RESUMEN
OBJECTIVE: To investigate the rate of seropositivity of anti-JC virus (JCV) antibodies in a German multiple sclerosis (MS) cohort treated with natalizumab in the postmarketing setting and to assess anti-JCV serostatus in samples obtained before diagnosis of progressive multifocal leukoencephalopathy (PML). METHODS: This was a blinded, retrospective cross-sectional and longitudinal analysis for anti-JCV antibodies using a confirmatory 2-step ELISA on 2,782 blood samples obtained from 2,253 patients nationwide for routine testing for anti-natalizumab antibodies during open-label treatment between 2007 and 2010. RESULTS: Of the natalizumab-treated patients with MS, 58.8% tested positive for anti-JCV antibodies. The rate of seropositivity was higher in males and increased with age, with a plateau between age intervals 20-29 and 30-39 years. In longitudinal analyses, 19 of 194 (9.8%) patients converted from anti-JCV antibody-negative to seropositive status over 7.7 months; 4.7% reverted from antibody-positive to seronegative status over 7.9 months. Antibody levels, especially in the latter group, were low, indicating fluctuations around the lower cut point of the assay. Neither anti-JCV serostatus nor antibody levels were associated with immunosuppressive pretreatment, duration of natalizumab treatment, or anti-natalizumab antibodies. All samples obtained from 10 patients who developed PML were seropositive (13 samples before PML diagnosis [2.0-37.6 months]; 2 samples at diagnosis). Antibody levels in these samples were higher than those in samples from seropositive patients who did not develop PML. CONCLUSIONS: These data argue for the potential clinical utility of JCV serology for PML risk stratification. However, further investigations of fluctuations in serostatus and of antibody levels for a more precise understanding of the predictive value are warranted.
Asunto(s)
Anticuerpos Monoclonales Humanizados/uso terapéutico , Anticuerpos Antivirales/sangre , Inmunosupresores/uso terapéutico , Virus JC/inmunología , Leucoencefalopatía Multifocal Progresiva/diagnóstico , Esclerosis Múltiple/inmunología , Esclerosis Múltiple/virología , Adulto , Ensayos Clínicos como Asunto , Estudios de Cohortes , Estudios Transversales , Femenino , Alemania/epidemiología , Humanos , Leucoencefalopatía Multifocal Progresiva/epidemiología , Leucoencefalopatía Multifocal Progresiva/inmunología , Leucoencefalopatía Multifocal Progresiva/virología , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Esclerosis Múltiple/tratamiento farmacológico , Esclerosis Múltiple/epidemiología , Natalizumab , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Método Simple CiegoRESUMEN
BACKGROUND: Mitoxantrone is highly efficacious in the treatment of severe multiple sclerosis (MS). Mitoxantrone therapy-related acute leukemia (TRAL) has recently become the focus of interest. METHODS: A case report of fatal TRAL following mitoxantrone therapy is presented with a discussion on the differential diagnosis and risk factors. The interdisciplinary development of diagnostic and therapeutic algorithms is presented from a haematological and neurological point of view. RESULTS: We describe the case of a 34-year-old MS patient who developed TRAL following mitoxantrone therapy (cumulative dose 45 mg/m(2) body surface). The patient died from endocarditis. TRAL is a rare but potentially fatal complication of mitoxantrone therapy with a wide variation of reported incidence. Thus far, no specific risk factors relating for example to preceding therapy and treatment regimens have been identified. Frequent laboratory controls and early bone marrow aspiration are mandatory for suspected TRAL as the condition is potentially curable. CONCLUSIONS: TRAL needs to be considered in the risk-benefit assessment of mitoxantrone therapy, however, the exact incidence and risk factors (e.g. dosage, treatment regimen) are still unclear. The risks are controllable under close surveillance and early diagnosis is important for prognosis. Future investigations need to concentrate on identification of potential risk factors.