New York Times looks at Hamilton's chimera defense

nytimes.com (free reg. required) | Cheating, or an Early Mingling of the Blood?

New York Times health and fitness reporter Gina Kolata talks to some researchers who lend at least some credence to Tyler Hamilton's defense, and interviews the MIT professor, David Housman, who assisted in Hamilton's defense. Housman, a molecular biology professor, believes that chimerism could cause a person to produce non-matching red blood cells off and on through their life, which could possibly account for the inconsistencies in Hamilton's blood tests through the 2004 season. He also professes doubt that the test is sufficiently reliable.

A Seattle hematologic oncologist, who routinely performs flow cytometer measurements, called the test "quite finicky from experiment to experiment."

Kolata also talks to Ross Brown, the Australian scientist who helped develop the test in question, and defended the test in Hamilton's hearing before the US Anti-Doping Agency. Brown admitted that chimerism is a possibility, but that in 20,000 samples, he had never seen a convincing sign of a chimera in blood.

But Dr. Ann Reed of the Mayo Clinic says that 50 to 70 percent of healthy people are actually surviving twins of chimera. Rather than blood testing, she tests against DNA. Her opinion explains somewhat more fully why Hamilton and his advisers wanted to do DNA testing on the tested samples.

Reed also suggested that chimerism might explain some organ rejections that are otherwise unexplained.

Kolata wrote a book, Ultimate Fitness: The Quest for Truth about Exercise and Health, that I enjoyed, although I found it a tad unfocused.