There are now more than 20 American patients who have the symptoms of Aids, with low white blood cell counts, but who repeatedly test negative for HIV-1 or HIV-2. Two cases have been reported from France and one in Edinburgh.
Scientists do not know whether a new virus or another form of HIV is responsible. Some believe that the illness is a rare form of an immuno-deficiency unrelated to Aids.
Two scientific papers which discuss these cases are now awaiting publication. One of the authors, Dr Jeffrey Laurance, of Cornell University, New York, refused to discuss the paper before publication.
Dr James Curran, leader of the Center for Disease Control's HIV/Aids Programme in Atlanta, said there was no firm evidence of a new type of HIV, or of any transmittable agents involved in these cases. But he urged doctors to report any more cases immediately. 'HIV causes Aids. Something else causes what we have heard about here; it may be a defective virus or not a virus at all.'
The CDC was forced to respond after an article, which appeared in Newsweek magazine, said that the Center was monitoring six of these cases. A meeting was called yesterday in Amsterdam, where the International Conference on Aids is being held, to discuss the implications of the report. Several more doctors came forward to report similar cases. Dr Graham Bird, of Edinburgh University, said he was treating one such patient. Dr Luc Montaigner, co- founder of HIV, said he had treated two patients. A defective form of HIV-1 had been isolated from the urine of one patient but was not present in their blood. He said it was unlikely that a new form of HIV was responsible.