EBV lymphoproliferative disease of host origin after haploidentical stem cell transplantation

Incidence of Epstein-Barr virus in pediatric leukemia in the Sudan

BACKGROUND

Results of several studies have suggested a probable etiologic association between Epstein-Barr virus (EBV) and leukemias; therefore, the aim of this study was to investigate the association of EBV in childhood leukemia.

METHODS

A direct isothermal amplification method was developed for detection of the latent membrane protein 1 (LMP1) of EBV in the peripheral blood of 80 patients with leukemia (54 had lymphoid leukemia and 26 had myeloid leukemia) and of 20 hematologically healthy control subjects.

RESULTS

EBV LMP1 gene transcripts were found in 29 (36.3%) of the 80 patients with leukemia but in none of the healthy controls (P < .0001). Of the 29 EBV(+) cases, 23 (79.3%), 5 (17.3%), and 1 (3.4%) were acute lymphoblastic leukemia, acute myeloid leukemia, and chronic myeloid leukemia, respectively.

CONCLUSION

EBV LMP1 gene transcriptional activity was observed in a significant proportion of patients with acute lymphoblastic leukemia. EBV infection in patients with lymphoid leukemia may be a factor involved in the high incidence of pediatric leukemia in the Sudan.

Clinical and immunologic outcomes following haplocompatible donor lymphocyte infusions

We retrospectively analyzed the characteristics of 16 consecutive pediatric patients who received one or more G-CSF-mobilized donor lymphocyte infusions (DLI) following a T-cell-depleted haplocompatible hematopoietic SCT (HSCT) to enhance immune recovery and/or treat an infection. The median time from HSCT to administration of first DLI was 12 weeks and the median dose of DLI administered was 3 x 10(4)/kg (range, 2.5-6 x 10(4)/kg). The incidence of Grade I-II acute GVHD was 19% (95% confidence interval (CI), 6-44%), and there were no cases of Grade III-IV acute GVHD. Chronic GVHD developed in 13% (95% CI, 2-37%) of patients. In surviving patients who did not undergo a second stem cell infusion, T-cell numbers and function increased to a protective level in a median of 3 months (range, 2-12.5 months) following the first DLI administration. In patients given DLI for treatment of an infection, 75% (95% CI, 46-92%) cleared their infection after a median of 9 weeks (range, 1-27 weeks). In patients with CMV infection, the development of CMV-specific T cells was observed following DLI. The 1-year overall survival following haplocompatible DLI was 71% (95% CI, 59-83%), with a median follow-up of 16 months from the first DLI.

Perspective on the role of haploidentical transplantation in the management of hematologic malignancies: why do it?

Haploidentical hematopoietic stem cell transplantation (HSCT) using mismatched family member donors has historically been complicated by high rates of nonrelapse toxicity and the need for laboratory expertise in depleting grafts of T lymphocytes. Over the past decade, improvements in supportive care, the increased use of peripheral-blood stem cell grafts, and improved T-cell depletion techniques have reduced the incidence of graft failure and lowered the rate of nonrelapse mortality. In addition, clinical studies have demonstrated that the donor-recipient mismatch may be beneficial in this setting, stimulating an immunologic cell-mediated antileukemia effect that results in lower disease recurrence rates. All of these advances have led to improvements in outcomes following haploidentical HSCT, making it an attractive option available to some patients. Because most patients do not have a matched related donor available and time to identify an unrelated donor may be excessive, haploidentical HSCT is a potentially curative option for these patients.