Pulmonary involvement in patients with HTLV-I-associated myelopathy: increased soluble IL-2 receptors in bronchoalveolar lavage fluid.
A chronic spastic myelopathy associated with HTLV-I infection (HTLV-I-associated myelopathy: HAM) shows subclinical pulmonary involvement with bronchoalveolar T lymphocytosis. In the present study, we investigated 18 patients with HAM: five HTLV-I carriers without myelopathy and 13 normal control subjects seronegative for HTLV-I to determine if soluble IL-2 receptors (IL-2R), a marker of lymphocyte activation, were increased in serum and bronchoalveolar lavage (BAL) fluid from HAM patients. Serum IL-2R levels were significantly increased in patients with HAM as compared to normal control subjects (HAM versus control subjects: 633 +/- 395 versus 278 +/- 53 U/ml, p less than 0.01). There was also an increase of serum IL-2R levels in one of five HTLV-I carriers. BAL levels of soluble IL-2R were low but detectable in four normal control subjects and in one HTLV-I carrier. In HAM patients, however, soluble IL-2R levels in BAL fluid were remarkably elevated (173 +/- 110 U/mg of albumin) and were nearly 13 times higher on average than in serum (BAL fluid/serum ratio: 13 +/- 10). In patients with HAM, lavage IL-2R levels correlated well with the number of T lymphocytes (CD3+ cells) and CD4+ cells in BAL fluid (p less than 0.01). Furthermore, BAL lymphocytes obtained from HAM patients synthesized DNA spontaneously when cultured in vitro. These results suggest that, in HAM, T lymphocytes increased in the lung are activated locally to produce soluble IL-2R. Based on the results of this study, we conclude that immunologic mechanism(s) may play an important role in the development of pulmonary lesions in HAM patients.
Sugimoto
M
M
First Department of Internal Medicine, Kumamoto University Medical School, Japan.
Nakashima
H
H
Matsumoto
M
M
Uyama
E
E
Ando
M
M
Araki
S
S
D000328:Adult; D000368:Aged; D001992:Bronchoalveolar Lavage Fluid / Q000032:analysis*; D002353:Carrier State / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D005260:Female; D015490:HTLV-I Infections / Q000378:metabolism; D015368:Human T-lymphotropic virus 1; D006801:Humans; D008171:Lung Diseases / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D008214:Lymphocytes / Q000145:classification / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015493:Paraparesis, Tropical Spastic / Q000150:complications*; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D012995:Solubility; D013601:T-Lymphocytes / Q000473:pathology
D015375:Receptors, Interleukin-2; D004247:DNA