A Chicago Gay and Lesbian Hall of Fame inductee, Urso was best known in Chicago's LGBT community as a longtime medical coordinator with the Multi-Site AIDS Cohort Study (MACS), the world's largest and longest-running HIV study. Urso spent 17 years on the study, administering to hundreds of men both medically and emotionally.

"She was always the champion of lost causes," remembered John Weldt, who worked with Urso on the MACS.

A heterosexual nurse, Urso began working at HBHC in 1990, when stigma around AIDS was still thick and HIV-related deaths were many.

According to the Gay and Lesbian Hall of Fame website, "Urso recalled that, while being interviewed for the position, she was asked if she felt comfortable visiting the homes of gay men. A bit put off by the question, she replied that she had been very comfortable with gay men long before it was considered 'fashionable.'"

Danny Kopelson, a longtime LGBT activist and HIV fundraiser, befriended Urso when she started working for HBHC.

"Somehow, you just never expected to see an older straight woman in this position," Kopelson said.

Urso supervised exams. But her talents went beyond her medical duties. Many of her patients referred to her as her as their "second mother."

She regularly sent birthday cards to patients, sat with them in the waiting room and bickered with colleagues who she felt were not taking care of patients the way they should. When her patients became too ill to travel to HBHC, she visited them in their homes.

"Often, families learned their sons were gay and dying at the same time," said Kopelson. "Many stood by their sons' sides, and many did not. But Marilyn was always there."

Before going to work at HBHC, Urso owned Toy Gallery, a children's toy store in Old Town. Later in life, she owned Maple Leaf Park, a recreational area in Earlville, IL. In her spare time, she wrote screen plays and published a book of games.

But most in the LGBT community recall her dedication to those society marginalized and ostracized. Urso, they said, did not fear her patients or the virus they carried.

Colleagues remember Urso as a rebel, quick to embrace patients but equally quick to scold other healthcare providers who did not give the job their undivided attention.

Still, Kopelson credits Urso with a high retention rate of MACS volunteers. According to him, Urso wrote volunteers thank-you cards and went out of her way to make them feel important.

Urso left HBHC in 2007 but remained active in the community, consulting on HIV care.

"Over the years, I know one of the things that made Marilyn most happy was witnessing the development of new HIV medications and knowing that AIDS was no longer the same death sentence it once was," said Kopelson. "She witnessed the worst of AIDS and also how it developed into a more manageable virus."

In 2009, Urso was inducted as a "friend of the community" into the Gay and Lesbian Hall of Fame. The honor thrilled her, and she brought her family to the ceremony.

In November, Urso was diagnosed with lung cancer, within days of her sister Betty Murphy's diagnosis of cancer. The two sisters also died a few days apart.

Urso was secretive about her age, said Weldt. Not even her official obituary contains a birthday or age, but Weldt believes she was in her 80s.

A memorial service will not be held for Urso, per her request. According to her Chicago Tribune obituary, friends are asked to donate to a charity of their choice instead.