title: [Role of immunity in the development of progressive multifocal leukoencephalopathy: a report of three patients with type B lymphoma and humoral immunodeficiency and six others with acquired immunodeficiency syndrome].
abstract: BACKGROUND
  Progressive multifocal leukoencephalopathy (PML) caused by JC virus (JCV) mostly occurs in different conditions of impaired cellular immunity like acquired immunodeficiency syndrome (AIDS) and rarely when humoral immunity is involved. PML remains unusual although there is a high prevalence of JCV among the population and immunosuppression is not rare because of chemotherapies.
  
  
  METHODS
  We present two groups of patients: first, we studied reports of three patients suffering from lymphoma type B who developed a PML, proved by cerebral biopsy. The second group included six HIV-infected patients who developed a PML. No biopsy was made but MRI and the physical examination suggested strong arguments for the diagnosis.
  
  
  RESULTS
  In the first group, PML was furthered by humoral immunosuppression (rate of immunoglobulin G under 4 g/l). Average survival was five months. In the second group, HIV-infected patients had a survival range from 2 to 58 months after the first PML symptoms and one of them is still alive.
  
  
  CONCLUSIONS
  Humoral immunosuppression in lymphoma can contribute to the development of PML. PML prognosis is often severe but prolonged survivals were described. So it is necessary to restore a sufficient immunity level. But immunity failure may be insufficient to lead to PML. In the case of lymphomas, the role of malignant lymphocytes in multiplication and mutation of JCV might be an interesting pathophysiological hypothesis.
authors.affiliation: Service de Neurologie, Centre Hospitalier de Belfort-Montbéliard. imalkoun@ch-belfort-montbeliard.rss.fr
authors.forename: I
authors.initials: I
authors.lastname: Malkoun
authors.forename: E
authors.initials: E
authors.lastname: Vidry
authors.forename: E
authors.initials: E
authors.lastname: Revenco
authors.forename: M-C
authors.initials: MC
authors.lastname: Drobacheff
authors.forename: E
authors.initials: E
authors.lastname: Berger
authors.forename: L
authors.initials: L
authors.lastname: Rumbach
mesh_terms: D000328:Adult; D000361:Agammaglobulinemia / Q000209:etiology; D000368:Aged; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000276:immunology; D006801:Humans; D016867:Immunocompromised Host; D007577:JC Virus / Q000502:physiology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000150:complications / Q000276:immunology; D007968:Leukoencephalopathy, Progressive Multifocal / Q000209:etiology* / Q000401:mortality / Q000821:virology; D016393:Lymphoma, B-Cell / Q000150:complications / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016019:Survival Analysis; D014775:Virus Activation / Q000276:immunology