RESUMO
Revision is made to 121 Chilean patients with progressive adult spastic paraparesis (PSPs) associated to HTLV-I. Epidemiologic, clinical, diagnosis and associated illnesses aspects are analyzed as well as the pathogenesis. The follow-up of patients during several years allowed defining the evolutional profile, establishing the causes of death and studying the virus' behavior. Pathogenesis hypothesis arose from the neuropathological search to define the mechanisms of damage supported on immunohystochemical studies. It was confirmed that the CNS illness is a degenerative process linked to a central axonopathy which expresses flaws in the axoplasmic transport, particularly affecting the corticospinal tracts, although there is a more extended myeloencephalic involvement. Furthermore, the virus is capable of producing a multisystemic illness that may simultaneously involve the nervous system; the hematological system; the exocrine glands; the hepatic, lung, muscular and bone parenchymas.
Se revisan las paraparesias espásticas progresivas del adulto (PEPAs) producidas por el HTLV-I, en 121 pacientes chilenos. Se analizan los aspectos epidemiológicos, clínicos, diagnósticos, las enfermedades asociadas, y la patogenia. El seguimiento de los pacientes durante varios años permitió definir el perfil evolutivo, establecer las causas de muerte y estudiar el comportamiento del virus. De los casos con anatomía patológica surgieron hipótesis, que han permitido definir mecanismos de daño, sustentados en estudios inmunohistoquímicos. Se pudo confirmar que la enfermedad del SNC es un proceso degenerativo, vinculado a una axonopatía central que expresa fallas del transporte axoplásmico, que afecta particularmente la vía corticoespinal, aunque existe un compromiso más extenso mielo-encefálico. Además, el virus es capaz de producir una enfermedad multisistémica, que puede comprometer simultáneamente el sistema nervioso, el sistema hematológico, las glándulas exocrinas, el parénquima hepático, pulmonar, muscular y óseo.
Assuntos
Humanos , Masculino , Adolescente , Adulto , Feminino , Pessoa de Meia-Idade , Infecções por HTLV-I/complicações , Paraparesia Espástica Tropical/etiologia , Paraparesia Espástica Tropical/mortalidade , Paraparesia Espástica Tropical/patologia , Axônios/patologia , Causas de Morte , Evolução Clínica , Chile/epidemiologia , Seguimentos , Paraparesia Espástica Tropical/fisiopatologiaRESUMO
The human T-cell lymphotropic virus type 1 (HTLV-1) is the causative agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HT). Although it is widely believed that virus infection and host immune response are involved in the pathogenic mechanisms, the role of the immune system in the development and/or maintenance of HT remains unknown. We performed an analysis of the peripheral blood leukocyte phenotype for two different subcohorts of HTLV-1-infected individuals to verify the existence of similar immunological alterations, possible laboratory markers for HT. The leukocyte population balance, the activation status of the T lymphocytes, and the cellular migratory potential of T lymphocytes, monocytes, and neutrophils were evaluated in the peripheral blood of HTLV-1-infected individuals classified as asymptomatic individuals, oligosymptomatic individuals, and individuals with HT. Data analysis demonstrated that a decreased percentage of B cells, resulting in an increased T cell/B cell ratio and an increase in the CD8+ HLA-DR+ T lymphocytes, exclusively in the HT group could be identified in both subcohorts, suggesting its possible use as a potential immunological marker for HT for use in the laboratory. Moreover, analysis of likelihood ratios showed that if an HTLV-1-infected individual demonstrated B-cell percentages lower than 7.0%, a T cell/B cell ratio higher than 11, or a percentage of CD8+ HLA-DR+ T lymphocytes higher than 70.0%, this individual would have, respectively, a 12-, 13-, or 22-times-greater chance of belonging to the HT group. Based on these data, we propose that the T cell/B cell ratios and percentages of circulating B cells and activated CD8+ T lymphocytes in HTLV-1-infected patients are important immunological indicators which could help clinicians monitor HTLV-1 infection and differentiate the HT group from the asymptomatic and oligosymptomatic groups.