Haploidentical hematopoietic stem cell transplantation (haploHSCT) with conditioning regimens using post-transplant cyclophosphamide (PTCy) for peripheral blood stem cell (PBSC) grafts is limited by comparably higher rates of acute and chronic graft-versus-host disease (GVHD). Antithymocyte globulin (ATG) may mitigate this risk. We evaluated haploHSCT after reduced-intensity conditioning (RIC) with ATG, PTCy, and cyclosporine to prevent rejection and GVHD. Fifty adults underwent haploHSCT from August 2016 to February 2018. RIC included fludarabine (30 mg/m2/day on days -5 to -2), busulfan (3.2 mg/m2/day on days -3 and -2), and total body irradiation (200 cGy) on day -1. Unmanipulated PBSCs were infused on day 0. GVHD prophylaxis included ATG (4.5 mg/kg over days -3 to -1), PTCy (50 mg/kg/day on days +3 and +4), and cyclosporine from day +5. Median age was 56 years (range, 22 to 70 years); 25 (73.5%) patients were in first complete remission (CR1), 5 (14.7%) were in second complete remission (CR2), and 8 (23.5%) had active disease. Median time to neutrophil engraftment was 16 days (range, 8 to 43 days). At day +100, the cumulative incidence of acute GVHD of any grade, and grades III to IV was 38.3% and 5.2%, respectively. Mild chronic GVHD was seen in 15.5%. Cytomegalovirus (CMV) reactivation occurred in 37 (74%) cases and CMV disease occurred in 4 (11.5%) cases. Epstein-Barr virus (EBV) reactivation occurred in 21 (61.8%) patients. The incidence of histologically confirmed post-transplantation lymphoproliferative disorder (PTLD) was 5.8%. Four patients received rituximab. There were no CMV, EBV, or PTLD-related deaths. Six-month and 1-year overall survival (OS), cumulative incidence of relapse (CIR), and nonrelapse mortality (NRM) were 73.9%, 10.2%, and 19.4%, respectively, and 48.1%, 16% and 38.2%, respectively. Infection was the most common cause of death (18%). Unmanipulated haploidentical PBSC transplantation following RIC with ATG, PTCy, and cyclosporine as a GVHD prevention strategy results in low rates of acute and chronic GVHD.

BK virus-associated hemorrhagic cystitis (BK-HC) is a common complication after allogeneic hematopoietic stem cell transplantation (allo-HCT), with incidences up to 70%. Cidofovir is an antiviral agent with growing evidence as a therapeutic intervention. To assess the safety profile and efficacy of intravenous and intravesical cidofovir in allo-HCT patients with BK-HC, a retrospective study was undertaken of the allo-HCT cohort who received cidofovir for symptomatic BK-HC (hematuria with BK viruria or viremia) from January 2010 until March 2017 in a single transplant center in Ontario, Canada. The primary outcome measure was a reduction in BK-HC severity (graded from 1 to 4); secondary outcomes included overall survival, BK virus titers, and the onset of acute kidney injury. Twelve allo-HCT patients received cidofovir for BK-HC, with pretreatment clinical severity of 3 (50%) or 4 (50%). Cidofovir was administered via intravenous (33%), intravesical (58%), or both modalities (8%). After a median cumulative dose of 10 mg/kg (range, 1 to 37), mean BK-HC grade decreased significantly by 1.8 (3.5 precidofovir, 1.7 postcidofovir, P < .01). Sixty-six percent of patients had at least partial response to cidofovir, with similar response rates between intravenous (66%) and intravesical (62%) administration. Sixty-seven percent of patients died, and 33% of patients experienced renal toxicity, including 2 patients receiving intravesical therapy. In this retrospective series, there was a significant reduction in BK-HC severity after cidofovir administration; most patients achieved at least partial response after cidofovir administration. Even with intravesical instillation, acute kidney injury remains a potential complication of cidofovir. Although cidofovir may be an efficacious therapy for BK-HC, albeit with potential demonstrated toxicities, further prospective trials are needed.

Glycogen storage disease (GSD) type 1 is a rare autosomal recessive inherited condition. The 1b subtype comprises the minority of cases, with an estimated prevalence of 1 in 500,000 children. Patients with glycogen storage disease type 1b are often treated with granulocyte colony stimulating factor (G-CSF) for prolonged periods to improve symptoms of inflammatory bowel disease (IBD) and in the face of severe neutropenia to decrease risk of infection. Long-term G-CSF treatment may result in an increased risk of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) possibly due to increased marrow stress resulting in telomere shortening. To our knowledge, there have been two published cases of AML in GSD type 1b patients following long-term G-CSF exposure. Here, we report two further cases of AML/MDS-related changes in patients GSD type 1b treated with G-CSF. One patient developed AML with complex karyotype after 20 years of G-CSF treatment. The second patient was found to have short telomeres after 10 years of G-CSF exposure, but no evidence of acute leukemia at present. The third patient developed AML/MDS after 25 years of G-CSF use, with short telomeres prior to bone marrow transplant. Together these cases suggest that GSD type 1b patients with prolonged G-CSF exposure may be at an increased risk of MDS/AML states associated with G-CSF-induced shortened telomeres. We recommend that any GSD1b patients with prolonged G-CSF should have routine telomere assessments with monitoring for MDS if telomere shortening is observed, and with particular attention warranted if there is unexplained loss of G-CSF responsiveness.

Allogenic hematopoietic stem cell transplant (HCT) recipients are at risk of many infections. Nontuberculous mycobacteria (NTM) are increasingly recognized as clinically significant pathogens in this population. We investigated the incidence and risk factors for NTM infection after allogeneic HCT. This retrospective cohort study included all patients with allogeneic HCT at our institution during 2001 to 2013. Patients who developed significant NTM infection (NTM disease) were identified. Multivariable modeling was used to identify risk factors for NTM disease, and a risk score model was constructed to identify high-risk patients. Of 1097 allogeneic HCT patients, 45 (4.1%) had NTM isolated and 30 (2.7%) had NTM disease (28 [93.3%] exclusively pulmonary, 2 [6.7%] pulmonary plus another site). Incidence of NTM infection by competing risk analysis was 2.8% at 5 years (95% CI, 1.9% to 4.0%). The median time to diagnosis was 343 days (range, 19 to 1967). In Fine-Gray proportional hazards modeling, only global severity of chronic graft-versus-host disease (cGVHD) (HR, 1.99; 95% CI, 1.12 to 3.53; P = .019,) and cytomegalovirus (CMV) viremia (HR, 5.77; 95% CI, 1.71 to 19.45; P = .004) were significantly associated with NTM disease. Using these variables a risk score was calculated: 1 point for CMV viremia or moderate cGVHD and 2 points for severe cGVHD. The score divided patients into low risk (0 to 1 points, n = 820 [77.3%], 3-year NTM risk 1.2%), intermediate risk (2 points, n = 161 [15.4%], 3-year NTM risk 7.1%), and high risk (3 points, n = 56 [5.4%], 3-year NTM risk 14.3%). NTM disease after allogeneic HCT is common. Severe cGVHD and CMV viremia are associated with increased risk, permitting risk stratification.