The impact of monitoring Epstein-Barr virus PCR in paediatric bone marrow transplant patients: can it successfully predict outcome and guide intervention?

BACKGROUND: Epstein-Barr virus (EBV) associated lymphoproliferative disease is a complication of haemopoietic stem cell transplantation (HSCT). In certain groups (unrelated and mismatched donor transplants, T-cell depleted) the risk may be as high as 25% with significant morbidity and mortality. Strategies to predict the impending development of this disorder and allow early intervention have therefore assumed importance. We routinely screen the peripheral blood of all recipients of allogeneic HSCT to detect EBV DNA by quantitative polymerase chain reaction (PCR) technology and report here how this correlates with clinical disease and management. PROCEDURE: Data on 28 successive patients who underwent HSCT at our institution were reviewed. The relationship between EBV reactivation demonstrated by quantitative PCR and development of post transplant lymphoproliferative disease (PTLD) was determined. RESULTS: EBV reactivation occurred in 68% of patients, however only 7% developed clinical PTLD. Patients with high level reactivation (n = 9) had more frequent episodes of reactivation and all patients who progressed to overt PTLD were found in this group. In contrast none of those patients with low level reactivation (n = 10) or persistently negative results (n = 9) showed any signs of clinical disease. Anti-CD20 monoclonal antibody (Rituximab) therapy was instigated in both cases of proven PTLD and three cases of high level reactivation with successful outcomes. Response to treatment was associated with a prompt decline in viral copy number. CONCLUSIONS: Our results indicate that EBV reactivation is a common occurrence in the paediatric allogeneic transplant setting and that only a proportion of patients will progress to PTLD. Frequent monitoring may help to predict those at highest risk and guide intervention.

Rapid detection and quantification of CMV DNA in urine using LightCycler-based real-time PCR.

A real-time quantitative PCR-hybridisation assay was developed for the detection of human cytomegalovirus DNA in clinical material. The assay is based on a LightCycler (LC) and provides both rapid results (<1 h) and quantification over a broad dynamic range (2 x 10(3)-5 x 10(8) CMV DNA copies/ml). Given that the assay showed a 3-fold increase in sensitivity compared to detection of early antigen fluorescent foci (DEAFF) testing of urine samples, we investigated the practicality of testing surveillance such specimens from immunocompromised patients at risk of CMV disease. Over a 12-month period, CMV DNA was detected in 81 (7%) of 1154 urine samples examined. A total of 28 patients tested positive; urine viral loads were higher in 13 infants being investigated for suspected congenital infection (median 1.6 x 10(5) copies/ml) compared with 15 transplant recipients (median 9 x 10(3) copies/ml). Urine samples could be tested directly without processing such that results were available in <1h. Real-time PCR provided information on the quantification of CMV DNA in urine and proved a reliable method for the surveillance of immunocompromised patients at risk of CMV disease. This approach should facilitate a better understanding of the epidemiology and natural history of CMV disease. Moreover, LC-based quantitative PCR is a potentially valuable tool for the management of CMV disease; assisting with the prompt initiation of treatment and assessing therapeutic response.