Earliest AIDS Case Is Called Into Doubt
Earliest AIDS Case Is Called Into Doubt
© New York Times 1995
WHAT was believed to be the earliest known case of AIDS, dating to 1959, may not have been AIDS after all, new scientific evidence shows.
The case of David Carr, a 25-year-old man who died in 1959 in Manchester, England, has taken another perplexing twist.
Mr. Carr's mysterious symptoms, which were so extraordinary that his doctors wrote up his case in 1960 in an international medical journal, The Lancet, and saved many samples from his organs, were identified in 1990 as resulting from AIDS. This made Mr. Carr's the earliest well-documented case of AIDS and promised to help establish the history of the epidemic.
The AIDS epidemic was first recognized in 1981, in the United States. But it was not until 1990 that two University of Manchester doctors, George Williams and Gerald Corbitt, were able to use the then-new polymerase chain reaction technique to analyze Mr. Carr's stored tissues for H.I.V., the virus that causes AIDS. The P.C.R. technique amplifies tiny bits of DNA hundreds of times in a few minutes. Identifying part of the sequence of H.I.V. in the DNA extracted from the tissue cells, they reported, again in The Lancet, that Mr. Carr's strange malady was AIDS.
The dating of the Manchester AIDS case had several nonscientific consequences. It appeared to give the lie to a theory being put about by the Soviet K.G.B. that H.I.V. had escaped from an American germ warfare laboratory. Its early date seemed to contradict a theory advanced in Rolling Stone that AIDS originated in the polio vaccines tested in Africa in the late 1950's. And the case could be cited as evidence that AIDS was abroad in the Western world well before the epidemic appeared among gay men in the United States.
The find had scientific value as well, in that it would allow researchers to assess the pattern of evolution of the fast-mutating organism, by comparing the 1959 strain with current strains. In such work, scientists use computers to construct phylogenetic, or family, trees comparing various strains of H.I.V.
"That is why we went after it so hard," said Dr. David Ho, who decided to analyze the virus sequence in further detail. Dr. Ho heads the Aaron Diamond AIDS Research Center in New York City and was a member of a panel that refuted the polio vaccine theory in 1992. He wrote to Dr. Corbitt in July 1992 to ask for samples of Mr. Carr's stored tissues, and later he asked Dr. Williams for more.
But to Dr. Ho's amazement, he could isolate H.I.V. from only one sample that the British researchers sent him, and the genetic map made of the virus's fingerprints differed so much from what he expected that he went on to do even more tests.
Most critically, the additional tests showed the tissues sent to Dr. Ho were from at least two people.
Something is badly wrong with the Manchester results, in Dr. Ho's view, but whatever it is, there is no longer any proof that Mr. Carr died of AIDS.
University of Manchester officials strongly reject Dr. Ho's findings. Prof. James Burnie, a professor of bacteriology at the university who was not an author of the 1990 report, said in a statement:
"There is no doubt the original findings as reported in The Lancet in July 1990 were correct. We have already carried out an informal inquiry which has validated this."
But the university is planning further investigations, the statement said, and in a brief interview, Professor Burnie said, "The issue is not anywhere near dead."
Dr. Ho is sure of his findings, which are to be published soon in Nature. Details of his work were described in The Independent of London last month.
In the first set of material, Dr. Ho found H.I.V.-1, the dominant type of AIDS virus in the world, in DNA extracted from Mr. Carr's kidney. But although he found no virus in DNA from the bone marrow, he passed over the finding because his focus was on identifying the molecular sequences and comparing them to those found in Manchester.
"They matched up, and we were happy with that," Dr. Ho said.
It was only after Dr. Ho and his assistant, Dr. Tuofu Zhu, achieved their main goal, a genetic map of the virus from the samples provided by Dr. Corbitt, that he began to notice puzzling findings. The 1959 strain, he found, bore a close resemblance to strains of H.I.V. isolated from contemporary patients.
"We couldn't make any sense of this," Dr. Ho said. So he sent the data to Dr. Gerald Myers, who runs an H.I.V. sequence data bank at the Los Alamos National Laboratory in New Mexico and to Dr. Eddie Holmes at Oxford University in England.
Dr. Myers and Dr. Holmes agreed that the strain was not consistent with what they would expect a 1959 virus to look like. "It was aberrant," Dr. Myers said in an interview.
H.I.V. mutates constantly. A strain dating from 1959 would be expected to look different from 1990 strains. But few such differences could be seen, Dr. Myers said.
Only a small group of experts knew about Dr. Ho's genetic map of the virus -- and only now is it being made available to scientists through the Los Alamos data bank. One of those who saw it earlier was Dr. Beatrice Hahn, an expert in the evolution of AIDS viruses at the University of Alabama in Birmingham, who urged Dr. Ho to dig harder.
Dr. Myers asked Dr. Ho if he was sure the virus he saw was not a contaminant from his own laboratory. Dr. Ho pointed out that the laboratory in Manchester had found the same sequence, meaning that "any contamination could not have occurred in our laboratory," he said.
"They got the same sequence in Manchester and Dr. Corbitt said the work was done in a laboratory that never processed H.I.V," Dr. Ho said.
"We wanted it to be true," Dr. Ho said, adding that he initially resisted Dr. Myers's skepticism. Valid findings would "mean that the virus had not changed much in 30 years, indicating the virus had been with us for centuries."
To resolve the issue, Dr. Ho's team needed to test the actual tissue, not repeat tests on the original shipment of DNA. So in November 1993 Dr. Ho asked Dr. Williams for more samples. Dr. Williams did not send them until February 1994.
Dr. Ho extracted DNA and used P.C.R. to isolate H.I.V. and similar viruses from each of seven tissues from different organs sent by Dr. Williams and four sent by Dr. Corbitt. But Dr. Ho's team could detect no virus after many attempts in any of the second batch of tissues. The tests did identify a globin gene present in all cells in both sets of samples, an indication that the tissue had not totally decayed.
"We had to conclude that we could not verify the initial results with the new set of tissues," Dr. Ho said.
To investigate the discrepancy, his team undertook forensic tests to identify genetic markers on both the original and the second shipment of material, Dr. Ho said.
There was no match. One explanation might have been that contamination had occurred when, say, a knife used to cut one specimen was not cleaned before use on a second specimen. But the British scientists said they had taken precautions to avoid such problems.
Only one explanation remained, Dr. Ho said: "We had to conclude that the material came not from one person but at least two individuals."
Dr. Ho's only isolation of H.I.V. was from a kidney DNA sample that appears to have been contaminated by another clinical specimen. "Whether that is an accident or something else we have no way of saying," Dr. Ho said.
Clearly, the findings "raise serious doubts about the authenticity of the 1959 case," Dr. Ho said.
Dr. Myers said that if all the tissues supplied in the second set are indeed shown to be tissues from Mr. Carr, as seems likely, "then he never had AIDS."
But AIDS is not completely eliminated because the techniques, as advanced as they are, may not be able to detect H.I.V. in tissue that has been stored for 35 years, Dr. Ho said.
"There are a lot of discrepancies that need to be explained," he said.
Dr. Ho said Dr. Corbitt had written him saying he wanted to be a co-author of a retraction of the 1990 Lancet report because the findings were invalidated by the latest tests. But Dr. Corbitt said he could not comment beyond the news release, as requested by his employer, the Central Manchester Healthcare Trust. Dr. Williams could not be located.
Dr. Ho said that it would take another scientific team several months to confirm or reject his findings, and that he was eager for such an effort to be made.
Dr. Robin Weiss, an AIDS virus expert at the Institute of Cancer Research in London, said in an interview that he had written to the University of Manchester offering to undertake the project.
Professor Burnie said the Manchester team was trying to decide which scientists would be acceptable to both sides to undertake confirmation studies. "It's very awkward," he said.
The Trust and University of Manchester have asked Dr. Ho to return the samples. Dr. Ho said he had agreed, though so much was used up in the testing that "we are looking at practically empty vials."
"The best thing would be to send the stuff directly to the independent scientist rather than sending it back to Manchester," Dr. Ho said. "The Manchester team could get new material and send it directly to that independent laboratory."
Mr. Carr's body was cremated, so there is no way to get new samples. But several scientists said his lung tissue, which is believed to be still stored in Manchester, could be re-examined for evidence of a fungus, Pneumocystis carinii, and the cytomegalovirus. Both were identified in the autopsy report. If the stored sample checks out as being Mr. Carr's, it could be tested for H.I.V.
There are many theories about the origins of AIDS. A prevailing belief is that H.I.V. was around for a long time and that on many occasions humans became infected when they killed monkeys or other primates for food. Because the infection took place in remote areas and the virus was not transmitted to anyone, or only to a few others, such cases would have gone undetected.
But, the theory holds, in the late 1950's as society became more mobile, transmission of the virus increased tremendously. Many people moved from remote areas to cities, practicing free sex and health workers used contaminated needles.
AIDS "either came from naturally infected chimpanzees or from a third species of monkeys that gave it independently to humans and chimps," said Dr. Hahn, an expert in the evolution of AIDS viruses.
But others believe H.I.V. resulted from a recent mutation of a formerly benign virus.
Another very early case of H.I.V. infection was in an individual in Zaire, who was part of a study conducted in 1959 for other purposes. Blood tests performed by four laboratories have found evidence of H.I.V.-1, said Dr. Andre J. Nahmias of Emory University who oversaw the testing, but no effort was made to isolate the virus.
Contrary to widespread belief, a small amount of that individual's blood does exist. It is in a freezer in Atlanta, Dr. Nahmias said in an interview. Because the techniques used in culturing and sequencing H.I.V. have been improving rapidly, Dr. Nahmias said he would not yield any of "the precious little serum in the vial" until he found the scientist who had the best method for such tests. If the sequencing is done, it could provide the information scientists had sought in Mr. Carr's case.
For now, the oldest documented case of AIDS from which H.I.V. has been sequenced is a 1976 case in Zaire, Dr. Myers said.