title: Decreased reactivity to PPD among HTLV-I carriers in relation to virus and hematologic status.
abstract: Data on human T-cell lymphotropic-virus-type-I (HTLV-I) status and hematology from 528 individuals were analyzed for associations with low reactivity to the purified protein derivative (PPD) of Mycobacterium tuberculosis recall antigen. Subjects were classified as HTLV-I carriers with abnormal lymphocytes (Ably), carriers without Ably, and seronegatives. All carriers had a significant 2.6-fold risk of being low responders to PPD compared with the seronegatives, carriers with Ably having the highest relative risk. Carriers with HTLV-I-antibody titer > or = 1:256, or with other detectable markers of virus status such as antibody to tax and proviral DNA, had increased risk for low response to PPD similar to the estimate for HTLV-I seropositivity alone, compared with the seronegatives. Subjects with a low lymphocyte count had 3.5 times the risk for being low responders to PPD, compared with subjects with high counts. Similarly, subjects with a low monocyte count had 2.0 times the risk for low reactivity of those with a moderate to high count. Results were not confounded by age, sex, smoking or alcohol drinking. Using multiple logistic regression, only HTLV-I seropositivity and low lymphocyte and monocyte counts were predictive of low reactivity to PPD. Analysis indicates that suppression of delayed-type hypersensitivity is associated with HTLV-I infection per se, and not with viral replication or load. Furthermore, this effect may occur in part via changes in the number and function of lymphocytes and monocytes. Such a mechanism may involve altered cytokine production in carriers and concomitant changes in cell populations involved in delayed-type hypersensitivity.
authors.affiliation: Department of Epidemiology, Harvard School of Public Health, Boston, MA.
authors.forename: S L
authors.initials: SL
authors.lastname: Welles
authors.forename: N
authors.initials: N
authors.lastname: Tachibana
authors.forename: A
authors.initials: A
authors.lastname: Okayama
authors.forename: S
authors.initials: S
authors.lastname: Shioiri
authors.forename: S
authors.initials: S
authors.lastname: Ishihara
authors.forename: K
authors.initials: K
authors.lastname: Murai
authors.forename: N E
authors.initials: NE
authors.lastname: Mueller
mesh_terms: D002353:Carrier State / Q000097:blood* / Q000276:immunology*; D005260:Female; D015481:HTLV-I Antibodies / Q000097:blood; D015490:HTLV-I Infections / Q000097:blood* / Q000276:immunology*; D006801:Humans; D007958:Leukocyte Count; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D012016:Reference Values; D012044:Regression Analysis; D014374:Tuberculin Test
chemical_list: D015481:HTLV-I Antibodies