Susan Slater

Control of an Outbreak of Human Parainfluenza Virus 3 in Hematopoietic Stem Cell Transplant Recipients

Human parainfluenza virus 3 (HPIV3) infection can cause significant morbidity and mortality in patients undergoing hematopoietic stem cell transplantation (HSCT). There are no standard guidelines for the prevention and control of HPIV3 in the outpatient setting. After 2 HSCT inpatients diagnosed with HPIV3 were noted to have had multiple recent HSCT outpatient clinic (OPC) visits, an investigation of policy and procedures in the HSCT OPC was undertaken, and active surveillance for respiratory viral illness was instituted in the at-risk HSCT population. Between July 19 and August 30, 2005, 13 patients were diagnosed with HPIV3 infection. Morbidity in affected patients was significant, and mortality was high (38.5%) and not affected by antiviral therapy. Molecular typing identified several genetically distinct groups of the hemagglutinin-neuraminidase gene of the 11 available isolates. Based on sequence relatedness among the isolates and the demographic and exposure history of the patients, in many of these cases HPIV3 infection likely was acquired in the HSCT OPC. The major infection control interventions were introduced between August 20 and August 24. An epidemic curve revealed that HPIV3 infection frequency peaked between August 17 and August 26, with no cases identified after August 30. Prompt attention and focus on infection control interventions were associated with a rapid decrease in the number of incident cases. Policies and procedures regarding patients with respiratory viral illnesses in HSCT OPC populations should be formulated and universally reinforced with HSCT clinic staff to prevent the spread of these infections.

Nonmyeloablative allogeneic hematopoietic stem cell transplant for the treatment of patients with hematologic malignancies using busulfan, fludarabine, and total body irradiation conditioning is effective in an elderly and infirm population

The BuFluTBI conditioning regimen was designed with the primary goal of reducing non-relapse mortality (NRM) while maximizing primary disease control in patients ineligible for myeloablative conditioning. Patients with hematologic malignancies for whom limited long-term survival was expected with standard therapy were administered an outpatient conditioning regimen of busulfan 3.2 mg/kg IV on day -5, fludarabine 30 mg/m(2) IV on days -4, -3, -2, and 200 cGy of total body irradiation (TBI) followed by stem cell infusion from related or unrelated donors. GVHD prophylaxis included cyclosporine and mycophenolate mofetil. 147 patients were enrolled from 2005-2011; 59% with myeloid disease and 41% with lymphoid disease. The median age was 64, and the median comorbidity index (HCT-CI) score was 3. Overall survival (OS), with 3.2 years median follow-up, was 60% at 1 year and 48% at 2 years, with projected OS 37% at 5 years. Relapse rates were 29% at 1 year and 33% at 2 years, with relapse mortality of 13% at 1 year, and 20% at 2 years. Nonrelapse mortality (NRM) at 1 year was 27% and 33% at 2 years. 54% of patients developed grade II-IV aGVHD and 67% of patients developed cGVHD within 2 years. On multivariate analysis, HCT-CI score 4 or greater, pre-transplant KPS less than 90, delayed platelet engraftment of more than 15 days, and grade II-IV aGVHD were found to be independent predictors of poor survival. There was no difference in OS or PFS between lymphoid and myeloid malignancies. BuFluTBI is an efficacious NMA regimen, active in both myeloid and lymphoid disease, and is ideally suited for use in patients age 65 and older or with an HCT-CI of 4 or greater.

Post-transplant Relapse

Despite the advances in the field of stem cell transplantation, relapse remains a major source of mortality. CIBMTR data identify relapse as the cause of death in 78% of autologous transplant patients, 34% of related allogeneic transplant patients, and 23% of unrelated transplant patients. With the advent of reduced intensity transplants allowing more patients to proceed with transplant, there have been reports of higher than anticipated relapses. Management of relapse post-transplant requires assessment of multiple host/recipient factors and often is limited by the compromised status of the recipient.

Acute graft-versus-host disease

Despite advances in HLA typing, acute GvHD remains a leading cause of morbidity and mortality among allogeneic transplant recipients. It is estimated that 30–50% of patients who receive stem cell products from HLA-identical siblings will develop grades 2–4 GvHD, while rates of GvHD in matched unrelated donor transplants are estimated to be between 50 and 70%. Acute GvHD has historically been defined as occurring prior to day +100 and chronic GvHD as occurring after day +100. However, recently there has been a move to define GvHD based on the clinical symptoms and pathologic findings rather than by an arbitrary timeline. The outcome of acute GvHD is dependent on the overall grade of GvHD and the patient’s response to initial treatment.