Immune deficiency explains rampant caries in some children

November 27, 2017

Researchers at Umeå University in Sweden have made a novel discovery connecting genetic innate immunity deficiencies to rampant caries and increased risk of dental caries affecting about one in five children. The results could lead to a better way of identifying high-risk patients and treat their caries. The study has been published in the journal EBioMedicine.

In a five-year study, in which saliva and isolated bacterial strains from a large number of was analyzed and the dental health monitored, the research group recently established that some high-risk children have a more virulent variant of the caries bacterium Streptococcus mutans. The same research group now shows that high-risk children also have genetic defects in innate and adaptive immunity, making them more vulnerable against oral bacteria and streptococci in general.

"Most people consider caries to be a lifestyle condition caused by bad eating- and oral hygiene routines that lead to acidic pH levels in the mouth, which in turn damage the enamel and promote the colonization of acid-producing bacteria such as S. mutans," says Nicklas Strömberg, professor and Head at the Department of Cariology at Umeå University and Västerbotten County Council, and first author of the article.

"Our results now show that this correlation is accurate for approximately four out of five , who have a small-to-moderate risk of developing caries because their composition of salivary innate immunity proteins make them relatively resistant to caries. However, we have shown that so-called high-risk individuals, which are about one in five individuals, carry a genetically different composition of the same salivary innate immunity proteins, making them highly susceptible to caries independent of eating- or oral hygiene habits or S. mutans-infection."

One in five children in Sweden is considered a high-risk individual when it comes to the risk of developing . These high-risk individuals do not respond to traditional caries prevention or treatment, and bio markers cannot predict future risk of caries in the group. Chronic caries infection and missing teeth are also risk factors for systemic diseases such as stroke and cardiovascular diseases.

Innate and adaptive immunity deficiencies explain high-risk individuals for caries

A research group led by Nicklas Strömberg have in the current study followed 452 children (between ages 12 and 17) in Västerbotten over a five year period. After genetic analysis of their DNA, the children were divided into various risk groupings based on genetic variation in PRH1 and PRH2, encoding salivary acidic proline-rich proteins. At a five-year follow-up, the researchers could see how caries had developed in the various risk groupings.

The results showed that children with high susceptibility or risk for caries had defective proteins in their saliva. The defective salivary proteins in question were acidic and basic proline-rich proteins and the adhesive salivary agglutinin (or DMBT1). According to the researchers, the defective proteins probably fail to mediate the same innate and adaptive immunity responses that serve to protect individuals with small-to-moderate caries risk from the oral bacterial flora.

The researchers describe how allelic variation in PRH1 and PRH2, encoding acidic proline-rich proteins, separate children into different caries susceptibility or risk groupings. As expected, children with a low-to-moderate susceptibility or risk for caries along with a genetically intact set of proteins were found to develop caries from bad eating and oral hygiene routines and S. mutans-infection. However, the children with high susceptibility develop caries independent of eating- or oral hygiene routines or S. mutans-infection but from the immune deficiency. Accordingly, when children were treated with dental braces the high risk children exclusively developed several times more caries after 5 years. The researchers believe this is due to plaque accumulation and impaired saliva flow as a result from the dental braces.

"This new knowledge about genetic susceptibility groupings could be used to improve individualized dental care. Children in the higher risk group could then be diagnosed before caries lesions and symptoms arise. In this way, prevention could be implemented at a young age when caries can be prevented more easily. High-risk children can presently be treated with intensified prevention and in the future we will hopefully be able to use immune-supplementation as a way to strengthen their oral immunity," explains Nicklas Strömberg.

Dental costs, including those pertaining to treatment, amount to 5 % of global health care-related costs. Caries is the most common cause for failure of fillings and prosthetic replacements. The ability to detect high-risk individuals early could yield large savings for society and individuals both in terms of suffering and costs.

Explore further: Highly virulent bacterium causes rampant caries in some children

More information: Nicklas Strömberg et al, Genetic- and Lifestyle-dependent Dental Caries Defined by the Acidic Proline-rich Protein Genes PRH1 and PRH2, EBioMedicine (2017). DOI: 10.1016/j.ebiom.2017.11.019

Related Stories

Highly virulent bacterium causes rampant caries in some children

September 28, 2017
Researchers at Umeå University in Sweden have made a novel discovery connecting highly variant types of the caries bacterium Streptococcus mutans and their adhesive function to children with rampant caries and increased ...

How caries-causing bacteria can survive in dental plaque

November 2, 2017
Cariogenic bacteria live in biofilm and attack dental enamel by converting sugar and starch into acids that dissolve out calcium from the enamel. This process can cause caries. The dissolution of calcium increases the concentration ...

Predicting caries risk at 30-months of age in medical settings

March 19, 2016
Today at the 45th Annual Meeting & Exhibition of the American Association for Dental Research, researcher Margherita Fontana, University of Michigan School of Dentistry, Ann Arbor, USA, will present a study titled "Predicting ...

Microbiome associated with severe caries in Canadian First Nations children

March 18, 2016
Today at the 45th Annual Meeting & Exhibition of the American Association for Dental Research, researcher Robert Schroth, University of Manitoba, Children's Hospital Research Institute of Manitoba, Winnipeg, Canada, will ...

Hyperglycemia may cause caries but not periodontal disease

August 14, 2017
(HealthDay)—For rodents with diabetes, periodontal inflammation may be derived from dental caries rather than periodontal disease (PD), according to a study published online Aug. 9 in Diabetes.

Pediatricians should be involved in oral health care

November 24, 2014
(HealthDay)—Pediatricians should perform oral health assessments and help maintain and restore oral health for the youngest children, according to a policy statement from the American Academy of Pediatrics (AAP) published ...

Recommended for you

Injuries from window blinds send two children to the emergency department every day

December 11, 2017
Most homes have them. They help keep our rooms warm or cold and even add a pop of color to tie the décor together. But window blinds can cause serious injuries or even death to young children. A new study from the Center ...

Blood flow altered in brains of preterm newborns vs. full-term infants

December 4, 2017
Cerebral blood flow (CBF) of key regions of newborns' brains is altered in very premature infants and may provide an early warning sign of disturbed brain maturation well before such injury is visible on conventional imaging, ...

HPV vaccine is effective, safe 10 years after it's given

November 29, 2017
A decade of data on hundreds of boys and girls who received the HPV vaccine indicates the vaccine is safe and effective long term in protecting against the most virulent strains of the virus, researchers report.

Antibiotics administered during labor delay healthy gut bacteria in babies

November 28, 2017
Antibiotics administered during labour for Group B Streptococcus (GBS) affect the development of gut bacteria in babies, according to a study from McMaster University.

Stress in pregnancy linked to changes in infant's nervous system, less smiling, less resilience

November 23, 2017
Maternal stress during the second trimester of pregnancy may influence the nervous system of the developing child, both before and after birth, and may have subtle effects on temperament, resulting in less smiling and engagement, ...

Molecules in spit may be able to diagnose and predict length of concussions

November 20, 2017
Diagnosing a concussion can sometimes be a guessing game, but clues taken from small molecules in saliva may be able to help diagnose and predict the duration of concussions in children, according to Penn State College of ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.