Hello Health Rounds readers! Today we have another example of why diversity matters in clinical research. A new study disproves the age-old theory - developed based on studies in mostly white volunteers - that youth-onset diabetes is always the result of an immune system attack on the pancreas. We also feature a report on two trials of a new drug option for patients with hard-to-control Crohn's disease.

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The U.S. Department of Health and Human Services has launched a reform of the organ-transplant system and threatened to close a major procurement body, after a probe found premature attempts to start organ retrieval while patients showed signs of life.

A new discovery could change how type 1 diabetes is diagnosed and managed in individuals of African descent, researchers say.

In type 1 diabetes, the insulin-producing beta cells in the pancreas stop working in childhood or young adulthood. The disease is attributed to an autoimmune process in which the immune system produces so-called autoantibodies that mistakenly attack the pancreas.

But studying 894 volunteers in Cameroon, Uganda and South Africa with youth-onset diabetes, researchers found that 65% of them did not have the usual autoantibodies typically seen in people with type 1 diabetes in other parts of the world. Nor did they have the genes that usually predispose to the disease, or features consistent with other known types of diabetes, such as type 2 and malnutrition-related diabetes.

“This suggests that many young people in this region have a different form of type 1 diabetes altogether and is not autoimmune in origin,” study leader Dana Dabelea of the University of Colorado Anschutz Medical Campus said in a statement.

Comparing the data to studies in the U.S., the researchers found that 15% of Black Americans diagnosed with type 1 diabetes had a form of the disease similar to the patients in Sub-Saharan Africa, characterized by negative autoantibodies and a low genetic risk score, according to a report in The Lancet Diabetes and Endocrinology.

White Americans with type 1 diabetes, however, showed the typical autoimmune pattern, and even if they didn’t have detectable autoantibodies, their genetics still pointed to autoimmune diabetes.

Clinicians in parts of Africa had long suspected that some children diagnosed with type 1 diabetes did not quite fit the standard profile, the researchers said.

Most studies to date have focused on white Western populations, overlooking regional and genetic diversity in disease presentation, they noted.

“These findings are a wake-up call,” study co-leader Professor Moffat Nyirenda of the London School of Hygiene & Tropical Medicine Uganda Research Unit said in a statement.

“They challenge our assumptions about type 1 diabetes and show that the disease may present differently in African children and adolescents. We urgently need to deepen our investigations into the biological and environmental factors driving this form of diabetes and ensure our diagnostic and treatment approaches are fit for purpose in African settings.”

A commercially available psoriasis drug could become a new first- or second-line treatment for Crohn’s disease, researchers say.

They compared Johnson & Johnson’s Tremfya to Stelara, a leading Crohn’s disease drug from the same company, in two late-stage trials involving a total of 1,021 patients.

Trial participants all had moderate to severe disease despite treatment with other types of medications, according to a report of the trials published in The Lancet.

By the end of the 48-week trials, 70% of Tremfya patients reached remission, compared to 63% with Stelara and 13% with placebo, the researchers found.

Tremfya was also effective in achieving remission without the need for long-term steroid use, which can lead to serious side effects. At 48 weeks, 84% of Tremfya patients had successfully stopped using steroids, compared to 72% of those taking Stelara.

Overall, patients receiving Tremfya “showed significantly higher rates of endoscopic healing and deep remission, critical indicators linked to fewer disease flares, hospitalizations, and long-term complications,” study leader Dr. Bruce Sands from the Icahn School of Medicine at Mount Sinai in New York said in a statement.

Tremfya blocks the action of a specific subunit on the IL-23 protein that plays an important role in colon inflammation in Crohn’s disease. It also inhibits a protein called CD-64 on immune cells, blocking them from producing IL-23 in the first place.

AbbVie’s Skyrizi and Lilly’s Omvoh block the same subunit on IL-23 but they don’t block CD-64.

Stelara inhibits a different IL-23 subunit and a second protein called IL-12.

The U.S. Food and Drug Administration approved Tremfya for treatment of moderately to severely active Crohn’s disease in March 2025. The drug had already been approved for treating inflammatory bowel disease, as well as psoriasis and related cases of arthritis.