title: Influence of HTLV-1 on the clinical, microbiologic and immunologic presentation of tuberculosis.
abstract: BACKGROUND
  HTLV-1 is associated with increased susceptibility to Mycobacterium tuberculosis infection and severity of tuberculosis. Although previous studies have shown that HTLV-1 infected individuals have a low frequency of positive tuberculin skin test (TST) and decreasing in lymphoproliferative responses compared to HTLV-1 uninfected persons, these studies were not performed in individuals with history of tuberculosis or evidence of M. tuberculosis infection. Therefore the reasons why HTLV-1 infection increases susceptibility to infection and severity of tuberculosis are not understood.The aim of this study was to evaluate how HTLV-1 may influence the clinical, bacteriologic and immunologic presentation of tuberculosis.
  
  
  METHODS
  The study prospectively enrolled and followed 13 new cases of tuberculosis associated with HTLV-1 (cases) and 25 patients with tuberculosis without HTLV-1 infection (controls). Clinical findings, bacterial load in the sputum, x-rays, immunological response and death were compared in the two groups.
  
  
  RESULTS
  There were no differences in the demographic, clinical and TST response between the two study groups. IFN-γ and TNF-α production was higher in unstimulated cultures of mononuclear cells of case than in control patients (p < 0.01). While there was no difference in IFN-γ production in PPD stimulated cultures, TNF-α levels were lower in cases than in controls (p = 0.01). There was no difference in the bacterial load among the groups but sputum smear microscopy results became negative faster in cases than in controls. Death only occurred in two co-infected patients.
  
  
  CONCLUSIONS
  While the increased susceptibility for tuberculosis infection in HTLV-1 infected subjects may be related to impairment in TNF-α production, the severity of tuberculosis in co-infected patients may be due to the enhancement of the Th1 inflammatory response, rather than in their decreased ability to control bacterial growth.
authors.affiliation: Serviço de Imunologia do Complexo Hospitalar Universitário Professor Edgard Santos, Universidade Federal da Bahia, Salvador, BA, Brazil.
authors.forename: Maria de Lourdes
authors.initials: Mde L
authors.lastname: Bastos
authors.forename: Silvane B
authors.initials: SB
authors.lastname: Santos
authors.forename: Anselmo
authors.initials: A
authors.lastname: Souza
authors.forename: Brooke
authors.initials: B
authors.lastname: Finkmoore
authors.forename: Ohana
authors.initials: O
authors.lastname: Bispo
authors.forename: Tasso
authors.initials: T
authors.lastname: Barreto
authors.forename: Ingrid
authors.initials: I
authors.lastname: Cardoso
authors.forename: Iana
authors.initials: I
authors.lastname: Bispo
authors.forename: Flávia
authors.initials: F
authors.lastname: Bastos
authors.forename: Daniele
authors.initials: D
authors.lastname: Pereira
authors.forename: Lee
authors.initials: L
authors.lastname: Riley
authors.forename: Edgar M
authors.initials: EM
authors.lastname: Carvalho
mesh_terms: D000293:Adolescent; D000328:Adult; D058491:Bacterial Load; D005260:Female; D015490:HTLV-I Infections / Q000150:complications*; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology* / Q000472:pathogenicity*; D011446:Prospective Studies; D013902:Radiography, Thoracic; D013183:Sputum / Q000382:microbiology; D016019:Survival Analysis; D018417:Th1 Cells / Q000276:immunology; D014376:Tuberculosis / Q000150:complications* / Q000276:immunology / Q000382:microbiology / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D055815:Young Adult
chemical_list: D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma