Evening star., 1951-08-15
FiIterubIe Virus Isolated
In Fight on Leukemio
Discovery Opens New Approach
To Study of Blood Concer'
By Thomas R. Henry

A fllterable virus which appears to
be an antagonist to leukemia, among
the most invariably fatal of human
diseases, has been isolated by workers
at the National Cancer Institute here.
The discovery opens a new approach
to this malignant disease, which is es-
sentially cancer of the blood" char
acterized by enormous increase in GER
tain types Of white blood strains.
The virus is quite close to the great
family of microscopically invisible or
ganismS, most minute of living things.
which themselves are responsible for
some of the most deadly diseases.
Pathologists at the National Institute
of Health believe that it is similar.
although not identical, with the virus
which causes lymphocytic choreomenin-
gifts, human malady first discovered
about ten years ago which is bacterial
meningitis in It's course but is seldom
fatal.
This new virus was isolated from the
blood OF strain of mice in which leu
kemla is always present. It is highly
probable, however, that it exists in ma
ture independent of leukemia cells.
Lasting Changes Noted.
When injected into mice this virus
causes a severe illness. The disease.
however, seldom proves fatal. With the
mildest strain yet found it is not fatal,
but certain lasting changes are found
IN various bodily organs. 1t is, pri-
marily, killer of blood cells especially
white blood cells which are the major
factor in leukemia. 1t appears to kill
more leukemia than normal cells, pre-
sumably because there are more of
them.
Curiously enough, when the virus ia
injected into mice infected with leu
kenia these mice debut apparently
not of leukemia When the animals are
inoculated with both leukemia cells and
the virus. autopsy shows very little evi-
dence OF leukemia, per sc. Death, how
ever, apparently has been due to a
combination Of the two agents.
The findings are reported by Drs. L.
w. Law and Thelma B. Dunn Of the Ma
tional Cancer Institute staff. They are
cautious in their conclusions because
obviously the virus in its present form
cannot be considered as a treatment
of leukemia. 1t is about in the status,
as are various other cancer treatments
which have been tried. of curing the
disease but killing the patient
A curious fact is that the leukemia-
virus inoculated mice live for longer
or shorter periods than would be ex-
pected for animals infected with leu
kemia alone according to the method of
incubation. When the incubation is
sub-cutaneous. or under the skin. life
is considerably prolonged. When in
traperitoneal inoculations are made.
they mean length of life is considerably
reduced.
Implications Are Vague.
Possible implications for human
leukemla victims are vague. The virus
has been found only in one breed Of mice
and only in few of these. The dis
covery, in fact, was largely matter Of
good luck, according to DR.. Law. There
is no evidence that it would cause any
reaction whatsoever in any other animal,
or in human being. Any experiments
with it naturally would be extremely
dangerous.
The malady caused in mice by the
virus alone is serious. There is a weight
loss of at least ten per cent. The animals
become sluggish and breathing is
crease in the number of white blood
cells, as would be expected following q
severe infection.
AS with other viruses, one inocula-
tion apparently provides immunity for
life.
The idea of fighting leukemia-or, for
that matter, other forms of cancer
is not new, it is explained, but none
up to date have met with success. This
particular virus. however, seems to have
an intimate. if not actually direct, as
sociation with the leukemia itself. It
may even be new kind of organism on
earth, for according to some theories
virus types are coming into existence
constantly, but few survive competition.
At present intensive study of the new
organism is being conducted by Ma
tional Institute of Health workers in
order to establish, so far as possible, its
relationships and behavior.