Scientists identify how gene mutation triggers immune disease

LOS ANGELES, Jan. 30 (Xinhua) -- U.S. scientists have identified how a gene mutation affects T cell function to promote immune disorders and then tested a treatment based on the discovery--successfully fixing donated immune cells from a 16-year-old boy with an abnormally low level of white blood cells called lymphopenia.

Immune system disorders lead to abnormally low immune activity (deficiency) or overactivity (autoimmunity). Immune deficiency diseases decrease the body's ability to fight infection, while autoimmunity prompts the body to attack its own tissues. Both are common causes of illness, and malfunctioning T cells are linked to both.

The discovery, detailed in a paper published on Tuesday in Nature Communications, centers on mutation of the gene known as GTPase of immunity-associated protein 5 (Gimap5), which is important to the healthy formation and function of CD4+ T cells, one of the immune system's super soldiers against infection and disease.

The protein associated with the Gimap5 gene, also Gimap5, is important because it regulates a protein that inactivates an enzyme called GSK3, researchers at the Cincinnati Children say in a news release.

"Our data suggest GSK3 inhibitors will improve T cell survival and function and may prevent or correct immune-related disorders in people with Gimap5 loss-of-function mutations," Kasper Hoebe, PhD, Division of Immunobiology, was quoted as saying in a statement. "Therapeutically targeting this pathway may be relevant for treating people with Gimap5 mutations linked to autoimmunity in Type 1 diabetes, systemic lupus erythematosus or asthma."

According to the study, if GSK3 isn't inactivated it causes DNA damage in T cells that are expanding, causing the cells to not survive or function correctly.

The team, led by Hoebe, also identified a 16-year-old human patient with lymphopenia, who carried a rare, homozygous Gimap5 mutation that resulted in a complete lack of Gimap5 protein.

In mice and human blood cells, the researchers tested drugs that inhibit GSK3, improving immune system function in mice and restoring normal T cell function in the human cells.

GSK3 inhibitors already are used to treat other diseases like Alzheimer's, mood disorders and diabetes mellitus.

Researchers said additional research is needed before the data have clinical relevance for patients. New experiments are underway to translate the findings into the clinic, said Hoebe. Enditem