Human T lymphotropic virus type I-associated myelopathy. A report of 10 patients born in the United States
W. A. Sheremata, J. R. Berger, W. J. Harrington Jr, D. R. Ayyar, M. Stafford and E. DeFreitas
Department of Neurology, University of Miami/Jackson, Fla. 33101.
Human T lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM)
(tropical spastic paraparesis/HAM) has rarely been reported in the United
States. We present 10 well-documented cases with positive Western
immunoblot test results and polymerase chain reactions for HTLV-I. The
clinical and laboratory features of these American-born patients resemble
those previously reported series of tropical spastic paraparesis and HAM
from the Caribbean and Japan, but important differences were observed. In
our study there were equal numbers of whites and blacks and of men and
women. Age at onset was younger than that reported from the Caribbean and
Japan. Rate of progression to paraparesis varied but was more rapid than
previously reported. Half were transfusion recipients but six had multiple
sexual partners, with one regularly interacting with prostitutes and
reporting a history of drug abuse. Although more rapid progression was seen
in the transfusion recipients, this did not explain the earlier age of
onset in this group of patients. The HTLV-I, and the associated myelopathy,
are endemic in Florida, suggesting that immigration from, and proximity, to
the Caribbean basin are contributing risk factors.
