Czechoslovak Ambassador Rita Klimova's own personal "Prague Spring" came one day this winter when, after her second round of chemotherapy for acute leukemia, doctors at Johns Hopkins sent her home for good. Less than a year ago, they had held out little hope.

"I had about five or six weeks to live," Klimova said yesterday at a White House reception for the Leukemia Society of America. "And I'm in complete remission now. I got wonderful treatment at Johns Hopkins. It was, in part -- I don't understand the details -- paid for by the Leukemia Society."

Standing beside her as she talked to reporters was the society's national honorary chairman and host of the party. "It couldn't have happened 20 years ago, you know," said First Lady Barbara Bush. "That's the Leukemia Society."

Klimova's bout with the disease came a few months after she arrived in the United States to take up her post as ambassador. After doctors at Walter Reed diagnosed "smoldering leukemia," she struggled to decide whether to return home, where the disease is "not treatable," a spokesman for her said yesterday, or stay in Washington. As Klimova, 58, put it at the time, her decision was a financial one and depended on whether she could find treatment that "fits into someone's research plans."

"Theoretically," she said then, "I should have gone home immediately because of the hospital bills" at Arlington Hospital, where she was initially treated. When Burton Lee, President Bush's White House doctor, learned of her illness, he arranged for her to be admitted to Walter Reed. She said later she was "grateful that decision-making was taken off my shoulders."

Looking extremely fit yesterday, Klimova said she will return to Hopkins for a six-month checkup, then, after that, once a year. Mrs. Bush, whose association with the society is longstanding, said leukemia research had made "exciting" strides since her own daughter, Robin, 3, died of juvenile leukemia in 1953.

Though childhood leukemia still takes the lives of more children between the ages of 3 and 14 than any other disease, about seven out of every 10 victims are now cured, according to the society, which recently formed a new foundation to raise research funds for pediatric leukemia.