The role of point-of-Care Musculoskeletal Ultrasound for Routine Joint evaluation and management in the Hemophilia Clinic - A Real World Experience.

BACKGROUND: The use of musculoskeletal ultrasound (MSKUS) for point-of-care (POC) evaluation of hemophilic arthropathy is growing rapidly. However, the extent to which MSKUS influences clinical treatment decisions is unknown. METHODS: We conducted a three-year, prospective, multi-center study at three hemophilia treatment centers in the United States to evaluate the utilization of POC-MSKUS for routine clinical decision-making in adult persons with hemophilic arthropathy. Bilateral elbows, knees and ankles were assessed clinically [Hemophilia Joint Health Score (HJHS)] and with POC-MSKUS by the Joint TissueActivity and Damage Exam (JADE) protocol at baseline and approximately annually for two additional times. Treatment decisions, including physical therapy (PT) and "medical" (joint injections/aspirations, referrals to orthopedics, changes/adjustments of hemostatic plans, and use of oral anti-inflammatory medications) were recorded in relation to POC-MSKUS. RESULTS: Forty-four persons [median age 37 years (IQR 29, 51)], mostly with severe Hemophilia A on clotting factor prophylaxis, completed 129 visits, yielding 792 joint exams by POC-MSKUS and HJHS [median at baseline 27 (IQR 18, 42)] over a median follow up of 584 days (range: 363 to 1072). Among 157 management decisions, 70% were related to PT plans (n = 110) and 30% were "medical". Point-of-care MSKUS influenced 47/110 (43%) PT plans, mostly informing treatment of specific arthropathic joints (45/47 plans) in patients with high HJHS. Physical therapy plans influenced by POC-MSKUS directed more manual therapy/therapeutic exercises, while plans based on physical exam were focused more on global exercises and wellness. Treatment decisions were mostly based on the identification of specific musculoskeletal abnormalities visualized by POC-MSKUS. Of note 20/47 (43%) POC-MSKUS plans included de-escalation strategies, thereby reducing exercise intensity, mostly for joint instability and subclinical hemarthroses. Point-of-care MSKUS also informed 68% (32/47) of "medical" decisions, surprisingly mostly for injections/aspirations and referrals to orthopedics, and not for adjustments of hemostatic treatment. Although not formally studied, ultrasound images were used frequently for patient education. CONCLUSION: Routine joint evaluations with POC-MSKUS resulted in few changes regarding medical management decisions but had a profound effect on the formulation of PT plans. Based on these findings, new studies are essential to determine the benefit of MSKUS-informed management plans on joint health outcomes.

Acquired Hemophilia A (FVIII Deficiency) Associated with Papillary Thyroid Cancer: Treatment with Recombinant Porcine FVIII.

Acquired hemophilia A (AHA) is a rare autoimmune disorder caused by autoantibodies against Factor VIII (FVIII). It has a high mortality due to bleeding complications. FVIIa-based bypassing agents are the first line of treatment but not always effective. Recombinant porcine (rp) FVIII (Obizur®) was recently approved for rescue treatment but with little evidence-based information regarding efficacy. We report a case of papillary thyroid cancer associated with AHA malignancy that responded to a single dose of rpFVIII after failure to achieve hemostasis with FVIIa-based bypassing products.

Phase 1, single-dose escalating study of marzeptacog alfa (activated), a recombinant factor VIIa variant, in patients with severe hemophilia.

Essentials Marzeptacog alfa (activated) [MarzAA] is a novel variant of activated human factor VII. A phase 1 dose escalation trial of MarzAA was conducted in subjects with severe hemophilia. MarzAA was safe and tolerated at intravenous doses up to 30 µg kg-1 Data observed support further trials for hemophilia patients with inhibitors to factors VIII/IX. SUMMARY: Background Marzeptacog alfa (activated) (MarzAA), a new recombinant activated human factor VII (rFVIIa) variant with four amino acid substitutions, was developed to provide increased procoagulant activity and a longer duration of action in people with hemophilia. Objectives To investigate the safety, tolerability, immunogenicity, pharmacokinetics (PK) and pharmacodynamics (PD) of single ascending intravenous bolus doses of MarzAA in non-bleeding patients with congenital hemophilia A or B with or without inhibitors. Methods This international, phase 1, open-label study (NCT01439971) enrolled males aged 18-64 years with severe hemophilia A or B, with or without FVIII or FIX inhibitors. Subjects were assigned to single-dose MarzAA cohorts (0.5, 4.5, 9, 18 or 30 µg kg-1 ). Blood sampling was performed predose and postdose, and subjects were monitored for 60 days postdose. Safety endpoints included adverse events, vital sign changes, electrocardiograms, laboratory abnormalities, and immunogenicity; secondary endpoints included evaluation of PK and PD. Results Overall, in 25 patients, MarzAA was well tolerated at all dose levels tested, and was not associated with dose-limiting toxicity. No treatment-emergent severe or serious adverse events occurred. MarzAA showed linear dose-response PK across the 4.5-30 µg kg-1 dose range, with a terminal half-life of ⁓ 3.5 h. Dose-dependent shortening of the activated partial thromboplastin time and prothrombin time, and evidence of an increase in peak thrombin as determined with a thrombin generation assay, were observed at all doses. Conclusions MarzAA was tolerated at doses up to 30 µg kg-1 . The safety profile and pharmacological effects observed support further clinical trials for the treatment of hemophilic patients with inhibitors.

Musculoskeletal ultrasound for intra-articular bleed detection: a highly sensitive imaging modality compared with conventional magnetic resonance imaging.

Essentials The best imaging modality for joint blood detection in hemophilia is unknown. Blood appearance and detection thresholds were studied with ultrasound and conventional MRI. Ultrasound is sensitive to low volume and concentration of blood, whereas conventional MRI is not. The findings establish the validity of ultrasound for rapid bleed detection in hemophilia care. SUMMARY: Background There is increasing demand for musculoskeletal ultrasound (MSKUS) to detect hemophilic joint bleeding, but there is uncertainty regarding blood detection concentration thresholds or if magnetic resonance imaging (MRI) is more accurate. Aims Compare the sensitivity of blood detection by MSKUS and MRI. Methods Increasing blood concentrations in plasma were imaged with MSKUS and MRI 1-2 h, 3-4 days and 7 days after blood withdrawal in vitro, and after injection into cadaveric pig joints. Additionally, effusions in the joints of two patients with hemophilia joints were imaged, followed by aspiration. MSKUS was performed using an 8-18-MHz linear transducer; MRI was performed at 3T using T1-weighted and T2-weighted fat-suppressed sequences. Images were reviewed by a hematologist certified in MSKUS and a musculoskeletal radiologist. Results MSKUS permitted the detection of blood in vitro and in pig joint spaces at concentrations as low as 5%, demonstrated by the presence of echogenic signals that were absent with plasma alone. In contrast, no differences between fluids were discernible on the T1-weighted or T2-weighted MRI images. Results were confirmed in the two patients with hemophilia. Blood clots demonstrated varying and dynamic echogenicity patterns over time and, using MRI, were visualized best with T2 sequences. Conclusion MSKUS is extremely sensitive in detecting low concentrations of intra-articular blood and in discriminating between bloody and non-bloody fluid, whereas conventional MRI is not. These observations demonstrate the advantages of MSKUS over MRI in detecting intra-articular blood, and show that MSKUS is ideal for rapid bleed detection in the clinic.

Ledipasvir-sofosbuvir and sofosbuvir plus ribavirin in patients with chronic hepatitis C and bleeding disorders.

INTRODUCTION: Chronic hepatitis C virus (HCV) infection is prevalent among patients with inherited bleeding disorders and is a leading cause of mortality in those with haemophilia. AIM: We evaluated the efficacy and safety of ledipasvir-sofosbuvir and sofosbuvir plus ribavirin in patients with chronic HCV genotype 1-4 infection and an inherited bleeding disorder. METHODS: Ledipasvir-sofosbuvir was administered for 12 weeks to patients with genotype 1 or 4 infection and for 12 or 24 weeks to treatment-experienced cirrhotic patients with genotype 1 infection. Patients with genotype 2 and 3 infection received sofosbuvir plus ribavirin for 12 and 24 weeks respectively. RESULTS: The majority of the 120 treated patients had a severe bleeding disorder (55%); overall, 65% of patients had haemophilia A and 26% of patients had haemophilia B; 22% were HIV coinfected. Sustained virologic response at 12 weeks posttreatment was 99% (98/99) in patients with genotype 1 or 4 infection; 100% (5/5) in treatment-experienced cirrhotic patients with genotype 1 infection; 100% (10/10) in patients with genotype 2 infection; and 83% (5/6) in patients with genotype 3 infection. There were no treatment discontinuations due to adverse events (AEs). The most frequent non-bleeding AEs were fatigue, headache, diarrhoea, nausea and insomnia. Bleeding AEs occurred in 22 patients, of which all but one were considered unrelated to treatment. CONCLUSION: Treatment with ledipasvir-sofosbuvir for patients with HCV genotype 1 or 4 infection or sofosbuvir plus ribavirin for patients with genotype 2 or 3 infection was highly effective and well tolerated among those with inherited bleeding disorders.

Efficacy and safety of point-of-care ultrasound-guided intra-articular corticosteroid joint injections in patients with haemophilic arthropathy.

INTRODUCTION AND OBJECTIVES: Intra-articular corticosteroid injections are standard of care for managing joint pain secondary to osteoarthritis or rheumatoid arthritis but are rarely used in haemophilic arthropathy. We have introduced and evaluated the efficacy and safety of ultrasound-guided corticosteroid injections for pain relief in patients with haemophilic arthropathy. PATIENTS AND METHODS: Ultrasound-guided intra-articular injections performed on haemophilia patients at UCSD between March 2012 and January 2016 were analysed. Needle placement and injection (40 mg triamcinolone; 3-5 mL lidocaine) were performed with musculoskeletal ultrasound and Power Doppler. Analysis included patient demographics, joint-specific parameters such as tissue hypervascularity and effusions, pain relief, and procedure-associated complications. RESULTS: Forty-five injections (14 ankles, 13 elbows, 18 knees) were administered in 25 patients. Advanced arthropathy with hypervascularity and/or effusions was present in 91% and 61% of joints, respectively. Ninety-one per cent of injections resulted in pain relief which was significant in 84% (>30% reduction). Median pain score was reduced from 7 of 10 to 1 of 10 (P < 0.001), usually within 24 h. Median duration of pain relief was 8 weeks (range 1-16 weeks). Haemophilia B patients experienced longer periods of relief, and high Pettersson scores were associated with shorter duration of relief. There were no procedure-associated complications. Repeat ultrasound of eight joints within 4 weeks of injection demonstrated nearly complete resolution of hypervascularity. CONCLUSIONS: Point-of-care ultrasound enabled intra-articular corticosteroid injections that provided highly effective, safe, and relatively long-lasting pain relief in haemophilic arthropathy. This approach should be used to improve pain management in haemophilic arthropathy.

Haematuria is not a risk factor of hypertension or renal impairment in patients with haemophilia.

INTRODUCTION: An increased prevalence of hypertension has been reported in patients with haemophilia compared to the age-matched general population, although the causes were unclear. To date, there has been limited data implicating haemophilia-specific risk factors such as renal bleeding. AIM: This two-centre prospective cohort study aimed to assess the prevalence of gross/microscopic haematuria, and the associations between haematuria, blood pressure and renal function. METHODS: Of 135 adult males, with mild to severe haemophilia followed by the British Columbia and University of California San Diego Hemophilia Treatment Centers were included. Screening urinalysis and microscopy were performed during all routine visits. Haematuria was defined as history of gross haematuria or >3 red blood cells per high-power field on microscopy in the absence of urinary tract infections. Logistic regressions were used to examine the significance of haematuria and other potential hypertension risk factors. RESULTS: The prevalence of hypertension was 44%, of whom 31% achieved adequate blood pressure control. Despite the high prevalence of haematuria (34%), renal dysfunction was rare. On univariate analysis, age, diabetes, dyslipidemia and obesity were associated with hypertension. On multivariate analysis, only age remains as a significant predictor of hypertension. Haematuria was not associated with hypertension, renal insufficiency or haemophilia severity. CONCLUSION: In this cohort, hypertension and haematuria were prevalent while renal disease was rare. Haematuria was not associated with a diagnosis of hypertension or renal dysfunction. Larger prospective studies are needed to elucidate the mechanisms for increased prevalence of hypertension in haemophilia.

Point-of-care musculoskeletal ultrasound is critical for the diagnosis of hemarthroses, inflammation and soft tissue abnormalities in adult patients with painful haemophilic arthropathy.

We previously demonstrated in adult patients with haemophilia (PWH) that hemarthrosis is present in only ~1/3rd of acutely painful joints by using point-of-care-musculoskeletal ultrasound (MSKUS). Therefore, other unrecognized tissue abnormalities must contribute to pain. Using high resolution MSKUS, employing grey scale and power Doppler, we sought to retrospectively (i) investigate soft tissue abnormalities in painful haemophilic joints and (ii) to determine to what extent MSKUS findings, functional or radiographic joint scores correlate with biomarkers of inflammation in PWH. Findings were correlated with Hemophilia Joint Health Scores (HJHS), Pettersson scores, high sensitivity C-reactive protein and von Willebrand factor activity and antigen levels. A total of 65 MSKUS examinations for acute and chronic joint pains were performed for 34 adult haemophilia patients, mostly for chronic joint pains (72.3%). The most prominent findings (66.5%) pertained to inflammatory soft tissue changes including synovitis, tendinitis, enthesitis, bursitis and fat pad inflammation. Effusions were present in 55.5% and 46.8% of MSKUS performed for acute and chronic pain, respectively. Of those, 90.0% were bloody during acute and 47.6% during persistent pains. While inflammatory biomarkers correlated well with overall HJHS and total Pettersson scores (P < 0.05), they did not differ between those patients with synovitis and those without. MSKUS is emerging as an important modality to diagnose treatable musculoskeletal abnormalities contributing to pain in haemophilic arthropathy, and therefore seems critical for a personalized approach to haemophilia care. The role of biomarkers in this setting remains less clear and requires further investigation.

Risk assessment for coronary heart disease in patients with haemophilia: a single centre study in the United States.

In haemophilia, coronary heart disease (CHD) occurs at a similar frequency as in the general population, but the contributing risk factors in haemophilia are incompletely understood. To investigate risk factors and 10-year CHD risk in a single centre cohort of patients with haemophilia (PWH) ≥20 years old (n = 89). We retrospectively applied the modified Framingham National Cholesterol Education Program/Adult Treatment Panel (NCEP/ATP) III risk prediction equation. Three risk levels were defined: <10% (low), 10-20% (intermediate) and >20% (high). Results were compared to the National Health and Nutrition Examination Survey (NHANES). Mean age in both cohorts was similar. Compared to NHANES, systolic blood pressures were significantly higher in PWH, but current smoking and cholesterol were lower. CHD risk differed significantly between PWH and NHANES (P = 0.005) with a higher proportion of PWH classified at low risk (77.5% vs. 61.0%). The proportion of low risk patients was also significantly higher for severe haemophilia patients compared to non-severe haemophilia patients (88.6% vs. 66.7%, P = 0.02). Among PWH, and compared to PWH who were hepatitis C (HepC) negative, HepC positive patients had significantly lower cholesterol, LDL and triglycerides. The CHD risk of HepC positive patients differed significantly from NHANES (P = 0.03) with a lower proportion of HepC positives being classified as high risk (5.7% vs. 17.3%). Favourable CHD risk classification in PWH may be influenced by low cholesterol associated with HepC infection. Estimates of CHD risk in PWH by composite scoring may not be accurate and will require studies correlating risk factors with incident CHD.

Improved hemostasis in hemophilia mice by means of an engineered factor Va mutant.

BACKGROUND: Factor (F)VIIa-based bypassing not always provides sufficient hemostasis in hemophilia. OBJECTIVES: To investigate the potential of engineered activated factor V (FVa) variants as bypassing agents in hemophilia A. METHODS: Activity of FVa variants was studied in vitro using prothrombinase assays with purified components and in FV- and FVIII-deficient plasma using clotting and thrombin generation assays. In vivo bleed reduction after the tail clip was studied in hemophilia A mice. RESULTS AND CONCLUSIONS: FVa mutations included a disulfide bond connecting the A2 and A3 domains and ones that rendered FVa resistant to inactivation by activated protein C (APC). '(super) FVa,' a combination of the A2-A3 disulfide (A2-SS-A3) to stabilize FVa and of APC-cleavage site mutations (Arg506/306/679Gln), had enhanced specific activity and complete APC resistance compared with wild-type FVa, FVL eiden (Arg506Gln), or FVaL eiden (A2-SS-A3). Furthermore, (super) FVa potently increased thrombin generation in vitro in FVIII-deficient plasma. In vivo, (super) FVa reduced bleeding in FVIII-deficient mice more effectively than wild-type FVa. Low-dose (super) FVa, but not wild-type FVa, decreased early blood loss during the first 10 min by more than two-fold compared with saline and provided bleed protection for the majority of mice, similar to treatments with FVIII. During the second 10 min after tail cut, (super) FVa at high dose, but not wild-type FVa, effectively reduced bleeding. These findings suggest that (super) FVa enhances not only clot formation but also clot stabilization. Thus, (super) FVa efficiently improved hemostasis in hemophilia in vitro and in vivo and may have potential therapeutic benefits as a novel bypassing agent in hemophilia.

Rapid musculoskeletal ultrasound for painful episodes in adult haemophilia patients.

Little objective information exists about musculoskeletal bleeding patterns in haemophilic arthropathy. Bleeding is assumed to be the cause of painful joints or muscles. Clotting factor treatment is provided empirically, but often does not alleviate pain. We hypothesized that perception of pain aetiology is unreliable, and introduced point-of-care high-resolution musculoskeletal ultrasound (MSKUS) to differentiate intra-articular bleeds vs. joint inflammation, and intra-muscle bleeds vs. other regional pain syndromes. To assess painful musculoskeletal episodes in adult haemophiliacs, we used rapid MSKUS, employing grey scale and power Doppler examination. Forty episodes in 30 adult haemophiliacs were evaluated. Thirty three of the 40 episodes were patient-reported as 'bleeding', five as 'arthritis-type' pain and two as 'undecided'. Of the 33 bleeding reports, only 12 were confirmed by MSKUS; the other episodes revealed other pathology. In contrast, three of five perceived arthritis flares were reclassified as bleeds. Similarly, physician assessment was incorrect in 18 of 40 instances. Swelling and warmth were present in approximately half of confirmed bleeding and non-bleeding episodes, and therefore not useful clinically. Few of the painful episodes were symptom controlled at the time of MSKUS. Management changed based on objective imaging findings in >70% of episodes, which resulted in symptom improvement >60% of the time. Significant discrepancies exist between MSKUS findings and patient/physician-perceived pain classification as bleeding or other musculoskeletal symptoms. Current practice of prescribing clotting factor or conservative measures based on pain perception seems inadequate and suggests that point-of-care imaging should be included into modern haemophilia care.

Obesity is an independent predictor of poor survival in metastatic breast cancer: retrospective analysis of a patient cohort whose treatment included high-dose chemotherapy and autologous stem cell support.

The purpose of the study was to identify predictors of long-term survival in metastatic breast cancer (MBC). A cohort of 96 patients, who received high-dose chemotherapy with autologous stem cell support (HD-ASCT) as part of their treatment, was analyzed. Percent long-term survival at 10 years was 24.5% (CI 17.2-34.9%) when metastasis was diagnosed and 14.4% (CI 8.7-23.9%) when MBC was diagnosed. Survival was impacted significantly by body mass index (BMI). Median overall survival from initial diagnosis or from time of metastasis for patients with BMIs ≤30 and >30 (obese) was 7.1 (CI 4.4-8.7) and 3.2 years (2.41-6.75), respectively, or 3.2 or 2.3 years (all P = 0.02). Also, obesity was the only independent patient-related predictor of time to metastasis and of survival. While obesity is linked with poor outcomes in earlier stages of breast cancer, this has not been previously reported for MBC.

The rate of marrow recovery and extent of donor engraftment following transplantation of ex vivo-expanded bone marrow cells are independently influenced by the cytokines used for expansion.

Successful stem cell transplantation depends on cell dose, and this is particularly true for placental/cord blood transplantation in which it has been clearly shown that both the success of engraftment as well as the speed of white cell and platelet recovery are dependent on the nucleated cell dose in the graft. Thus, if stem cell numbers could be increased, the speed as well as the likelihood of engraftment might be improved. We studied the effect of two different cytokine combinations--kit ligand (KL), interleukin-3 (IL-3), and Flt-3 ligand supplemented with thrombopoietin and IL-11 (combination 1) or granulocyte/macrophage colony-stimulating factor (GM-CSF) and G-CSF (combination 2)--for their ability to affect speed and extent of engraftment using limited numbers (5 x 10(4)) of murine bone marrow (BM) light-density (LD) cells or their progeny expanded ex vivo in the presence one or the other cytokine combination for 6 days. With combination 1, we found that speed of platelet recovery was enhanced, but at the expense of white blood cell (WBC) recovery and percent donor engraftment. Furthermore, the cytokine combination that best maintained donor engraftment, combination 2, did so at the expense of platelet recovery. In no case was percent donor engraftment improved over 5 x 10(4) unmanipulated LD BM cells. These results are consistent with the interpretation that immediate recovery of blood cells of different lineages and longterm donor engraftment are separate functions that can be influenced by the choice of cytokines used during the ex vivo expansion process.

Murine bone marrow cells cultured ex vivo in the presence of multiple cytokine combinations lose radioprotective and long-term engraftment potential.

The desire to improve engraftment following transplantation of limited numbers of hematopoietic stem cells (HSC) has spurred the investigation of ex vivo stem cell expansion techniques. While surrogate outcomes, such as an increase in SCID-repopulating cells, suggest successful stem cell expansion in some studies, it is not clear that such assays predict outcomes using a more clinically relevant approach (e.g., myeloablation). We have addressed this by testing three cytokine combinations for their ability to increase the radioprotective and long-term marrow reconstitution capacity of hematopoietic cells cultured ex vivo. Low numbers of light-density (LD) mouse bone marrow (BM) cells or their expanded product were injected into lethally irradiated (9 Gy) congenic recipients. Survival rates and percent donor engraftment were compared at 2, 5, and 7 months post-transplant. The three cytokine combinations used were: (i) kit-ligand (L), thrombopoietin (Tpo), Flt-3 L; (ii) cytokines in (i) plus interleukin-11 (IL-11); (iii) cytokines in (ii) plus IL-3. At 7 months post-transplant, LD cell doses of 10(4), 2-2.5 x 10(4), and 0.5-1.0 x 10(5) gave predictable survivals of 20-30%, 40-70%, and 100%, respectively. Mean percent donor engraftments were 54.9% (SEM 36%), 55.7% (SEM 36%), and 76.3% (SEM 21%), respectively. When cells expanded for 3 or 5-7 days with the various cytokine combinations were transplanted into different groups of mice, survival rates and percent donor engraftment were almost uniformly poorer than results obtained with unmanipulated cells, and cells expanded for 5-7 days led to poorer outcomes than cells expanded for 3 days. Overall, ex vivo expansion of LD BM cells with the cytokine combinations chosen failed to improve transplant outcomes in this model.

Ecto-diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A)-hydrolase is expressed as an ectoenzyme in a variety of mammalian and human cells and adds new aspects to the turnover of Ap4A.

Ap4A and other dinucleotides participate in the regulation of hemostasis and blood pressure control. With the exception of two previously reported surface anchored ectoAp4A-hydrolases on bovine aortic endothelial and chromaffine cells, all Ap4A-hydrolases reported are intracellular or freely soluble. We demonstrated that ectoAp4A-hydrolases are present on a broad variety of cell types of different species: rat mesangial, bovine corneal epithelial, human Hep-G2 and peridontal cells. Ectoenzyme properties were evaluated on rat mesangium cells. Chromatography of purified plasma membranes on Sephacel 300 resulted in enrichment of ectoAp4A-hydrolase and in separation from ectoATPase. In contrast to ATPase, Ap4A-hydrolase was stable at room temperature. EctoAp4A-hydrolase also recognized ATP as substrate, and therefore is not highly specific. The molecular weight was 180 kD. Unlike ectoAMPase ectoAp4A-hydrolase was not attached via a glycosyl-phosphatidylinositol (GPI)-moiety. Concentrations of PI-PLC 10-100-fold higher than effective for ectoAMPase cleavage (10-100 mU/ml) plus extensively extended incubation times up to eight hours did not result in cleavage of ectoAp4A-hydrolase. The enzyme ectoAp4A-hydrolase might presage a direction for pharmaceutical manipulation in the control of blood pressure and hemostasis.

Placental/umbilical cord blood (PCB) stem cells for transplantation: early clinical outcomes and the status of ex vivo expansion strategies.

Placental/umbilical cord blood (PCB) stem cells for transplantation provide a potentially useful alternative for patients who do not have an HLA-matched family or unrelated bone marrow donor. Concerns regarding this source of stem cells include the limited number of stem cells in a PCB unit and the delayed time to platelet engraftment. Because of the limited number of stem cells, there is a very clear cell dose effect for both success of engraftment and time to engraftment. As a result, many transplant centers will only consider PCB stem cells as a second choice for transplanting adults, despite the very favorable profile of post-transplant graft-versus-host disease (GvHD). This has resulted in considerable interest in the development of ex vivo stem cell expansion strategies. This review outlines the current status of PCB transplant outcomes as well as the status of our understanding of stem cell expansion with the currently available technologies. A stem cell dose-limiting effect on outcome will result in a narrower window of clinical indications for the use of this stem cell source, despite the acknowledged reduction in GvHD. The trade-offs between poor engraftment and reduction in fatal or severe chronic GvHD remain to be quantitated.