Use of multiple T cell-directed intact ricin immunotoxins for autologous bone marrow transplantation

The monoclonal antibodies (MoAb) T101, G3.7, 35.1, and TA-1 were conjugated to intact ricin using a thioether linkage. These MoAb detect, respectively, the CD5[gp67], CD7[p41], CD2[p50], and [gp95, 170] determinants that are found in the vast majority of cases of T cell acute lymphocytic leukemia (T-ALL). The resulting immunotoxins (ITs) and an equimolar mixture of these ITs were evaluated as potential purgative reagents for autologous transplantation in T-ALL. Leukemic cell lines were used to compare the kinetics of protein synthesis inactivation mediated by each IT. The cells were treated with IT in the presence of lactose in order to block the native binding of ricin. The observed rates of protein synthesis inactivation correlated with target antigen expression detected by fluorescence-activated cell sorter analysis. Of the four ITs, T101-ricin (T101-R) exhibited the fastest rate of inactivation, followed in order by G3.7-ricin, TA-1-ricin, and 35.1-ricin. At concentrations greater than 300 ng/mL, a cocktail containing an equimolar amount of all four ITs (referred to as the four- IT cocktail) exhibited kinetics that were as fast or faster than those of T101-R. The long-term cytotoxic effects of individual ITs and the four-IT cocktail were evaluated using a sensitive clonogenic assay. Each IT was specifically cytotoxic and inhibited 1 to 4 logs of clonogenic leukemic cells at doses (300 to 600 ng/mL) that can be used clinically. The four-IT cocktail was highly cytotoxic; a concentration of 300 ng/mL inhibited greater than 4 logs of leukemic cells while sparing the majority of committed (CFU-GM, CFU-E) and pluripotent (CFU- GEMM) hematopoietic stem cells. The determination of both short-term kinetics of protein synthesis inactivation and longer-term inhibition of clonogenic growth allowed new insight into cell killing by IT. Our results suggest that ITs continue to act on clonogenic target cells for a period of three to five days. Interestingly, the four-IT cocktail was not as potent against clonogenic leukemic cells as T101-R alone, although it exhibited kinetics of protein synthesis inhibition that were as fast as those of T101-R alone. This finding suggests that internalized ITs may differ in the length of time they remain active within the cell. Our results also demonstrate the importance of using several different assays to evaluate IT reagents.     

Transplantation of Haploidentical TcRaß‐Depleted Hematopoietic Cells Allows for Optimal Timing and Sustained Correction of the Metabolic Defect in Children With Infantile Osteopetrosis

In osteopetrosis, osteoclast dysfunction can lead to deafness, blindness, bone marrow failure, and death. Hematopoietic cell transplantation (HCT) is currently the only curative treatment, but outcome remains disappointing. Although a rapid progression toward HCT is detrimental to prevent further progress of disease manifestations, 70% of cases lack an HLA‐matched sibling and require alternative stem cell sources. We present two cases of osteopetrosis that successfully received an HCT with haploidentical TcRαβ‐depleted cells from one of the parents. These cases showed no further disease progression, had restoration of functional osteoclasts, and illustrate this approach to enable prompt HCT with ready available parental donors and rapid and sustained hematological, including osteoclast, recovery. © 2016 American Society for Bone and Mineral Research.     

Complications of distraction lengthening in the hand

This study examined the features of 16 complications from 51 distraction lengthenings in the hands of 43 patients. From 1996 to 2006, 24 metacarpals and 27 phalanges were lengthened at a rate of 0.5 and 0.25 mm/day, respectively, using a callus distraction technique. The indications were congenital (33 cases in 27 patients) and traumatic (18 cases in 16 patients) deformities. The average percentage lengthening in the phalanges and metacarpals was 62% (16 mm) and 63% (34 mm), respectively. The distraction rates in the phalanges and metacarpals were 69 and 52 days/cm, respectively. The overall complication rate was 31%. Major complications requiring secondary procedures were non-union (one case), fracture (one case), premature union (one case), angulations (two cases) and dislodgment of pins (two cases). The minor complications encountered were delayed callus formation (four cases), joint stiffness (four cases) and soft tissue thinning (one case). Traumatic deformities had more complications than the congenital ones (nine of 18 cases and seven of 33 cases, respectively). The phalanges had a higher rate of complication than the metacarpals (11 of 27 cases and four of 24 cases, respectively). Most patients with complications except for two children with dislodgment were as satisfied with the final results as those without complications. Although callus distraction in the hand requires a long treatment period and has a relatively high rate of complication, it appears to be effective in achieving adequate bone length. A high level of patient compliance and prompt management of complications by an experienced surgeon are essential for achieving good results.     

Lipid Levels: A Link Between Cardiovascular Disease and Osteoporosis?

Epidemiological observations support a positive relationship between cardiovascular diseases (CVD) and osteoporosis, where cholesterol has been indicated to be a possible link. Only a few studies have investigated the relation between lipids and BMD, but the association remains unclear. We studied the relationship between serum lipids and BMD of the calcaneus. A cross‐sectional population‐based study was performed, based on data from the Longitudinal Aging Study Amsterdam, including 620 men and 635 women, 65–88 yr of age. BMD was measured by quantitative ultrasound (QUS), velocity of sound (VOS; m/s), and broadband ultrasound attenuation (BUA; dB/MHz). Models were adjusted for age, body mass index, physical activity, smoking, alcohol, diabetes mellitus, hypertension, testosterone, and 25‐hydroxyvitamin D. No association was found between total cholesterol (TC) and QUS. Men and women in the highest quartile of high‐density lipoprotein cholesterol (HDL‐c) had a significantly lower QUS (men—VOS: β = ?20.8, p = 0.00; BUA: β = ?5.2, p = 0.02; women—VOS: β = ?18.6, p = 0.00) compared with men and women in the lowest quartile. An even stronger positive association was seen between TC/HDL‐c ratio and QUS (men—VOS: β = 21.8, p = 0.00; BUA: β = 5.5, p = 0.01; women—VOS: β = 19.2, p = 0.00; BUA: β = 3.6, p = 0.05). Our analysis shows that the lipid profile that is favorable in the prevention of CVD (i.e., high levels of HDL‐c and low TC/HDL‐c ratio) is unfavorable for QUS. These results indicate that HDL‐c levels do not explain the association between osteoporosis and CVD.     

Immunohistochemical localization of membrane and alpha-granule proteins in human megakaryocytes: application to plastic-embedded bone marrow biopsy specimens

Using a new technique for antigen localization, we have demonstrated platelet proteins in megakaryocytes in plastic-embedded biopsy specimens of normal human bone marrow. In a series of 25 specimens, megakaryocytes showed labeling with antibodies to the integral membrane glycoproteins IIIa, IIb, and the IIb-IIIa complex; granule membrane protein 140; and five alpha-granule matrix proteins: thrombospondin, factor VIII-related antigen, beta-thromboglobulin, platelet factor 4, and fibrinogen. The antibodies to the membrane glycoproteins IIIa, IIb, and IIb-IIIa produced diffuse cytoplasmic staining and heavier staining on the plasma membrane, whereas the antibodies to the alpha-granule matrix proteins produced a distinct granular staining within the cytoplasm. Staining for granule membrane protein 140 was also granular in distribution. Rare mononuclear cells consistent with megakaryocyte precursors were labeled with these markers. Other enzyme histochemical and lectin-binding studies showed that the enzyme alpha-naphthyl acetate esterase, the lectin Ulex europaeus I, and the periodic-acid Schiff reaction were consistent, but not specific, markers of megakaryocytes. This immunohistochemical technique should facilitate the examination of qualitative and quantitative changes in megakaryocytes in a variety of physiologic and pathologic processes.     

Physician communication styles in initial consultations for hematological cancer

Objective

To characterize practices in subspecialist physicians’ communication styles, and their potential effects on shared decision-making, in second-opinion consultations.

Methods

Theme-oriented discourse analysis of 20 second-opinion consultations with subspecialist hematologist-oncologists.

Results

Physicians frequently “broadcasted” information about the disease, treatment options, relevant research, and prognostic information in extended, often-uninterrupted monologs. Their communicative styles had one of two implications: conveying options without offering specific recommendations, or recommending one without incorporating patients’ goals and values into the decision. Some physicians, however, used techniques that encouraged patient participation.

Conclusions

Broadcasting may be a suboptimal method of conveying complex treatment information in order to support shared decision-making. Interventions could teach techniques that encourage patient participation.

Practice implications

Techniques such as open-ended questions, affirmations of patients’ expressions, and pauses to check for patient understanding can mitigate the effects of broadcasting and could be used to promote shared decision-making in information-dense subspecialist consultations.     

Characteristics and management of the haemophilia‐associated pseudotumours

The management of haemophilia‐associated pseudotumours presents an ongoing challenge to the haematologist, surgeon and interventional radiologist alike. There is a range of therapeutic approaches including factor replacement, embolization, radiotherapy and a variety of surgical interventions. However, there remains little evidence regarding the most appropriate treatment. We aimed to evaluate the available options of management for the haemophilia‐associated pseudotumour. A literature review was performed using relevant terminology and reviewed for treatment approaches and outcomes. The results demonstrated that most of the data is from single case reports with a small number of single‐ and multicentre case series. In total, 133 patients with 134 described pseudotumours were identified. Adequate haemostatic control with factor replacement was a key component to successful treatment. Surgical excision was the most commonly reported surgical intervention with various composites used for filling of the surgical cavity. The use of radiotherapy has been described particularly in the paediatric population and sites of difficult surgical access. Embolization can be considered as a method of presurgical optimization. Patients with both factor inhibitors and pseudotumours have poorer postoperative outcomes. This review demonstrates that although a lack of large‐centre, randomized studies, timely surgical intervention with adequate haemostatic support and the consideration adjuvant therapies in selected cases can achieve acceptable outcomes in this cohort of patients.