Relationship between Helicobacter pylori infection and histologic features of gastritis in biopsy specimens in gastroduodenal diseases, including evaluation of diagnosis by polymerase chain reaction assay

We investigated the relationship between Helicobacter pylori infection and the histologic features of gastritis in gastroduodenal disease, and evaluated the diagnostic usefulness of the polymerase chain reaction (PCR) assay for the detection of H. pylori before and after eradication therapy. Endoscopic biopsy specimens from 81 patients with gastroduodenal disease were examined for the presence of H. pylori by culture and histologic examination. Histologic features of gastritis were classified according to the updated Sydney System, and results of the PCR assay were compared with those of histologic examination, using histologic scores. The density of H. pylori was significantly correlated with polymorphonuclear neutrophil activity and chronic inflammation. These findings suggest that the grades of infiltration of polymorphonuclear neutrophil cells and chronic inflammatory cells correspond to the density of H. pylori infection assessed by the updated Sydney System. Patients with positive results on PCR assay and negative results on histologic examination may have a low density of H. pylori because of severe atrophy in the gastric mucosa. Differences in results for the PCR assay and histologic examination were found in 2 of 12 patients in the detection of H. pylori after eradication therapy. According to the results of the PCR assay and histologic features before and after eradication, the gastric tissue-based PCR assay for H. pylori after eradication may be too sensitive to judge successful eradication of H. pylori.

Role of platelet-activating factor acetylhydrolase gene mutation in Japanese childhood IgA nephropathy

Platelet-activating factor (PAF) is a potent mediator of inflammatory injury in renal diseases. PAF is degraded to inactive products by PAF acetylhydrolase. Recently, a point mutation (G to T transversion) of the PAF acetylhydrolase gene was observed at position 994, and this mutation was found to contribute to the variability in plasma PAF levels, with undetectable plasma PAF acetylhydrolase activity occurring in homozygous patients (TT genotype) and reduced levels of activity in heterozygous patients (GT genotype). Therefore, we investigated the effect of the PAF acetylhydrolase gene mutation on the pathogenesis and progression of immunoglobulin A (IgA) nephropathy. Genomic DNA was obtained from 89 children with IgA nephropathy and 100 controls. We identified the PAF acetylhydrolase gene mutation (G994T) by polymerase chain reaction. There was no significant difference in genotypic frequency between patients and controls. However, urinary protein excretion at the time of biopsy was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. The percentage of glomeruli with mesangial cell proliferation was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. These results indicate the PAF acetylhydrolase gene mutation may influence the degree of proteinuria and the extent of mesangial proliferation in the early stage of childhood IgA nephropathy.

Hemolytic uremic syndrome associated with immunoglobulin A nephropathy: a case report and review of cases of hemolytic uremic syndrome with glomerular disease

A 35-year-old man with immunoglobulin A (IgA) nephropathy who developed hemolytic uremic syndrome (HUS) presented with transient elevation of serum creatinine, thrombocytopenia, and hemolytic anemia with fragmented red cells with nephrotic syndrome. Hemolytic anemia and the temporarily deteriorated renal function were improved after hemodialysis and plasma exchange. Histological findings were consistent with HUS and IgA nephropathy. Including this case, we reviewed the cases of HUS accompanied by glomerular diseases reported from 1969 to 1996. Surprisingly, most cases showed nephrotic syndrome at the onset of HUS. Several possible relationships between HUS and nephrotic syndrome are discussed.

Expression, abundance, and RNA polymerase binding properties of the delta factor of Bacillus subtilis

The delta protein is a dispensable subunit of Bacillus subtilis RNA polymerase (RNAP) that has major effects on the biochemical properties of the purified enzyme. In the presence of delta, RNAP displays an increased specificity of transcription, a decreased affinity for nucleic acids, and an increased efficiency of RNA synthesis because of enhanced recycling. Despite these profound effects, a strain containing a deletion of the delta gene (rpoE) is viable and shows no major alterations in gene expression. Quantitative immunoblotting experiments demonstrate that delta is present in molar excess relative to RNAP in both vegetative cells and spores. Expression of rpoE initiates from a single, sigmaA-dependent promoter and is maximal in transition phase. A rpoE mutant strain has an altered morphology and is delayed in the exit from stationary phase. For biochemical analyses we have created derivatives of delta and sigmaA that can be radiolabeled with protein kinase A. Using electrophoretic mobility shift assays, we demonstrate that delta binds core RNAP with an apparent affinity of 2.5 x 10(6) M-1, but we are unable to demonstrate the formation of a ternary complex containing core enzyme, delta, and sigmaA.

Measurement of serum leptin in patients with chronic renal failure on hemodialysis

BACKGROUND

Leptin, the product of the obese gene, is produced exclusively in fat cells.

SUBJECTS, MATERIALS AND METHODS

To evaluate the clinical significance of measuring serum leptin in 56 patients with chronic renal failure on hemodialysis (HD), we measured leptin levels using radioimmunoassay in 34 normal volunteers and in 56 patients on HD.

RESULTS

Normal serum leptin averaged 5.7 +/- 0.7 (mean +/- SEM) ng/ml, which correlated significantly (p < 0.001) with the body fat percentage as measured by bioelectrical impedance analysis. Serum leptin in HD patients ranged from 1.3 to 142 ng/ml. The mean serum leptin analyzed after the logarithmic conversion was 5.6 ng/ml, which was not significantly different from the normal control value, although the body fat percentage was significantly lower than normal volunteers. There was a significant (p < 0.01) positive correlation between body fat percentage and serum leptin in both normal controls and HD patients. The slope of the regression curve was steeper in HD patients than in normal controls.

CONCLUSION

(1) serum leptin levels to body fat mass are significantly higher in HD patients than controls; (2) the variability is much wider in HD patients; and (3) a significant relation exists between percent body fat and log serum leptin, the relation being steeper in HD patients than in controls.

Redox-dependent regulation of nuclear import of the glucocorticoid receptor

A number of transcription factors including the glucocorticoid receptor (GR) are regulated in a redox-dependent fashion. We have previously reported that the functional activity of the GR is suppressed under oxidative conditions and restored in the presence of reducing reagents. In the present study, we have used a chimeric human GR fused to the Aequorea green fluorescent protein and demonstrated that both ligand-dependent and -independent nuclear translocation of the GR is impaired under oxidative conditions in living cells. Substitution of Cys-481 for Ser within NL1 of the human GR resulted in reduction of sensitivity to oxidative treatment, strongly indicating that Cys-481 is one of the target amino acids for redox regulation of the receptor. Taken together, we may conclude that redox-dependent regulation of nuclear translocation of the GR constitutes an important mechanism for modulation of glucocorticoid-dependent signal transduction.

Single-strand conformation polymorphism analysis of apple stem grooving capillovirus sequence variants

ABSTRACT In an earlier study, we demonstrated that isolates of apple stem grooving capillovirus (ASGV) from fruit trees comprise at least two to four sequence variants that differ considerably from each other in nucleotide sequence. In order to characterize the population of sequence variants within a single tree, we applied a combination of an immunocapture reverse transcription-polymerase chain reaction (IC-RT-PCR) and a single-strand conformation polymorphism (SSCP) analysis of a nested asymmetric PCR product. In the SSCP analysis of the PCR products from ASGV-infected apple, Japanese pear, or European pear trees, two to four bands were detected in samples from all trees, indicating that ASGV exists as a mixture of sequence variants. The composition of sequence variants (the number of bands and their relative quantity) differed among leaf samples from different branches, showing that each sequence variant is distributed unevenly within an individual tree. The SSCP analysis of isolates after serial passage in Chenopodium quinoa plants indicated that passages changed the composition of sequence variants originally contained in ASGV isolates; i.e., some sequence variants dominated and others decreased to undetectable levels.

Direct association with thioredoxin allows redox regulation of glucocorticoid receptor function

The glucocorticoid receptor (GR) is considered to belong to a class of transcription factors, the functions of which are exposed to redox regulation. We have recently demonstrated that thioredoxin (TRX), a cellular reducing catalyst, plays an important role in restoration of GR function in vivo under oxidative conditions. Although both the ligand binding domain and other domains of the GR have been suggested to be modulated by TRX, the molecular mechanism of the interaction is largely unknown. In the present study, we hypothesized that the DNA binding domain (DBD) of the GR, which is highly conserved among the nuclear receptors, is also responsible for communication with TRX in vivo. Mammalian two-hybrid assay and glutathione S-transferase pull-down assay revealed the direct association between TRX and the GR DBD. Moreover, analysis of subcellular localization of TRX and the chimeric protein harboring herpes simplex viral protein 16 transactivation domain and the GR DBD indicated that the interaction might take place in the nucleus under oxidative conditions. Together these observations indicate that TRX, via a direct association with the conserved DBD motif, may represent a key mediator operating in interplay between cellular redox signaling and nuclear receptor-mediated signal transduction.

Redox regulation of the glucocorticoid receptor

Redox regulation is currently considered as a mode of signal transduction for coordinated regulation of a variety of cellular processes. The transcriptional regulation of gene expression is also influenced by cellular redox state, most possibly through the oxido-reductive modification of transcription factors. The glucocorticoid receptor belongs to a nuclear receptor superfamily and acts as a ligand-dependent transcription factor. We demonstrate that the glucocorticoid receptor function is regulated via redox-dependent mechanisms at multiple levels. Moreover, it is suggested that redox regulation of the receptor function is one of dynamic cellular responses to environmental stimuli and plays an important role in orchestrated crosstalk between central and peripheral stress responses.

Two-year cyclosporin treatment in children with steroid-dependent nephrotic syndrome

We describe a prospective study of 2-year moderate-dose cyclosporin (CS) treatment in 13 children with steroid-dependent minimal change nephrotic syndrome (MCNS). CS treatment was commenced at 100-150 mg/m2 per day after remission was attained with prednisolone therapy, was adjusted to a target trough level of 100 ng/ml, and was administered for 2 years. The number of relapses during CS treatment significantly decreased compared with before CS treatment, all patients were able to discontinue prednisolone therapy, and steroid toxicity was reduced; 54% of patients remained in remission during CS treatment. Renal biopsies performed before CS treatment all showed MCNS without tubulointerstitial lesions. Creatinine clearance and urinary beta 2-microglobulin levels during CS treatment were normal in all patients, but renal biopsies performed after CS treatment revealed chronic CS nephrotoxicity in 7 patients. Clinical data, including CS dose and CS trough blood levels, were not significantly different between patients with and without nephrotoxicity. In conclusion, 2-year moderate-dose CS treatment in children with steroid-dependent MCNS is effective in preventing relapse and decreasing steroid toxicity. This treatment can, however, result in a high incidence of chronic nephrotoxicity. Renal function is not a reliable indicator of chronic CS nephrotoxicity. Renal biopsy is therefore necessary to monitor chronic CS nephrotoxicity.

Apple chlorotic leaf spot virus 50 kDa protein is targeted to plasmodesmata and accumulates in sieve elements in transgenic plant leaves

We investigated the in situ localization of the 50 kDa protein encoded by ORF2 of Apple chlorotic leaf spot virus (ACLSV) genome which is thought to be a movement protein. In immunogold electron microscopy of ACLSV-infected Chenopodium quinoa leaves, the 50 kDa protein was localized on plasmodesmata and nearby cytoplasm. Observation of transgenic Nicotiana occidentalis leaves expressing the 50 kDa protein fused to enhanced green fluorescent protein (EGFP) by fluorescence and confocal laser scanning microscopes revealed that green fluorescence was observed as spots on the cell wall or strands passing through the cell wall of several cell types, i.e., epidermal, palisade and spongy mesophyll and collenchyma cells. In transverse and longitudinal sections of leaf veins of transgenic plants showed that the 50K-EGFP fusion accumulated in sieve elements and formed an extensive interconnecting network of threadlike structure. These results indicated that ACLSV 50 kDa protein can target plasmodesmata and traffic into sieve elements.

A controlled trial of combined therapy for newly diagnosed severe childhood IgA nephropathy. The Japanese Pediatric IgA Nephropathy Treatment Study Group

The most appropriate treatment for patients with IgA nephropathy is controversial. Treatment with prednisolone, azathioprine, heparin-warfarin, and dipyridamole early in the course of disease may prevent immunologic renal injury in children with severe IgA nephropathy. To determine whether similar results can be obtained with a combination of just heparin-warfarin and dipyridamole, the effects of such treatment were compared to those of treatment with prednisolone, azathioprine, heparin-warfarin, and dipyridamole in 78 children with newly diagnosed IgA nephropathy showing diffuse mesangial proliferation. The patients were randomly assigned to receive either prednisolone, azathioprine, heparin-warfarin, and dipyridamole for 2 yr (group 1) or heparin-warfarin and dipyridamole for 2 yr (group 2). All of the 40 patients in group 1 and 34 of the 38 patients in group 2 completed the trial. The mean urinary protein excretion fell in group 1 patients (P < 0.0001), but remained unchanged in group 2 patients. The mean serum IgA concentration was reduced in group 1 patients (P = 0.0002), but was unchanged in group 2 patients. BP and creatinine clearance were normal at the end of the trial in all but one group 2 patient, who developed chronic renal insufficiency. The percentage of glomeruli showing sclerosis was unchanged in group 1 patients, but increased in group 2 patients (P = 0.006). The intensity of mesangial IgA deposits decreased in group 1 patients (P = 0.02), but remained unchanged in group 2 patients. In conclusion, the present study shows that treatment of children with severe IgA nephropathy with prednisolone, azathioprine, heparin-warfarin, and dipyridamole for 2 yr early in the course of disease reduces immunologic renal injury and prevents increase of sclerosed glomeruli.

Platelet-activating factor acetylhydrolase gene mutation in Japanese nephrotic children

BACKGROUND

Platelet-activating factor (PAF) may be involved in the pathogenesis of steroid-responsive nephrotic syndrome (SRNS). PAF is degraded to inactive products by PAF acetylhydrolase. We have investigated whether PAF acetylhydrolase gene mutation is involved in SRNS in Japanese children.

METHODS

We identified a point mutation in the PAF acetylhydrolase gene (G994T) using the polymerase chain reaction in 101 Japanese children with SRNS and 100 healthy Japanese.

RESULTS

There was no difference in the genotype and allele frequencies between patients with SRNS and normal controls. The mean number of relapses during the first year after onset was significantly higher in the 26 patients who were heterozygous for the mutant allele (GT) than in 75 wild-type homozygotes (GG) (2.61 +/- 1.98 vs. 1.33 +/- 1.35; P = 0.0019).

CONCLUSIONS

We conclude that analysis of the PAF acetylhydrolase gene mutation at position 994 in Japanese children with SRNS allows the identification of patients who are more likely to have a disease relapse.

Maternal thyroid function in multiple pregnancy: the variable thyrotropic activity of human chorionic gonadotropin

The present study was undertaken to evaluate thyroid function and thyrotropic action of hCG in multiple pregnancy. We examined serum samples from 9 multiple pregnant women (3 triplets and 6 twins) and 27 singleton pregnant women as control subjects. Serum hCG levels in multiple pregnancy were higher than those in singleton pregnancy in the second and third trimesters (P < 0.01). The mean free T3 and T4 concentrations in multiple pregnancy did not differ from those in singleton pregnancy in each trimester. Serum hCG levels showed a statistically significant positive correlation with free T3 and T4 levels in singleton pregnancy (P < 0.001). However, these correlations were not observed in multiple pregnancy. Thyroid stimulation activity (TSA) determined by cAMP accumulation in FRTL-5 cells in multiple pregnancy sera was significantly higher than that in singleton pregnancy in the first trimester (P < 0.05), but did not differ in the second and third trimesters. Moreover, TSA did not show any correlation with serum hCG levels in multiple pregnancy in contrast with the results in normal pregnancy. A bioactivity/immunoreactivity ratio of hCG in multiple pregnancy was lower than in singleton pregnancy in the second and third trimesters. The discrepancy between immunoreactivity and thyrotropic activity of hCG may be caused by the variable thyrotropic potency of heterogeneous hCG molecules in multiple pregnancy.

[Standard versus long-term prednisolone with sairei-to for initial therapy in childhood steroid-responsive nephrotic syndrome: a prospective controlled study]

The most appropriate initial treatment for children with steroid-responsive nephrotic syndrome is controversial. Initial treatment with 18-week prednisolone and the Chinese herbal medicine. Sairei-to, may prevent subsequent relapse. To determine whether similar results can be obtained with a combination of just initial 8-week prednisolone and Sairei-to, we compared the effects of such treatment with those of treatment with 18-week prednisolone and Sairei-to in 196 children with steroid-responsive nephrotic syndrome. The patients were randomly assigned to receive 8-week (group 1) or 18-week (group 2) prednisolone for the initial therapy. All patients received Sairei-to for 2 years in addition to prednisolone. Eighty-eight of the 98 patients in group 1 and 83 of the 98 patients in group 2 completed their trial. At entry, the two groups of patients did not differ in their clinical and laboratory findings. During the 2-year trial, 62 group 1 patients (70%) and 54 group 2 patients (65%) had relapses, and 19 group 1 patients (21%) and 20 group 2 patients (24%) had frequent relapses. The present study demonstrates that a combination of initial 8-week prednisolone and 2-year Sairei-to is effective in children with steroid-responsive nephrotic syndrome.

Activated mesangial cells produce vascular permeability factor in early-stage mesangial proliferative glomerulonephritis

Vascular permeability factor (VPF), also known as vascular endothelial growth factor (VEGF), is a multifunctional cytokine involved in angiogenesis, inflammation, and wound healing. Although VPF/VEGF has been reported to be produced only by glomerular podocytes in glomeruli, it was found that it is produced by human cultured mesangial cells (MC). Therefore, immunohistochemical analysis (using indirect immunofluorescence and in situ hybridization) of VPF/VEGF in normal kidneys (n = 7) and biopsy specimens taken from 83 patients with renal diseases, including mesangial proliferative glomerulonephritis (PGN) (n = 58), was performed to examine whether VPF/VEGF is produced by MC in human PGN. In all of the healthy subjects and all of the patients except those with PGN (disease control subjects), VPF/VEGF protein and mRNA were detected mainly in podocytes. However, in some PGN patients, VPF/VEGF protein was demonstrated clearly in MC as well as in podocytes, as some of the VPF/VEGF was colocalized with alpha-smooth muscle actin, a marker of activated MC, and VPF/VEGF mRNA was expressed by MC and podocytes. Mesangial VPF/VEGF expression level increased significantly in PGN patients with early lesions (P < 0.01 versus healthy subjects or disease control subjects, P < 0.05 versus PGN with later lesions). The time between biopsy and disease onset was significantly shorter in PGN patients with than in those without mesangial VPF/VEGF expression (P < 0.01). These findings provide the first evidence that activated MC are a source of VPF/VEGF in human PGN, and indicate that mesangial VPF/VEGF expression is characteristic of early lesions of PGN. Because VPF/ VEGF plays a pivotal role in tissue repair, MC-produced VPF/VEGF may play pathophysiologic roles, including promoting recovery from glomerular injuries, in early-stage PGN.

Quantitative measurements for type 1 deiodinase messenger ribonucleic acid in human peripheral blood mononuclear cells: mechanism of the preferential increase of T3 in hyperthyroid Graves' disease

To evaluate the regulatory mechanism of human Type 1 iodothyronine deiodinase (D1) gene expression, we measured the D1 mRNA levels in peripheral blood mononuclear cells (PBMC) in normal control subjects and in patients with Graves' disease. We used competitive reverse transcriptase-polymerase chain reaction with the deleted complimentary RNA of D1 as the standard for quantification. The D1 mRNA levels in PBMC were increased significantly in patients with Graves' disease compared with that in normal controls. There was a significant (p < 0.01) positive correlation (r=0.698) between D1 mRNA level and serum T3 concentration. When PBMC from the normal volunteers were cultured with various doses of T3, the quantity of D1 mRNA increased significantly in a dose-dependent manner. These findings indicate that PBMC D1 mRNA is actually up-regulated by T3 in vivo, and we postulate that a vicious spiral of increasing T3 and D1 is responsible for the exacerbation of thyrotoxicosis in hyperthyroid Graves' disease.

Binary computer-generated holograms for security applications from a synthetic double-exposure method by electron-beam lithography

We have developed a new multiplexing method for producing binary computer-generated holograms (CGH's) for security applications. This method is based on double recording of two types of coding method upon binary CGH's. The CGH synthesized by the proposed method can have multiple image planes from the region close to the hologram (image region) to infinity (Fraunhofer region) without severe degradation of reconstructed images in the image region. A CGH containing simultaneous image- and Fourier-type holograms is fabricated by electron-beam lithography. Some experimental results are presented.

Seroprevalence of immunoglobulin G antibodies against Helicobacter pylori among endoscopy personnel in Japan

BACKGROUND

The seroprevalence of immunoglobulin G antibodies against Helicobacter pylori in endoscopy personnel was determined to investigate whether gastrointestinal endoscopists and endoscopy nurses in Japan are at an increased risk for H. pylori infection and to clarify risk factors for H. pylori infection during endoscopy.

METHODS

One hundred twenty-one gastrointestinal endoscopists and endoscopy nurses provided personal information, including their observance of infection-control measures, by means of self-administered questionnaire. One hundred one age-matched healthy individuals undergoing routine physical examinations served as controls. Serum samples from each subject were examined with enzyme-linked immunosorbent assay for the presence of IgG antibodies against H. pylori.

RESULTS

Among younger subjects (< 40 years old), endoscopists and endoscopy nurses had higher seropositive rates than did control subjects (p < 0.05). Among older subjects (> or = 40 years old), the seropositive rate did not differ between endoscopy personnel and control subjects (p = 0.2174). However, among older seropositive subjects, endoscopy personnel had significantly higher antibody titers than did control subjects (p < 0.01). Older seropositive endoscopists performed significantly more examinations per month than did their seronegative colleagues (p < 0.05). Furthermore, younger seropositive endoscopy nurses performed significantly more examinations per month than did seronegative nurses (p < 0.05).

CONCLUSIONS

Gastrointestinal endoscopists and endoscopy nurses in Japan are at high risk for H. pylori infection. The risk of H. pylori infection is correlated with the frequency of endoscopic examinations, especially in older gastrointestinal endoscopists and younger endoscopy nurses.

Expression of type IV collagen in the developing human kidney

The distribution of alpha1-6 chains of type IV collagen (alpha1-6(IV)) in human fetal kidneys was examined by indirect immunofluorescence. By 11 weeks of gestation, alpha1, 2, 3, 4, and 6(IV) were already present, but alpha5(IV) appeared relatively late, at 21 weeks. Alpha1(IV) and alpha2(IV) were present in all basement membranes, alpha3(IV) and alpha4(IV) were restricted to the glomerular basement membrane and parts of the tubular basement membrane. Alpha5(IV) was distributed in the glomerular basement membrane, Bowman's capsule, and parts of the tubular basement membrane. Alpha6(IV) was present in the Bowman's capsule, parts of the tubular basement membrane, and occurred in parts of the glomerular basement membrane at the early capillary loop stage, but disappeared during the later capillary loop stage.

Rectal mucosal hemodynamics, evaluated by reflectance spectrophotometry, in patients with chronic hepatitis

To evaluate rectal mucosal hemodynamics in patients with chronic hepatitis, we employed reflectance spectrophotometry and examined the results in relation to the presence and severity of chronic hepatitis. Twenty-six patients with histologically diagnosed chronic hepatitis and 21 controls were examined for rectal vascular findings by endoscopy. Indices (I) of rectal mucosal oxygen saturation (ISO2) and rectal mucosal hemoglobin (IHb) concentration were measured. To minimize the effects of systemic anemia, the IHb was divided by blood Hb concentration, giving the rectal index for Hb (RHb). The relationship between rectal mucosal hemodynamics and the histological grade of chronic hepatitis was studied. Rectal vascular lesions were observed in three patients with chronic hepatitis (11.5%). The RHb in patients with chronic hepatitis was significantly higher than that in the controls (5.74 +/- 0.71 and 4.82 +/- 1.12, respectively; P < 0.01). There was no significant difference in ISO2 levels (44.23 +/- 5.84 and 41.94 +/- 4.91, respectively). No significant correlation was observed between rectal mucosal hemodynamics and the histological severity of chronic hepatitis, although rectal mucosal hemodynamics changed in patients with chronic hepatitis. Early vascular changes were observed in the rectal mucosa of patients with chronic hepatitis.

Comparison of alpha5(IV) collagen chain expression in skin with disease severity in women with X-linked Alport syndrome

X-Linked Alport syndrome is caused by mutations in the type IV collagen alpha5 chain gene. Male patients usually develop end-stage renal disease, whereas female patients have more variable phenotypes from asymptomatic hematuria to end-stage renal disease. The variable phenotypes in female patients may be attributable to different X-chromosome inactivation patterns. Therefore, the correlation between disease severity and the degree of alpha5 chain expression in the epidermal basement membrane of female patients with X-linked Alport syndrome was examined. To estimate the disease severity in X-linked Alport syndrome, the ratios of protein to creatinine in single voided urine samples were used. Expression of the alpha5 chain in the epidermal basement membrane was examined by an indirect immunofluorescence method using an anti-alpha5 chain monoclonal antibody. A total of 25 female patients with X-linked Alport syndrome from 17 families was examined. Multiple regression analysis using disease severity as the response variable, and age, family history of nephritis, female and male family history of end-stage renal disease, serum creatinine concentration, and alpha5(IV) expression ratio in the epidermal basement membrane as explanatory variables showed that only alpha5(IV) expression ratio was a significant factor, and that it showed a highly significant negative association with disease severity (adjusted r2=0.71, P=0.0001). These findings suggest that variable alpha5 chain expression, possibly caused by different X-inactivation patterns, is responsible for the variable disease severity in female patients with X-linked Alport syndrome, and that immunohistochemical examination of alpha5 chain expression in the epidermal basement membrane may be a simple and useful method for predicting patient outcome.