Regrets, countercharges mark fraud dispute.

Introducing yet another twist in an extraordinarily long-running probe of scientific fraud, Nobel laureate David Baltimore says he now regrets his vigorous defense of a coauthor on a 1986 paper published in CELL. The National Institutes of Health completed a report in March charging that the CELL paper contained false statements and that data used to support that paper's principal findings had been fabricated.

NIH's office of scientific integrity also found evidence that notebooks used to defend the disputed paper contained concocted data (SN: 3/30/91, p.196). The notebooks belonged to immunologist Thereza Imanishi-Kari, one of six authors on the now-disputed paper.

"I recognize that I may well have been blinded to the full implications of the mounting evidence [against my coauthor] by an excess of trust," says Baltimore, now president of Rockefeller University in New York City.

The challenged study described the indirect insertion of a foreign gene into the immune cells of mice. The authors claimed that the mouse's natural gene then began to mimic the inserted gene, producing a special antibody.

The specter of scientific misconduct arose when Margot O'Toole, a postdoctoral scientist working for Imanishi-Kari, discovered evidence in May 1986 that research notebooks did not support the CELL paper's conclusions.

Although Baltimore had previously dismissed O'Toole's allegations, he now lauds her courage in pursuing the case. In his new statement, obtained by SCIENCE NEWS last week, he says, "I regret and apologize to [O'Toole] for my failure to act vigorously enough in my investigation of her doubts."

Says O'Toole, "I appreciate Dr. Baltimore's words of praise for me, but his apology does not go to the heart of the question." Baltimore has stated he had no knowledge of false statements in the 1986 paper or of fabricated data in the lab notebooks. Yet on June 16, 1986, Imanishi-Kari told Baltimore that she had not obtained the results reported in their paper, according to O'Toole. "Dr. Baltimore told me that 'this kind of thing' was not unusual, and that he would take no corrective action," O'Toole recalls.

Indeed, the NIH report quoted Baltimore as saying: "In my mind, you can make up anything that you want in your notebooks..." Baltimore's new statement says that the earlier comment was not intended to condone fraud: "I wish to state unequivocally that I have never condoned falsity by a scientist."

Though Baltimore was not the subject of the initial NIH investigation, he may face additional questions as NIH probes a possible cover-up of the fraud.