The clinical significance of autoantibodies to the proliferating cell nuclear antigen (PCNA).

Autoantibodies targeting the proliferating cell nuclear antigen (PCNA) were first described over 30 years ago and are historically most commonly associated with systemic lupus erythematosus (SLE). The primary antigenic target is a 34 kDa protein that is part of the DNA polymerase delta multi-protein complex. A number of diagnostic platforms have incorporated PCNA into their diagnostic assays and algorithms. However, little is known about the clinical utility of autoantibodies to PCNA, especially with novel detection systems. This review will focus on the history of the discovery of the PCNA autoantigen and the current status of the diagnostic significance of anti-PCNA and suggest future studies that are required to strengthen our understanding of their clinical utility.

NEFA/nucleobindin-2 is a target autoantigen of the anti-Wa antibody and is associated with transfer RNA.

OBJECTIVES: The anti-Wa antibody found in systemic sclerosis patients reacts with a transfer RNA (tRNA)-associated 48-kDa protein and immunoprecipitates several tRNAs. We investigated the Wa antigen and its binding to tRNA species. METHODS: We performed molecular cloning of the Wa antigen and made its recombinant protein. To investigate Wa antigen distribution in the cell, we performed an indirect immunofluorescence study. To determine the Wa-bound tRNA species, we performed a reverse transcription (RT)-polymerase chain reaction (PCR) using the RNAs immunoprecipitated by anti-Wa antibody as templates, and synthetic primers of mammalian tRNA sequences. To clarify the tissue expression of Wa antigen, we performed quantitative and semi-quantitative PCR of the cDNA. RESULTS: We demonstrated that the Wa antigen was identical to NEFA (DNA binding/EF-hand/acidic amino acid rich region), otherwise known as nucleobindin-2. A full-length and an alternative splice variant cDNA lacking exon 11 were isolated by cloning NEFA cDNA. Anti-Wa-positive sera stained both the nucleus and cytoplasm of HEp-2 cells. RT-PCR suggested that Wa binds at least six tRNA species. In human tissues, NEFA is expressed predominantly in exocrine glands. CONCLUSIONS: We have demonstrated that the Wa antigen is NEFA or nucleobindin-2, which binds specific tRNA species, and is distributed in specific human tissues.

Comparison of the efficacies of amantadine treatment of swine-origin influenza virus A H1N1 and seasonal influenza H1N1 and H3N2 in Japan (2008-2009).

Amantadine is not thought to be effective for the treatment of swine-origin influenza virus (S-OIV) based on an analysis of genetic sequences of the M2 protein. However, the actual clinical efficacy of amantadine has not been well documented. Here, we were able to compare the efficacies of amantadine and neuraminidase inhibitors. Subjects consisted of 428 patients, including 144 with seasonal influenza (flu) identified between 2008 and 2009, and 284 with S-OIV identified between July 1 and November 30, 2009. Diagnosis of flu was established using a rapid diagnostic kit obtained commercially in Japan. Body temperature sheets were obtained from 95% of the S-OIV patients. Times required to recover normal body temperature were compared among subjects using different antiviral drugs. Genetic abnormalities in the M2 protein were also investigated in 66 randomly selected subjects from within the patient pool. Overall, the average hours required to recover normal body temperature in S-OIV patients treated with amantadine (160 cases), with oseltamivir (59 cases), or with zanamivir (65 cases) were 33.9 ± 20.7, 31.7 ± 16.0, or 36.3 ± 21.6, respectively. These differences were not statistically significant. The N31S abnormality was found in all 14 samples taken from the H3N2 patients and in all of the 23 samples taken from in S-OIV patients. However, this abnormality was not found in any of the 30 samples taken from seasonal H1N1 patients. Amantadine was found to be equally effective in treating S-OIV patients as neuraminidase inhibitors. The genetic abnormality resulting in S31N amino acid conversion identified in some of the H3N2 and S-OIV patients is thought to alter the function of M2 protein only mildly.

PBC screen: an IgG/IgA dual isotype ELISA detecting multiple mitochondrial and nuclear autoantibodies specific for primary biliary cirrhosis.

A dual isotype (IgG, IgA) enzyme-linked immunosorbent assay (ELISA) designed to provide enhanced detection of primary biliary cirrhosis (PBC)-specific autoantibodies against both major mitochondrial and nuclear antigens has been developed and recently become commercially available. The assay (PBC Screen) simultaneously detects IgG and IgA autoantibodies to the immunodominant portions of the 3 major mitochondrial (MIT3) and nuclear (gp210, and sp100) antigens. The aim of this study was to compare the performance of the PBC Screen to the combined performance obtained with individual IgG ELISAs to MIT3, gp210, and sp100 on a large group of selected patients from multiple centers. A total of 1175 patients with PBC and 1232 subjects without PBC were evaluated. Non-PBC groups included healthy controls (624) as well as individuals with autoimmune hepatitis (281), primary sclerosing cholangitis (77), viral hepatitis (91 hepatitis B and 98 hepatitis C), other liver diseases (31), and other infectious or autoimmune diseases (30). The PBC Screen at the receiver operator characteristic optimized cutoff of 27.8 units, had an overall sensitivity of 83.8%, specificity of 94.7% and area under curve of 0.9212. This was similar to the specificity of 96.1% obtained by the combined results of individual MIT3, sp100, and gp210 IgG ELISAs (kappa index at 0.898). Of the 253 PBC patients without AMA detectable by immunofluorescence, 113 (44.7%) were interpreted as positive for PBC-specific autoantibodies. In conclusion, the PBC Screen is an appropriate first-line test for the diagnosis of PBC, including for patients negative for markers assessed using conventional methods.

The role of Ca2+ signaling in cell function with special reference to exocrine secretion.

Inositol 1,4,5-trisphosphate (IP3) is a second messenger that induces the release of calcium from the endoplasmic reticulum (ER). The IP3 receptor was discovered as a developmentally regulated glycophosphoprotein, P400, that is absent in strains of mutant mice. The crystal structures of the IP3-binding core and N-terminal suppressor sequence of the IP3 receptor have been identified. The IP3-binding core's affinity to IP3 is similar among the three isoforms of IP3 receptors; however, the N-terminal IP3-binding suppressor region is responsible for isoform-specific IP3-binding affinity tuning. Various pathways for the trafficking of IP3 receptors have been identified; for example, the ER forms a meshwork on which IP3 receptors move by lateral diffusion, and vesicular ER subcompartments containing IP3 receptors move rapidly along microtubules using a kinesin motor. Furthermore, IP3 receptor messenger RNA within messenger RNA granules also moves along microtubules. Recently, we discovered that IP3 receptors play a crucial role in exocrine secretion. ERp44 works as a redox sensor in the ER and regulates IP3 type 1 receptor activity. IP3 receptor also releases IP3 receptor-binding protein released with IP3 (IRBIT). IRBIT is a pseudoligand for IP3 that regulates the frequency and amplitude of calcium oscillations through the IP3 receptor. IRBIT binds to pancreas-type sodium bicarbonate cotransporter 1, which is important for acid-base balance. Type 2 and 3 double-deficient mice show a deficit in saliva and lacrimal and pancreatic juice secretion. Type 1 IP3 receptor influences brain-derived neurotrophic factor production.

A comparison of the frequency of antibodies to cyclic citrullinated peptides using a third generation anti-CCP assay (CCP3) in systemic sclerosis, primary biliary cirrhosis and rheumatoid arthritis.

The objective was to investigate the frequency of anti-cyclic citrullinated peptides (CCP) antibodies in systemic sclerosis (SSc) and primary biliary cirrhosis (PBC), utilizing a new "third generation" anti-CCP ELISA (anti-CCP3) kit and a conventional anti-CCP2 assay. Patients with PBC, SSc, RA, and normal controls were included in the study. Serum samples were screened for autoantibodies by indirect immunofluorescence (IIF), antibodies to CCP by a second- and third-generation ELISA, antibodies to "scleroderma" antigens (CENP B, Scl-70, PM/Scl and fibrillarin-Scl-34) by a line immunoassay (LIA), and IgM RF by ELISA. The frequency of anti-CCP2 antibodies in SSc and PBC samples was 14.8% (11/74) and 6.2% (5/80), respectively, and the frequency of anti-CCP3 antibodies in SSc was 13.5% (10/74) and in PBC was 3.7% (3/80). By comparison, in the RA group the frequency of anti-CCP3 and anti-CCP2 antibodies was 79.1% (38/48) and 77% (37/48), respectively. Anti-CCP3 ELISA had a sensitivity, specificity, and positive and negative likelihood ratios (LR) of 79% (95% confidence interval [CI] = 64-89%), 93% (95% CI = 88-96%), 11.8 (95% CI = 6.8-20.3), and 0.22 (95% CI = 0.12-0.38), respectively. By comparison, the anti-CCP2 assay had a sensitivity, specificity, and positive and negative LRs of 77% (95% CI = 62-87), 90% (95% CI = 85-94), 8.3 (95% CI = 5.2-13.2), and 0.25 (95% CI = 0.15-0.42), respectively. In patients with SSc, there was an association of anti-CCP2 antibodies with the presence of arthritis, but there was no association of anti-CCP2 or anti-CCP3 with anti-CENP B, anti-Scl 70, or RF. This study confirmed the high specificity and sensitivity of both anti-CCP assays for the diagnosis of RA. The presence of anti-CCP antibodies in SSc was only correlated with the presence of arthritis.

Longer virus shedding in influenza B than in influenza A among outpatients treated with oseltamivir.

OBJECTIVE: To compare the persistence, susceptibility and resistance of influenza A and influenza B viruses in oseltamivir therapy in outpatients of various ages. METHODS: Virus isolation was done before and 4-6 days after the initiation of oseltamivir therapy for 148 patients with influenza A/H3N2 and for 66 with influenza B in the 2003-2004 and 2004-2005 influenza seasons. Neuraminidase inhibition assay and neuraminidase or hemagglutinin sequence analysis were done using influenza viruses isolated from these patients. RESULTS: The virus isolation rate after oseltamivir therapy was significantly higher for influenza B (33.3%) than for influenza A/H3N2 (12.8%, p<0.001). The mean IC(50) values before and after oseltamivir therapy were significantly higher in patients with influenza B (10.82 and 11.32nM, respectively) than in patients with influenza A/H3N2 (0.94 and 0.81nM, respectively, both p<0.001). No significant differences in IC(50) among each age group, or no significant increase in IC(50) from before to after oseltamivir therapy was observed. Neuraminidase or hemagglutinin sequence analysis revealed no known genotype with resistance to oseltamivir. CONCLUSION: Virus persistence after oseltamivir therapy was longer and IC(50) values were higher in influenza B than influenza A.

Inositol 1,4,5-trisphosphate receptors are autoantibody target antigens in patients with Sjögren's syndrome and other systemic rheumatic diseases.

IP(3)R2 and IP(3)R3 double knock-out mice present with exocrine dysfunctions such as secretion deficits of saliva and pancreatic juice. Therefore, we investigated whether the presence of antibodies to IP(3)Rs could be found in patients with Sjögren's syndrome, and the location of the epitopes. Subjects included 35 primary Sjögren's syndrome, 39 secondary Sjögren's syndrome, 144 rheumatoid arthritis, and 96 other connective tissue disease patients. As controls, 33 healthy subjects were included. Immunoblot was conducted using recombinant proteins IP(3)R1, IP(3)R2, and IP(3)R3 made from full-length cDNA, and core, T604, and EL for epitope mapping. Antibodies to IP(3)R1 in sera from patients with primary Sjögren's syndrome, secondary Sjögren's syndrome, and rheumatoid arthritis were found to be positive in 17 of 35 (48.6%), 13 of 39 (33%), and 34 of 124 (27.4%) cases, respectively. These frequencies were significantly higher than the 1 of 33 (3.0%) found in normal healthy subjects. The frequency of anti-IP(3)R2 antibodies in rheumatoid arthritis was found to be higher than those found in Sjögren's syndrome, systemic lupus erythematosus, and systemic sclerosis. Anti-IP(3)R2 antibodies found in rheumatoid arthritis primarily recognized residues 578-2171 of the internal coupling and regulatory domain. On the other hand, anti-IP(3)R1 found in Sjögren's syndrome recognized residues 224-604 of the core protein IP(3)R1. Anti-IP(3)R1 antibodies were present in 48.6% of primary Sjögren's syndrome and in 3.0% of normal healthy subjects. Anti-IP(3)R2 antibodies were detected most frequently in rheumatoid arthritis. Locations of the antigenic epitopes were found to differ among the disease conditions.

A case of limited cutaneous systemic sclerosis developing anti-mitochondria antibody positive primary biliary cirrhosis after acute myocardial infarction.

In this report, we present a 63-year-old woman who had limited cutaneous systemic sclerosis and subsequently developed typical primary biliary cirrhosis after an acute myocardial infarction. The patient initially developed Raynaud's phenomenon, and 4 years later visited the clinic in 1994 complaining of abdominal distress, xerostomia, and xerophthalmia. A diagnosis of limited cutaneous systemic sclerosis was based on Raynaud's phenomenon, sclerodactyly and anti-centromere antibodies. She was also found to have anti-inositol 1,4,5-trisphosphate receptor 3 (IP(3)R3) antibodies, but anti-mitochondrial antibodies were only weakly positive. Seven years later, she developed vertigo and nausea, and was hospitalized due to complaints of an oppressive sensation of the anterior chest. Electrocardiogram results showed a reduction of R waves and ST segment elevation in II, III, and aVf leads. Coronary angiography showed 99% obstruction of the left anterior descending artery and 50% of stenosis of the right coronary artery. Three years later, the patient was noted to have anti-mitochondrial antibodies. Retrospective analysis of the patient's sera showed that IP(3)R3 antibodies were decreasing. Since myocardium is particularly rich in mitochondria, it is thought that myocardial infarction may have been the triggering event that initiated antigen-presenting cells to selectively induce an anti-mitochondrial antibody response.

Factors influencing the effectiveness of oseltamivir and amantadine for the treatment of influenza: a multicenter study from Japan of the 2002-2003 influenza season.

BACKGROUND: To evaluate the effectiveness of oseltamivir and amantadine for the treatment of influenza with respect to various clinical factors, a prospective multicenter study of the influenza season of 2002-2003 was done with 2163 patients whose condition was diagnosed by an antigen-detection test kit. METHODS: Oseltamivir was administered to 803 patients with influenza A (A+Os group) and 684 patients with influenza B (B+Os group). Amantadine was administered to 676 patients with influenza A (A+Am group). RESULTS: For each group, the duration of fever (i.e., body temperature, > or = 37.5 degrees C) was significantly shorter in patients who received the drug within 12 h after the onset of symptoms than in patients who received the drug > 12 h after the onset. For all 3 groups, the duration of fever was shorter in patients with a highest temperature < 39 degrees C than in patients with temperatures > or = 39 degrees C. The duration of fever was significantly longer for the B+Os group than for the A+Os group. Multiple regression analysis found that the type of influenza, the highest body temperature, and the time between the onset of symptoms and the start of treatment are independent factor that influence the duration of fever. CONCLUSIONS: Early administration increases the benefit of anti-influenza drugs--not only the benefit of oseltamivir treatment for influenza A, but also the benefit of amantadine treatment for influenza A and oseltamivir treatment for influenza B. Oseltamivir may be less effective as a treatment for influenza B than for influenza A. A highest body temperature of > or = 39 degrees C was an indicator of a longer duration of fever.

[Case of primary biliary cirrhosis patient with anti-p97/VCP antibodies presenting a mild clinical course].

In this study, we present a case of mild PBC that had anti-p97/VCP. A 53-year-old woman had been suspected of having chronic liver disease since 1983. In 1998, she visited the clinic, complaining of struma and pruritus. Laboratory findings on the first visit showed elevated levels of alkaline phosphatase (ALP) 454 IU/l(110-360), gammaGTP 250IU/l(-45) and IgM 671mg/dl(35-220). A screening of anti-mitochondrial antibody test was positive at a 1:80 dilution. A liver biopsy specimen revealed PBC at Scheuer stage 1. Following a treatment of ursodeoxycolic acid (UDCA) 300mg/day for 6 months, AMA and IgM were reduced to 1:20 and 220mg/dl, respectively. However, she was found to have low titer of anti-p97/VCP antibodies, determined by immunoprecipitation of radiolabeled recombinant protein produced by in vitro translation and transcription of the full length p97 cDNA. She has continued to be clinically stable following administration of UDCA 300mg. A PBC patient with anti-p97/VCP antibody showed a milder clinical course, suggesting some beneficial role of this antibody.

[Clinical symptoms of influenza infection in the 2002-2003 season].

The highest body temperature and clinical symptoms during the influenza infection were analyzed on 2,145 patients with influenza, (type A: 1,408cases, type B: 737cases: confirmed by a rapid diagnosis kit, Capilia FluA, B), and for 670 patients with a negative response to the rapid diagnosis kit (controls). The study was a multi-center study of the 2002-2003 influenza season. The percentages of patients with fever over 38 degrees C, 38.5 degrees C and 39 degrees C were significantly higher in influenza A than in influenza B or controls (16-64 yrs). Over 80% of the patients in all age groups of 0-6 yrs, 7-15 yrs, 16-64 yrs or over 64 yrs with influenza A or B had a cough. The percentage of patients with cough was significantly higher for patients with influenza A or B than for controls under 65 yrs. The percentages of influenza A or B patients with rhinorrhea or loss of appetite were significantly higher than in controls under 65 yrs. The percentage of patients reporting fatigue, headache or myalgia was significantly higher for influenza A than for controls of 16-64 yrs. Differences in symptoms, including fever, were minimal between influenza A and B patients under 16 yrs, and also among influenza A, B and controls in patients over 64 yrs. The percentage of patients with cough was not different among the three age groups by influenza A or B. However, the percentage of patients with rhinorrhea, loss of appetite, vomiting or diarrhea was higher in children under 16 yrs than in adults aged 16-64 yrs in influenza A or B. In conclusion, consideration must be given to the patient's age and the type of influenza when doing a symptomatic diagnosis of influenza. In addition, the use of a rapid diagnosis kit seems necessary for the diagnosis of influenza in elderly patients, who may have no specific symptoms of influenza.

Identification of the B-cell epitopes of the early endosome antigen 1 (EEA1).

Early endosome antigen 1 (EEA1) is a target autoantigen in patients diagnosed with neurological and other autoimmune conditions. Eighteen of 65 sera (28%) that displayed a vesicular cytoplasmic staining pattern also immunoprecipitated the recombinant EEA1. These 18 sera were selected for further clinical, serological and epitope mapping studies. Thirty-six percent of the 18 patients had neurological diseases. Seventeen sera (94%) reacted with the partial length EEA1 constructs that included the C-terminal zinc finger (+FYVE) and the methyl accepting domain (LeuMA: amino acids 82-1411) in an addressable laser bead assay suggesting that the assay may be used for rapid laboratory detection of anti-EEA1 antibodies. Three of seven sera selected for epitope mapping studies bound to EEA1 peptides represented by amino acids 1096-1125, and two reacted with peptides represented by amino acids 1296-1320. One serum reacted only with the C-terminal peptide 1096-1125. The remaining serum reacted with other EEA1 epitopes. This data was supported by the observations that all the sera immunoprecipitated the C-terminal +FYVE (EEA1 1064-1411) construct, a peptide that also contained the linear epitopes 1096-1140. The limited epitope mapping studies suggest that the sera from patients with non-neurological diseases recognized epitopes in the central and C-terminal EEA1 domains, whereas the patients with neurological disease recognized a more restricted set of epitopes in the C-terminal.

[Detection of anti-early endosome antigen 1 antibody in sera showing cytoplasmic vesicular staining, taken from patients with connective tissue diseases].

An early endosome antigen previously reported by F.T. Mu could be stained on cytoplasmic vesicles of HEp-2 cells. Here, we have investigated autoantibodies against cytoplasmic vesicular antigens, especially against early endosome antigen 1. Twelve sera were selected on the basis of cytoplasmic vesicular staining patterns of HEp-2 cells. Protein-immunoprecipitation using 35S-methionine labeled HeLa lysates, and RNA immunoprecipitation using 32P-labeled HeLa lysates were conducted to characterize the cognate antigens. Nine of 12 sera reacted with proteins in the range of 162-180 kDa, three of which were found to react specifically with the 162 kDa 35S methionine labeled recombinant early endosome antigen 1. These proteins were not associated with common RNA. Although complete clinical information was not available, some of the patients had rheumatoid arthritis(RA). In addition, the RNA-IPP results suggest that other patients included one each with SLE, SSc, polymyositis, and Sjögren's syndrome. Anti-early endosome antigen 1 antibody was found in 25%(3 of 12) of sera known to stain cytoplasmic vesicles. The reactive sera came mostly from patients with RA. The sera was from one case each of clinical-confirmed RA, SLE and Sjögren's syndrome.

Profile and clinical significance of anti-nuclear envelope antibodies found in patients with primary biliary cirrhosis: a multicenter study.

Primary biliary cirrhosis (PBC) sera contain antibodies which recognize various nuclear envelope proteins of which antibody against gp210 has been proven to be diagnostic for disease. In contrast, the clinical significance of another nuclear envelope antibody, anti-p62 antibody has not been well investigated. In the present study, we have analyzed anti-nuclear envelope antibodies by indirect immunofluorescence and immunoblot using rat liver nuclear envelope proteins and wheat germ agglutinin-bound fraction. Test sera were obtained from 175 patients with PBC and from 120 controls. Anti-gp210, anti-lamina associated polypeptide 2, anti-lamin B receptor, and anti-p62 complex antibodies were detected with a frequency of 26% (46 of 175), 6% (11 of 175), 9% (16 of 175), and 13% (15 of 115), respectively. The confirmation of Scheuer's stage IV was made with a frequency of 27% (4 of 15) in PBC patients with anti-p62 complex antibody, in contrast to only 2% (2 of 100) in PBC patients without anti-p62 complex antibody. This difference was found to be statistically significant. The presence of anti-p62 complex antibody may be related with the progressive or advanced state of PBC.

Participation of a fusogenic protein, glyceraldehyde-3-phosphate dehydrogenase, in nuclear membrane assembly.

We found an autoimmune serum, K199, that strongly suppresses nuclear membrane assembly in a cell-free system involving a Xenopus egg extract. Four different antibodies that suppress nuclear assembly were affinity-purified from the serum using Xenopus egg cytosol proteins. Three proteins recognized by these antibodies were identified by partial amino acid sequencing to be glyceraldehyde-3-phosphate dehydrogenase (GAPDH), fructose-1,6-bisphosphate aldolase, and the regulator of chromatin condensation 1. GAPDH is known to be a fusogenic protein. To verify the participation of GAPDH in nuclear membrane fusion, authentic antibodies against human and rat GAPDH were applied, and strong suppression of nuclear assembly at the nuclear membrane fusion step was observed. The nuclear assembly activity suppressed by antibodies was recovered on the addition of purified chicken GAPDH. A peptide with the sequence of amino acid residues 70-94 of GAPDH, which inhibits GAPDH-induced phospholipid vesicle fusion, inhibited nuclear assembly at the nuclear membrane fusion step. We propose that GAPDH plays a crucial role in the membrane fusion step in nuclear assembly in a Xenopus egg extract cell-free system.