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Health Rounds: Adjusting gut bacteria may help with peanut allergies

By Thomson Reuters Aug 7, 2026 | 6:17 AM

By Nancy Lapid

Aug 7 (Reuters) – We also feature a small study that should reassure women about the safety of becoming pregnant after undergoing CAR T-cell therapy for autoimmune diseases.

GUT BACTERIA TREATMENT MAY EASE SEVERE PEANUT ALLERGIES

Fecal transplants that adjust the assortment of bacteria in the intestines can ease severe peanut allergies ​in some patients, a pilot study suggests.

Researchers recruited 10 young adults with severe peanut allergies who reacted ‌to mere traces of peanuts and had them swallow frozen “poop pills” containing feces — including strains of helpful bacteria — from donors with healthy gut microbiomes.

Three months later, three participants could tolerate eating multiple peanuts, researchers reported in Science Translational Medicine.

In the next round of the study, another five volunteers took antibiotics before the fecal transplant to see if the donor bacteria transferred more successfully when they didn’t’ have to compete with ‌the ​participants’ own resident gut microbes.

Three of the five improved in peanut tolerance and ⁠ingested more than four peanuts before reacting, ⁠suggesting the antibiotics did increase the efficiency of the microbiome transfer.

Blood tests showed those who responded to the therapy had increased levels of so-called bile salts, which help the small intestine break down fats for better absorption.

The beneficial bacteria from the fecal transplants seemed to be more adept at processing bile salts than the original bacteria ​in the allergic participants.

In additional experiments, the team also found that by helping to process the bile salts, the good bacteria increased levels of immune cells that protect from allergic reactions.

“This landmark study was the first to demonstrate that ⁠a microbiome-based therapy may improve food allergy in people while also ⁠revealing how gut bacteria, their metabolites, and the immune system work together to influence treatment ​response,” study leader Dr. Rima Rachid of Boston Children’s Hospital said in a statement.

“Larger studies of fecal and microbiota transplantation are ​now essential to confirm these findings, identify the patients most likely to benefit, and discover beneficial ‌bacteria that could be developed into targeted probiotic therapies for food allergy,” she said.

PREGNANCY AFTER CAR T-CELL THERAPY APPEARS SAFE

Women treated with CAR T-cell therapy for a variety of autoimmune diseases can safely become pregnant afterward, a small study suggests.

CAR-T therapy involves removing a patient’s white blood cells, modifying them in a laboratory, and reinfusing and multiplying them with the modifications ⁠helping to “reset” the body’s immune defenses.

CAR-T therapies were originally used only in cancer patients, but researchers are increasingly testing them for autoimmune diseases like lupus, multiple sclerosis, and rheumatoid arthritis, all of which commonly afflict women of childbearing age.

Pregnancies in the ⁠presence of autoimmune diseases are linked with ‌higher risks for mothers and babies. While CAR-T treatments can put patients into drug-free ⁠remission, the safety of pursuing pregnancy afterward is unclear because the treatment is so ​new.

For the ‌current study, researchers tracked 14 pregnancies in 13 women with autoimmune diseases who had ​received CAR ⁠T-cell therapy.

All conceptions occurred spontaneously without assisted reproductive technologies, according to a report in The New England Journal of Medicine.

“The findings were notably reassuring,” the researchers said.

All eight babies born so far were healthy, full-term, with normal growth and immune markers, they reported.

No CAR T-cells or related complications were found in any newborn and no disease flares occurred during any pregnancy.

Another five pregnancies are still underway, according to the report.

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(Reporting by Nancy ​Lapid; Editing by Bill Berkrot)