Influence of human T lymphotropic virus type I infection on the etiology of community-acquired pneumonia.
BACKGROUND
Human T lymphotropic virus type I (HTLV-I), the cause of human T cell leukemia, is associated with a high incidence of several other infectious diseases. However, the relationship between pulmonary infections and HTLV-I infection is still unclear.


OBJECTIVE
A large-scale retrospective study was conducted on hospital inpatients to evaluate the relationship between community-acquired pneumonia (CAP) and HTLV-I infection.


METHODS
The present study included 4,666 hospitalized patients during 1991-2007. Three hundred and thirteen of them were diagnosed as CAP. The presence of serum HTLV-I antibody was determined in all patients on admission. Prevalence of HTLV-I infection was analyzed between CAP patients and all inpatients. We also compared HTLV-I-positive CAP patients and HTLV-I-negative CAP patients for severity and manifestation of pneumonia.


RESULTS
The prevalence of HTLV-I was higher in CAP patients than in all inpatients (18.9%: 13.7%, p=0.011). The rates of renal diseases and collagen vascular disorders were higher in the HTLV-I-positive CAP patients than in the HTLV-I-negative CAP patients. Multivariate analysis revealed that HTLV-I infection, gender, COPD and collagen vascular disorders were all independent risk factors for CAP. The severity indices of CAP, the PORT score and the CURB-65 score, were higher in the HTLV-I-positive patients than in the HTLV-I-negative patients.


CONCLUSIONS
This study demonstrates that HTLV-I infection might be an independent risk factor for CAP and that HTLV-I-infected patients tend to demonstrate a relatively severe form of pneumonia.
Atsumi
Eriko
E
Department of Medicine and Therapeutics, Control and Prevention of Infectious Diseases, Faculty of Medicine, University of the Ryukyus, Okinawa. eriko-a@sj8.so-net.ne.jp
Yara
Satomi
S
Higa
Futoshi
F
Hirata
Tetsuo
T
Haranaga
Shusaku
S
Tateyama
Masao
M
Fujita
Jiro
J
D000328:Adult; D000368:Aged; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology; D005260:Female; D015481:HTLV-I Antibodies / Q000097:blood; D015490:HTLV-I Infections / Q000150:complications*; D015368:Human T-lymphotropic virus 1; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011014:Pneumonia / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index
D015481:HTLV-I Antibodies