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Biomedical subjects

M Amagai

Publications and source records attributed to M Amagai.

At least 73 records · Page 4Linked to original sources
PubMed2000

[Two cases of Trichophyton mentagrophytes infection contracted from a hamster and a chinchilla].

We report two cases of Trichophyton mentagrophytes infection. Case 1: A 10-year-old girl visited Tokyo Electric Power Hospital in June 1994 for evaluation of an erythematous lesion on her head. Three months of topical steroid therapy exacerbated the lesion with pustular formation. Histopathological and mycological examination revealed that the patient had tinea capitis caused by T. mentagrophytes. T. mentagrophytes was also isolated from her pet, a hamster. Case 2: A-14-year-old girl was referred to Shonan Clinic in January 1996 with scaly erythema on her face. She had been treated with neticonazole hydrochloride at another clinic, but the lesion became worse. Direct microscopic examination of the scale was negative at that time, so treatment with topical steroid was started. After 10 days, the lesion was almost cured, but one month later it recurred with an annular distribution. KOH preparation of the scale revealed mycelia and T. mentagrophytes was isolated on culture. T. mentagrophytes was also isolated from her pet, a chinchilla. In both cases, the oral administration of itraconazole at 50 mg/day was effective. The isolated pathogen was identified as Arthroderma vanbreuseghemii with species-specific primers of chitin synthase 1 gene. T. mentagrophytes is one of the most common dermatophytes isolated from man and animals. Rodents like the hamster and the chinchilla have recently become popular as pets in Japan. We should be aware that rodents may carry this kind of fungal pathogen as they become even more popular as pets.

Adolescent↗
PubMed2000

[Plasma cell leukemia presenting with circulating villous lymphocytes and an indolent clinical course].

A 73-year-old man was admitted to our hospital in July 1996 because of lymphoctyosis and lumbago. Physical examination revealed hepatomegaly and anemia. Hematologic examination showed a hemoglobin concentration of 9.6 g/dl and a leukocyte count of 32,700/microliter with 74% abnormal mononuclear cells. In Wright-Giemsa stained blood films, these cells had short villi arising from 1 or 2 poles. Immunophenotyping of peripheral mononuclear cells showed moderate to strong expression of CD10, CD24, CD38, and sIg lambda, but not of CD19, CD20, or CD25. Southern blot analysis of the peripheral mononuclear cells demonstrated rearranged monoclonal bands in the C lambda. Urine immunoelectrophoresis detected a monoclonal band identifiable as lambda-type Bence Jones protein. In addition, bone X-ray studies disclosed multiple osteolytic lesions. A diagnosis of plasma cell leukemia was made, and the patient was placed on chemotherapy consisting of cyclophosphamide and prednisolone. No notable improvement in laboratory findings was seen but the patient experienced an indolent clinical course. He died of pneumonia in January 1998. The morphological and clinical findings were unusual for a case of plasma cell leukemia. This case study suggested that signs of lymphocytosis require immunophenotypic and electron microscopic studies for the differential diagnosis of plasma cell leukemia.

Aged↗
PubMed1999

Desmoglein 3-ELISA: a pemphigus vulgaris-specific diagnostic tool.

BACKGROUND: Pemphigus vulgaris (PV) is an autoimmune-blistering disease of the skin and mucous membranes caused by autoantibodies against desmoglein 3 (Dsg3), an epidermal desmosomal adhesion protein of the cadherin family. Cloning of the Dsg3 gene and expression of the protein in a native conformation enabled the recent development of a specific and sensitive enzyme-linked immunosorbent assay (ELISA) for the detection of PV autoantibodies. OBJECTIVES: To evaluate serum samples from patients with PV and other dermatologic diseases for anti-Dsg3 antibodies. To compare ELISA values with autoantibody titers obtained by classic indirect immunofluorescence (IIF). DESIGN: Serum samples from patients with PV and various other bullous and nonbullous skin diseases were tested for anti-Dsg3 reactivity by ELISA. SETTING: Ambulatory and hospitalized patients from a university hospital. PATIENTS: Fifty-two serum samples from 11 patients with PV, and serum samples from 11 patients with bullous pemphigoid, 12 patients with other bullous diseases, 22 patients with various nonbullous skin disorders, and 10 healthy individuals were tested. RESULTS: Forty-seven (98%) of 48 serum samples from patients with PV that were positive by IIF on monkey esophagus were also reactive by Dsg3-ELISA, whereas 4 of 4 IIF-negative PV serum samples showed no reactivity by ELISA. In addition, negative ELISA results were obtained from 11 of 11 serum samples from patients with bullous pemphigoid, 10 of 12 serum samples from patients with other bullous skin disorders, 7 of 9 serum samples from patients with autoimmune-connective tissue diseases, and 13 of 13 serum samples from patients with other nonbullous skin diseases. Interestingly, 1 patient with paraneoplastic pemphigus had positive ELISA results. There was a positive correlation (r = 0.654) between ELISA values and IIF titers within the whole population with PV. In addition, when multiple serum samples from 1 patient with PV sampled over a 2-year period were tested, ELISA reactivity paralleled both the IIF titers and the clinical course. CONCLUSION: The Dsg3-ELISA is a sensitive, objective, and PV-specific test that should be considered as an adjunct test for the management of patients with PV.

Adult↗
PubMed1999

Desmoglein 1 and desmoglein 3 are the target autoantigens in herpetiform pemphigus.

OBJECTIVE: To determine the cell surface autoimmune target of herpetiform pemphigus (HP). DESIGN: Serum samples of HP were examined by immunoblot studies with human epidermal extracts, enzyme-linked immunosorbent assay with baculovirus-expressed recombinant desmoglein (rDsg) 1 and rDsg3, and immunoadsorption assay with rDsg. PATIENTS: Twenty serum samples were obtained from patients with HP who have typical clinical and histological features. All serum samples showed positive staining against keratinocyte cell surfaces by indirect immunofluorescence studies with healthy human skin. RESULTS: Immunoblot results showed that of 17 HP serum samples, only 5 reacted with a 160-kd band and 1 reacted with a 130-kd band. Results of enzyme-linked immunosorbent assays with rDsg1 and rDsg3 demonstrated that of 20 HP serum samples, 16 were positive against Dsg1 and 4 were positive against Dsg3. No serum samples reacted with both. Furthermore, in 19 of 20 HP serum samples, immunoreactivity against keratinocyte cell surfaces was completely removed by preincubation with rDsg1 and rDsg3 as shown by indirect immunofluorescence, excluding a possibility that these HP sera contain autoantibodies against other cell surface molecules. CONCLUSIONS: Dsg1 and Dsg3 are the major cell surface target molecules of HP, suggesting that most cases of HP are clinical variants of pemphigus foliaceus and that the rest might be variants of pemphigus vulgaris.

Autoantigens↗
PubMed1999

Phosphatidylcholine-specific phospholipase C, but not phospholipase D, is involved in pemphigus IgG-induced signal transduction.

The precise mechanism of the acantholysis after pemphigus IgGs bind to desmoglein (Dsg) 3 and/or Dsg 1 on the cell surface is as yet unknown. We have previously reported that pemphigus IgG (P-IgG) causes a transient increase in intracellular calcium and inositol 1,4,5-trisphosphate concentration, and subsequent activation of protein kinase C (PKC) in DJM-1 cells, a squamous cell carcinoma line. In order to see whether phosphatidylcholine (PC)-specific phospholipase C (PLC) or phospholipase D (PLD) is involved in the P-IgG-induced signaling process, the production of 1,2-diacylglycerol (DAG) and phosphatidylbutanol (PBut), a potential marker for the determination of PLD activity in the presence of butanol, was determined in DJM-1 cells. A biphasic accumulation of DAG, which consisted of a first transient phase and a second sustained phase, was observed. The second phase of DAG accumulation was profoundly inhibited by pretreatment with D609, a selective inhibitor of PC-PLC, but not by propranolol, an inhibitor of phosphatidate phosphohydrolase. Pemphigus serum after preadsortion of antibodies to Dsg 3 and Dsg 1 with recombinant Dsg 3 and Dsg 1 did not show formation of DAG. PBut was not generated following the addition of P-IgG. In addition, the levels of [3H]phosphocholine, a direct metabolite of PC-PLC, were elevated after the addition of P-IgG. These results suggest that the PC-PLC pathway plays a major role in P-IgG-induced transmembrane signaling by causing prolonged generation of DAG, which may lead to long-term activation of PKC.

Bridged-Ring Compounds↗
PubMed1999

Paraneoplastic pemphigus associated with Castleman tumor, myasthenia gravis and bronchiolitis obliterans.

BACKGROUND: Cases of paraneoplastic pemphigus (PNP) have been reported associated with various lymphoproliferative malignancies and benign Castleman tumors, with the most severe course and fatal outcome seen in patients with bronchiolitis obliterans. OBJECTIVE: The aim was to establish immunologic associations by coexistence of Castleman tumor, myasthenia gravis, and bronchiolitis obliterans and to evaluate the treatment modalities. METHODS: Clinical studies included computed tomography of the mediastinum, computed tomography and magnetic resonance imaging of the abdominal cavity, and quantitative electromyography. Direct and indirect immunofluorescence on various substrates, immunoblot analysis, immunoprecipitation, and specific enzyme-linked immunosorbent assay using recombinant desmogleins (Dsg) were performed as immunologic assays. RESULTS: Direct and indirect immunofluorescence including rat bladder showed intercellular antibodies. Immunoblotting disclosed antibodies to envoplakin (210 kd protein) and periplakin (190 kd protein); in addition, immunoprecipitation detected antibodies to desmoplakin I (250 kd protein). Antibodies to Dsg3 (pemphigus vulgaris antigen) were detected by specific enzyme-linked immunosorbent assay. Myasthenia gravis was controlled by drugs; however, mucocutaneous changes were not fully responsive to corticosteroids and cyclophosphamide pulses, cyclosporine, and intravenous immunoglobulins. The surgical removal of Castleman tumor did not change the course of the disease. The fatal outcome was the result of bronchiolitis obliterans that occurred after the surgery and was only transitionally controlled by plasmapheresis. CONCLUSION: This is the first case of paraneoplastic pemphigus associated with Castleman tumor, myasthenia gravis, and bronchiolitis obliterans. Despite a benign character of the tumor the patient died, as do all patients with bronchiolitis obliterans. Massive plasmapheresis has only a transient effect. We confirmed the presence of antibodies to Dsg 3, in addition to the set of specific paraneoplastic pemphigus antibodies against various proteins of plakin family.

Adult↗
PubMed1999

The new pemphigus variants.

Pemphigus describes a group of autoimmune diseases characterized by blisters and erosions of the skin and mucous membranes, acantholysis by histology, and autoantibodies directed against epidermal cell surface components. Since the early 1970s, the following new clinical variants of pemphigus have been reported: pemphigus herpetiformis, IgA pemphigus, and paraneoplastic pemphigus. In recent years, significant data have been obtained from laboratory investigation on these rare and atypical variants, especially regarding their specific target antigens. We review these variants, their clinical presentations, histologic findings, immunopathology, target antigens, theories of pathogenesis, treatment modalities, and clinical courses.

Acantholysis↗
PubMed1999

The clinical phenotype of pemphigus is defined by the anti-desmoglein autoantibody profile.

BACKGROUND: Some patients with pemphigus vulgaris (PV) have mucous membrane erosions with minimal skin involvement (mucosal dominant type), and others show extensive skin blisters and erosions in addition to mucous membrane involvement (mucocutaneous type). Patients with pemphigus foliaceus (PF) show only skin involvement. OBJECTIVE: The purpose of this study is to determine whether there is a difference in autoantibody profile among mucosal dominant PV, mucocutaneous PV, and PF. METHODS: Antibody titer against desmoglein 1 (Dsg 1) and desmoglein 3 (Dsg3) were measured with enzyme-linked immunosorbent assay using recombinant Dsg1 and Dsg3. Sera were obtained during clinically active disease from 24 patients with mucosal dominant PV, 20 with mucocutaneous PV, and 23 with PF. RESULTS: All sera samples from patients with mucosal dominant PV sera were negative against Dsgl but positive against Dsg3. All sera samples from those with mucocutaneous PV were positive against both Dsg1 and Dsg3. All sera samples from patients with PF were positive against Dsg1, but negative against Dsg3. CONCLUSION: Each subtype has its own anti-Dsg autoantibody profile, indicating that the clinical phenotype of pemphigus is defined by the autoantibody profile.

Autoantibodies↗
PubMed1999

Autoimmunity against desmosomal cadherins in pemphigus.

Pemphigus is a unique and interesting autoimmune disease, in which autoantibodies play a major pathogenic role and cause blister formation. Several questions raised from clinical observation in pemphigus have been answered with logic at the molecular level owing to recent remarkable progress in research in the field of pemphigus. The clinical phenotype of classic pemphigus, pemphigus vulgaris (PV) and pemphigus foliaceus (PF), is defined by anti-desmoglein autoantibody profile. Sera containing anti-Dsg3 IgG alone cause mucosal dominant PV with limited skin involvement. Sera containing both anti-Dsg3 and anti-Dsg1 cause mucocutaneous PV, which affects both the skin and mucous membrane. Sera containing only anti-Dsg1 cause PF, which shows cutaneous but no mucosal involvement. In herpetiform pemphigus (HP) most sera recognize Dsg1 and the rest of them recognize Dsg3, indicating that HP is a clinical variant of PF or PV. Patients with paraneoplastic pemphigus (PNP) have autoantibodies against multiple molecules. Now we know that they have autoantibodies against all members of the plakin family, which are cytoplasmic proteins and include desmoplakin, BPAG1, envoplakin, periplakin, and plectin. Cell surface target antigens of PNP, which blister-inducing pathogenic autoantibodies attack, were finally discovered to be Dsg3 and Dsg1. Therefore, PNP is characterized as an autoimmune disease against plakin molecules and desmogleins. Autoimmune targets of IgA pemphigus are likely more heterogeneous than originally thought. So far, desmocollin 1, Dsg3, and Dsg1 are known as their target antigens. Thus, pemphigus has become one of well-characterized tissue-specific autoimmune diseases. Pemphigus will be a good model disease in the next century to address the central issue of autoimmune disease and basic immunology; why and how do patients with autoimmune diseases start to recognize self as non-self?

Animals↗
PubMed1999

HLA-DRB1 polymorphisms and autoimmune responses to desmogleins in Japanese patients with pemphigus.

Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are caused by autoantibodies against keratinocyte adhesion molecules desmoglein 3 (Dsg3) and desmoglein 1 (Dsg1), respectively. To determine possible major histocompatibility complex (MHC) class II associations with autoantibody responses to desmogleins, haplotype and allele distributions, along with molecular polymorphisms of HLA-DR and -DQ genes were analyzed based on the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) results in 85 Japanese patients with pemphigus. Each of 55 PV patients carried at least one allele of HLA-DRB1*04 and DRB1*14 subtypes, with significant increases of HLA-DRB1*0406/DQA1*0301/DQB1*0302, DRB1*14/DQA1*0104/DQB1*05 and DRB1*1406/DQA1*0503/ DQB1*0301 haplotypes compared to normal controls. The HLA-DRB1*04 and DRB*14 alleles carried by PV patients shared hydrophobic amino acid residues Phe26, Leu67 and Val86, as well as hydrophilic amino acid residues at positions 70 and 71 on the DRB1 beta chain. HLA-DR/DQ distributions did not differ among PV patients according to the presence or absence of anti-Dsg1 co-existing with anti-Dsg3. Thirty PF patients, all producing autoantibodies only to Dsg1, showed more diverse HLA-DR/DQ distributions, sharing hydrophobic amino acid residues at positions 26 and 67, as well as hydrophilic amino acid residues at positions 70 and 71, of the DRB1 chain. These findings suggest that autoantibody responses to desmogleins might be regulated by amino acid residues at positions 26, 67, 70, 71 and 86 at peptide binding sites of HLA-DRB1 molecules, and that autoimmune responses to Dsg3 might be more strictly regulated by specific amino acid residues at these positions on the HLA-DRB1 chain than responses to Dsg1.

Alleles↗
PubMed1999

Usefulness of enzyme-linked immunosorbent assay using recombinant desmogleins 1 and 3 for serodiagnosis of pemphigus.

Pemphigus is an autoimmune blistering disease with two major subtypes, pemphigus vulgaris (PV) and pemphigus foliaceus (PF). Patients with pemphigus have circulating antidesmoglein (Dsg)1 and/or anti-Dsg3 IgG autoantibodies. We have previously developed enzyme-linked immunosorbent assays (ELISAs) using recombinant Dsg1 and Dsg3 expressed by baculovirus as a diagnostic tool for pemphigus. The purpose of this study was to evaluate the practical application of these ELISAs for clinical use with a large number of serum samples. We used 81 PV sera, 48 PF sera, 114 bullous pemphigoid (BP) sera, 124 collagen disease sera, nine sera of other non-pemphigus bullous diseases and 179 normal control sera. A cut-off value was determined by receiver-operating-characteristic plots. Forty-seven of 48 PF sera (97.9%) were positive in the Dsg1 ELISA and 79 of 81 PV sera (97.5%) were positive in the Dsg3 ELISA, while only two (1. 1%) and four (2.2%) of 179 normal sera were positive in Dsg1 and Dsg3 ELISAs, respectively. However, some disease control sera of BP and collagen diseases exceeded the cut-off value. Introduction of a grey zone helped to decrease the number of these false-positive sera. Furthermore, in three patients studied, the respective Dsg1 and Dsg3 ELISA scores showed parallel fluctuation with the disease activity along the time course. We conclude that Dsg1 and Dsg3 ELISAs provide a simple, sensitive and highly specific assay for the diagnosis of patients with PV and PF and that these ELISAs may be a valuable tool to monitor the disease activity. We also propose diagnostic criteria for pemphigus based on ELISA reactivity: if a serum is positive against Dsg3 it indicates a diagnosis of PV, regardless of reactivity against Dsg1; if a serum is negative for Dsg3 and positive for Dsg1, it indicates a diagnosis of PF.

Aged↗