Measles vaccination and inflammatory bowel disease

CD24 is upregulated in inflammatory bowel disease and stimulates cell motility and colony formation

BACKGROUND

We investigated whether CD24 (reportedly a stem cell marker and adhesion molecule) was expressed in regenerative mucosa in inflammatory bowel disease (IBD) and whether it could be functionally relevant.

METHODS

CD24 expression was examined in 10 cases of IBD and the relationship of CD24 with Wnt signaling was tested using dominant negative (DN)-TCF4 expression. For functional evaluation, CD24 was 1) cloned and forcibly expressed in HCT116 (which expresses very low levels of CD24) and 2) knocked-down by RNA interference in HT29 (which expresses high levels of CD24). The effect of altered CD24 expression on proliferation/apoptosis, staurosporine-induced apoptosis, colony formation in soft agar, migration, and invasion was examined.

RESULTS

CD24 was not expressed in normal tissue, while 10/10 cases of IBD showed CD24 upregulation. Inhibition of Wnt signaling with DN-TCF4 caused CD24 downregulation. Forced expression of CD24 did not influence cell proliferation, apoptosis, or staurosporine-induced apoptosis but it did significantly enhance colony forming efficiency (P < 0.01). Furthermore, there was increased transwell migration (P < 0.001) and invasion (P < 0.03) and there was increased cell migration in wounding assays. Conversely, knockdown of CD24 reduced transwell migration (P < 0.01) and invasion (P < 0.01) and reduced cell motility in wounding assays. CD24 knockdown did not influence proliferation, apoptosis resistance, or staurosporine-induced apoptosis.

CONCLUSIONS

This is the first study to report upregulation of CD24 in regenerating tissue in IBD. This may be regulated by Wnt signaling and can confer enhanced colony forming ability and enhanced cell motility-features that may be important in tissue healing in the colon.

Measles-mumps-rubella vaccine and the development of autism

The measles-mumps-rubella (MMR) vaccine has been postulated to cause a form of autism characterized by regression and bowel symptoms, and onset occurring shortly after vaccination. It is also claimed that, as a result, there has been a dramatic increase in autism prevalence. These hypotheses have now been tested in a number of epidemiologic studies that are reviewed in this article. None has found any evidence of the existence of a phenotypically distinct form of autism in children who received the MMR vaccine or of a clustering of onset symptoms in children who are autistic after receiving the MMR vaccine. There is no proof that the overall risk of autism is higher in children who were vaccinated with MMR or of an increase in autism prevalence associated with the use of the MMR vaccine. No epidemiologic evidence suggests an association between MMR vaccination and autism. Moreover, epidemiologic evidence against such an association is compelling.

Measles vaccination and inflammatory bowel disease: a national British Cohort Study

OBJECTIVE

Measles vaccination has been suggested as a risk for inflammatory bowel disease. Atypical age of measles infection has also been associated with Crohn's disease. This study was designed to examine the relationship of measles vaccination and age of measles vaccination with later inflammatory bowel disease.

METHODS

A prospective population-based national birth cohort was used, of those born in 1 wk in April 1970 in Great Britain. The data are from 7616 responding members of the 1970 British Cohort Study with complete vaccination data, who were traced at age 26 yr. A diagnosis of Crohn's disease, ulcerative colitis, and diabetes mellitus (a control disease) was obtained by survey at age 26 yr, and confirmed by physicians. Vaccination data were from survey at age 5 yr. Measles and mumps infection data were obtained from the survey at age 10 yr. Adjustment was made for sex, household crowding in childhood, and father's social class at birth.

RESULTS

No statistically significant association was found between measles vaccination status at 5 yr and Crohn's disease (adjusted odds ratio [OR] 0.67, 95% confidence interval [CI] 0.27-1.63), ulcerative colitis (adjusted OR 0.57, 95% CI 0.20-1.61), or diabetes (adjusted OR 0.75, 95% CI 0.33-1.74). There was a statistically significant trend (p = 0.040) with increasing age of measles vaccination for risk of Crohn' s disease, although this was based on very few cases vaccinated after age 2 yr.

CONCLUSIONS

In this cohort, monovalent measles vaccination status is not associated with inflammatory bowel disease by age 26 yr. Older age at measles vaccination needs to be examined in other studies to confirm whether it is a genuine risk for Crohn's disease.

Early measles virus infection is associated with the development of inflammatory bowel disease

OBJECTIVE

The measles virus has been implicated as a possible etiological agent in the development of inflammatory bowel disease (IBD). Measles infection at an early age is associated with subacute sclerosing panencephalitis, a degenerative neurological condition caused by persistent measles infection of the central nervous system. We sought to determine whether infection with measles virus at an early age was also associated with an increased risk of developing IBD.

METHODS

Patients with measles infection diagnosed before the age of 5 yr were identified through the diagnostic indices of the Mayo Clinic and the Rochester Epidemiology Project. A questionnaire was used to ascertain a subsequent history of IBD, which was confirmed by records from the subjects' physicians. The risks of developing Crohn's disease and ulcerative colitis were calculated relative to expected rates for these conditions in the Olmsted County, Minnesota population.

RESULTS

Of 1164 eligible cases, 662 (57%) completed the questionnaire. There were six confirmed cases of Crohn's disease and six of ulcerative colitis. The expected number of cases was 1.9 for Crohn's disease (standardized incidence ratio [SIR] 3.1, 95% confidence interval [CI] 1.1-6.8) and 2.0 for ulcerative colitis (SIR 3.0, CI 1.1-6.5). There was a trend towards a higher risk of developing IBD with an earlier age of infection.

CONCLUSIONS

Early measles infection is associated with an increased risk of developing Crohn's disease and ulcerative colitis. The risk may be higher with earlier infection.

Autism: not an extremely rare disorder

OBJECTIVE

To study autism over time in order to ascertain whether there has been an increase in its prevalence in recent years.

METHOD

All English language papers on the prevalence of autism were reviewed. Ten of the studies retrieved were not used in the final analysis because they did not meet full criteria for inclusion in the review. The remaining 20 studies, published between 1966 and 1997, were subdivided into US studies (n=2) and non-US studies (n=18), and the latter group was subdivided into four 8-year periods.

RESULTS

The early studies yielded prevalence rates of under 0.5 in 1000 children, whereas the later ones showed a mean rate of about 1 in 1000. There was a marked difference in prevalence rates between those studies that included some children born before 1970 (low rates) and those that included only children born in 1970 and after (high rates). This is probably due to the lower rates obtained by use of criteria strictly based on Kanner's description of his syndrome. The US studies reported atypically low rates. There was a highly significant estimated increase with calendar year in the non-US studies (3.8% per year).

CONCLUSION

It is concluded that autism is considerably more common than was previously believed. The possible reasons for the higher reported rates are discussed.

Measles vaccines: a review of adverse events

A great deal of controversy has recently been generated over the publication of several articles implicating measles vaccine in the induction of Crohn's disease and autism. The publication of this work has already had a negative impact on measles vaccine acceptance in the UK. These allegations are particularly troubling because they arise in the context of increased use of measles vaccine as global control of measles nears and the international community considers strategies for a drive towards eradication. In 1994, the US Institute of Medicine reviewed the world literature and published a comprehensive review of adverse events associated with measles-containing vaccines. Reviewing the literature published between 1994 and the present day, reveals that there is considerable new data suggesting that modified gelatin rather than egg proteins is responsible for most episodes of anaphylaxis following measles vaccination. New work weakens the possible links between measles vaccine and subacute sclerosing panencephalitis and Guillain-Barré syndrome, but strengthens the rare association of measles-containing vaccines with post infectious encephalomyelitis. The alleged associations between measles vaccination and Crohn's disease and autism are based upon weak science and have largely been refuted by a large volume of stronger work. A review of the data generated in the last 4 years amply demonstrates the continued efforts of the scientific community to monitor and understand true measles vaccine-associated adverse events. The rapidity and clarity of this same community's debunking of the spurious associations with Crohn's disease and autism suggests that those charged with vaccination programmes have learned from past mistakes. During 30 years of worldwide use, measles vaccination has proven to be one of the safest and most successful health interventions in the history of mankind. It is not a 'perfect' vaccine, but the benefits of measles vaccination far outweigh the risks even in countries with low incidence of measles and high rates of measles vaccine coverage.