The risk of alloimmunization to c (Rh4) in R1R1 patients who present with anti-E

BACKGROUND: Because the Rh antigens E (Rh3) and c (Rh4) are relatively immunogenic, it has been suggested that R1R1 (E-, c-) patients who present with anti-E alone receive prophylactic c- (Rh: -4) red cell transfusions. STUDY DESIGN AND METHODS: To determine the utility of this approach, the transfusion records of 100 consecutive R1R1 patients with anti-E identified over a 6-year period were reviewed. RESULTS: Thirty-two (32%) had anti-c concurrent with anti-E. Twenty-seven of the 68 patients who presented with anti-E alone received random (i.e., not typed for c [Rh4]) red cell transfusions. Five (18.5%) of the 27 subsequently developed anti-c 13 to 193 days (mean, 50) after transfusion of 2 to 14 (mean, 8) red cell units. None of the five had clinical evidence of hemolysis that could be attributed to a delayed hemolytic transfusion reaction. Twenty-two (81.5%) of the 27 failed to develop anti-c even after transfusion of 1 to 41 (mean, 9; median, 7) red cell units. CONCLUSION: The overall rate of immunization to c (Rh4) antigen in R1R1 patients with anti-E was 37 percent. Production of anti- c following transfusion to R1R1 patients with anti-E occurred in 18.5 percent of the cases in this series, which could have been avoided by the prophylactic use of R1R1 (E-, c-) blood for transfusion. The prophylactic use of c- (Rh: -4) blood in this patient population may be justified by the high immunization rate and the potential risk of delayed hemolytic transfusion reaction.     

Prolonged neutropenia resulting from antibodies to neutrophil-specific antigen NB1 following marrow transplantation

Marrow graft failure is a significant cause of morbidity following bone marrow transplantation. A case is reported of marrow graft failure due to neutrophil antibodies. A 13-year-old girl with a large granular lymphocytosis and chronic neutropenia was treated with granulocyte transfusions prior to undergoing a transplant with bone marrow from a partially matched, unrelated donor. Following the transplant, a bone marrow biopsy showed engraftment of donor myeloid cells, but the recipient remained neutropenic. Testing of the serum for neutrophil antibodies found that the recipient's serum had a high-titer neutrophil antibody. Immunoprecipitation studies using the marrow recipient's serum and 125I surface-labeled neutrophils showed that the antibody reacted to the neutrophil-specific antigen NB1. Phenotyping of neutrophils from the marrow donor found that they expressed NB1 antigen, and, in a crossmatch assay, the recipient's serum reacted with donor neutrophils. Despite treatment with granulocyte-macrophage– colony-stimulating factor, the marrow transplant recipient remained neutropenic and died of polymicrobial sepsis and aspergillosis 38 days after the transplant. The presence of high-titer antibodies to neutrophil-specific antigen NB1 in this patient following transplant likely prevented the recovery of her peripheral blood neutrophils and contributed to her death.     

荷载角质细胞生长因子纳米微囊脱细胞真皮的制备、特性及其对表皮干细胞群生长的作用

目的:构建一种荷载有角质细胞生长因子且能控制释放的新型组织工程化皮肤。方法:实验于2006-03/12于中山大学附属第二医院干细胞研究中心及中山大学高分子研究所进行。①材料:角质细胞生长因子(CytolLAB公司),牛血清白蛋白(Amresco公司),聚乳酸-羟基乙酸共聚物(由中山大学高分子化学研究所合成,聚乳酸与聚羟基乙酸摩尔比为75∶25,相对分子质量为50000),脱细胞真皮(北京桀亚莱福生物技术有限公司)。②方法:采用超声乳化-溶剂挥发及低温干燥方法,将角质细胞生长因子以牛血清白蛋白作联接包裹在聚乳酸-羟基乙酸共聚物内制成纳米微囊,根据公式计算微囊成球率、载药量及包封率;将微囊溶解于二氯甲烷中,进行体外释放实验检测不同时间牛血清白蛋白吸光度,作出牛血清白蛋白释放曲线;将角质细胞生长因子纳米微囊交联于脱细胞真皮表面,制成荷载角质细胞生长因子纳米微囊脱细胞真皮(KGF-ADM),在扫描电镜下观察微囊形态、分布及其与脱细胞真皮连接情况;采用Ⅰ型胶原酶复合胰蛋白酶消化的方法,从门诊健康患者无菌手术切除的包皮组织中获取表皮细胞单细胞悬液,经免疫荧光检测,证实其中含表皮干细胞,将表皮干细胞群分别接种于KGF-ADM及聚乳酸-羟基乙酸共聚物上,于恒温箱中培养3d后,在扫描电镜下观察细胞形态、生长情况及其与材料连接情况。结果:①纳米微囊成球率为85%,载药量为17.3%,包封率为73.5%。②纳米微囊中牛血清白蛋白可以控制缓慢释放,其释放曲线显示初期释放速度较快(前5d累计释放约40%),后进入缓慢释放期(30d累计释放约75%)。③扫描电镜检测显示纳米微囊形态规则,在KGF-ADM表面分布均匀,与KGF-ADM联接良好,部分分布于KGF-ADM深面;表皮干细胞群在KGF-ADM上生长活跃,细胞形态良好,部分形成克隆。结论:采用该方法可成功构建荷载角质细胞生长因子纳米微囊的新型组织工程化皮肤。     

Antibodies against Mycobacterium paratuberculosis in Crohn's disease

Until recently the investigation of serological responses to mycobacteria in patients with Crohn's disease has been hindered by the considerable degree of cross-reactivity between antigens of M. paratuberculosis, and other mycobacterial subspecies. We evaluated the serological response of Crohn's disease patients to a recently identified species-specific 18 kDa protease-resistant antigen corresponding to M. paratuberculosis bacterioferritin. The 18 kDa antigen was purified from M. paratuberculosis as previously described. Serum was obtained from 40 patients with Crohn's disease, 15 with ulcerative colitis, 25 coeliac patients, and 21 normal blood donors. Antibody levels were measured by enzyme-linked immunosorbent assay (ELISA), with anti-human IgA and IgG alkaline phosphatase conjugate. Antibody titres were expressed as the dilution giving 1/3 of the plateau binding value of a standard positive serum (MT/3). Disease activity of the Crohn's disease cases was assessed using the Harvey- Bradshaw index. There was no statistically significant elevation of the mean IgG or IgA MT/3 titres of Crohn's disease patients over controls. No patients had antibody titres greater than two standard deviations above the mean control MT/3 titres, and there was no significant correlation between Crohn's disease activity and level of antibody titres. These findings make it unlikely that M. paratuberculosis is of primary pathogenic importance in Crohn's disease.      

Granulocyte colony-stimulating factor "mobilized" peripheral blood progenitor cells accelerate granulocyte and platelet recovery after high-dose chemotherapy

Hematopoietic growth factors have been used to accelerate engraftment after bone marrow transplantation and to "mobilize" peripheral blood progenitor cells (PBPC). We report on the data in 85 consecutive patients with Hodgkin's disease who were treated in a single institution using different methods to obtain PB progenitor cells. Use of granulocyte colony-stimulating factor for mobilization resulted in a significantly accelerated time to recovery of granulocytes (10 days v 12 days, P < .01) when compared with "nonmobilized" PBPC recipients. Similarly, use of mobilized PBPC resulted in a significantly accelerated time to platelet engraftment (13 days v 30 days, P < .001) when compared with "nonmobilized" recipients. Moreover, there was a statistically significant difference in total costs in favor of the group receiving "mobilized" PBPC.     

Protection of mice from lethal doses of methotrexate by transplantation with transgenic marrow expressing drug-resistant dihydrofolate reductase activity

Marrow cells from previously established lines of transgenic mice expressing either of two different methotrexate (MTX)-resistant dihydrofolate reductases (DHFRs) were transplanted into recipient animals to determine the resultant in vivo protective effect against toxicity associated with MTX administration. Sublethally irradiated, untransplanted animals were first used to establish conditions of low- dose MTX administration resulting in substantial hematopoietic toxicity with undetectable gastrointestinal toxicity. Under these conditions, low survival rates were observed for normal or transgenic animals not expressing drug-resistant DHFR activity, whereas transgenic animals expressing either the arg22 (line 04) or trp31 (line 03) DHFR variants survived. Transplantation of 10(6) marrow cells from either transgenic lines 03 or 04 rescued normal FVB/N recipient animals from low-dose MTX administration, which was lethal for animals transplanted with 10(6) normal FVB/N marrow cells. Reduced survival of transgenic line 04 marrow recipients was observed when twofold or fourfold doses of MTX were administered. However, when 10(7) transgenic line 04 marrow cells were infused, the recipients were found to be resistant to a MTX dose that was not only lethal for animals transplanted with 10(7) normal FVB/N marrow cells, but also lethal for normal, untransplanted FVB/N mice. Histologic analysis showed protection of both marrow and gastrointestinal tissues from MTX toxicity in transgenic line 04 marrow transplant recipients. Thus, exclusive expression of MTX-resistant DHFR activity in the marrow had a substantial, systemic chemoprotective effect in animals, which could be applied for improved utilization of MTX for antitumor chemotherapy.