Experience with donors matched for minor blood group antigens in patients with sickle cell anemia who are receiving chronic transfusion therapy

Clinically significant alloimmunization to red cell antigens occurred in 28 percent of transfused patients in a sickle cell clinic. Therefore, a prospective study was undertaken to determine whether matching donors carefully for 17 blood group antigens would diminish the risk of further alloimmunization in patients on a chronic transfusion program. Alloantibodies had developed previously in 8 of the 12 patients. After chronic transfusion with selected donors, four new antibodies developed in three patients. Three antibodies were due to errors in phenotyping or matching, and one was due to an antigen that was not tested for in the protocol. The incidence of developing antibodies per unit transfused was diminished tenfold when selected donors were used. Autoantibodies developed in five patients (42%), but these did not seriously interfere with the transfusion therapy. It was concluded that matching for red cell antigens may diminish the incidence of alloimmunization in patients with sickle cell anemia requiring transfusion.     

Hyperhemolytic transfusion reaction in sickle cell disease

BACKGROUND: An atypical form of life-threatening hemolytic transfusion reaction (HTR) in patients with sickle cell disease (SCD) has been well described in the literature. Continuation of blood transfusion may be lethal, as it can further exacerbate hemolysis. The pathophysiologic mechanism of HTR is not well understood. CASE REPORTS: Two cases of severe HTR in SCD after the transfusion of compatible RBC units are reported. Hemolysis of both autologous and transfused cells was documented in Case 1 by urine Hb high-performance liquid chromotography. Multispecific HLA antibodies were identified in Case 1. Reticulocytopenia was noted in both cases during the acute hemolytic process. This was followed by a rise in reticulocyte count during receipt of IVIG and steroid therapy. Bone marrow examination during reticulocytopenia in Case 2 showed erythroid hyperplasia. CONCLUSION: In SCD, both mature sickle cells and sickle reticulocytes adhere more readily to macrophages. In view of the bone marrow aspiration results, it appears that the recipients' HbS cells are destroyed by hyperactive macrophages and that the reticulocytopenia observed during HTR is likely to be due to peripheral consumption (i.e., destruction by macrophages), rather than suppression of erythropoiesis. Cessation of hemolysis during IVIG and steroid treatment may be due to IVIG's blocking of the adhesion of sickle cells and reticulocytes to macrophages, together with steroid suppression of macrophage activity.     

Adenotonsillectomy in children with sickle cell disease

The pediatric patient with sickle cell disease risks having a vasoocclusive episode during adenotonsillectomy under general anesthesia. With proper patient selection and appropriate perioperative management, adenotonsillectomy can be accomplished safely in children with sickle cell disease. We review the management of 10 children with sickle hemoglobinopathies who had adenotonsillectomy. Indications for surgery were recurrent streptococcal infections in four and obstructive sleep apnea in six of these children. No complications resulted from any of these procedures, and the mean length of postoperative hospitalization was 2.4 days. The principal feature of preoperative management was the transfusion of red blood cells to suppress the patient's endogenous erythropoiesis and to reduce the concentration of sickle cell hemoglobin to less than 30%. Though a prospective, multi-institutional clinical trial will ultimately be required to settle the issue of the safest preoperative management of children with sickle cell disease, balancing the risks of transfusion-related complications against anesthesia-related complications, our experience supports the operative safety of hypertransfusion therapy in children with sickle cell disease.     

Distinct patterns of response to transfusion therapy for different chronic complications of sickle cell disease: A useful insight

Two main sub-phenotypes have been described in sickle cell disease: one with higher baseline haemoglobin and a higher rate of painful crises and one with lower baseline haemoglobin, increased markers of haemolysis and a higher incidence of pulmonary hypertension, priapism and leg ulcers. We compared the patterns of response to regular automated red cell exchange transfusion over a five-year period of 21 patients with recurrent painful crises from the first group and 3 patients with pulmonary hypertension and 5 with recurrent severe stuttering priapism form the second and found them to be distinctly different. Response for pain is slow and increases gradually over years. The most pronounced clinical benefit and the one that appears first is a reduction in the severity rather than the frequency of painful crises. In contrast to the slow and gradual response we see for pain, response of patients with pulmonary hypertension and priapism is immediate with significant clinical improvement even after the first transfusion. The response appears to be directly correlated to the HbS level as the symptoms of both conditions invariably recur rapidly when transfusions are delayed or discontinued but resolve again once they are re-instituted.     

Modified method of exchange transfusion in sickle cell disease

The treatment of various complications of sickle cell disease has included red cell exchange in the past, and the development of automated pheresis equipment has greatly simplified such exchanges. Traditionally, the patient's red cells have been exchanged while their plasma was returned to them. Recently, plasma factors have been thought to play a role in the pathogenesis of vasoocclusive events. Therefore, we performed whole blood exchange, which consisted of replacement of the patient's plasma with albumin and saline in addition to the usual replacement of erythrocytes. A total of 32 whole blood exchanges were performed on 12 patients with a variety of complications of their disease. The procedure was done using standard pheresis equipment and was relatively simple to perform. There were no serious complications and the clinical outcome was good with 10 out of 12 patients experiencing improvement.