Yelena Bonner, wife of dissident Soviet physicist Andrei Sakharov, emerged here today after 19 months of internal exile in the closed city of Gorki and soon left for medical treatment in Italy and later in the United States. She declined any comment about herself or her husband.

A handful of Soviet friends kissed and hugged her farewell at Moscow's Sheremetyevo airport, and later said they expected her to return in "several months."

Sakharov apparently remains in Gorki, a city off-limits to foreigners 250 miles east of here, where he was banished in 1980. When asked about Sakharov's health, which has been fragile, Bonner simply shrugged.

In a short airport statement to a crowd of reporters, Bonner, 62, said, "I made an agreement that if I would be allowed to return, I wouldn't have contact with correspondents, or give interviews or press conferences.

"Thank you for your attention and in general for your interest in our situation over the years," she said, rejecting a rush of journalists' questions. "But I want to return home and don't hinder me from that."

"She feels poorly," a friend said, motioning reporters away, "She's not well."

When Soviet authorities informed western officials four weeks ago that Bonner would be allowed to travel to the West, the unexpected move was widely greeted in the western community here as a gesture on the part of the Soviet leadership.

After watching Soviet customs agents carefully examine the contents of her luggage, Bonner waved a bouquet of red carnations, passed through the tight security controls, and boarded an Alitalia jetliner for Rome.

Bonner arrived in Rome accompanied by her son Alexei Semyono and son-in-law Yefrem Yankelevich, who had joined the flight at a stop in Milan. Walking out of the airport VIP section to face the cameras, Bonner said through an interpreter, "I'm very happy to be in Italy because I love Italy and the Italians . . . I beg all my friends here to excuse my silence," reported Loren Jenkins of The Washington Post.

[To the mob of reporters she repeated that "because I want to return to my country, I do not want to speak with the mass media." She is expected to go to the Tuscan city of Sienna Tuesday to enter an eye clinic, where she was treated twice in the 1970s.]

After treatment in Italy, Bonner is to fly to Boston for heart bypass surgery. Her daughter and son-in-law live in a Boston suburb.

Since May 1984, Soviet authorities had not allowed Bonner to leave Gorki, despite hunger strikes by Sakharov, who has pleaded with authorities to allow his wife to seek medical care abroad.

Sakharov, 64, a Noble Peace Prize laureate who campaigned with Bonner against alleged human rights abuses in the Soviet Union, was sent to Gorki in 1980 after denouncing the Soviet invasion of Afghanistan. The move was designed to keep him out of the reach of foreigners, Soviet officials have explained.

Thereafter, Bonner shuttled between Gorki and Moscow, funneling information about Sakharov to the dissident and western communities. In May 1984, Soviet authorities prevented her from traveling to Moscow, and the Soviet press accused her and Sakharov of preparing to mount an anti-Soviet campaign abroad.

In late October of this year, Soviet authorities leaked information to the western press that Bonner had received a visa to travel to the West. Western diplomats interpreted the move as a gesture to ease East-West tensions before the summit meeting of U.S. and Soviet leaders last month in Geneva.

Last week, Bonner returned to her Moscow apartment, but a round-the-clock militia guard at her apartment building barred western correspondents' access to her.

Today, Bonner appeared thinner than in photographs of her taken last year. She sat and watched as six customs officers carefully sifted through the clothes and paraphernalia she had packed into seven suitcases. The officers counted the U.S. dollars and Italian lira she had brought along, and checked the jars of caviar, children's books and Russian records in her luggage.

"You see," she said to a friend after the 25-minute search, "it was not so bad." Then she put on her brown coat and matching fur hat and dissappeared through the control station.