Rare Leukemia Tentatively Traced to Virus Related to Cause of AIDS
A UCLA researcher has demonstrated for the first time that a rare form of leukemia is probably caused by a virus that is a close relative of the virus that causes AIDS.
The finding is potentially important because the virus has been found to have infected a significant percentage of intravenous drug users in New York City, one of the groups that is at high risk of contracting acquired immune deficiency syndrome.
For the record:
12:00 a.m. March 6, 1987 For the Record
Los Angeles Times Friday March 6, 1987 Home Edition Part 1 Page 2 Column 1 Metro Desk 3 inches; 79 words Type of Material: Correction
In a story that appeared on Feb. 17 reporting that a rare form of leukemia had been tentatively traced to a specific virus, it was incorrectly reported that hairy cell leukemia usually results in death within about six months after diagnosis. Actually, victims of this form of leukemia may survive for 10 years or more. The story also described the virus linked to the leukemia as “a close relative of the virus that causes AIDS.” There is division within the medical community about how close a relationship exists between the suspected leukemia virus and the AIDS virus.
Many of those who have been infected by the virus are at risk of developing leukemia, molecular virologist Irvin S. Y. Chen said here at a meeting of the American Assn. for the Advancement of Science.
Chen said he fears that the virus will have the same potential to spread through the general population as the AIDS virus.
The virus in question is called human tumor leukemia virus-II or HTLV-II. A related virus, HTLV-I, has been shown to cause leukemia by virologist Robert Gallo of the National Cancer Institute and by investigators in Japan. HTLV-I is relatively common in Japan and rare in the United States.
A third member of the family, which Gallo discovered and named HTLV-III but which is more commonly known as the human immunodeficiency virus or HIV, causes AIDS.
Chen and Joseph Rosenblatt of UCLA isolated HTLV-II from two patients with a rare form of leukemia called hairy cell leukemia, so named because the affected white blood cells have hair-like appendages around their circumferences. Hairy cell leukemia, which usually results in death within about six months after diagnosis, is a disease of a class of white blood cells called B-cells. Its cause is unknown.
The two UCLA patients had an even rarer form of hairy cell leukemia in which white cells known as T-cells are affected. This form, Chen said, is “relatively benign,” and the patients survive much longer.
One of the two patients from which the virus was isolated contracted the disease in 1976 and is still alive. The second patient contracted the disease in 1984 and since has died.
Very little is known about the extent of human exposure to HTLV-II, Chen said. The virus is spread in the same fashion as the AIDS virus, through sexual intercourse, sharing of needles and blood transfusions. Because the virus does not survive outside living cells, however, it is not found in the blood concentrates given to hemophiliacs to stop bleeding.
In a recent study of intravenous drug abusers in New York City, Chen said, it was found that 16% had antibodies to the virus. An earlier study in England showed a 5% incidence among intravenous drug abusers.
‘Surprising’ Incidence
Chen said the high incidence of the virus in New York City addicts is “surprising.” This group also has the highest exposure to the AIDS virus, however; more than half the New York drug addicts have been exposed to HIV.
No studies of the incidence of HTLV-II have been performed in California. Chen noted, however, that the incidence of infection among intravenous drug users is probably lower than in New York City because the incidence of exposure to HIV is lower--about 16% in San Francisco and only 2% in Los Angeles.
