Abnormalities of immunoglobulin Al (IgAl) glycosylation have been described in patients with IgA nephropathy (IgAN), whether primitive or secondary to Henoch-Schönlein purpura. The Wiskott-Aldrich ...syndrome, an X-linked recessive disorder, is associated with abnormalities of IgA. Renal involvement with mesangial IgA deposition identical to that found in IgAN has been reported during this affection. We report the case of a female carrier of the Wiskott-Aldrich syndrome presenting with Henoch-Schönlein purpura and abnormalities of IgA glycosylation, as previously reported in patients with IgAN. The galactosylation abnormalities of IgA could be linked to the patient's status as carrier of the Wiskott-Aldrich syndrome and could contribute to the pathogenesis of IgAN.
Forty-two patients with renal disease due to diabetic nephropathy (14 patients), tubulointerstitial disease (14 patients) and glomerular disease (14 patients) underwent measurement of glomerular ...filtration rate (GFR) by the 51Cr-EDTA 'one-shot' method and simultaneous serum beta 2-microglobulin, serum creatinine and creatinine clearance estimation. Serum creatinine was a significantly better predictor of GFR than serum beta 2-microglobulin in patients with diabetic nephropathy, whereas both methods were equally useful predictors of GFR in non-diabetic renal disease. Serum creatinine measurement remains the best method for detecting early reduction of GFR on a serum sample.
IgA nephropathy (IgAN) is characterized by mesangial deposits of polymeric IgA (pIgA). The pathological consequences of IgA deposition are believed to center on direct interaction between IgA and the ...glomerular mesangial cell (MC). We have characterized a novel mesangial receptor that recognizes the Fc portion of IgA. Five primary MC cultures were evaluated for IgA binding by flow cytometry, and specificity of binding was determined by competitive inhibition. Relative affinities of the receptor for all IgA isoforms were also determined, and binding of pIgA1 was compared to monomer. The identified Fc receptor was then compared with CD89, hitherto the only other Fcalpha receptor reported. CD89 protein and mRNA expression were detected by conventional and intracellular flow cytometry, sequencing of reverse transcription-polymerase chain reaction (RT-PCR) products, and Northern blotting. All MCs constitutively expressed a receptor that bound IgA in an Fcalpha-dependent fashion. The receptor recognized secretory and serum IgA1 and IgA2 equally, but pIgA bound with much greater affinity than monomer. At no time were we able to detect CD89 synthesis, although three novel CD89-related mRNA transcripts were identified by RT-PCR. We have clearly demonstrated that MCs consistently express an FcalphaR distinct from the myeloid FcalphaR CD89. This novel receptor binds pIgA with high affinity and may therefore mediate the mesangial injury that follows IgA deposition in IgAN. While immunogenically distinct, the mesangial Fcalpha receptor may share some molecular homology with CD89, as mRNA transcripts with partial identity to CD89 were found in all five MC cultures.
A study in 10 patients (eight male, two female; mean age 61.9 +/- 10.7 years) suffering from multiple myeloma (MM) and end-stage renal failure (ESRF) is detailed. Continuous ambulatory peritoneal ...dialysis (CAPD) was the preferred mode of chronic dialysis in all the patients. Survival after diagnosis was 32.2 +/- 23.9 months. Survival after starting dialysis was 24.6 +/- 20.6 months. All patients on CAPD were adequately dialyzed and in good fluid control. Peritonitis was the main problem on CAPD (one episode per 5.6 patient-months). The majority of peritonitis episodes responded to intraperitoneal antibiotic therapy. One patient with Staphylococcus aureus peritonitis, septicemia, and neutropenia secondary to chemotherapy, died. Recommendations for prophylaxis and treatment of peritonitis are given. Three patients were transferred to hemodialysis. The use of subclavian vein catheters during hemodialysis was associated with a high incidence of gram-positive septicemia. Alkylating agent-based chemotherapy resulted in hematological responses in five patients. Survival after diagnosis in those responders was 47.4 +/- 25.6 months, compared with 17.0 +/- 7.2 months in the nonresponders (P less than 0.05). All responders subsequently relapsed. Four patients died with progressive myeloma. Bone marrow suppression resulted in a high blood transfusion requirement, neutropenia, and thrombocytopenia associated with bleeding into the gastrointestinal tract and central nervous system. Uremic myeloma patients can be adequately dialyzed using CAPD. Those patients who do not have an initial hematological response have a poor prognosis.
Isolated microscopic haematuria is a common finding in the genitourinary clinic. The conventional approach to investigation includes urological referral for cystourethroscopy if renal imaging is ...normal. However the diagnostic yield is very low; in particular urothelial malignancy at age < 40 years is rare. Glomerular disease is increasingly recognized as a common cause of microscopic haematuria. In this study 50 patients with persistent microscopic haematuria detected at a genitourinary clinic underwent renal biopsy. Twelve (24%) had an abnormal biopsy--IgA nephropathy 6 (12%), thin membrane nephropathy 3 (6%), other glomerulonephritis 3 (6%). In 7 others no abnormality was found but information was incomplete as electron microscopy was unavailable. It is important to establish these diagnoses since some patients will develop progressive renal disease. In this clinical setting renal biopsy will give diagnostic and prognostic information, protects from repeated urological investigation, and allows reassurance if renal histology is normal. Renal biopsy is recommended for patients age < 40 years with persistent microscopic haematuria. An algorithm for the investigation of microscopic haematuria is presented.
The DQw7 allele at the HLA-DQB locus is associated with susceptibility to IgA nephropathy in Caucasians. The frequencies of the MHC class II HLA-DR and DQ alleles in 36 Caucasian patients with IgA ...nephropathy (IgAN) were analyzed by RFLP analysis and allele specific oligonucleotide (ASO) probing of specifically amplified genomic DNA. The class II alleles HLA-DR4 (52.7%) and DR5 (30.5%) were increased in the patient group compared to 1103 UK Caucasoid controls, but these increases were not statistically significant. However, there was a significant increase in the HLA-DQw7 allele frequency (71%) (c = 27.8%, χ2 = 29.2, P < 0.001, Relative Risk = 6.17). This can be explained by linkage disequilibrium between the DQw7 allele at the DQBl locus and DRB1 genes of some DR4 and all DR5 haplotypes. The polymorphic portion of the DQα chains from DR4, DQw7 and DR5, DQw7 haplotypes differ but they have identical DQβ chains. DNA encoding DQw7 allele at the DQBl locus was sequenced in two patients and was identical to that previously published. We conclude that the DQw7 allele at the DQBl locus is strongly associated with susceptibility to IgAN in Caucasians.
Membranous nephropathy (MN) is a 'non-proliferative' glomerulonephritis. However, visceral glomerular epithelial cell (vGEC) proliferating cell nuclear antigen staining and increased glomerular ...histone mRNA in passive Heymann nephritis (PHN), suggest that vGECs may enter the cell cycle and undergo DNA synthesis. We used in situ hybridisation for histone mRNA, an S-phase specific marker, to investigate this possibility and identify the cellular origin of histone mRNA in PHN and MN.
PHN was induced in 16 Sprague-Dawley rats. There were 8 saline/serum controls. 12 animals were sacrificed on days 5 and 10. Renal biopsies from 10 proteinuric cases with MN and matched controls were studied.
Day-5 Heymann animals demonstrated more S-phase cells/glomerulus than controls (0.53 +/- 0.09 vs. 0.195 +/- 0.045; p < 0.01). Glomerular S-phase cells were also increased in patients compared to controls (0.24 +/- 0.07 vs. 0.04 +/- 0.018; p < 0.03). In both experimental and human MN, the peripheral location and morphology of glomerular histone mRNA-positive cells was typical of vGECs.
The results in PHN indicate that vGECs recently injured with antibody and complement enter into the cell cycle and undergo DNA synthesis. The S-phase vGECs in MN may indicate the persistence of immune injury. Whether or not this process leads to cell replication is open to question.
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