Containing AIDS in Japan (Part 4)

ATL: An AIDS relative
endemic in Japan

By William Wetherall

This article was commissioned but not published by The Japan Times as Part 4 of a four part series on AIDS in Japan filed 25 March 1987.

Parts 1 and 2 were published, but Parts 3 and 4 were cancelled after a hemophilia patient support group called the editor and protested that the remarks made about hemophiliacs in Part 2 either were not true or were a matter of opinion, and should not have been published on the National page, which is a news page.

An expanded version of this part was later published on the Health page.
See AIDS relative endemic in Japan.

The knowledge that enabled the rapid discovery of the AIDS virus in 1983 by French researchers, and in 1984 by American researchers, largely came from Japanese and American efforts in the late 1970s and early 1980s to find the causes of an infectious cancer called ATL (adult T-cell leukemia) that is endemic to parts of Japan.

The disease begins when a virus called HTLV-1 (human T-cell lymphotropic virus) attacks white blood cells, known as T lymphocytes, and causes them to proliferate malignantly.

Just the opposite occurs in AIDS. The AIDS virus kills T4 white blood cells, which are crucial to the immune system. As the immune system is disabled, the body becomes vulnerable to other infections.

ATL is endemic in several parts of Japan, in Haiti and Jamaica in the Caribbean, and possibly in New Guinea. It is common in the north of South America, which faces the Caribbean, and in parts of Africa. And some cases are known in most other areas where data is available.

Statistics on ATL incidence are confusing. Most reports claim that about one million people in Japan are carrying the virus. One says that carriers are increasing at the rate of 40,000 each year. A second states that each year 200 or 300 people develop symptoms, and a third observes that one in 2,000 carriers are stricken every year.

Once the malignancy begins, death comes quickly. The course of the disease can run from one month to over six years. One report puts the median survival from time of diagnosis to death at 4.4 months. This means that 50% of all patients die within five months. Practically all of the rest die within two years.

Like the AIDS virus, the ATL virus is spread primarily through blood, intimate contact, and congenital infection--in other words, contaminated blood transfusions, needle sharing by drug addicts, homosexual or heterosexual contact, infection in the womb of mothers who harbor the virus, and milk from an infected mother's breast.

There are also indications that the ATL virus can be carried by mosquitoes. Not coincidentally, an article in a recent issue of the American journal Futurist forecast that by December 1989, it will be discovered that AIDS can be spread by mosquitoes.

In Japan, the main route of infection may be from mother to child during breast feeding, but also from husband to wife over the years of their sexual relationship. The latency period is long--40 or more years--and most patients are between the ages of 40 and 60.

In order to prevent the spread of this infectious cancer, Japan began to screen all blood for the presence of ATL (HTLV-1) antibodies in November 1986, along with screening for AIDS antibodies. And female ATL carries are being counseled not to breast feed.

Earliest reports described ATL as endemic mainly in Kyushu and Okinawa. On the basis of these, Robert Gallo, at the National Cancer Institute in the United States, suggested that 16th-century Portuguese traders may have brought the ALT virus to Japan in their African slaves or monkeys. (Scientific American, December 1986)

Kyoto University virologist Hinuma Yorio thinks differently. Hinuma reports that about 8% of the populations of Kyushu and Okinawa are carriers of the ATL virus, compared with from 0.3% to 1.2% for the rest of Japan. From Hokkaido to Okinawa, the rates are highest for isolated coastal areas and remote islands, not cities.

Relatively high rates of ATL are found in the region west of the Hidaka range in Hokkaido (apparently among Ainu Japanese); the Sanriku coast of Iwate; Tobishima off the coast of Yamagata; the Oki islands off Shimane; the tip of Kii peninsula in Wakayama; Muroto and Ashizuri points in Kochi; Uwajima in Ehime; Iki and Tsushima islands in the Korean straits; the Goto islands near Nagasaki; and Okinawa.

Neighboring Korea and China seem to have very few ATL carriers.

Hinuma speculates that Japan was first occupied by "native old mongoloid carriers", whose gene pools became diluted about two millennia ago by the continental "Yamato new mongoloid non-carriers" who came to Japan via Korea and settled primarily in the interior of Honshu, centering on Nara and Kyoto. (Chuo Koron, March 1986)

Studies comparing the immunological traits of dogs, field mice, and people in Japan and the rest of Asia, seem to support the theory that Central Asians recently settled in the heart of Japan, and that even today, genetic mixture is less complete to the south and north.

In 1985, Hinuma shared a major cancer award with Gallo and compatriot researchers Miyoshi Isao and Takatsuki Kiyoshi. Takatsuki was the first to describe ATL, then known as Takatsuki disease, later called new leukemia. Miyoshi was the first to culture ATL cells, and Hinuma further described the ATL virus, which Gallo had discovered and named in 1978. (Bungei Shunju, special issue, April 1987)