Etiology
No
occupational
causes
or
geographic
predispositions
are
recognized
____________________
pulmonary
Langerhans
cell
histiocytosis
X
(
PLCH
)
.
People
with
PLCH
,
almost
invariably
,
are
____________________
smokers
.
Antigenic
stimulation
from
1
or
more
components
of
____________________
smoke
is
likely
responsible
for
the
disease
.
Because
only
a
few
tobacco
smokers
develop
the
disease
,
other
____________________
factors
,
such
as
host
genetics
and
environmental
exposures
,
most
likely
____________________
an
important
role
in
pathogenesis
.
Some
reports
in
____________________
literature
also
describe
PLCH
developing
following
____________________
and
/
or
chemotherapy
for
lymphoma
.
Additional
investigation
is
needed
to
____________________
our
understanding
of
this
disease
process
.
