Avaliação da função neutrofílica em indivíduos infectados pelo HTLV-I. / Evaluation of the neutophil function in HTLV-I Infected individuals.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Human T-cell lymphotropic virus-type I (HTLV-I) induces activation and spontaneous proliferation of T cells with production of type-I pro-inflammatory cytokines (IFN-γ and TNF-α). However, little is known about the innate immune response in HTLV-I infection. HTLV-I infected individuals have higher spontaneous neutrophil activation than HTLV-I seronegative individuals, as shown by the Nitroblue tetrazolium (NBT) assay. The spontaneous production of cytokines in vivo may activate neutrophils, cells involved in defense against bacteria, viruses, fungi and protozoa. The objective of this study is to evaluate neutrophil function in HTLV-I infected individuals. The ability of neutrophils (PMNs) isolated from the peripheral blood to express activation markers (CD62L and CD66b), to produce peroxynitrite (ONOO-) involved in the microbicidal activity and to secrete chemokines (CXCL8 and CCL4) involved in the in recruitment of leukocytes were measured in cells cultures unstimulated and stimulated with LPS or Leishmania amazonensis promastigotes (an intracellular pathogen model). In addition, the ability of neutrophils to control L. amazonensis infection was evaluated. In this study, 18 HTLV-I infected individuals and 14 HTLV-I seronegative individuals were evaluated. The unstimulated neutrophils from HTLV-I infected individuals tended to be more activated than neutrophils from HTLV-I seronegative individuals (p=0,07), as demonstrated by loss of CD62L. The stimulation of the neutrophils from HTLV-I infected individuals and from HTLV-I seronegative individuals with LPS or L. amazonensis led to cellular activation, but no difference was showed between the two groups. After stimulation with LPS, a trend the higher percentage of ONOO- positive neutrophils was observed in HTLV-I infected individuals when compared with the HTLV-I seronegative individuals(p=0,07). The percentage of ONOO- positive neutrophils in cultures unstimulated and stimulated with L. amazonensis wasnt different between the groups studied. The levels of CXCL8 and CCL4 released by neutrophils unstimulated and stimulated with LPS or L. amazonensis did not show a difference between HTLV-I infected individuals and HTLV-I seronegative individuals. There was no difference in the percentage of neutrophils infected with L. amazonensis or the number of amastigotes /100 PMNs from HTLV-I infected individuals as compared with HTLV-I seronegative individuals. These results suggest that although neutrophils from HTLV-I infected individuals are more activated than neutrophils from HTLV-I seronegative controls, their ability to kill an intracellular pathogen did not differ to that observed in the control group.

ASSUNTO(S)

htlv-i imunologia neutrophils htlv-i neutrófilos l. amazonensis l. amazonensis

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