Autoantibodies In Japanese Patients Research Articles

Association Between HLA Alleles and Autoantibodies in Dermatomyositis Defined by Sarcoplasmic Expression of Myxovirus Resistance Protein A.

The diagnosis in the studies analyzing HLA of dermatomyositis (DM) was based on a combined clinical category of polymyositis/DM. This retrospective study investigated the associations of HLA with 5 DM-specific autoantibodies in Japanese patients diagnosed by muscle pathology. We diagnosed Japanese patients with DM based on sarcoplasmic expression of myxovirus resistance protein A. These patients underwent investigation for 5 DM-specific autoantibodies and HLA genotyping. Of 175 patients (83 males and 92 females; range 1-86 yrs; mean 46 yrs), 173 (98.9%) had 1 of the 5 autoantibodies. Seven alleles-A*02:07, B*46:01, DRB1*04:07, DRB1*07:01, DRB1*08:03, DQB1*06:01, and DPB1*02:02-were more frequently detected in the patients with DM than healthy controls, but these associations were not significant after multiple testing correction. Stratifying by DM-specific autoantibodies, we found the associations of 6 already known and 7 new alleles-B*48:01, B*52:01, C*12:02, DRB1*04:05, DRB1*15:02, DPB1*05:01, and DPB1*09:01-with subsets of DM. Moreover, significant associations of 5 alleles with antinucleosome remodeling deacetylase complex (Mi-2) remained after multiple testing correction. In particular, the DRB1*04:07 (odds ratio [OR 28.9]; corrected P = 2.7 × 10-6) and DQB1*06:01 (OR 4.0; corrected P = 1.6 × 10-4) alleles were significantly more prevalent in patients with anti-Mi-2 antibody than in controls. This study demonstrates DM-specific autoantibodies defined immunogenetic subsets of DM.

Neutralizing Type I Interferon Autoantibodies in Japanese Patients with Severe COVID-19.

PurposeAutoantibodies (aAbs) to type I interferons (IFNs) have been found in less than 1% of individuals under the age of 60 in the general population, with the prevalence increasing among those over 65. Neutralizing autoantibodies (naAbs) to type I IFNs have been found in at least 15% of patients with life-threatening COVID-19 pneumonia in several cohorts of primarily European descent. We aimed to evaluate the prevalence of aAbs and naAbs to IFN-α2 or IFN-ω in Japanese patients who suffered from COVID-19 as well as in the general population.MethodsPatients who suffered from COVID-19 (n = 622, aged 0–104) and an uninfected healthy control population (n = 3,456, aged 20–91) were enrolled in this study. The severities of the COVID-19 patients were as follows: critical (n = 170), severe (n = 235), moderate (n = 112), and mild (n = 105). ELISA and ISRE reporter assays were used to detect aAbs and naAbs to IFN-α2 and IFN-ω using E. coli-produced IFNs.ResultsIn an uninfected general Japanese population aged 20–91, aAbs to IFNs were detected in 0.087% of individuals. By contrast, naAbs to type I IFNs (IFN-α2 and/or IFN-ω, 100 pg/mL) were detected in 10.6% of patients with critical infections, 2.6% of patients with severe infections, and 1% of patients with mild infections. The presence of naAbs to IFNs was significantly associated with critical disease (P = 0.0012), age over 50 (P = 0.0002), and male sex (P = 0.137). A significant but not strong correlation between aAbs and naAbs to IFN-α2 existed (r = − 0.307, p value < 0.0001) reinforced the importance of measuring naAbs in COVID-19 patients, including those of Japanese ancestry.ConclusionIn this study, we revealed that patients with pre-existing naAbs have a much higher risk of life-threatening COVID-19 pneumonia in Japanese population.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10875-022-01308-3.

Efficacy of a new enzyme-linked immunosorbent assay system for three islet cell autoantibodies in Japanese patients with acute-onset type 1 diabetes.

To evaluate the clinical efficacy of a new enzyme-linked immunosorbent assay (ELISA) system for simultaneously detecting three islet cell autoantibodies against glutamic acid decarboxylase (GADA), insulinoma-associated antigen-2 (IA-2A), and zinc transporter 8 (ZnT8A) (3 Screen ICA ELISA) in Japanese patients with acute-onset type 1 diabetes (T1D). In addition, clinical factors affecting the 3 Screen ICA ELISA index were investigated. We compared the positivity values of 3 Screen ICA ELISA with that of each autoantibody alone in 97 patients with acute-onset T1D (mean age 48.7 years, 49% male) and 100 non-diabetic subjects (mean age 47.0 years, 50% male). Serum thyroid stimulating hormone receptor antibody, thyroid peroxidase antibody (TPOAb) and thyroglobulin autoantibody levels were also evaluated. The cut-off value of the 3 Screen ICA ELISA was determined based on the 97th percentile of 100 non-diabetic controls (threshold for positivity, ≥14 index). The mean age of disease onset and duration of diabetes were 34.2 years and 14.5 years, respectively. Among all T1D patients, the positivity of 3 Screen ICA ELISA was 71.1%, while that of GADA, IA-2A, and ZnT8A were 59.8%, 25.8%, and 25.8%, respectively. The median 3 Screen ICA index was 121.9 (8.7-468.2) and was associated with titers of each autoantibody, most so with GADA, and was significantly higher in TPOAb-positive patients than in TPOAb-negative patients. Our findings suggests that the 3 Screen ICA ELISA may be a time-saving diagnostic tool for evaluating islet autoantibodies in acute-onset T1D patients.

Autoantibodies in Japanese patients with ocular myasthenia gravis.

IntroductionThe majority of patients with myasthenia gravis (MG) initially present with ocular symptoms, but it is difficult to predict which cases will remain as ocular MG (OMG) or will progress to generalized MG. Herein we evaluated the serologic profile of Japanese OMG and its relationship with clinical features.MethodsSeventy‐three patients with OMG from five Japanese myasthenia gravis (MG) centers were enrolled. Live cell‐based assays (CBAs) were used to determine the presence of autoantibodies (Abs) to clustered adult (2α, β, δ, ε) and fetal (2α, β, δ, γ) acetylcholine receptor (AChR) isoforms, muscle‐specific receptor tyrosine kinase (MuSK), and lipoprotein receptor–related protein‐4 (LRP4).ResultsThirty‐four of 73 (46.5%) serum samples were positive for Abs against both the adult‐type and fetal‐type AChR, as expected, but 7 (9.6%) and 2 (2.7%) were positive only for fetal or adult AChR‐Abs, respectively. Four (5.4%) samples were positive for MuSK‐Abs, but two of these also contained antibodies to fetal AChR or LRP4. Twenty‐six (35.6%) samples were seronegative.DiscussionAbs against fetal‐specific AChR, MuSK, and LRP4 are found in some patients with OMG. Future studies attempting to predict conversion from ocular symptoms to generalized MG may benefit from measurement of these antibodies.

Myositis-specific autoantibodies in Japanese patients with juvenile idiopathic inflammatory myopathies

Objectives: The aim of our study is to clarify the association of myositis-specific autoantibodies (MSAs) with clinical and laboratory features in Japanese patients with juvenile idiopathic inflammatory myopathies (JIIMs).Methods: We retrospectively analyzed the frequency of MSAs and their association with clinical or laboratory findings in 25 Japanese patients with JIIMs in Hokkaido district.Results: Eighteen of the 25 patients (72%) were positive for MSAs; seven with anti-melanoma differentiation associated gene (MDA) 5 (28%), five with anti-transcriptional intermediary factor (TIF)-1γ (20%), four with anti-MJ/nuclear matrix protein (NXP)-2 (16%), two with anti-Jo-1 (8%), one with anti- HMG-CoA reductase, one with anti-signal recognition peptide (SRP) antibodies (4% each), including co-existence and transition of MSAs in one patient each. Anti-MDA5 antibodies were related to interstitial lung disease (ILD) and arthritis but not to amyopathic juvenile dermatomyositis. Drug-free remission was achieved, once ILD was overcome in this group. Anti-TIF-1γ antibodies were associated with typical rashes and mild myositis. Anti-MJ/NXP2 and anti-SRP antibodies were associated with severe muscle weakness. No patient was complicated with malignancy.Conclusion: Anti-MDA5 antibodies are prevalent and closely associated with ILD in our series compared with other countries. There was no apparent difference in clinical features associated with other MSAs among races.

S12-3. Anti-LRP4 autoantibodies in Japanese patients with myasthenia gravis

Low-density lipoprotein receptor-related protein 4 (LRP4) is crucial membrane protein in the development and function of neuromuscular junctions and motor neurons. And, it is currently known myasthenia gravis (MG) is caused by antibodies to the acetylcholine receptor (AChR), muscle-specific kinase (MuSK), and LRP4. MuSK and LRP4 are coreceptors for agrin in the signaling pathway that causes clustering of AChR. We demonstrated anti-LRP4 antibodies played a key role in MG. LRP4 is essential for maintaining the structural and functional integrity of the neuromuscular junction and that loss of muscle LRP4 in adulthood alone is sufficient to cause myasthenic symptoms. MG with anti-LRP4 antibodies (LRP4-MG) is considered a rare subtype of MG, however, LRP4 autoantibodies have been recently detected in some motor neuron disease (MND) patients, and LRP4 is required for presynaptic and postsynaptic differentiation. We developed the luciferase immunoprecipitation systems for LRP4 autoantibodies detection and with this assay we studied for four years the sera from Japanese patients who had been suspected of MG or other neurological diseases with general myasthenia and/or muscle weakness. The clinical and therapeutic implications of the anti-LRP4 antibody positivity remain to be clarified, and further studies are necessary to elucidate the pathogenic potential of these autoantibodies.

Lack of KIR4.1 autoantibodies in Japanese patients with MS and NMO.

Objectives:To examine anti-KIR4.1 antibodies by 2 different assays in Japanese patients with multiple sclerosis (MS) or neuromyelitis optica (NMO).Methods:One hundred sixty serum samples from 57 patients with MS, 40 patients with NMO/NMO spectrum disorder (NMOSD), and 50 healthy controls (all were Japanese) were tested with ELISA using a synthetic peptide of the first extracellular portion of human KIR4.1. In addition, we attempted to detect anti-KIR4.1 immunoglobulin G in the serum by the luciferase immunoprecipitation systems (LIPS) with the full length of human KIR4.1 produced in a human cell line, which is highly sensitive to single or multiple epitopes.Results:We failed to detect antibodies to the peptide fragment KIR4.183–120 in any case of MS and NMO/NMOSD using ELISA. Antibodies to the recombinant full length of KIR4.1 protein were detected in only 2 patients with MS and none in the patients with NMO/NMOSD by the LIPS assay.Conclusions:We developed 2 different methods (ELISA and LIPS) to measure autoantibodies to KIR4.1 in serum. We detected anti-KIR4.1 immunoglobulin G at a very low frequency in Japanese patients with MS or NMO/NMOSD. Serologic testing for human KIR4.1-specific antibodies is unlikely to improve the diagnosis of MS or NMO/NMOSD in Japanese patients.

Type 1 diabetes and autoimmunity.

.Type 1 diabetes (T1D) is an organ-specific autoimmune disease caused by the autoimmune response against pancreatic β cells. T1D is often complicated with other autoimmune diseases, and anti-islet autoantibodies precede the clinical onset of disease. The most common coexisting organ-specific autoimmune disease in patients with T1D is autoimmune thyroid disease, and its frequency is estimated at > 90% among patients with T1D and autoimmune diseases. The prevalence of anti-thyroid antibodies in children with T1D at disease onset is about 20% and is particularly common in girls. Furthermore, patients with anti-thyroid antibodies are 18 times more likely to develop thyroid disease than patients without anti-thyroid antibodies. Therefore, for early detection of autoimmune thyroid disease in children with T1D, measurement of anti-thyroid antibodies and TSH at T1D onset and in yearly intervals after the age of 12 yr is recommended. Anti-islet autoantibodies are predictive and diagnostic markers for T1D. The most frequently detected autoantibodies in Japanese patients are GAD autoantibodies (~80%) followed by IA-2 autoantibodies (~60%), insulin autoantibodies (~55%) and ZnT8 autoantibodies (~50%). In a combined analysis, 94% of Japanese patients with T1D can be defined as having type 1A diabetes. Furthermore, autoantibodies to ZnT8 and IA-2 are associated with childhood-onset and acute-onset patients. Thus, it is important to develop a diagnostic strategy for patients with type 1A diabetes in consideration of the age or mode of disease onset.

Low prevalence of anti-small ubiquitin-like modifier activating enzyme antibodies in dermatomyositis patients

Background. The myositis-specific autoantibodies that characterize certain forms of inflammatory myopathy are useful in diagnosing dermatomyositis (DM) / polymyositis and predicting its prognosis. Autoantibodies to small ubiquitin-like modifier activating enzyme (SAE) have been identified as a DM-marker antibody in European Caucasians. Objective and methods. This study investigates the frequency and clinical characteristics of anti-SAE autoantibodies in Japanese patients with DM. Sera from 110 Japanese patients, including 13 with juvenile DM, were screened for anti-SAE antibodies by enzyme-linked immunosorbent assays. Positive sera were further examined by immunoblotting of the immunoprecipitates. Results. Only two patients (1.8%) were confirmed to have anti-SAE antibodies, and neither of these two patients had amyopathic or juvenile DM. One patient with anti-SAE had DM complicated with pulmonary arterial hypertension, and the other had cancer-associated DM. Both had hallmark cutaneous manifestations of DM. Conclusion. This is the first report of anti-SAE antibodies from an Asian single center cohort. Although Japanese patients with anti-SAE antibodies have a clinical phenotype similar to that of Caucasian patients, their frequency was lower in the Japanese patients than in the previously reported Caucasian patients.

High prevalence of primary biliary cirrhosis and disease-associated autoantibodies in Japanese patients with systemic sclerosis

Objective To investigate the prevalence of primary biliary cirrhosis (PBC) and PBC-associated autoantibodies in Japanese systemic sclerosis (SSc) patients.Methods Clinical data from 225 Japanese SSc patients were retrospectively obtained. Serum samples from these patients were examined for PBC-associated autoantibodies, anti-mitochondrial M2 antibodies (AMA), anti-sp100 antibodies (anti-sp100), and anti-gp210 antibodies (anti-gp210) by enzyme-linked immunosorbent assay.Results Of 225 patients, 37 (16.4%) had AMA, 13 (5.8%) had anti-sp100, and 3 (1.3%) had anti-gp210. Three patients were positive for both AMA and anti-sp100, and 2 were positive for both AMA and anti-gp210. PBC was found in 22 (9.8%) patients positive for AMA with or without anti-sp100 or anti-gp210, but not in those with anti-sp100 or anti-gp210 without AMA. Furthermore, 13 patients lacking these three antibodies were diagnosed with or suspected of PBC by liver biopsy and/or their clinical manifestation. Multivariable analysis revealed that AMA and anti-centromere antibodies were independently associated with PBC in SSc patients, while anti-sp100 and anti-gp210 were not.Conclusions This study has demonstrated even higher prevalence of both PBC-associated autoantibodies and PBC in the Japanese SSc population than in the Caucasian SSc population. AMA and anti-centromere antibodies are likely to indicate increasing risk of PBC in SSc patients.

High prevalence of primary biliary cirrhosis and disease-associated autoantibodies in Japanese patients with systemic sclerosis

To investigate the prevalence of primary biliary cirrhosis (PBC) and PBC-associated autoantibodies in Japanese systemic sclerosis (SSc) patients. Clinical data from 225 Japanese SSc patients were retrospectively obtained. Serum samples from these patients were examined for PBC-associated autoantibodies, anti-mitochondrial M2 antibodies (AMA), anti-sp100 antibodies (anti-sp100), and anti-gp210 antibodies (anti-gp210) by enzyme-linked immunosorbent assay. Of 225 patients, 37 (16.4%) had AMA, 13 (5.8%) had anti-sp100, and 3 (1.3%) had anti-gp210. Three patients were positive for both AMA and anti-sp100, and 2 were positive for both AMA and anti-gp210. PBC was found in 22 (9.8%) patients positive for AMA with or without anti-sp100 or anti-gp210, but not in those with anti-sp100 or anti-gp210 without AMA. Furthermore, 13 patients lacking these three antibodies were diagnosed with or suspected of PBC by liver biopsy and/or their clinical manifestation. Multivariable analysis revealed that AMA and anti-centromere antibodies were independently associated with PBC in SSc patients, while anti-sp100 and anti-gp210 were not. This study has demonstrated even higher prevalence of both PBC-associated autoantibodies and PBC in the Japanese SSc population than in the Caucasian SSc population. AMA and anti-centromere antibodies are likely to indicate increasing risk of PBC in SSc patients.

Anti-Tribbles Homolog 2 Autoantibodies in Japanese Patients with Narcolepsy

Anti-Tribbles Homolog 2 Autoantibodies in Japanese Patients with Narcolepsy

Anti-Tribbles Homolog 2 Autoantibodies in Japanese Patients with Narcolepsy

Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness and cataplexy. The association with human leukocyte antigen (HLA)-DQB1*0602 and T-cell receptor alpha locus suggests that autoimmunity plays a role in narcolepsy. A recent study reported an increased prevalence of autoantibodies against Tribbles homolog 2 (TRIB2) in patients with narcolepsy. To replicate this finding, we examined anti-TRIB2 autoantibodies in Japanese patients with narcolepsy. We examined anti-TRIB2 autoantibodies against a full-length [35S]-labeled TRIB2 antigen in Japanese patients with narcolepsy-cataplexy (n = 88), narcolepsy without cataplexy (n = 18), and idiopathic hypersomnia with long sleep time (n = 11). The results were compared to Japanese healthy controls (n = 87). Thirty-seven healthy control subjects were positive for HLA-DRB1*1501-DQB1*0602. We also examined autoantibodies against another Tribbles homolog, TRIB3, as an experimental control. Autoantibodies against TRIB2 were found in 26.1% of patients with narcolepsy-cataplexy, a significantly higher prevalence than the 2.3% in healthy controls. We found that anti-TRIB3 autoantibodies were rare in patients with narcolepsy and showed no association with anti-TRIB2 indices. No significant correlation was found between anti-TRIB2 positivity and clinical information. We confirmed the higher prevalence and specificity of anti-TRIB2 autoantibodies in Japanese patients with narcolepsy-cataplexy. This suggests a subgroup within narcolepsy-cataplexy might be affected by an anti-TRIB2 autoantibody-mediated autoimmune mechanism.

Emergence of anti-islet autoantibodies in Japanese patients with type 1 diabetes

Circulating anti-islet autoantibodies in sera are used as a predictive marker for type 1 diabetes (T1D). We here report two Japanese patients with autoimmune thyroid disease complicated with T1D in whom the time course of anti-islet autoantibodies were observed before the clinical onset of diabetes. Case 1: A woman who had developed Graves' disease at age 25 was diagnosed with type 2 diabetes at age 31; six months later, insulin therapy was started. At age 36 she was diagnosed with T1D due to glutamic acid decarboxylase 65 autoantibodies (GAD65Ab)-positive status and decreased C-peptide levels. With stored sera we retrospectively followed her anti-islet autoantibodies. GAD65Ab, zinc transporter 8 autoantibodies (ZnT8Ab) and insulin autoantibodies (IAA) were found to be positive at age 25. IAA soon turned negative, but GAD65Ab and ZnT8Ab remained positive with high levels. Insulinoma-associated antigen-2 autoantibodies (IA-2Ab) emerged 2 years before the initiation of insulin therapy. She has T1D-susceptible HLA-DRB1-DQB1 haplotypes, (*)0405- (*)0401/(*)0802-(*)0302. Case 2: A 49-year-old woman with hypothyroidism due to 19 years' history of atrophic thyroiditis noticed marked thirst, polyuria and weight loss. On admission she was diagnosed as T1D due to GAD65Ab-positive findings and poor C-peptide response to i.v. glucagon. Retrospective serology revealed the emergence of GAD65Ab and IAA just after the clinical onset. IA-2Ab and ZnT8Ab never developed. She has T1D-susceptible and -resistant HLADRB1- DQB1 haplotypes, (*)0901-(*)0303/(*)1502-(*)0601. The autoantibody profile and the mode of diabetes onset in the two cases were remarkably different. These cases imply that anti-islet autoantibodies do not always precede the onset of T1D.

Unusually high frequency of autoantibodies to PL‐7 associated with milder muscle disease in Japanese patients with polymyositis/dermatomyositis

Autoantibodies to aminoacyl transfer RNA synthetases, such as histidyl (Jo-1), threonyl (PL-7), alanyl (PL-12), glycyl (EJ), and isoleucyl (OJ), are closely associated with a subset of patients with polymyositis/dermatomyositis (PM/DM) complicated by interstitial lung disease (ILD). Anti-Jo-1 is by far the most common, found in 15-25% of patients with PM/DM, whereas the other types are found in only approximately 3% of these patients. In this study, the clinical associations of these autoantibodies in Japanese patients with PM/DM were investigated. The diagnoses of PM/DM and amyopathic DM (ADM) were based on the Bohan and Peter criteria and Sontheimer's definition, respectively. Sera from 36 Japanese patients with PM/DM (13 with PM, 20 with DM, 3 with ADM) were screened by immunoprecipitation and by enzyme-linked immunosorbent assay (for Jo-1). Clinical and laboratory data were collected. The frequencies of autoantibodies to Jo-1 (22%) and to EJ, OJ, and PL-12 (3-6%) were similar to those found in previous studies, including studies of Japanese subjects. However, anti-PL-7 was found in 17% of patients, in contrast to a frequency of 1-4% in previous studies (P < 0.02-0.0002). The 6 anti-PL-7-positive patients were not related, and no skewing in year or month of disease development, place of residence or work, or occupation was found. All patients had ILD, consistent with the clinical features of antisynthetase-positive patients. The patients with anti-PL-7 had lower serum muscle enzyme levels and milder muscle weakness (P < 0.05) compared with anti-Jo-1-positive patients. Anti-PL-7 was found at an unusually high frequency in this group of Japanese patients with myositis. Although anti-PL-7, similar to anti-Jo-1, is associated with PM/DM with ILD, muscle involvement in the patients with anti-PL-7 appeared to be milder than that in the anti-Jo-1 subset.

Anti-DNA topoisomerase II α autoantibodies in Japanese patients with systemic sclerosis

The pathogenesis and etiology of systemic sclerosis (SSc) remain unknown, but the presence of several autoantibodies is recognized as one of its prominent features. The clinical significance of anti-DNA topoisomerase II alpha antibody (anti-topo II alpha Ab) remains unknown in Japanese patients with SSc. To determine the prevalence and clinical correlation of anti-topo II alpha Ab in Japanese patients with SSc. Serum samples were obtained from 103 Japanese patients with SSc. Control serum samples were obtained from 43 healthy Japanese volunteers. Anti-topo II alpha Abs were determined by enzyme linked-immunosorbent assay.IgG anti-topo II alpha Ab levels were significantly increased in SSc patients (n=103) compared to normal controls (n=43; P<0.005). IgG or IgM anti-topo II alpha Ab was detected in 19% (20/103) of SSc patients when absorbance values higher than the mean+2SD of control serum samples were considered positive. By contrast, IgG or IgM anti-topo II alpha Ab was observed in only 7% (3/43) of healthy individuals. The presence of pulmonary fibrosis was more frequently detected in SSc patients with IgG anti-topo II alpha Ab than those without the Ab (P<0.05). Moreover, % DLco and % VC were significantly decreased in SSc patients with anti-topo II alpha Ab relative to those without the Ab (P<0.05 and P<0.01, respectively). The elevated levels of both erythrocyte sedimentation rate and C-reactive protein were also more frequently observed in SSc patients positive for IgG anti-topo II alpha Ab (P<0.005). The results of the present study indicate that anti-topo II alpha Ab represent one of the autoantibody specificities detected on SSc patients and may be regarded a serological marker of pulmonary fibrosis in Japanese patients with SSc.

Low frequency of anti-SLA/LP autoantibody in Japanese adult patients with autoimmune liver diseases: analysis with recombinant antigen assay

Anti-soluble liver antigen/liver pancreas (SLA/LP) autoantibody has been proposed to be one of the autoantibodies characterizing autoimmune hepatitis (AIH). Recently, one of the autoantigens to anti-SLA/LP was identified as a UGA suppressor tRNA-associated protein. Although the function of this protein remains unknown, the recombinant protein has been prokaryotically expressed. Using this protein as an antigen, a recombinant immunoassay for anti-SLA/LP autoantibody has been established and the frequency and significance of this autoantibody have been discussed in European countries. So, in the present study, we investigated anti-SLA/LP autoantibodies in Japanese patients with autoimmune liver diseases using the recombinant antigen ELISA and Western blot assay. Seventy-five patients with AIH type 1, 5 with AIH type 2, 46 with primary biliary cirrhosis, 10 with primary sclerosing cholangitis, 47 with chronic hepatitis C, 48 with systemic lupus erythematosus, 3 with cryptogenic hepatitis, and 40 normal controls were the subjects of the present study. Anti-SLA/LP autoantibodies were detected in only 5 of 75 (6.7%) patients with AIH type 1, but in none of the other 159 patients or 40 normal controls. The clinicopathologic features of anti-SLA/LP-positive AIH type 1, including carriers of HLA DR locus variations, were not significantly different from anti-SLA/LP-negative patients except for the mortality rate. Anti-SLA/LP autoantibody was detected at a low frequency in Japanese patients with AIH type 1 and did not significantly influence clinical features. However, since it has high disease-specificity to AIH type 1, further analysis of SLA/LP may contribute to help clarify the pathogenesis of AIH type 1.

Association of the TAP2*Bky2 allele with presence of SS-A/Ro and other autoantibodies in Japanese patients with systemic lupus erythematosus.

We previously reported that a new allele of transporter associated with antigen processing (TAP) 2 gene, TAP2*Bky2 (Val577), was significantly increased in Japanese patients with Sjögren's syndrome (SS) and had a strong association with SS-A/Ro antibody production. In the present study, it was investigated whether the association of TAP2*Bky2 with SS-A/Ro antibody production was also found in Japanese patients with systemic lupus erythematosus (SLE). Polymorphisms of the TAP1 and TAP2 genes were determined in 114 Japanese SLE patients by the polymerase chain reaction-single-stranded conformation polymorphism (PCR-SSCP) method. The allele frequencies of the TAP1 and TAP2 genes in SLE patients were not significantly different from those in controls, although the allele frequency of TAP2*Bky2 was slightly higher in SLE patients than in healthy control subjects (9.2% vs 5.5%, P = 0.126). The allele frequency of TAP2*Bky2 was significantly higher in SLE patients with oral ulcers than in those without. It was noteworthy that TAP2*Bky2 was significantly associated with the appearance of not only SS-A/Ro antibody but also SS-B/La, nRNP, and Sm antibodies in the patients. The association of TAP2*Bky2 was found with the antibody production to both 60 and 52kDa SS-A/Ro antigens. As TAP2*Bky2 had a strong linkage disequilibrium with DRB1*08032, TAP2*Bky2 or its haplotype with DRB1*08032 may be involved in SS-A/Ro antibody production not only in SS but also SLE patients, indicating that TAP2*Bky2 may be a susceptible gene not only to the disease of SS but also to the SS-A/Ro autoantibody production.

Prevalence of 52-kd and 60-kd Ro/SS-A autoantibodies in Japanese patients with polymyositis/dermatomyositis

To determine the prevalence of 52-kd and 60-kd Ro/SS-A antibodies in Japanese patients with polymyositis/dermatomyositis, we examined serum samples from 61 patients with PM/DM, 10 patients with primary Sjögren's syndrome, and 25 healthy control subjects. Six serum samples possessed anti-Ro/SS-A antibodies and were positive for anti-Ro52, anti-Ro60, or both. Two reacted with both Ro52 and Ro60, and 4 reacted with Ro52 alone. The results suggest that Ro52 is the main antigen of anti-Ro/SS-A antibodies in patients with polymyositis/dermatomyositis and that its coexistence with other defined antibodies suggests the existence of a subgroup of patients with various serologic abnormalities. (J Am Acad Dermatol 2002;47:148-51.)

Characterization of Anti-Myocardial Autoantibodies in Japanese Patients With Dilated Cardiomyopathy.

Few previous reports have comprehensively screened all the anti-myocardial autoantibodies (AMCA) in relation to other clinical profiles in patients with idiopathic dilated cardiomyopathy (IDC), so the present study used both immunohistochemistry (FITC) and immunoblotting (IB) for screening patients with IDC in order to characterize the clinical significance of AMCA. Sera were collected from 100 patients with IDC and age-matched 100 healthy control subjects (CTL). For FITC, an unfixed frozen section of human myocardium was used for the standard indirect immunofluorescence; for IB, total cardiac homogenates of the same myocardium were blotted to serum at 2 sets of dilution (1:200 and 1:10,000). The positive rates of AMCA detection for each method were as follows (IDC vs CTL); 39% vs 6% for FITC, 38% vs 4% for IB (1:200), and 10% vs 0% for IB (1:10,000). Fifty-nine patients with IDC and 8 CTL were positive for AMCA by either method, and 18 patients with IDC and 2 CTL were positive for AMCA by both methods. IB-positivity at 1:200 was an independent predictor by multiple logistic regression analysis of non-sustained ventricular tachycardias as well as left ventricular end-diastolic diameter and plasma norepinephrine concentration.