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Query: UMLS:C0004352 (autism)
 32,579 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has been reported that measles virus may be present in the intestine of patients with Crohn's disease. Additionally, a new syndrome has been reported in children with autism who exhibited developmental regression and gastrointestinal symptoms (autistic enterocolitis), in some cases soon after MMR vaccine. It is not known whether the virus, if confirmed to be present in these patients, derives from either wild strains or vaccine strains. In order to characterize the strains that may be present, we have carried out the detection of measles genomic RNA in peripheral mononuclear cells (PBMC) in eight patients with Crohn's disease, three patients with ulcerative colitis, and nine children with autistic enterocolitis. As controls, we examined healthy children and patients with SSPE, SLE, HIV-1 (a total of eight cases). RNA was purified from PBMC by Ficoll-paque, followed by reverse transcription using AMV; cDNAs were subjected to nested PCR for detection of specific regions of the hemagglutinin (H) and fusion (F) gene regions. Positive samples were sequenced directly, in nucleotides 8393-8676 (H region) or 5325-5465 (from noncoding F to coding F region). One of eight patients with Crohn disease, one of three patients with ulcerative colitis, and three of nine children with autism, were positive. Controls were all negative. The sequences obtained from the patients with Crohn's disease shared the characteristics with wild-strain virus. The sequences obtained from the patients with ulcerative colitis and children with autism were consistent with being vaccine strains. The results were concordant with the exposure history of the patients. Persistence of measles virus was confirmed in PBMC in some patients with chronic intestinal inflammation.
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PMID:Detection and sequencing of measles virus from peripheral mononuclear cells from patients with inflammatory bowel disease and autism. 1131 48

The hypothesis that MMR vaccines cause autism was first raised by reports of cases in which developmental regression occurred soon after MMR vaccination. A previous study found no evidence to support this hypothesis. It has recently been suggested that MMR vaccine might cause autism, but that the induction interval need not be short. The data from the earlier study were reanalysed to test this second hypothesis. Our results do not support this hypothesis, and provide further evidence against a causal association between MMR vaccination and autism.
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PMID:MMR and autism: further evidence against a causal association. 1139 96

For decades after Kanner's original paper on the subject was published in 1943, autism was generally considered to be a rare condition with a prevalence of around 2-4 per 10,000 children. Then, studies carried out in the late 1990s and the present century reported annual rises in incidence of autism in pre-school children, based on age of diagnosis, and increases in the age-specific prevalence rates in children. Prevalence rates of up to 60 per 10,000 for autism and even more for the whole autistic spectrum were reported. Reasons for these increases are discussed. They include changes in diagnostic criteria, development of the concept of the wide autistic spectrum, different methods used in studies, growing awareness and knowledge among parents and professional workers and the development of specialist services, as well as the possibility of a true increase in numbers. Various environmental causes for a genuine rise in incidence have been suggested, including the triple vaccine for measles, mumps and rubella (MMR]. Not one of the possible environmental causes, including MMR, has been confirmed by independent scientific investigation, whereas there is strong evidence that complex genetic factors play a major role in etiology. The evidence suggests that the majority, if not all, of the reported rise in incidence and prevalence is due to changes in diagnostic criteria and increasing awareness and recognition of autistic spectrum disorders. Whether there is also a genuine rise in incidence remains an open question.
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PMID:The epidemiology of autistic spectrum disorders: is the prevalence rising? 1221 59

In a subgroup of children with autism-spectrum like conditions symptoms seem to appear as a 'regression' (in normal development). It has been postulated that the onset of such autistic symptoms may involve an autoimmune response against the central nervous system and that the antigenic determinant could possibly be gastrointestinal in origin. It has been suggested that the presence of the measles virus and 'autistic enterocolitis' demonstrates the possibility that the MMR triple vaccine may be mediating the inflammation with possible production of antibodies against the virus containing vaccine. Such an antibody may share antigenic determinant to molecules found in the gut. We propose that this may be secretin or its receptor, found in the gut as well as in the central nervous system. The antibody response to the gut may also conceivably occur in the brain at a critical time in development. The modulation of development by secretin may be a static event possibly occurring at a specific time in early childhood development and if it involves an autoimmune response then a disruption in development may result. These hypothesized events can only occur if the MMR vaccine shares antigenic determinants that resemble secretin or any of its receptor types and remains to be studied.
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PMID:Does the MMR vaccine and secretin or its receptor share an antigenic epitope? 1271 Aug 97

In 1998, a report was published describing 12 patients with inflammatory bowel conditions and regressive developmental disorders consisting primarily of autism. The authors hypothesised that MMR vaccine may have been responsible for the bowel dysfunction which subsequently resulted in the neurodevelopmental disorders. The suggestion that measles vaccine may cause autism through a persistent bowel infection generated much interest since it provided a possible biological mechanism for a causal association. Epidemiological studies, however, have not found an association between MMR vaccination and autism. Autism has a strong genetic component and its associated neurological defects probably occur during embryonic development. It seems unlikely that a vaccination that is given after birth could cause autism. In a minority of cases, autism may have onset after 1 year of age (regressive autism) but the one epidemiological study that included such cases did not find an association with MMR vaccination. Currently, the weight of the available epidemiological and related evidence does not support a causal link between MMR vaccine and autism.
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PMID:MMR vaccination and autism: is there a link? 1290 45

MMR is a live attenuated vaccine. Indian children show almost 90% seroconversion against measles and rubella and 90% against mumps. Several adverse effects have been reported. Epidemiological studies do not support a causative link between MMR and autism, IBD or GBS. There is an association between the Urabe strain of mumps vaccine and viral meningitis. Vaccine associated thrombocytopenia has been reported. Severe hypersensitivity reactions occur, mainly due to the gelatin component. Outbreaks of measles occur in areas of high measles vaccine coverage, when susceptible individuals accumulate. A second dose is given mainly to vaccinate those who missed the first dose or had primary vaccine failure, rather than to boost waning antibody levels. The possibility or eradication of mumps with a second dose of mumps vaccine is being considered.
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PMID:Measles, mumps, rubella (MMR) vaccine. 1294 Mar 81

Vaccinations protect to a high degree against infectious diseases, but may cause side effects. In the Netherlands since 1962 the adverse events following immunizations are registered and analysed by the National Institute of Health and Environment (RIVM). Since 1983 a permanent Committee of the Dutch Health Council reviews adverse events reported to the RIVM. With the so-called killed vaccines the side effects are mainly local (redness, swelling, pain) or general (fever, listlessness, irritability, sleep and eating problems). They are seen mainly after DPT-IPV vaccination against diphtheria, pertussis, tetanus and poliomyelitis. Some side effects occur rarely (collapse reactions, discoloured legs, persistent screaming and convulsions) and very rarely serious neurological events are reported. After MMR vaccination against measles, mumps and rubella, cases of arthritis, thrombocytopenia and ataxia are reported sporadically. Usually, they have a spontaneous recovery. During recent years a scala of diseases or symptoms have been associated with vaccination (presumed side effects). Careful and extensive investigations have shown that such hypotheses could not be supported. Examples are allergic diseases as asthma, diabetes mellitus, multiple sclerosis (after hepatitis B vaccination), autism and inflammatory bowel disease (after MMR vaccination) and sudden infant death syndrome. The total number of cases where at least a possible relation between side effects and vaccination is observed--apart from local reactions and moderate general symptoms--is very rare (about 0.25 per 1000 vaccinations) and does not balance the benefits from vaccination. There appears increasing doubt about the use and safety of vaccinations. More research is needed about the motives of people to choose for and against vaccination. The education about vaccination for parents and professionals who are involved with vaccination has to be improved. Internet can play an important role.
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PMID:[Childhood vaccinations anno 2004. II. The real and presumed side effects of vaccination]. 1503 89

Contested reports associating the MMR vaccine with autism have resulted in diminished confidence and uptake of the vaccine in the UK. This postal survey of parent's decisions, attitudes and use of information about MMR immunisation was constructed from questions derived from in-depth qualitative work. The setting was a Primary Care Trust in northeast England (N=996). Both MMR-accepting and refusing parents were supportive of immunisation, yet the high level of concern about the safety of the vaccine expressed even by parents who had immunised their children is worrying in its implications for public confidence and trust in health care. The findings suggest that the ability of practitioners to provide effective professional advice about MMR vaccine could be undermined if a government were to directly promote the vaccine to parents. Practitioners should continue to provide parents with accurate information, while communicating respect for parents' intentions to protect their children's health.
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PMID:A survey of UK parental attitudes to the MMR vaccine and trust in medical authority. 1615 22

Safety of vaccines must be excellent to make vaccine's strategy acceptable, since it usually has a deferred individual benefit but immediate adverse drug reactions (ADRs). Pharmacovigilance of vaccines after their marketing is crucial because, prior to its availability on the market, the size of clinical trials is insufficient to identify rare or deferred adverse effects. The Pharmacovigilance is based on "spontaneous reporting" of ADRs to the Pharmacovigilance Regional Centre (PVRC) which establishes a relationship between each drug taken by the patient and the ADRs occurrence (imputability). This method is crucial to generate alerts, but under-estimates the real frequency of ADRs (1 to 10% of severe ADRs are reported). Thus pharmacoepidemiology studies are necessary to confirm the alerts identified by spontaneous reporting. ADRs can be specific, related to the antigen of an attenuated alive virus vaccine (lymphocyte meningitis after anti-mumps vaccine) or non-specific, related to a component different from the antigen (aluminium hydroxide involved in the "macrophagic myofasciitis", allergic reactions to neomycin, latex, egg or gelatine). Importance of Pharmacovigilance of vaccines is illustrated. Data, especially case-control studies, about the relationship between multiple sclerosis and hepatitis B vaccine are summarised. Data about the relationship between Crohn's disease or autism and MMR vaccine are analysed. As vaccines are used in healthy people, their safety must be excellent to be accepted. To monitor them after their marketing is the unique way to detect rare ADRs. This surveillance is made through reporting of ADRs to the PVRC. However, an active and intensive surveillance of ADRs as the one set up from the marketing of Prevenar should be systematic.
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PMID:[Pharmacovigilance of vaccines]. 1634 70

The immunopathogenesis of autism is presented schematically in Fig. 1. Two main immune dysfunctions in autism are immune regulation involving pro-inflammatory cytokines and autoimmunity. Mercury and an infectious agent like the measles virus are currently two main candidate environmental triggers for immune dysfunction in autism. Genetically immune dysfunction in autism involves the MHC region, as this is an immunologic gene cluster whose gene products are Class I, II, and III molecules. Class I and II molecules are associated with antigen presentation. The antigen in virus infection initiated by the virus particle itself while the cytokine production and inflammatory mediators are due to the response to the putative antigen in question. The cell-mediated immunity is impaired as evidenced by low numbers of CD4 cells and a concomitant T-cell polarity with an imbalance of Th1/Th2 subsets toward Th2. Impaired humoral immunity on the other hand is evidenced by decreased IgA causing poor gut protection. Studies showing elevated brain specific antibodies in autism support an autoimmune mechanism. Viruses may initiate the process but the subsequent activation of cytokines is the damaging factor associated with autism. Virus specific antibodies associated with measles virus have been demonstrated in autistic subjects. Environmental exposure to mercury is believed to harm human health possibly through modulation of immune homeostasis. A mercury link with the immune system has been postulated due to the involvement of postnatal exposure to thimerosal, a preservative added in the MMR vaccines. The occupational hazard exposure to mercury causes edema in astrocytes and, at the molecular level, the CD95/Fas apoptotic signaling pathway is disrupted by Hg2+. Inflammatory mediators in autism usually involve activation of astrocytes and microglial cells. Proinflammatory chemokines (MCP-1 and TARC), and an anti-inflammatory and modulatory cytokine, TGF-beta1, are consistently elevated in autistic brains. In measles virus infection, it has been postulated that there is immune suppression by inhibiting T-cell proliferation and maturation and downregulation MHC class II expression. Cytokine alteration of TNF-alpha is increased in autistic populations. Toll-like-receptors are also involved in autistic development. High NO levels are associated with autism. Maternal antibodies may trigger autism as a mechanism of autoimmunity. MMR vaccination may increase risk for autism via an autoimmune mechanism in autism. MMR antibodies are significantly higher in autistic children as compared to normal children, supporting a role of MMR in autism. Autoantibodies (IgG isotype) to neuron-axon filament protein (NAFP) and glial fibrillary acidic protein (GFAP) are significantly increased in autistic patients (Singh et al., 1997). Increase in Th2 may explain the increased autoimmunity, such as the findings of antibodies to MBP and neuronal axonal filaments in the brain. There is further evidence that there are other participants in the autoimmune phenomenon. (Kozlovskaia et al., 2000). The possibility of its involvement in autism cannot be ruled out. Further investigations at immunological, cellular, molecular, and genetic levels will allow researchers to continue to unravel the immunopathogenic mechanisms' associated with autistic processes in the developing brain. This may open up new avenues for prevention and/or cure of this devastating neurodevelopmental disorder.
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PMID:Immunological findings in autism. 1651 56


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