We present the results of tests carried out to detect alloimmunization against red cells in 1,200 patients (607 males and 593 females), transfused and followed up during the period 1981-1987 in our hospital. Of these patients, 1,135 were thalassemic and 65 had sickle cell/beta-thalassemia. In 162 patients who received blood matched for the AB0, rhesus and Kell systems from their first transfusion, the immunization rate was very low (3.7%). In a pilot group consisting of 83 patients with the same clinical characteristics, who received blood matched only for the AB0 and Rh-D antigens, there was a significant difference in the frequency of alloantibodies (15.7%, p less than 0.001). Of 1,038 patients who received blood only matched for AB0 and Rh-D 244 (23.5%) with one or more red cell alloantibodies were identified. Of these 1,038 patients, 973 were exclusively thalassemic. In 220 (22.6%) of them, alloantibodies were found. The sickle cell beta-thalassemia patients presented alloantibodies with a higher frequency (36.9%, 24/65). Only one antibody was found in 114 patients (51.8%) and two or more in 106 patients (48.2%). The alloimmunization significantly concerned the rhesus (34.0%) and Kell (29.8%) systems. Anti-Kell was most often identified (28.5%). Alloimmunization appears considerably lower in patients in whom blood transfusion is started before the age of 3 than in those in whom it is started after that age (20.9 vs. 47.5%, p less than 0.0001).

The 5-transmembrane receptor AC133 is expressed on a subpopulation of human hematopoietic cells that includes the CD34(bright) cells. We evaluated the developmental potential of AC133+CD34(bright) and AC133(dim/-)CD34+ cells isolated from 5 cord blood (CB) samples by studying the in vitro proliferative and differentiative potential of each population in both progenitor and mature cell expansion cultures. Seven-day culture of AC133+CD34(bright) cells with a cytokine combination favoring primitive progenitor cells causes a significant increase in CD34+, CFU-C and noncycling stem/progenitor cells HPP-Q (High Proliferative Potential-Quiescent), whereas culture of AC133(dim/-)CD34+ cells shows a limited increase in committed progenitor cells only. HPP-Q cells were not found in freshly isolated AC133(dim/-)CD34+ nor in expanded CD34+ cells derived from AC133(dim/-)CD34+ cells. No statistically significant difference was observed between the 1-week expanded AC133+ and the initial AC133+CD34(bright) cells regarding their clonogenic efficiency (CE), while expanded CD34+ cells derived from AC133(dim/-)CD34+ cells exhibited a decreased CE. Subexpansion of the reselected AC133+ derived from AC133+CD34(bright) cells reveals a further increase of stem/progenitor cells and the 14-day expanded AC133+ cells reveal an unchanged CE. Subexpansion of reselected 7-day CD34+ cells derived from AC133(dim/-)CD34+ cells was not possible. Culture of AC133+CD34(bright) cells in cytokines that favor megakaryopoiesis or erythropoiesis resulted in a significant expansion of CD41+ and CD71+ cells, respectively; AC133(dim/-)CD34+, in comparison, showed a limited potential to megakaryocytic differentiation and a decreased production of erythroid cells. Our data indicate that early high proliferating stem/progenitor cells and early committed progenitors are present in AC133+CD34(bright) cells, but not in AC133(dim/-)CD34+ cells; the latter represent late committed progenitors with limited proliferative potential.

We present the results of tests carried out to detect alloimmunization against red cells in 1,200 patients (607 males and 593 females), transfused and followed up during the period 1981:1987 in our hospital. Of these patients, 1,135 were thalassemic and 65 had sickle cell/β-thalassemia. In 162 patients who received blood matched for the AB0, rhesus and Kell systems from their first transfusion, the immunization rate was very low (3.7%).In a pilot group consisting of 83 patients with the same clinical characteristics, who received blood matched only for the AB0 and Rh-D antigens, there was a significant difference in the frequency of alloantibodies (15.7%, p<0.001). Of 1,038 patients who received blood only matched for AB0 and Rh-D 244 (23.5%) with one or more red cell alloantibodies were identified. Of these 1,038 patients, 973 were exclusively thalassemic. In 220 (22.6%) of them, alloantibodies were found. The sickle cell B-thalassemia patients presented alloantibodies with a higher frequency (36.9%, 24/65). Only one antibody was found in 114 patients (51.8%) and two or more in 106 patients (48.2%). The alloimmunization significantly concerned the rhesus (34.0%) and Kell (29.8%) systems. Anti-Kell was most often identified (28.5%). Alloimmunization appears considerably lower in patients in whom blood transfusion is started before the age of 3 than in those in whom it is started after that age (20.9 vs. 47.5%, p<0.0001).

The authors report on three children with beta-thalassemia major, class II, III, and III according to the Pesaro classification, with a body weight of 16, 62, and 50 kg, respectively, who received grafts using both umbilical cord blood (UCB) and bone marrow (BM) stem cells from their HLA-matched siblings. The number of UCB nucleated cells collected was 2 x 10(7)/kg, 1.2 x 10(7)/kg, and 2.5 x 10(7)/kg, respectively, and was considered insufficient to secure engraftment. The authors increased the number of hematopoetic progenitors by harvesting BM from the same donors. All 3 patients showed prompt engraftment with neutrophil recovery on days 17, 18, and 17 post-transplant, respectively, and platelet recovery on days 19, 25, and 22 post-transplant, respectively. One patient had remarkably increased HbF of values 31, 19, and 12% at 3, 6, and 12 months post-transplant, respectively, which were accompanied by an increase in the G gamma/A gamma ratio, suggesting UCB-derived hematopoetic reconstitution. All patients are alive and transfusion independent 23, 18, and 16 months post-transplant, respectively. For patients with homozygous beta-thalassemia who are at high risk of graft failure, either because of major prior alloimmunization or an insufficient amount of UCB stem cells, combined transplantation with UCB and BM could offer a quick and safe alternative therapy.

Bone marrow transplantation (BMT) can induce short- and long-term impairment of gonadal function. Patients with beta-thalassemia represent a special group, as their primary diagnosis and its treatment modalities are responsible for gonadal dysfunction. To address the effect of BMT on puberty and gonadal function, we investigated 25 patients (12 males) with thalassemia who received allogenic BMT during childhood or adolescence and at the post-transplant evaluation were at an age that the pubertal process should have started. Pubertal stage by Tanner of breast and pubic hair, as well as testicular volume were assessed pre-BMT once and post-BMT at least twice. Menstrual history was recorded. FSH, LH, testosterone and estradiol levels were also determined. The impact of BMT appears to be different in the two sexes. Males seem to have higher tolerance, as all males who were pubertal at the time of BMT had normal testosterone, and all but one normal gonadotropin levels. From those who were prepubertal at BMT, 62% proceeded to normal pubertal development. Post-menarcheal females seem to be an extremely sensitive group to the deleterious effect of the transplantation process, as 100% of the post-menarcheal females exhibited amenorrhea and elevated gonadotropin levels. These findings are important for pre- and post-BMT counseling.