New hope for Lyme disease prevention found in human sweat

Health

By Tracy Swartz

There may be new hope in the fight against Lyme disease, a tick-borne infection that sometimes results in chronic illness.

Researchers at MIT and the University of Helsinki have determined that human sweat contains a protein that inhibits the growth of a bacterium that causes the disease. One-third of the population carries a genetic variant of this protein, according to study findings published Tuesday in the journal Nature Communications.

“This protein may provide some protection from Lyme disease, and we think there are real implications here for a preventative and possibly a therapeutic based on this protein,” Michal Caspi Tal, a principal research scientist in MIT’s Department of Biological Engineering and one of the senior study authors, said in a statement.

The researchers analyzed the DNA and medical histories of 7,000 Finnish people who had been diagnosed with Lyme disease.

They were stunned to find a secretoglobin called SCGB1D2 suppressed bacterial growth. Secretoglobins are proteins that have been shown to protect the lungs — this particular one is secreted by sweat gland cells.

As part of this study, researchers exposed normal and mutated versions of SCGB1D2 to Borrelia burgdorferi, a bacterium that spurs Lyme disease.

The team found that the normal version of the protein “significantly” inhibited bacteria growth, but twice as much of the mutated protein was needed for similar results.

Mice injected with the bacteria exposed to the mutated SCGB1D2 became infected with Lyme disease but didn’t become ill with the normal version of the protein.

“In the paper we show they stayed healthy until day 10, but we followed the mice for over a month, and they never got infected,” Tal said. “This wasn’t a delay, this was a full stop. That was really exciting.”

Researchers in Estonia were able to replicate the results using data from 18,000 people with Lyme disease.

They don’t know how SCGB1D2 inhibits bacterial growth, or why the variant is not as effective.

They’re exploring using the protein to create skin creams to help prevent the illness and to treat antibiotic-resistant infections.

“We have fantastic antibiotics that work for 90% of people, but in the 40 years we’ve known about Lyme disease, we have not budged that,” Tal said. “10% of people don’t recover after having antibiotics, and there’s no treatment for them.”

According to estimates, some 476,000 Americans may be diagnosed with Lyme disease this year. 

Symptoms can include fever, chills, headaches, fatigue, muscle and joint aches and swollen lymph nodes or rashes — and if untreated, facial palsy, heart palpitations or irregular heartbeat, nerve pain, and inflammation of the brain and spinal cord.

Experts are warning that ticks are emerging earlier than usual this year — and we could be in for a severe season, thanks to a mild end to winter.