Eui Ho Kim

Monitoring Minimal Residual Disease in Leukemia Using Real-time Quantitative Polymerase Chain Reaction for Wilms Tumor Gene (WT1)

We previously showed that Wilms tumor gene (WT1) expression level, measured by quantitative reverse transcriptase polymerase chain reaction (RT-PCR), was useful as an indicator of minimal residual disease (MRD) in leukemia and myelodysplastic syndrome. However, in conventional quantitative RT-PCR (CQ-PCR), RT-PCR must be performed for various numbers of cycles depending onWT1 expression level. In the present study, we developed a new real-time quantitative RT-PCR (RQ-PCR) method for quantitatingWT1 transcripts. Results of intraassay and interassay variability tests demonstrated that the real-timeWT1 assay had high reproducibility.WT1 expression levels measured by the RQ- and the CQ-PCR methods were strongly correlated (r = 0.998). Furthermore, a strong correlation was observed amongWT1 transcript values normalized with 3 different control genes (β-actin,ABL, andglyceraldehyde-3-phosphate dehydrogenase) and between relativeWT1 transcript values withWT1 expression in K562 cells as the reference and absoluteWT1 transcript copy numbers per microgram RNA. WhenWT1 expression andminor bcr-abl expression were concurrently monitored in 2 patients withbcr-abl-positive acute lymphoblastic leukemia, both MRDs changed mostly in parallel, indicating the reliability and validity of our RQ-PCR method. In conclusion, this RQ-PCR method is convenient and reliable for monitoring MRD and enables routine clinical use of aWT1 assay.

Salvage haploidentical transplantation for graft failure using reduced-intensity conditioning

Graft failure is a major concern after cord blood transplantation (CBT) or HLA-haploidentical transplantation (haplo-SCT). As patients who undergo CBT or haplo-SCT almost always lack both matched-related and -unrelated donors, salvage transplantation would also be limited to either CBT or haplo-SCT. In this study, we assessed eight patients who received haplo-SCT as salvage therapy for graft failure. Five and three patients had received haplo-SCT and CBT, respectively, which resulted in graft failure. The median interval from the failed transplantation to salvage transplantation in six patients with primary graft failure was 33.5 days. The reduced-intensity conditioning regimen consisted of fludarabine, thiotepa, rabbit antithymocyte globulin and low-dose TBI. All eight patients achieved neutrophil engraftment, and seven patients achieved platelet recovery. The median times to neutrophil recovery and platelet recovery were 10 and 20 days, respectively. Three patients died from treatment-related causes: two from GVHD and one from rupture of carotid artery aneurysm. Five patients are alive, at a median follow-up of 946 days. The probability of overall survival at 5 years was 75%. These findings may serve as a rationale for giving precedence to haplo-SCT over CBT in salvage SCT after graft failure.

Combination of tacrolimus, methotrexate, and methylprednisolone prevents acute but not chronic Graft-Versus-Host disease in unrelated bone marrow transplantation

Background. Graft-versus-host disease (GVHD) is still a major problem in allogeneic bone marrow transplantation (BMT). Prophylactic regimens used against GVHD in unrelated BMT, including cyclosporine (CsA)-plus-methotrexate (MTX), CsA-plus-MTX-plus-prednisone, and tacrolimus (FK506)-plus-MTX, are still unsatisfactory (34–70% occurrence of grades II–IV GVHD). To address this problem, we examined the efficacy of FK506-plus-MTX-plus-methylprednisolone (mPSL) in 20 patients who underwent BMT from unrelated donors. Methods. All patients received FK506 beginning the day before transplantation at a dose of 0.03 mg/kg per day by continuous intravenous (IV) infusion. MTX was administered at a dose of 10 mg/m2 IV on day 1, and 7 mg/m2 on days 3, 6, and 11. Intravenous administration of mPSL was started at a dose of 2 mg/kg per day on day 1. In the absence of acute GVHD, mPSL was gradually tapered from day 29. Results. Development of acute GVHD was almost completely suppressed (one patient with grade I, none with grades II–IV). However, the incidence and severity of chronic GVHD did not decrease. Eight of 12 patients with extensive chronic GVHD died of thrombotic microangiopathy or infection. A vigorous fluctuation (>100 U/mL per 10 days) of the soluble interleukin 2 receptor level in the serum after engraftment was highly related to the occurrence of chronic GVHD. Conclusions. An FK506-plus(+)-MTX-plus(+)-mPSL prophylactic regimen could almost completely suppress acute GVHD but not chronic GVHD in unrelated BMT. In this GVHD prophylactic system, the extent of the change of soluble interleukin 2 receptor level may be a good predictor of development of chronic GVHD.

Unmanipulated reduced-intensity stem cell transplantation from a haploidentical donor mismatched at 3 HLA antigens to a patient with leukemic transformation of myelodysplastic syndrome: successful second transplantation after graft rejection.

We present the case of a patient with myelodysplastic syndrome who experienced leukemia transformation and subsequently underwent transplantation of unmanipulated peripheral blood stem cells from a haploidentical sibling mismatched at 3 HLA antigens, along with a reduced-intensity regimen (fludarabine, busulfan, and anti-T-lymphocyte globulin) and tacrolimus-containing graft-versus-host disease (GVHD) prophylaxis. The patient experienced graft rejection but successfully underwent a second transplantation from the same donor with a slightly intensified conditioning regimen. Although the patient developed life-threatening cytomegalovirus (CMV) pneumonia following the second transplantation, he recovered completely from the pneumonia with intensive supportive therapy. He is still in complete remission past day 1000 in the absence of GVHD. As far as we know, this report is the first to describe a successful second transplantation that was performed for graft rejection following HLA-haploidentical nonmyeloablative stem cell transplantation. Furthermore, we emphasize that patients should be carefully monitored for CMV infection when reduced-intensity conditioning is given repeatedly over a short period.

Successful treatment of bcr/abl-positive acute mixed lineage leukemia by unmanipulated bone marrow transplantation from an HLA-haploidentical (3-antigen-mismatched) cousin

Summary:We describe a patient with bcr/abl-positive acute mixed lineage leukemia who successfully underwent transplantation in primary induction failure, using unmanipulated bone marrow from a human leukocyte antigen (HLA)-haploidentical cousin. The tumor burden was successfully reduced by the administration of imatinib mesylate (STI571) before transplantation. As graft-versus-host disease (GVHD) prophylaxis, a combination of tacrolimus and a short course of methotrexate, methylprednisolone, and mycophenolate mofetil was used. Hematopoietic reconstitution was rapid, and acute GVHD was limited to the skin (grade I). The patient is still in complete remission past day +400. This successful case suggests that HLA-haploidentical transplantation using unmanipulated marrow from a distantly related relative can be considered for patients in urgent situations who do not have HLA-identical donors.