After the first week of a hearing into the claims of nearly 5,000 autistic children, the case of a tragically ill Arizona girl seemed to hinge on the legitimacy of an Irish laboratory's findings of measles virus fragments in the girl's GI tract.
Michelle Cedillo's complaint was framed, at the start, as a test case for the theory that two kinds of vaccines, one containing a weakened measles virus and the other the mercury-based preservative thimerosal, combined to cause autism in a subset of the thousands of children whose cases have been brought before the court.
The defense did not present a single expert on autism. On Monday, an experienced heavy metals toxicologist named H. Vasken Aposhian presented a theory of how thimerosal could have damaged the girl's immune system in a way that set her up for autism.
But none of Cedillo's other witnesses had much specialized knowledge in mercury or other metals, and the focus quickly shifted to the theory that the attenuated measles virus had created a persistent infection in her gut, causing a severe inflammation that resulted in brain damage and other injuries.
In order to win their case, it seems likely that Cedillos will have to convince the three special masters -- the judges, in effect, in the special "vaccine court" at the U.S. Court of Claims -- of the reliability of the witnesses' account that measles RNA was detected in her bowel and cerebrospinal fluid.
A biopsy from Cedillo's GI tract was sent in 2003 to Unigenetics, an Irish laboratory headed by Dr. John O'Leary, which reported finding the RNA. O'Leary and his colleagues had published a paper a year earlier that disclosed the discovery of measles RNA in the guts of several autistic children.
The lab also was said to have found evidence of measles in spinal taps of autistic children, but those results were never published. Last year, two journal articles reported an inability to replicate the O'Leary lab's findings. There was also a negative turn of events for the MMR/vaccine damage claimants in the British vaccine court. In that court, the government pays for families to sue, but will only continue the funding when it believes the chance of success is greater than 50 percent. After an expert report commissioned by the British court found problems in Unigenetics' testing of the samples, all but two of the British cases were defunded.
In testimony that followed Aposhian this past week, five additional witnesses for Cedillo expressed full support for the Unigenetics findings. Those witnesses were gastroenterologist Arthur Krigsman, molecular biologist Karin Hepner, immunologist Vera Byers, virus immunologist Ronald C. Kennedy and Marcel Kinsbourne, a pediatric neurologist who has testified in vaccine court hundreds of times.
The defendant (called the respondent in vaccine court) in this case is the Department of Health and Human Services, which for the past 18 years has assumed responsibility for compensating the families of children damaged by vaccines. The Department of Justice represents HHS in the courtroom.
The Justice lawyers picked at the expertise of the witnesses and their source articles. They pointed out discrepancies in Dr. Byers' resume and problems Dr. Krigsman has had with the Texas medical board. However, they made little effort to refute Unigenetics' findings. It seemed clear, however, that that job would be left to some of the 12 respondent witnesses who are scheduled to testify next week.
The Cedillo family's argument for how vaccines hurt their child was presented most efficiently by Kennedy, a virus immunologist at Texas Tech University. He posited that the 112.5 millionths of a gram of thimerosal contained in six vaccines administered to Michelle during her first seven months of life had damaged her immune system. When she received an MMR vaccine at 16 months, shortly before Christmas 1995, the weakened vaccine virus lodged in her gut, causing an inflamed bowel and eventually damaging her brain.
Michelle is very ill. In addition to her autism she suffers from inflammatory bowel disease, a seizure disorder and chronic eye inflammations that have left her 90 percent blind. She was pushed into the courtroom in a wheelchair because arthritis has left her unsteady on her feet, her mother testified.
But the theory that vaccines caused all this pain and suffering is shaping up as a very hard sell.
According to testimony in the trial, Michelle was a healthy baby prior to receiving the MMR vaccine. If the thimerosal she received had damaged her immune system prior to that, there were no manifestations of it. Michelle's parents first brought the case, in 1998, with a theory of damage from MMR. Thimerosal was tacked onto the claim, one of her attorneys said, after news accounts in 1999 of the Centers for Disease Control's request that the drug industry stop selling vaccines containing the preservative.
Perhaps one in 500,000 children who receives the MMR vaccination suffers a severe brain inflammation that can lead to lifelong mental disability -- presumably including autism. The vaccine court has awarded several dozen such children over the past two decades. Michelle's parents might have brought their claim under this theory; according to her mother's testimony and medical records, she suffered an intermittent high fever, up to 106 degrees, and severe diarrhea following the shot.
However, before it agrees to compensate children for a so-called MMR encephalopathy, the court generally requires evidence that the child lost consciousness for an extended period following the shot. Michelle does not seem to have had a seizure or loss of consciousness. Though concerned about the fever, her mother did not bring Michelle to the doctor until 10 days after it first spiked.
According to Mrs. Cedillo's testimony, her daughter became less responsive and stopped talking during that acute illness. In a heartbreaking home video shot in mid-February 1996 that was projected in the courtroom, Michelle is seen sitting in a toy caboose, flapping her arms. She ignores the entreaties of her mother and grandfather. A year later, she was diagnosed with autism.
Aposhian, who has more than 100 publications on heavy metal poisoning to his name, is hard of hearing and was obstreperous at times during his cross-examination on Monday. For example, he insisted that in vitro studies were nearly always reproducible in animals, and that animal studies were nearly always reliable models for human effects. This is not a belief to which most toxicologists would subscribe.
Also under cross-examination, Aposhian said that he was not an immunologist and that he had composed his theory of thimerosal-induced immunological damage "three or four weeks ago."
When Matanoski tried to get Aposhian to acknowledge that most if not all cases of clinical mercury poisoning in the past had involved doses hundreds or thousands of times higher than what was administered to children in vaccines, Aposhian insisted that dose was not necessarily important.
"[Toxicologists] no longer believe that the dose makes the poison," he said. Far more important was the developmental stage of the child when the mercury was administered, and his or her genetic susceptibility.
During the mid- to late-1990s, some children received nearly three times as much thimerosal in their vaccinations than did children a generation earlier. The cumulative amount surpassed EPA guidelines, according to some interpretations.
Interestingly, though, because she received some of her immunizations in combined shots, the total thimerosal injected into Michelle Cedillo was only about 40 millionths of a gram more than a child would have received 30 years ago, well before the supposed "autism epidemic" began.
The findings of half a dozen epidemiological studies that have showed no link between thimerosal administration and autism diagnosis do not necessarily count for much in this courtroom. Nor do data that show autism diagnoses continue to grow in California in cohorts of children who got little or not thimerosal in their vaccines.
But Aposhian's theory of harm, based largely on in vitro and animal studies of mercury, seems very thin. Next week's panel of experts, which includes two autism doctors, two pediatric neurologists and experts in all the other relevant fields, will certainly have much to say about it.