McMaster study reveals secrets of cystic fibrosis in baby sweat

A study from McMaster identifies new biological markers that can better determine the prognosis for children and young adults with cystic fibrosis.
Philip Britz-McKibbin, a chemistry and chemical biology professor at McMaster, led the study which can better determine how cystic fibrosis will manifest in patients, and get them the treatment they need early. (McMaster University)

New secrets have been revealed about how cystic fibrosis can manifest in young patients and how to treat it — and the answer lies in baby sweat.

Cystic fibrosis (CF), a genetic disease which affects children and young adults, comes with lifelong health complications including digestive problems and persistent lung infections.

A new McMaster University study, which was published in the journal ACS Central Science on Monday, sheds new light on how CF works and, researchers say, could lead to an improved prognosis and better therapies.

"There are chemical signatures in sweat that tell us an infant has CF even when they do not exhibit any symptoms," said Philip Britz-McKibbin, lead author of the study and a chemistry and chemical biology professor at McMaster University.

The easier it is to detect CF, the earlier it can be diagnosed, and the better people's chances are at living a longer, healthier life.- Joanna Valsamis, chief healthcare, research and advocacy officer at Cystic Fibrosis Canada

It is estimated that one in every 3,600 children born in Canada has CF, according to the charitable organization Cystic Fibrosis Canada. It is the most common fatal genetic disease affecting Canadian children and young adults, and there is no cure.

The disease is caused by a protein defect that affects many tissues, including those in the airways and the sweat glands. As a result, these tissues do not work properly and often result in persistent lung infections, which will eventually lead to death for the majority of patients.

The sweat test

Using a specialized technique developed at McMaster, scientists collected and analyzed sweat samples from infants in CF clinics at McMaster Children's Hospital and the Hospital for Sick Children in Toronto.

They identified several chemicals that were consistently associated with babies who had CF.

Sweat testing makes use of the fact that CF patients have an elevated level of chloride in their sweat, because their glands cannot absorb chloride back into the body as well as people who don't have it.

The McMaster study identifies new biological markers in the sweat of infants only a few weeks old, which is collected and used for treatment. A high level of salt (or more specifically, chloride) indicates the infant has the disease.

But making clinical decisions on treatment is complicated, Britz-McKibbin said, because the "sweat test" is not definitive about more borderline cases, so it does not reveal how the disease might progress for individual patients.

Moreover, he said, early tests to determine the risk of cystic fibrosis "tend to identify a lot of carriers — so infants who carry a mutation, but are usually not affected by the disease."

A better, longer life

Britz-McKibbin explained that the findings could help catch the disease early, which can help provide treatment to infants and determine how well they will respond to treatment growing up.

"With early and accurate screening, such therapies can be promptly introduced early in the patient's life before their symptoms manifest," Britz-McKibbin explained.

"This is expected to further increase the median age of survival for CF and improve the patient's quality of life by reducing or delaying the need for lung transplantation due to chronic and recurrent lung infections."

In addition, he explained, it would give a better idea of how well certain therapies work, such as nutritional supplements to improve the patient's growth and combat the common complication of malnutrition, as well as new pharmacological treatments to improve lung function.

The McMaster research was funded in part by Cystic Fibrosis Canada, which hailed the findings as a big step forward in helping improve patients' lives.

"The easier it is to detect CF, the earlier it can be diagnosed, and the better people's chances are at living a longer, healthier life", says Joanna Valsamis, chief healthcare, research and advocacy officer at Cystic Fibrosis Canada.

"CF Canada invests heavily in research that aims to improve the lives of people living with CF, and findings such as those from Dr. Britz-McKibbin are crucial to our understanding of the disease."