The Epstein-Barr virus load in the peripheral blood at the time of diagnosis of post-transplant lymphoproliferative disease (PTLD) is elevated 1000- to 10,000-fold compared to the level detected in normal latency. With the use of quantitative polymerase chain reaction (PCR), changes in the viral load over time can be measured with a two- to fourfold accuracy. This has allowed early detection of first-time infections and reactivations that may lead to PTLD and has provided an opportunity to intervene before symptomatic disease has occurred. Viral load monitoring has also been used to follow patients with PTLD and, along with other parameters, provided an assessment of the effectiveness of therapeutic protocols. Viral load monitoring has led to the discovery that at least two-thirds of transplant recipients become persistent viral load carriers. While the persistent load appears to be largely carried in latently infected memory B cells, more work is needed to clearly define this type of persistent infection and determine the risks associated with it. New diagnostic tests need to be developed to distinguish the persistent latent viral loads from viral loads that are likely to become symptomatic PTLD.

This study examines the impact of children's exposure to natural disaster against the backdrop of exposure to other traumatic events and psychosocial risks. One thousand three hundred ninety-eight Sri Lankan children aged 9-15 years were interviewed in 4 cross-sectional studies about exposure to traumatic life events related to the war, the tsunami experience, and family violence. Symptoms of posttraumatic stress disorder, somatic complaints, psychosocial functioning, and teacher reports of school grades served as outcome measures. A global outcome variable of "positive adaptation" was created from a combination of these measures. Data showed extensive exposure to adversity and traumatic events among children in Sri Lanka. Findings of regression analyses indicated that all 3 event types--tsunami and disaster, war, and family violence--significantly contributed to poorer child adaptation.

Epstein-Barr virus (EBV),

In this study, the characteristics of Ig-null B cells in high viral load carriers were examined by four-color flow cytometry. The frequency of Ig-null B cells in patients with high, low or undetectable virus loads was found that while patients with a high load had more Ig-null cells, these cells were also present in the low and undetectable load groups. As Ig-null cells from patients with no viral load were EBV-negative, EBV infection was not absolutely required for the generation or survival of Ig-null cells. Ig-null cells were CD19(+), sIg(-), CD5(-), CD10(-), CD27(-), CD23(-), CD38(-), and CD69(-) with variable surface expression of CD20 and CD40. Ig-null cells did not have a proliferating cell phenotype (Ki67(-)) and a high proportion were HLA class I(-) and class II(-). Virus copy number in CD19(+) Ig-null cell populations may be much higher than in CD19(+) Ig(+) cell populations. EBV infected Ig-null cells were common in blood specimens from pediatric solid organ transplant recipients and infected Ig-null cells may pose potential problems for immunotherapies that target infected B cells directly.