title: Spontaneous cell proliferation is associated with poor sensitivity to glucocorticoids in patients infected with HTLV.
abstract: BACKGROUND
  Human T-cell lymphotropic viruses (HTLV)-I/II have a special tropism for infecting T cells and inducing spontaneous lymphocyte proliferation. Leukaemia and neurological manifestations are associated with HTLV-I/II infections, and treatment is usually based on anti-inflammatory drugs including glucocorticoids. Although steroid resistance has been reported, it is unknown whether this condition is related to the infection itself or to the treatment.
  
  
  OBJECTIVE
  We investigated whether spontaneous cell proliferation is associated with T-cell sensitivity to glucocorticoids.
  
  
  METHODS
  Twenty-eight HTLV-I/II patients and 11 healthy age-matched controls took part in this study. Lymphocytes were isolated and cultured in vitro to measure spontaneous and mitogen-induced proliferation as well as cellular sensitivity to dexamethasone.
  
  
  RESULTS
  Patients with HTLV-I/II infection showed similar stimulated and unstimulated T-cell proliferation as well as comparable sensitivity to dexamethasone in vitro. There were no group differences in the frequency of glucocorticoid responders versus non-responders. However, T cells of patients with spontaneous proliferation were unresponsive to mitogenic stimulation and were remarkably more resistant to dexamethasone than cells of patients with normal proliferation.
  
  
  CONCLUSIONS
  These data suggest that the poor clinical response to steroids may be associated with spontaneous cell proliferation during HTLV infection.
authors.affiliation: Instituto de Pesquisas Biomédicas, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, Brazil.
authors.forename: R P
authors.initials: RP
authors.lastname: Lopes
authors.forename: M
authors.initials: M
authors.lastname: Menna-Barreto
authors.forename: M E
authors.initials: ME
authors.lastname: Bauer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D049109:Cell Proliferation; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology*; D004351:Drug Resistance; D005260:Female; D005938:Glucocorticoids / Q000494:pharmacology*; D015490:HTLV-I Infections / Q000097:blood*; D015491:HTLV-II Infections / Q000097:blood*; D006801:Humans; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000187:drug effects* / Q000502:physiology / Q000821:virology
chemical_list: D005938:Glucocorticoids; D003907:Dexamethasone