormalities leading to hematuria, such as renal stone, neoplasm, cystic lesion, hydronephrosis, dilated urinary tract, and bladder abnormalities.

Procedures

• The diagnosis of IgAN is based on the presence of IgA immunoglobulin in the glomerular mesangium. Percutaneous renal biopsy is essential for the confirmation of IgAN. Indications for biopsy include the following:
• • Macroscopic hematuria
  • Microscopic hematuria with significant proteinuria (>2 mg/kg/d)
  • Acute nephritic syndrome (hematuria with hypertension or renal insufficiency)
  • Nephrotic syndrome

Histologic Findings

The diagnostic histopathologic hallmark of IgAN by light, immunofluorescence, and electron microscopy is the presence of IgA in the glomerular mesangium.

With light microscopy, the most characteristic abnormality is mesangial enlargement produced by hypercellularity and mesangial matrix increase. The severity of renal involvement can be graded on the basis of mesangial cell proliferation.

• Minimal lesion: The glomeruli appear normal. The number of mesangial cells per peripheral mesangial area does not exceed 3. Small foci of tubular atrophy and interstitial lymphocyte infiltration may be present.
• Focal mesangial proliferation: The glomeruli show moderate-to-severe mesangial cell proliferation, ie, more than 3 mesangial cells per peripheral mesangial area. The proliferation may be associated with increased matrix; small crescent, capsular adhesions; and prolapsed.
• Diffuse mesangial proliferative and crescentic glomerulonephritis can occur.A small number of patients may have global sclerosis, tubular atrophy, interstitial fibrosis, and interstitial lymphocyte infiltrate.

Immunofluorescence microscopy demonstration of predominately mesangial deposition of IgA is pathognomonic of IgAN. Mesangial IgG, IgM, C3, and properdin may also be observed.

Electron microscopy demonstrates mesangial or perimesangial deposits occurring in the same distribution as observed with immunofluorescence microscopy.

TREATMENT

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Medical Care

IgAN posses a therapeutic challenge to both the children and the adult. Medical treatment must address the primary disease if a secondary form of IgAN is encountered.

Because spontaneous remission may occur, aggressive therapies that may introduce additional risk are probably not indicated in children with mild disease.

Risk factors for progressive renal disease include heavy proteinuria (protein excretion >2 mg/kg/d), reduced renal clearance (estimated GFR or measured CrCl <75% of normal), hypertension, renal biopsy showing proliferative glomerulonephritis, crescents, or advanced chronic disease. For children with progressive disease, several treatment options are available. No treatment has been shown to cure IgAN. Treatments tend to delay the progression in persons with risk factors (listed above) for progression.

• Children with the highest risk of progressive disease are most likely to benefit from therapy. The most appropriate treatment is not known. The agents most often reported to be effective for IgAN treatment include omega-3 polyunsaturated fatty acids, corticosteroids, and ACE inhibitors.
• The dosage and length of treatment for maximal benefit in children with IgAN are not known for these agents. In each case, the effectiveness of these therapies should be assessed initially and reassessed periodically to determine that treatment is beneficial and that benefits outweigh the risks.
• Several investigators have reported that corticosteroids and/or fish oil have slowed the deterioration in renal function (Dillon, 2001; Yoshikawa, 1999; Yoshikawa, 2001). However, the meta-analysis showed only 75% probability that fish oil was beneficial.
• Recent studies have indicated that converting enzyme inhibitors and angiotensin II receptor blocking agents are useful to reduce proteinuria, control blood pressure, and preserve renal function in IgAN.
• High-dose pulse methylprednisolone has shown to delay the development of renal failure.
• The primary treatments for IgAN involve therapy directed at reducing inflammatory-mediated renal injury, controlling hypertension, decreasing proteinuria, and managing sequelae of reduced renal function, if present.
• However, no convincing evidence has been published to date to support the use of fish oil, ACE inhibitor, and high-dose steroid for treatment in pediatric patients with IgAN. At present, no curative therapy exists for IgAN.
• The Japanese Pediatric IgA Study Group reported that in children with severe IgAN, treatment with the combination of azathioprine, prednisolone, heparin-warfarin, and dipyridamole ameliorates renal immunologic injury and delays progression. These agents work by improving renal inflammatory injury.
• Hotta et al reported that complete regression of IgAN was apparent in a group of patients treated with a combination of tonsillectomy, methylprednisolone, warfarin, alternate-day prednisolone, and dipyridamole (Hotta, 2002).
• Other treatments reported to provide benefit include the following:
• • Prophylactic antibiotic and tonsillectomy may reduce the episodes and frequency of gross hematuria. Beneficial effect remains questionable.
  • Glucocorticoids may benefit the few patients with minimal-change lesion, but long-term effects do not confirm any benefit. Alternate-day steroid therapy reduces long-term complications.
  • Plasmapheresis combined with an immunosuppressive drug is probably of value in patients with rapidly progressive crescentic diseases, but full recovery remains unlikely.
  • Phenytoin, danazol, azathioprine, dipyridamole, and heparin-warfarin have been tried but failed to influence the clinical and histologic course.
• Children with reduced renal function may need treatment for sequelae such as abnormalities in growth, bone mineralization, and reduced red blood cell production.
• Patients with end-stage renal disease require dialysis or transplantation.
• After renal transplantation, recurrent IgAN may result in graft loss. Current immunosuppressive regimens do not prevent recurrent IgAN.
• The recurrence of IgAN in renal allografts was initially considered benign, with a low incidence of graft failure caused by recurrent disease. Newer reports in adults show graft failure rates of 30 and 60% (see Wang, 2001; Odum, 1994; Park, 1996). No studies have been performed in children, but IgA recurrence may become a concern for long-term graft survival in children.

Surgical Care

Generally, surgical care is not necessary except for dialysis access or renal transplantation.

Consultations

Because IgAN has the potential to progress to end-stage renal disease, consultation with a pediatric nephrologist is necessary.

Diet

An American Heart Association step I diet is recommended for all children older than 2 years.

Activity

Typically, no activity restriction is necessary.

MEDICATION

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The risks and benefits of treatment with steroids, fish oil, or ACE inhibitors should be discussed with patients and parents. These agents theoretically may protect the kidney and prolong the interval between onset and renal failure.

Drug Category: Anti-inflammatory and immunosuppressive agents

These agents elicit anti-inflammatory and immunosuppressive properties and cause profound and varied metabolic effects. They modify the body's immune response to diverse stimuli and reduce immune-mediated renal injury resulting from IgA deposition in the kidney.

Drug Category: Fish oil

Several investigators have suggested that fish oil delays the progression of renal disease. The precise mechanism is not fully understood.

Drug Category: Angiotensin-converting enzyme (ACE) inhibitors

In 1980, captopril became the first ACE inhibitor approved by the US Food and Drug Administration. Subsequently, at least 40 compounds have been identified. ACE inhibitors reduce the production of angiotensin II, thereby, lowering intraglomerular filtration pressure, reducing proteinuria, and slowing the decline of glomerular function in several chronic renal diseases. All ACE inhibitors probably have similar renal protective effects.

FOLLOW-UP

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Further Inpatient Care

• Inpatient care is not necessary except for complications of renal failure, hypertension, dialysis, or renal transplantation.

Further Outpatient Care

• Medication must be taken as prescribed.
• A healthy diet and lifestyle is important.
• Patients should avoid obesity and smoking and other activities that negatively impact the cardiovascular system.

In/Out Patient Meds

• No specific change of medication is necessary to transition from inpatient to outpatient therapy.

Transfer

• No transfer is necessary.

Deterrence/Prevention

• No methods for deterrence or prevention of IgAN are known.

Complications

• Primary complications include those related to uncontrolled hypertension (eg, seizure, stroke, end-organ damage), renal insufficiency (eg, growth failure, bone demineralization, anemia), and adverse reactions to one of the prescribed medications.

Prognosis

• IgAN may follow a variable course, ranging from benign throughout childhood to rapidly progressive renal failure.
• Children with renal failure require dialysis and/or transplantation, but the prognosis for long-term survival is very good.

Patient Education

• Inform patients about specific disease processes when possible.
• Encourage patients to avoid risk factors, such as smoking, drugs, obesity, and poor medication compliance.
• For excellent patient education resources, visit eMedicine's Kidneys and Urinary System Center . Also, see eMedicine's patient education article Blood in the Urine.

MISCELLANEOUS

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Medical/Legal Pitfalls

• IgAN often progresses slowly to end-stage kidney disease. No well-established therapy has been found to prevent progression. Currently, treatment trials are in progress. Failure to make the diagnosis precludes offering the patient an opportunity to participate in a study that might be beneficial.

Special Concerns

• Careful management of hypertension is essential. If reduced renal function occurs, referral to a nephrologist is appropriate.

MULTIMEDIA

Section 10 of 11  

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Media file 1:  Glomerulus with mesangial hypercellularity and intact capillary loops. Trichrome Stain, original magnification 400x. Image courtesy of Patrick D Walker, MD.
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Media file 2:  Mesangial deposits of IgA. Fluoresceinated Anti-IgA Antibody, ImmunofluorescenceMicroscopy, original magnification 400x. Image courtesy of Patrick D Walker, MD.
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Media file 3:  Electron photomicrograph showing mesangial electron dense deposits (arrow). Uranyl acetate and lead citrate stain, original magnification 12,000x. Image courtesy of Patrick D Walker, MD.
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REFERENCES

Section 11 of 11

• Authors and Editors
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• Dillon JJ. Treating IgA nephropathy. J Am Soc Nephrol. Apr 2001;12(4):846-7. [Medline].
• Donadio JV Jr, Grande JP. Immunoglobulin A nephropathy: a clinical perspective. J Am Soc Nephrol. Aug 1997;8(8):1324-32. [Medline].
• Donadio JV Jr, Larson TS, Bergstralh EJ, Grande JP. A randomized trial of high-dose compared with low-dose omega-3 fatty acids in severe IgA nephropathy. J Am Soc Nephrol. Apr 2001;12(4):791-9. [Medline]. [Full Text].
• Emancipator SN. IgA nephropathy: morphologic expression and pathogenesis. Am J Kidney Dis. Mar 1994;23(3):451-62. [Medline].
• Floege J, Feehally J. IgA nephropathy: recent developments. J Am Soc Nephrol. Dec 2000;11(12):2395-403. [Medline].
• Galla JH. IgA nephropathy. Kidney Int. Feb 1995;47(2):377-87. [Medline].
• Hotta O, Furuta T, Chiba S, et al. Regression of IgA nephropathy: a repeat biopsy study. Am J Kidney Dis. Mar 2002;39(3):493-502. [Medline].
• Kobayashi Y, Sano T, Nakamura I, et al. Long-term effect of 2-year steroid therapy in progressive IgA nephropathy: A 30-year follow-up study compared with a non-steroid group. Nephrology (Carlton). Jan 2003;8 Suppl 4:A113-4. [Medline].
• Lai FM, Szeto CC, Choi PC, et al. Characterization of early IgA nephropathy. Am J Kidney Dis. Oct 2000;36(4):703-8. [Medline].
• Odum J, Peh CA, Clarkson AR, et al. Recurrent mesangial IgA nephritis following renal transplantation. Nephrol Dial Transplant. 1994;9(3):309-12. [Medline].
• Park SB, Joo I, Suk J, et al. IgA nephropathy in renal transplant recipients: is it a significant cause of allograft failure?. Transplant Proc. Jun 1996;28(3):1540-2. [Medline].
• Wang AY, Lai FM, Yu AW, et al. Recurrent IgA nephropathy in renal transplant allografts. Am J Kidney Dis. Sep 2001;38(3):588-96. [Medline].
• Wardle EN. Is IgA nephropathy induced by hyperproduction of interferon-alpha?. Med Hypotheses. 2004;62(4):625-8. [Medline].
• White RHR, Yoshikawa N, Freehally J. IgA nephropathy and Henoch-Schonlein nephritis. In: Barratt TM, Avner ED, Harmon WE, eds. Pediatric Nephrology. 4th ed. Baltimore, Md:. Lippincott, Williams & Wilkins;1999:691-706.
• Yoshikawa N, Ito H, Sakai T, et al. A controlled trial of combined therapy for newly diagnosed severe childhood IgA nephropathy. The Japanese Pediatric IgA Nephropathy Treatment Study Group. J Am Soc Nephrol. Jan 1999;10(1):101-9. [Medline].
• Yoshikawa N, Tanaka R, Iijima K. Pathophysiology and treatment of IgA nephropathy in children. Pediatr Nephrol. May 2001;16(5):446-57. [Medline].
• van Es LA, Massery SG, Glassock RJ, eds. IgA nephropathy. In: Textbook of Nephrology. Vol 1. 2001:733-741.

Article Last Updated: Jun 27, 2006