Karla Boos has been wanting to do Kevin Elyot's "Mouth to Mouth" since she saw the world premiere at the Royal Court Theatre in England nine years ago.

"I had an immediate reaction to it," Boos says. "I loved it, perhaps because its swings in tone felt true to life. That has made me want to do it ever since."

But, first, Boos' Quantum Theatre had to wait for its New York premiere ... and wait. The New Group Theatre in Manhattan, after taking it on and off of its schedule for several years, finally opened it in the fall.

"They believed there was big Broadway potential for this play," Boos says. "I didn't see it in New York, but it got a good review in The New York Times and then closed early. I think it was a victim of the economy."

New York's loss was Quantum's gain. Boos got the rights to "Mouth to Mouth" in December, just as its other January show was falling through, and now it opens at 121 7th Street in the Cultural District with Ronald Allan-Lindblom directing.

Told partly in flashbacks, "Mouth to Mouth" centers around a playwright struggling with AIDS, a pivotal moment in his past and his narcisssistic best friend.

"It's a play for middle-aged people, perhaps, about middle-aged people, behaving like lunatics," Boos writes in her press notes. "It's also stunningly about friendship, how we need each other. Most of all this real stuff comes to the audience through laughter, laughing at people who seem like someone you know -- oh yes, that would be YOURSELF. But it doesn't end with laughter; that would be too easy."

Boos appears on stage for the first time in three years as the playwright's aloof friend and mom of an only child, saying of the character, "You know how you get to a certain point in life where you're very self-involved and you don't see it?"

In fact, that Times review opened with the line, "Nobody really listens to anybody else in 'Mouth to Mouth' " before going on to say that "... Elyot also shares Chekhov's sense of life as a tragic comedy and conveys it through beautifully written, often funny encounters that throb with isolation and longing."

Joining Boos are John Shepard, Ken Bolden and Jeffrey Carpenter, actors all familiar to Quantum audiences. It's being produced in the Downtown office loft space where barebones staged "The Grey Zone."

"With the incredibly short time between getting the rights and first rehearsal, I was happy to have ANY space!," Boos says. "It's meant to be an urban, upscale loft, so it works really well for that actually."