FK506 in combination with methotrexate for the prevention of graft- versus-host disease after marrow transplantation from matched unrelated donors

The safety and potential efficacy of FK506 in combination with a short course of methotrexate (MTX) for the prevention of acute graft-versus- host disease (GVHD) after marrow transplantation from HLA-matched unrelated donors was evaluated in a single-arm Phase II study conducted at two centers. Forty-three patients, 15 to 54 (median 41) years of age, were transplanted for hematologic malignancies. Thirty-seven of 43 evaluable patients had evidence of sustained marrow engraftment. Five patients died before day 17 after transplantation. The median time to an absolute neutrophil count of > 0.5 x 10(5)/L was 21 (range, 14 to 30) days. Nephrotoxicity (serum creatinine concentration > 2 mg/dL or doubling of baseline) occurred in 32 patients (74% cumulative incidence during the first 100 days after transplant). Other adverse effects included hypertension (n = 27), hyperglycemia (n = 27), neurotoxicity (n = 9) and thrombotic thrombocytopenic purpura (n = 2). Severe veno- occlusive disease of the liver occurred in 9 (21%) of the 43 patients. Eighteen patients (42%) developed grades II to IV acute GVHD and five (12%) developed grades III to IV acute GVHD. Twelve of 25 evaluable patients developed extensive chronic GVHD within 1 year of marrow transplantation resulting in an estimate of the probability of developing this complication of 48%. The cumulative incidence of transplant-related mortality during the first 100 days was 37%. Kaplan- Meier estimates of disease-free survival at 2 years for good-risk, poor- risk, and all patients were 65%, 4%, and 32%, respectively. FK506 in combination with a short course of MTX appears active in preventing acute GVHD after marrow transplantation from unrelated donors. Further studies comparing the combination of FK506 and MTX with cyclosporine and MTX for the prevention of acute GVHD are warranted.     

Membrane abnormality in red blood cells with weak type B expression

The mechanisms of unusually weak blood group (A and B) expressions are not yet well understood. We examined properties of blood group galactosyltransferase (B-enzyme) and characteristics of red cell membrane components obtained from family members with A2Bm character. B- enzyme activity of the A1Bm plasma is in normal range, and kinetic properties (i.e., Km for UDP-Gal, Km for 2'-fucosyllactose, and pH optima) of B-enzyme from the A1Bm subjects are identical to that of normal B-enzyme. When A1Bm red cell were incubated with UDP-Gal and B- enzyme, the cells became strongly agglutinable with anti-B. When A1Bm membranes were incubated with B-enzyme or A-enzyme (i.e., blood group N- acetylgalactosaminyltransferase) and the appropriately labeled nucleotide sugar (UDP-Gal3H for B-enzyme and UDP-GalNAc3H for A- enzyme), significant incorporation of the sugar was observed. The amounts of the sugar incorporated into A1Bm membranes were about 40%- 50% of that incorporated into O membranes at saturation, indicating that about one-half of H-sites remained unglycosylated in A1Bm red cells. Examination of radioactive components by isoelectric focussing revealed that the labeled components of A1Bm membranes were distinctively different from that of O membranes. Therefore, one can conclude that the weak B expression is not due to direct mutation of ABO locus, but due to a secondary consequence of genetic abnormality of a membrane component (or components) associated with blood group substances.     

The diagnostic dilemma of congenital unstable hemoglobinopathies

Unstable hemoglobin variants represent a rare etiology of congenital hemolytic anemia. Without a high index of suspicion, plus proper laboratory testing and interpretation, the correct diagnosis can be elusive. We report on five children who were initially thought to have other congenital disorders such as hereditary spherocytosis or thalassemia, before β‐globin gene sequencing led to the definitive diagnosis. Recognizing the variable clinical presentation and laboratory data reported will aid clinicians in diagnosis of unstable hemoglobins variants in children with atypical forms of hemolytic anemia, particularly those with low pulse oximetry values or whose hemoglobin electrophoresis suggest β‐thalassemia trait. Pediatr Blood Cancer. 2010;55:1393–1395. © 2010 Wiley‐Liss, Inc.     

Multi-detector computed tomography evaluation of tracheobronchial anomaly in pediatric patients with left pulmonary artery sling

The left pulmonary artery sling (LPAS) is a rare vascular anomaly causing respiratory distress in which the left pulmonary artery arises from the posterior aspect of the right pulmonary artery,courses posteriorly to the right of the bronchus and passes between the trachea and oesophagus to reach the hilum of the left lung.The LPAS is frequently associated with tracheobronchial tree anomalies and congenital cardiac defects.Proper assessment of the tracheobronchial and cardiovascular anomaly is essential in LPAS for planning management of the patient.Currently,the most important prognostic factor is considered to be an associated tracheobronchial tree anomaly.1 The purpose of this study was to demonstrate the role of multi-detector computed tomography (MDCT) for diagnosing LPAS and assessing the anatomical relationship with tracheobronchial tree anomaly.     

Therapy for ongoing graft-versus-host disease induced across the major or minor histocompatibility barrier in mice with anti-CD3F(ab')2-ricin toxin A chain immunotoxin

A new pharmacologic agent, anti-CD3F(ab')2-ricin toxin A chain (RTA), was synthesized for the purpose of targeting T cells and as a means of treating established graft-versus-host disease (GVHD). The Fc region of anti-CD3 monoclonal antibody (MoAb) was removed to prevent its ability to activate T cells. The resulting F(ab')2 fragments were conjugated to deglycosylated RTA (dgRTA), a catalytic and potent phytotoxin. The resulting immunotoxin (IT) was potent (greater than 95% inhibition) and selective in inhibiting T-cell mitogenesis in vitro. In vivo, the IT depleted 80% of T cells in mice receiving bone marrow (BM) transplants. Transplantation in an aggressive acute GVHD model using C57BL/6 donor cells and H-2 disparate B10.BR recipients resulted in an infiltration of CD3-expressing cells and a median survival time (MST) of 20 to 30 days. A 5-day course of anti-CD3F(ab')2-RTA (30 micrograms/d intraperitoneally) beginning 7 days after GVHD induction was beneficial in treating established GVHD in these mice, as evidenced by significantly prolonged survival (MST, greater than 80 days), superior mean weight values, and improved clinical appearance. Neither intact anti-CD3, unconjugated anti-CD3 F(ab')2 fragments, nor a mixture of anti-CD4 and anti-CD8 MoAbs (which are highly effective in prophylactic models) were as effective. F(ab')2 fragments made from anti-Lyt-1 (the murine homologue of human anti-CD5) linked to RTA were also not effective, despite the fact that both anti-CD3F(ab')2-RTA and anti-Lyt- 1F(ab')2-RTA had similar half-lives of about 9 hours. The IT also increased MST in two aggressive models of GVHD across non-H-2 minor histocompatibility barriers, indicating that the usefulness of anti- CD3F(ab')2-dgRTA is not limited to a single-strain combination. This agent should be further investigated as an alternative to current strategies for treating steroid refractory GVHD.