ABSTRACT
BACKGROUND: This study evaluated the non-inferiority of dexamethasone (DEX) on day 1, with sparing on days 2-4 in cisplatin-based chemotherapy. METHODS: Patients with malignant solid tumors who were treated with cisplatin (≥50 mg/mĀ²) were randomly assigned (1:1) to receive either DEX on days 1-4 (Arm D4) or DEX on day 1 (Arm D1) plus palonosetron, NK-1 RA, and olanzapine (5 mg). The primary endpoint was complete response (CR) during the delayed (24-120 h) phase. The non-inferiority margin was set at -15%. RESULTS: A total of 281 patients were enrolled, 278 of whom were randomly assigned to Arm D4 (n = 139) or Arm D1 (n = 139). In 274 patients were included in the efficacy analysis, the rates of delayed CR in Arms D4 and D1 were 79.7% and 75.0%, respectively (risk difference -4.1%; 95% CI -14.1%-6.0%, P = 0.023). However, patients in Arm D1 had significantly lower total control rates during the delayed and overall phases, and more frequent nausea and appetite loss. There were no significant between-arm differences in the quality of life. CONCLUSION: DEX-sparing is an alternative option for patients receiving cisplatin; however, this revised administration schedule should be applied on an individual basis after a comprehensive evaluation. CLINICAL TRIALS REGISTRY NUMBER: UMIN000032269.
Subject(s)
Antiemetics , Antineoplastic Agents , Humans , Palonosetron/therapeutic use , Cisplatin/adverse effects , Neurokinin-1 Receptor Antagonists/therapeutic use , Antiemetics/therapeutic use , Olanzapine/therapeutic use , Dexamethasone/adverse effects , Vomiting/chemically induced , Quality of Life , Quinuclidines/adverse effects , Antineoplastic Agents/adverse effectsABSTRACT
AIM: To clarify the clinicopathological characteristics and role of periglomerular angiogenesis in IgA nephropathy. METHODS AND RESULTS: The renal biopsy specimens of 114 patients with IgA nephropathy were examined. Among them, 46 (40%) showed periglomerular angiogenesis around the glomeruli. CD34 and α-smooth muscle actin (α-SMA) staining in serial sections revealed that these vessels contained CD34+ α-SMA+ microarterioles along with CD34+ α-SMA- capillaries. We termed these "periglomerular microvessels (PGMVs)". Patients with PGMVs (PGMV group) had clinically and histologically more severe disease than those without PGMVs (non-PGMV group) at the time of biopsy. Even after adjusting for age, there were significant differences in the degree of proteinuria and estimated glomerular filtration rate reduction between the PGMV and non-PGMV groups. The PGMV group showed a higher incidence of segmental and global glomerulosclerosis and crescentic lesions than the non-PGMV group (P < 0.01). Here, PGMVs were undetectable in the acute and active inflammation phase, but were observed in the acute to chronic or chronic glomerular remodelling phase. PGMVs mainly developed around glomerular adherent lesions to the Bowman's capsule with small or minimal glomerular sclerotic lesions. Conversely, they were rarely observed in segmental sclerosis areas. CONCLUSION: The PGMV group is clinically and pathologically more severe than the non-PGMV group; however, they were undetectable in segmental sclerosis with mesangial matrix accumulation. PGMVs might occur after acute/active glomerular lesions, suggesting that PGMVs may inhibit segmental glomerulosclerosis progression and could be a marker for good repair response after acute/active glomerular injury in severe IgA nephropathy cases.
Subject(s)
Glomerulonephritis, IGA , Glomerulosclerosis, Focal Segmental , Humans , Glomerulonephritis, IGA/pathology , Sclerosis/pathology , Kidney Glomerulus/pathology , Glomerulosclerosis, Focal Segmental/pathology , Biopsy , Capillaries/pathologyABSTRACT
BACKGROUND: Identifying M-type phospholipase A2 receptor (PLA2R) is a landmark breakthrough for understanding adult idiopathic membranous nephropathy (iMN). However, potential roles for PLA2R in pediatric iMN have not been well investigated. METHODS: A total of 34 pediatric iMN patients who underwent kidney biopsy between 1972 and 2015 were enrolled in this study. The study cohort consisted of 15 children aged from 3 to 9Ā years and 19 aged from 10 to 15Ā years. In all cases, secondary causes of MN, including infections, autoimmune diseases, and others, were ruled out. We examined PLA2R glomerular staining in stored, formalin-fixed, paraffin-embedded kidney biopsy samples. Kidney biopsy specimens obtained from an adult patient with iMN and an adult patient with lupus-associated MN were also examined to assess our PLA2R staining procedure. RESULTS: Granular staining of PLA2R along glomerular capillary loops was present in two patients: an 11-year-old girl and 12-year-old boy identified during a school urine screening test and who presented with mild proteinuria at the time of biopsy. Interestingly, the intensity of PLA2R glomerular staining in these patients was weaker than that of a PLA2R-positive adult iMN patient. There were no PLA2R-positive patients among our cohort of children younger than 10Ā years. CONCLUSIONS: This preliminary study suggests PLA2R may play a role in some adolescent and preteen iMN patients but may be less frequently associated with iMN during childhood.
Subject(s)
Glomerulonephritis, Membranous/metabolism , Glomerulonephritis, Membranous/pathology , Kidney Glomerulus/metabolism , Kidney Glomerulus/pathology , Adolescent , Adult , Aging/pathology , Biomarkers , Biopsy , Child , Child, Preschool , Cohort Studies , Female , Fluorescent Antibody Technique , Humans , Male , Receptors, Phospholipase A2ABSTRACT
BACKGROUND: Steroid-resistant nephrotic syndrome (SRNS) is a genetically heterogeneous disorder for which more than 25 single-gene hereditary causes have been identified. METHODS: Whole exome sequencing was performed in a 3-year-old girl with SRNS. We analyzed the expression of Crb2 and slit diaphragm molecules in the patient's glomeruli, and compared it with that of controls or other nephrotic patients. RESULTS: Whole-exome analysis identified novel compound heterozygous mutations in exons 10 and 12 of CRB2 (p.Trp1086ArgfsX64 and p.Asn1184Thr, each from different parents; Asn1184 within extracellular 15th EGF repeat domain). Renal pathology showed focal segmental glomerulosclerosis with effaced podocyte foot processes in a small area, with significantly decreased Crb2 expression. Molecules critical for slit diaphragm were well-expressed in this patient's podocytes. Crb2 expression was not altered in the other patients with congenital nephrotic syndrome with NPHS1 mutations. CONCLUSIONS: These findings demonstrate that Crb2 abnormalities caused by these mutations are the mechanism of steroid-resistant NS. Although CRB2 mutations previously found in SRNS patients have been clustered within the extracellular tenth EGF-like domain of this protein, the present results expand the variation of CRB2 mutations that cause SRNS.
Subject(s)
Carrier Proteins/genetics , Membrane Proteins/genetics , Nephrotic Syndrome/genetics , Podocytes/metabolism , Anti-Inflammatory Agents , Child, Preschool , Drug Resistance , Exome/genetics , Female , Gene Expression Regulation, Enzymologic/genetics , Glomerulosclerosis, Focal Segmental/genetics , HEK293 Cells , Humans , Kidney Glomerulus/metabolism , Mutation/genetics , Steroids/therapeutic useABSTRACT
In Japan, urinary screening for preschool children has been obligatory since 1961. The system was reconsidered and has been under review since 2012, because many problems in the system had been identified, and its usefulness was uncertain. In the process, the following were analyzed: (i) frequency of urinary abnormalities identified on screening; (ii) diseases identified from urinary abnormalities; (iii) clinical course of children found to have urinary abnormalities; and (iv) screening for asymptomatic urinary tract infection (UTI) as a way of screening for congenital anomalies of the kidney and urinary tract. A computerized literature search was conducted, and study reports issued by the Ministry of Health, Labour and Welfare study group, and data of Akita City and Chiba City were reviewed. The prevalence of abnormal results at the first urinalysis was high, but at the second urinalysis the prevalence decreased in the range 1/6-1/20. The prevalence of tentative diagnosis at the third urinalysis was similar to the school urinary screening results. Serious illness was not found in children who had hematuria alone. In contrast, diseases requiring immediate attention were found in children with proteinuria, although the prevalence of proteinuria was not high. The dipstick method for leukocyturia was inefficient. The importance of two consecutive urinalyses before detailed examination, the lack of usefulness of screening for hematuria in 3-year-old children, and the importance of proteinuria were confirmed. Screening for asymptomatic UTI using urinary leukocytes was very inefficient.
Subject(s)
Mass Screening/methods , Urinary Tract/abnormalities , Urologic Diseases , Child, Preschool , Humans , Japan/epidemiology , Prevalence , Urinalysis , Urologic Diseases/congenital , Urologic Diseases/diagnosis , Urologic Diseases/epidemiologyABSTRACT
In Japan, pediatric urinary screening in schools for asymptomatic hematuria and proteinuria began in 1974 and has been very successful in detecting asymptomatic kidney diseases at an early stage. While the American Academy of Pediatrics recommended discontinuing urinalysis as a public health service in 2007, urinary screening in Japan has proven extremely successful in reducing the incidence of kidney failure with replacement therapy in children and young adults, especially through the early treatment of glomerulonephritis, such as immunoglobulin A nephropathy. Furthermore, the positivity rate on urinary screening in Japan is significantly lower than in the United States where the rate of false positive results is typically very high. Japan's seamless and efficient pediatric urinary screening may be a helpful example for other countries as well. However, the present investigation revealed several, unresolved problems with the system. For example, the methods used varied in terms of their cutoff point, additional examinations, and types of detailed testing. In Japan, various urinary screening methods are being tested to optimize the system for national use. Recently, the authors also recommended a system of detailed examinations, including beta-2 microglobulin testing and ultrasonography, to detect congenital anomalies of the kidney and urinary tract, the most common, underlying disease in kidney failure with replacement therapy, which is often overlooked until the symptoms have become grave. While school urinary screening has been ongoing for about 50 years and should be continued, improvements should also be made to it as needed.
ABSTRACT
BACKGROUND: The appropriate duration of antimicrobial therapy for febrile urinary tract infection (fUTI) in children has not been established. This study examined the optimal duration of treatment for fUTI in children. METHODS: We created a protocol that used fever duration to determine the duration of antibiotic administration. Transvenous antibiotics were administered until 3 days after resolution of fever, followed by oral antibiotics for 1 week. Diagnosis of fUTI was based on a fever of 37.5Ā°C or higher and a quantitative culture of catheterized urine yielded a bacteria count of ≥5 Ć 104. Acute focal bacterial nephritis (AFBN) and pyelonephritis (PN) were diagnosed on the basis of contrast-enhanced computed tomography (eCT) findings. We retrospectively reviewed treatment outcomes. RESULTS: Of the 78 patients treated according to our protocol, data from 58 were analyzed-49 children (30 boys) had PN and nine (three boys) had AFBN. Blood test results showed that patients with AFBN had significantly higher white blood cell counts and C-reactive protein levels than did those with PN; however, urinary findings and causative bacteria did not differ between groups. Time to resolution of fever and duration of intravenous antibiotic administration were significantly longer in patients with AFBN than in those with PN. However, average duration of AFBN treatment was 14.2 days, which was shorter than the previously reported administration period of 3 weeks. No recurrence was observed in AFBN patients. CONCLUSIONS: A protocol that used fever duration to determine the duration of antimicrobial treatment was useful. Invasive examinations, such as eCT, were not required.
Subject(s)
Anti-Bacterial Agents , Fever , Pyelonephritis , Urinary Tract Infections , Humans , Urinary Tract Infections/microbiology , Urinary Tract Infections/therapy , Urinary Tract Infections/drug therapy , Urinary Tract Infections/diagnosis , Male , Female , Fever/etiology , Fever/therapy , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/therapeutic use , Retrospective Studies , Child, Preschool , Time Factors , Pyelonephritis/therapy , Pyelonephritis/microbiology , Pyelonephritis/drug therapy , Infant , Child , Treatment Outcome , Tomography, X-Ray Computed , C-Reactive Protein/analysis , Nephritis/microbiology , Nephritis/therapy , Administration, Oral , Acute Disease , Duration of Therapy , Leukocyte Count , Administration, Intravenous , Clinical ProtocolsSubject(s)
IgA Deficiency/diagnosis , Immunoglobulin A/metabolism , Child , Child, Preschool , Diagnosis, Differential , Female , HumansABSTRACT
BACKGROUND: Although pediatric immunoglobulin A nephropathy (IgAN) is considered to have a good prognosis, few studies have investigated histological changes over time in IgAN. Serial renal biopsies were performed during the course of the disease and histological changes were observed in patients who did not receive immunosuppressive treatment. To our knowledge, this is the first report of two or more histological evaluations of renal biopsies from patients with pediatric IgAN who did not receive immunosuppressive drugs. METHODS: Forty-two patients with biopsy-proven IgAN who did not receive immunosuppressive agents and underwent serial renal biopsies were followed in our hospital between 1990 and 2003. This retrospective study evaluated findings from renal biopsy specimens and medical records. RESULTS: Analysis of histological findings showed that 19 of 42 patients improved and 16 showed exacerbation of mesangial proliferation. Seven patients showed no obvious histological changes. Of the improved cases, 11 showed spreading of chronic lesions, and there was a significant difference between patients with and without segmental glomerular sclerosis or adhesion at the first biopsy. Of the exacerbated cases, only 5 of 16 patients showed strong active lesions at the first renal biopsy. CONCLUSIONS: Histological changes were investigated in pediatric IgAN patients not receiving immunosuppressive treatment. The results suggest that, even if mesangial hypercellularity improves, chronic lesions may spread during the natural history of the disease. Predicting histological changes by using findings from renal biopsies performed early after onset is difficult; therefore, patients should be carefully followed.
Subject(s)
Glomerulonephritis, IGA , Glomerulosclerosis, Focal Segmental , Humans , Child , Glomerulonephritis, IGA/drug therapy , Retrospective Studies , Biopsy , Immunosuppressive Agents/therapeutic useABSTRACT
RATIONALE: Immune checkpoint inhibitors (ICIs) have shown efficacy for the treatment of various kinds of malignant tumors. However, ICIs can cause immune-related adverse events, such as arthritis. Nevertheless, the treatment of ICI-induced arthritis has not been established yet. Here we report a case of ICI-induced polyarthritis successfully treated using sarilumab and monitored using joint ultrasonography. PATIENT CONCERNS: A 61-year-old man presented with polyarthritis. He had been treated with nivolumab for recurrent renal cell carcinoma 11 months before. He developed ICI-induced nephritis (proteinuria and elevated serum creatinine) 3 months before, which resolved after discontinuing nivolumab for 1 month. Two months after resuming nivolumab, he developed polyarthralgia and joint swelling, which were suspected to be associated with nivolumab administration, and hence we discontinued nivolumab again. Laboratory tests revealed elevated C-reactive protein level and erythrocyte sedimentation rate, but were negative for rheumatoid factor and anti-cyclic citrullinated peptide antibody. Joint ultrasonography revealed active synovitis in several joints, but a joint X-ray revealed no bone erosion. DIAGNOSES: We diagnosed polyarthritis as ICI-induced arthritis because the findings were not typical of rheumatoid arthritis (no bone erosion and seronegativity) and the patient had already developed other immune-related adverse events (ICI-induced nephritis). INTERVENTIONS: After discontinuation of nivolumab, we started treatment with 15Ć¢ĀĀmg daily prednisolone and 1000Ć¢ĀĀmg daily sulfasalazine, although it was ineffective. Hence, we initiated 200Ć¢ĀĀmg biweekly sarilumab. OUTCOMES: Following sarilumab administration, polyarthritis improved rapidly, and joint ultrasonography confirmed the rapid improvement of synovitis. Hence, we tapered off the glucocorticoid treatment. No recurrence of renal cell carcinoma was noted for 2Ć¢ĀĀyears after the initiation of sarilumab despite no anti-tumor therapy. LESSONS: Sarilumab may serve as a good treatment option for treating refractory ICI-induced polyarthritis. Joint ultrasonography may contribute to the evaluation of ICI-induced polyarthritis and monitoring the effects of treatments.
Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Carcinoma, Renal Cell , Immune Checkpoint Inhibitors/adverse effects , Kidney Neoplasms , Synovitis , Carcinoma, Renal Cell/diagnostic imaging , Carcinoma, Renal Cell/drug therapy , Humans , Kidney Neoplasms/drug therapy , Male , Middle Aged , Neoplasm Recurrence, Local , Nephritis/chemically induced , Nivolumab/adverse effects , Synovitis/chemically induced , Synovitis/drug therapy , UltrasonographyABSTRACT
The May-Hegglin anomaly is characterized by inherited thrombocytopenia, giant platelets, and leukocyte cytoplasmic inclusion bodies. The Fechtner, Sebastian, and Epstein syndromes are associated with mutations of the MYH9-coding nonmuscle myosin heavy chain IIA, similar to the May-Hegglin anomaly, and are together classified as MYH9 disorders. MYH9 disorders may include symptoms of Alport syndrome, including nephritis and auditory and ocular disorders. A 6-year-old boy was diagnosed with an MYH9 disorder after incidental discovery of hematuria and proteinuria. Focal segmental glomerulosclerosis was detected on renal biopsy. However, despite no prior bleeding diatheses, he developed a large post-biopsy hematoma despite a preprocedural platelet transfusion calculated to increase the platelet count from 54,000/ĀµL to >150,000/ĀµL. Idiopathic thrombocytopenic purpura is a major cause of pediatric thrombocytopenia following acute infection or vaccination, and patients with MYH9 disorders may be misdiagnosed with idiopathic thrombocytopenic purpura and inappropriately treated with corticosteroids. Careful differential diagnosis is important in thrombocytopenic patients with hematuria and proteinuria for the early detection of thrombocytopenia. Patients with MYH9 disorders require close follow-up and treatment with angiotensin II receptor blockers to prevent the onset of progressive nephritis, which may necessitate hemodialysis or renal transplantation. The need for renal biopsy in patients with MYH9 disorders should be carefully considered because there could be adverse outcomes even after platelet transfusion.
Subject(s)
Glomerulosclerosis, Focal Segmental , Hearing Loss, Sensorineural/complications , Hematuria , Proteinuria , Thrombocytopenia/congenital , Biopsy , Child , Hearing Loss, Sensorineural/genetics , Hematoma/etiology , Humans , Male , Myosin Heavy Chains/genetics , Purpura, Thrombocytopenic, Idiopathic , Thrombocytopenia/complicationsABSTRACT
IgA vasculitis (IgAV) is the most frequent form of vasculitis in childhood which classically presents with purpura of the lower extremities, joint pain or swelling and abdominal pain. Though it is a self-limiting disease, and its prognosis is generally good, glomerulonephritis is one of the most important complications. IgAV is classified as a small vessel vasculitis, and though glomerulonephritis develops in IgAV, necrotizing arteritis is rarely seen. Here, we present a case of a 13-year-old girl with IgAV, glomerulonephritis, and necrotizing arteritis in the small renal arteries. There have been only a few reports of adult cases of IgAV with necrotizing arteritis in the kidneys, but there have been no pediatric cases. Some previous reports showed a high mortality rate and implied the possibility of overlap with other vasculitides. In the current report, a rare case of IgAV is described which exhibited necrotizing arteritis rather than overlap with another vasculitis, with a relatively typical clinical course for IgAV and laboratory tests.
Subject(s)
Glomerulonephritis/etiology , IgA Vasculitis/complications , Polyarteritis Nodosa/etiology , Adolescent , Female , Glomerulonephritis/pathology , Humans , Kidney Glomerulus/ultrastructure , Polyarteritis Nodosa/pathologyABSTRACT
Tubulointerstitial nephritis and uveitis (TINU) syndrome is considered to have a good prognosis even without any immunosuppressive therapy, although there is no histological evidence to support this. The objective of this study was to evaluate, retrospectively, serial renal biopsy findings in three girls with TINU syndrome who were treated with prednisolone. At presentation, all patients had significantly elevated urinary beta(2)-microglobulin levels (7583-19,313 microg/l) and high serum creatinine levels (0.93-1.3 mg/dl). The elevated beta(2)-MG and creatinine levels persisted for 1 month, and renal biopsies were performed to establish a definitive diagnosis. The initial biopsy specimens of all patients revealed marked interstitial enlargement consisting of infiltration of lymphocytes; there was also notable tubulitis and infiltration of eosinophils. All patients received prednisolone therapy following the diagnosis. A second renal biopsy was performed 9 months after the first biopsy for two of three patients, and 2 years later for the third patient. The biopsy specimens taken at 9 months still showed histological changes of acute inflammation; in contrast, that taken at 2 years showed a lower degree of acute inflammation, but scar formation was observed in some regions. Based on these results, we conclude that selected TINU syndrome patients require some immunosuppressive therapy.
Subject(s)
Kidney/surgery , Nephritis, Interstitial/diagnosis , Uveitis/diagnosis , Administration, Oral , Adolescent , Biopsy , Creatinine , Female , Follow-Up Studies , Humans , Nephritis, Interstitial/drug therapy , Prednisolone/administration & dosage , Prednisolone/therapeutic use , Steroids/administration & dosage , Steroids/therapeutic use , Time Factors , Treatment Outcome , Uveitis/drug therapy , beta 2-MicroglobulinABSTRACT
Anhidrotic ectodermal dysplasia (AED) is a rare hereditary disorder with a triad of sparse hair, dental hypoplasia, and anhidrosis. Here we report a case of AED with food allergy and atopic eczema. The patient was a 11-month-old boy admitted to our hospital with pyrexia for 2 weeks. He presented with a history of dry skin, eczema, and food allergy to egg. On clinical examination, his body temperature was 38.8Ā°C, with dry skin and eczema almost all over the body, sparse eyebrows, and scalp hair. Laboratory investigations and physical examination did not show any evidence of infection. Radioallergosorbent test was positive to egg yolk, egg white, ovomucoid, milk, house dust, and house dust mite. As the child did not sweat despite the high fever, we performed the sweat test which revealed a total lack of sweat glands. Genetic examination revealed a mutation of the EDA gene and he was diagnosed as AED. His pyrexia improved upon cooling with ice and fan. His mother had lost 8 teeth and her sweat test demonstrated low sweating, suggestive of her being a carrier of AED. AtopyĀ and immune deficiencies have been shown to have a higher prevalence in patients with AED. Disruption of the skin barrier in patients with AED make them more prone to allergic diseases such as atopic eczema, bronchial asthma, allergic rhinitis and food allergy. Careful assessment of the familial history is essential to differentiate AED when examining patients with pyrexia of unknown origin and comorbid allergic diseases.
ABSTRACT
IgA nephropathy (IgAN) patients have elevated serum levels of immune complexes consisting of IgA1 with galactose-deficient hinge-region O-glycans (Gd-IgA1) and anti-glycan IgG. These immune complexes deposit in the kidney and activate mesangial cells. To confirm that the activity of these immune complexes depends on the interaction of Gd-IgA1 with anti-glycan IgG, we generated in vitro analogous immune complexes using Gd-IgA1 myeloma protein and anti-glycan IgG from cord blood of healthy women. The Gd-IgA1 and anti-glycan IgG from cord-blood serum formed IgA1-IgG immune complexes that resembled those in sera of patients with IgAN. Furthermore, the ability to activate cellular proliferation was dependent on a heat-sensitive serum factor. In summary, we developed a new protocol for in-vitro formation of IgA1-IgG immune complexes, thus providing a new tool for studies of the pathogenesis of IgAN.
ABSTRACT
BACKGROUND: A school urinary screening (SUS) system has been conducted for 30 years in Japan, but the cross-sectional data have never been reported or analyzed. The purpose of the present study was to analyze the data epidemiologically. METHODS: All elementary and junior high school children in public school in Tokyo who had SUS performed by the Tokyo Health Service Association from 1974 to 2002 (approx. 400,000-600,000 children per year) were involved. The cross-sectional data were analyzed with Pearson's correlation coefficient. RESULTS: During the first 10 years of SUS, the prevalence of abnormal urinalysis in both the first and second screenings varied widely, and the result of the second screening was affected by that of the first screening. The results of both first and second screening were highly correlated with the prevalence of hematuria, especially microhematuria, in both elementary and junior high school children. They were also correlated with the prevalence of proteinuria in junior high school children. Important factors that affected the prevalence of hematuria and/or proteinuria were reagent strips and sampling method of urinalysis. CONCLUSIONS: In order to validate SUS, attention should be paid to quality controls of the screening method, such as the selection of reagent strips, and the participants should be instructed to strictly adhere to the sampling method.
Subject(s)
Urinalysis , Base Sequence , Child , Cross-Sectional Studies , DNA Primers , Hematuria/diagnosis , Hematuria/epidemiology , Hematuria/urine , Humans , Reagent Strips , TokyoABSTRACT
Characteristic features of IgA nephropathy (IgAN) include IgA1-containing immune complexes (IC) in the circulation, urine, and renal mesangium. IC contain IgA1 deficient in hinge region-associated galactose (Gal) and antibodies specific for antigenic determinants present on the hinge region. The biological effects of IC are primarily related to their molecular size and composition: when added to a culture of human mesangial cells, large IC exhibit a proliferative effect while small complexes are inhibitory. These activities have been observed using IC obtained from sera of IgAN patients or generated in vitro. Specifically, various preparations of human IgA1 with modified glycan moieties formed IC in vitro when incubated with sera from IgAN patients or healthy individuals, cord blood serum, or tissue culture supernatants of EBV-immortalized peripheral blood B cells secreting IgG. Interestingly, IgG antibodies specific for the IgA1 Gal-deficient hinge region are commonly found in sera of hominoid as well as non-hominoid primates and many other vertebrate species, and suggest the evolutionary uniqueness of the human IgA1 hinge region. Because of the molecular defect in IgA1 glycosylation and its subsequent recognition by naturally-occurring antibodies, experimental approaches that diminish or prevent formation of large immunostimulatory IC should be further explored.
Subject(s)
Antigen-Antibody Complex/immunology , Glomerulonephritis, IGA/immunology , Immunoglobulin A/immunology , Kidney/immunology , Antibody Specificity , HumansABSTRACT
IgA1 in the circulation and glomerular deposits of patients with IgA nephropathy (IgAN) is aberrantly glycosylated; the hinge-region O-linked glycans are galactose-deficient. The circulating IgA1 of patients with Henoch-Schoenlein purpura nephritis (HSPN) has a similar defect. This aberrancy exposes N-acetylgalactosamine-containing neoepitopes recognized by naturally occurring IgG or IgA1 antibodies resulting in formation of immune complexes. IgA1 contains up to six O-glycosylation sites per heavy chain; it is not known whether the glycosylation defect occurs randomly or preferentially at specific sites. We sought to define the aberrant glycosylation of a galactose-deficient IgA1 myeloma protein and analyze the formation of the immune complexes and their biological activities. Supplementation of serum or cord-blood serum with this IgA1 protein resulted in formation of new IgA1 complexes. These complexes stimulated proliferation of cultured human mesangial cells, as did the naturally-occurring IgA1-containing complexes from sera of patients with IgAN and HSPN. Uncomplexed IgA1 did not affect cellular proliferation. Using specific proteases, lectin Western blots, and mass spectrometry, we determined the O-glycosylation sites in the hinge region of the IgA1 myeloma protein and IgA1 proteins from sera of IgAN patients. The IgA1 myeloma protein had galactose-deficient sites at residues 228 and/or 230 and 232. These sites reacted with IgG specific to galactose-deficient IgA1. IgA1 from the IgAN patients had galactose-deficient O-glycans at the same residues. In summary, we identified the neoepitopes on IgA1 responsible for formation of the pathogenic immune complexes. These studies may lead to development of noninvasive diagnostic assays and future disease-specific therapy.
Subject(s)
Antigen-Antibody Complex/immunology , Glomerulonephritis, IGA/immunology , IgA Vasculitis/immunology , Immunoglobulin A/metabolism , Nephritis/immunology , Glomerular Mesangium/immunology , Glomerular Mesangium/metabolism , Glycosylation , Humans , IgA Vasculitis/complications , Immunoglobulin A/immunology , Nephritis/etiologyABSTRACT
BACKGROUND: Sera of IgA nephropathy (IgAN) patients contain high levels of circulating immune complexes composed of IgA1 molecules with aberrantly glycosylated hinge-region O-linked oligosaccharides and IgG or IgA1 antibodies with anti-glycan or anti-hinge-region peptide specificities. Due to damaged sieving properties of the glomerular capillary wall in IgAN, these immune complexes may appear in the urine. METHODS: We collected urine samples from 29 patients with biopsy-proven IgAN (Group I), 27 proteinuric patients with non-IgA nephropathies (Group II) and 28 healthy volunteers (Group III). The levels of urinary IgA and IgG and IgA-IgG-containing immune complexes were measured by ELISA and standardized for urinary creatinine concentrations. RESULTS: The urinary IgA and IgG levels were significantly higher in Groups I and II than in Group III. Although the excretion of IgA as a fraction of total urinary protein was not significantly greater in IgAN patients than in patients with other renal diseases, the excretion of aberrantly glycosylated IgA1 was observed by western blot in 68% of the IgAN patients but in none of the healthy controls. The urinary levels of IgA-IgG immune complexes were significantly higher in Group I than in Groups II (P < 0.01) and III (P < 0.05). There was no significant difference in the levels between Groups II and III. These immune complexes had a molecular mass between 650-850 kDa, as shown by size-exclusion chromatography. CONCLUSION: The amounts of urinary IgA-IgG-containing immune complexes were significantly higher in patients with IgAN than in patients with non-IgA nephropathies or healthy controls.
Subject(s)
Antigen-Antibody Complex/urine , Glomerulonephritis, IGA/immunology , Immunoglobulin A/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Biomarkers/urine , Biopsy , Blotting, Western , Enzyme-Linked Immunosorbent Assay , Female , Glomerulonephritis, IGA/pathology , Glomerulonephritis, IGA/urine , Humans , Immunoglobulin G/immunology , Male , Middle AgedABSTRACT
In Japan, the school urinary screening system facilitates early detection and treatment of membranoproliferative glomerulonephritis (MPGN) in childhood. The present study investigated the long-term prognosis in 19 children with diffuse MPGN type I who received steroid therapy. Before signs of glomerulonephritis were confirmed, all patients displayed abnormal urinalysis results, predominantly through school urinary screening. Treatment comprised a regimen of alternate-day prednisolone after steroid pulse or cyclophosphamide therapy, and follow-up was continued for 10-24 years. Excluding 1 patient on short-term therapy, 18 patients received long-term alternate-day prednisolone therapy for 4-12 years. Treatment was discontinued when amelioration was confirmed on renal biopsy. As of the last observation, urinary abnormalities and hypocomplementemia had disappeared in 15 patients, while mild proteinuria without hypocomplementemia remained in 4 patients. No patients required hemodialysis. Moreover, no severe adverse effects attributable to treatment were identified other than mild short stature. Early detection and therapy using pulse methylprednisolone followed by alternate-day prednisolone was thus confirmed as safe and useful for treating diffuse MPGN type I.