RESUMEN
BACKGROUND: In the context of the Official Medicines Control Laboratories plasma pool testing for Parvovirus B19 DNA, we use the cobas TaqScreen DPX test. When we re-evaluated this method using the 3rd B19 DNA WHO IS at the final concentration of 4 log IU/mL, we observed a titre lower than expected, i.e. 3.79 log IU/mL. Therefore, we further investigated the accuracy of the DPX test. MATERIALS & METHODS: The following B19V DNA materials were tested by using both the DPX test and an in-house real-time PCR: The 1st, 2nd and 3rd WHO ISs for B19V DNA The Non WHO B19V DNA Reference Material for NAT The Biological Reference Preparation B19 virus DNA for NAT testing, batch 1 . RESULTS: The DPX test showed a good accuracy for all B19V DNA materials with the exception of the 3rd WHO IS for B19V DNA. In fact, an underestimation of about 38% was observed for all dilutions of this standard with respect to the nominal titre. With the B19V in-house real-time PCR, all four materials proved to be well calibrated against the 1(st) WHO IS for B19V DNA, used as external standard curve. CONCLUSION: In this study, we demonstrated that the DPX test underestimates the B19V DNA content of the 3rd WHO IS for B19V DNA and that this is not due to an incorrect potency assigned to the standard but, most probably, to a mismatch between the primers/probe and the sequence of the target region in the 3rd WHO IS for B19V DNA.
Asunto(s)
ADN Viral/sangre , Infecciones por Parvoviridae/diagnóstico , Parvovirus B19 Humano/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Sondas de ADN/química , Sondas de ADN/metabolismo , ADN Viral/normas , Humanos , Infecciones por Parvoviridae/virología , Parvovirus B19 Humano/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/normas , Estándares de Referencia , Organización Mundial de la SaludRESUMEN
Despite combined treatment (surgery, radio--and chemotherapy) primary central nervous system lymphoma (PCNSL) has generally a poor prognosis. Long surviving cases (more than 5 years) are exceptional. We report a case of a patient completely symptom-free 79 months after craniotomy. Histological diagnosis was diffuse centroblastic-centrocytic malignant lymphoma. Immunohistological study of the lesion was performed. Repeated CT scans reveal no tumor recurrence and screenings for extraneural disease remain negative. The prognostic value of tumor histology is emphasized.