The results of the human trial are consistent with what they found in mice. Potential therapies often don’t make the jump. Gendelman said that roughly 80 percent of what works in mice does not work in humans.

The study involved 20 Parkinson’s patients — 10 received the drug, 10 got a placebo. Neither the patients nor the researchers knew who was receiving the drug and who was not. The researchers also studied 17 people who did not have Parkinson’s, known as controls, for comparison.

The researchers followed the patients for six months — two months before starting treatment, two months on treatment and two months after treatment ended. Patients generally tolerated the drug well, although some had mild to moderate side effects.

The researchers saw increases in protective regulatory T cells in the blood of patients who received the drug. They did not see the same increases in those who got the placebo.

A research team headed by Tony Wilson, an associate professor of basic and translational research at UNMC, also recorded physiological improvements in specific motor areas of the brains of patients who received the drug using a brain-imaging technique called magnetoencephalography.