Transfusion service knowledge and immunohaematological practices related to sickle cell disease and thalassemia.

OBJECTIVES: To assess current knowledge of National Heart, Lung and Blood Institutes (NHLBI) and Thalassemia International Federation (TIF) recommendations, blood banking practices and perceived challenges among transfusion services in the management of patients with haemoglobinopathies. BACKGROUND: Previous reports have demonstrated variations in transfusion practices for sickle cell disease (SCD) and thalassemia patients. Recently, NHLBI/TIF have provided transfusion recommendations for patients with haemoglobinopathies. METHODS: A cross-sectional survey was conducted of transfusion services from the state of Georgia previously identified as having SCD/thalassemia populations. The survey assessed transfusion service practices in pre-transfusion testing and blood product selection; awareness/implementation of NHLBI/TIF transfusion-based recommendations and perceived challenges in transfusing haemoglobinopathy patients. RESULTS: Responses were received from 35 of 49 (71%) institutions. Only institutions indicating transfusing SCD or thalassemia patients (32) were included in analysis. Seventy-one percent of non-sickle cell treatment centres (SCTCs) and 20% of non-thalassemia treatment centres follow NHLBI and TIF recommendations to perform a red blood cell phenotype beyond ABO/Rh(D) and provide Rh and Kell prophylactically matched units for SCD and thalassemia patients, respectively. Forty percent of institutions (33% of non-SCTCs) employ RBC genotyping to evaluate the red cell phenotype for SCD patients. Over 77% of institutions do not utilise a reliable method to identify SCD patients prior to transfusion, such as a required question/answer field on type/screen or crossmatch orders. CONCLUSION: Many healthcare systems' transfusion practices for haemoglobinopathy patients are discordant with NHLBI/TIF recommendations. Efforts are needed to increase awareness and implementation of current recommendations among all transfusion services seeing these patients.

Techniques for blood administration in sickle cell patients.

Transfusion therapy provides many benefits to Individuals with sickle cell disease but may lead to cardiovascular complications, alloimmunization, exposure to infection, and iron overload. Simple transfusion is used to increase oxygen-carrying capacity. Chronic simple transfusion is useful in preventing a number of complications in sickle cell disease. Acute erthrocyte exchange transfusion can reduce the percentage of cells containing sickle hemoglobin while decreasing volume overload and minimizing hyperviscosity. Chronic erythrocyte exchange transfusion reduces iron loading but Increases donor exposure. Directed odnation may reduce alloimmunization and exposure to infection.

Acute multiorgan failure syndrome: a potentially catastrophic complication of severe sickle cell pain episodes.

The purpose of this report is to characterize the acute multiorgan failure syndrome that complicates some episodes of sickle pain. A retrospective chart review was used to identify episodes of sickle pain complicated by the acute failure of at least two of three organs: lung, liver, or kidney. The defining criteria of organ failure were established, and the clinical characteristics, laboratory values, treatment methods, and outcomes were noted in episodes that met the criteria. Seventeen episodes of acute multiorgan failure were identified in 14 patients, 10 with sickle cell anemia and 4 with hemoglobin SC disease. Most episodes occurred during a pain event that was unusually severe for the patient. The onset of organ failure was associated with fever, rapid fall in hemoglobin level and platelet count, nonfocal encephalopathy, and rhabdomyolysis. Bacterial cultures were negative in all but four episodes. Aggressive transfusion therapy was associated with survival and with rapid recovery of organ function in all but one episode. The syndrome developed in patients who had previously exhibited relatively mild disease with little evidence of chronic organ damage and relatively high hemoglobin values in steady state. Acute multiorgan failure syndrome is a severe, life-threatening complication of pain episodes in patients with otherwise mild sickle cell disease. The syndrome appears to be reversed with prompt, aggressive transfusion therapy. High baseline hemoglobin levels may represent a predisposing factor.

Comparison of liquid and dried blood for neonatal hemoglobinopathy screening: laboratory and programmatic issues.

OBJECTIVES: To compare laboratory and programmatic issues in neonatal hemoglobin screening in two systems using either liquid cord blood or heel puncture blood dried on filter paper (DB) to determine the accuracy of hemoglobin phenotype; the collection rate of cord blood versus DB; and the types of and reasons for errors. METHODS: Cord blood samples for 6904 newborns were analyzed by electrophoresis in a large hospital laboratory. DB samples on the same cohort were analyzed by isoelectric focusing in a state public health laboratory. RESULTS: Interlaboratory concordance was 99.4% for 6904 matched specimen pairs, which included 27 disease and 596 carrier phenotypes. In 42 pairs, discordances for potential disease phenotypes occurred with cord blood samples. Errors involving carrier phenotypes occurred in 15 cord blood samples and 14 DB samples. Inconclusive results requiring repeat testing occurred more often in the cord blood testing system (92) than in the DB system (23). Clerical transcriptions and limitations of the techniques accounted for most laboratory errors. Noncompliance in sample collection occurred more frequently with cord blood (181) than DB (86). CONCLUSIONS: Both systems are subject to errors, but are equally reliable for neonatal hemoglobinopathy screening.

Reduction of pain episodes and prothrombotic activity in sickle cell disease by dietary n-3 fatty acids.

The effects of dietary n-3 fatty acids (n-3FAs) on the frequency of pain episodes and ex vivo blood tests of thrombosis have been evaluated in patients with sickle cell disease (SCD) utilizing a double-blind, olive oil-controlled clinical trial. Dietary n-3FA therapy (0.1 g/kg/d) was provided as menhaden fish oil (0.25 g/kg/d) containing 12% eicosapentaenoic acid (EPA), and 18% docosahexaenoic acid (DHA). Within 1 month dietary n-3FAs exchanged with n-6FAs in plasma and erythrocyte membrane phospholipids (p <0.01 in all cases). Treatment with dietary n-3FAs for 1 year reduced the frequency of pain episodes requiring presentation to the hospital from 7.8 events during the preceding year to 3.8 events/year (p <0.01; n = 5). By contrast, subjects receiving control dietary olive oil (n = 5) experienced 7.1 pain events/year, compared to 7.6 during the previous year (p >0.4). The reduction in episodes in n-3FA-treated subjects was also significant when compared to control subjects (p <0.01). Dietary n-3FA therapy was not associated with hemorrhagic, gastrointestinal or other adverse effects. Compared to 10 asymptomatic African-American controls, sickle cell subjects demonstrated significantly increased pretreatment: 1) flow cytometric expression of platelet membrane P-selectin (CD62p; p <0.01) and annexin V binding sites (p = 0.02); 2) plasma levels of platelet-specific secretory proteins platelet factor 4 (PF4) and beta-thromboglobulin (betaTG) (p <0.01 in both cases); 3) plasma products of thrombin generation, prothrombin fragment 1.2 (F1.2) and thrombin:antithrombin (TAT) complex (p <0.01 in both cases); and 4) plasma levels of thrombolytic products, D-dimer and plasmin:antiplasmin (PAP) complex (p <0.01 in both cases). Treatment with dietary n-3FAs concurrently decreased plasma levels of F1.2, D-dimer, and PAP (p <0.05, compared to olive oil controls), implying that the reduction in pain events was related to n-3FA-dependent inhibition of thrombosis. We conclude that dietary n-3FAs reduce the frequency of pain episodes perhaps by reducing prothrombotic activity in sickle cell disease.

Practical guide to the diagnosis of thalassemia. Council of Regional Networks for Genetic Services (CORN).

Thalassemias occur in individuals of all ethnic backgrounds and are among the most common genetic diseases worldwide. The diagnosis of thalassemia can easily be part of primary medical practice. Here we outline a practical approach to the detection of thalassemias in three common clinical settings. The first involves any patient with a low mean corpuscular volume (MCV) with or without anemia. The second is a neonatal screening result indicating possible presence of thalassemia. Finally, evaluation for thalassemia should be considered in the context of family planning or pregnancy in patients whose ethnicity indicates origin from high risk geographic areas. We also review the various types of the thalassemia syndromes and provide an overview of general therapeutic considerations.

Leg ulcers in sickle cell disease.

Leg ulcers are a frequent complication in patients with sickle cell anemia and S/beta thalassemia causing significant physical disability and negative psychologic and social impact. Systematic conservative approaches to treatment using gentle debridement and control of edema result in rapid healing of most ulcers. Chronic recalcitrant ulcers are a challenge to the clinician and patient. Controlled clinical trials are not available to fully define the therapeutic approach to the chronic leg ulcers.

Intracranial aneurysms in sickle-cell anemia: clinical features and pathogenesis.

Intracranial aneurysms are an unusual complication of sickle-cell anemia; only 15 patients have been described in the world literature. An additional 15 patients with sickle-cell anemia and subarachnoid hemorrhage (SAH) from ruptured intracranial aneurysms are presented. There was a high incidence of multiple aneurysms (60%); some of which were in unusual locations. The clinical and pathological features of this series of patients have provided a paradigm for acquired aneurysm formation that may be applicable to other intracranial aneurysms. Thirteen patients underwent craniotomy and clip ligation; the perioperative management of these patients is discussed. Of these 13, eight had a good recovery, three were left with moderate disability, one patient died of surgical complications, and one died of complications related to sickle-cell anemia. Two of the 15 patients died of SAH. The authors propose that endothelial injury from the abnormal adherence of sickle erythrocytes to the endothelium is the initiating event in arterial wall injury. Subsequently, there is fragmentation of the internal elastic lamina and degeneration of the smooth-muscle layer. Hemodynamic stress at these loci of arterial wall damage results in aneurysm formation. This hypothesis also explains other cerebrovascular manifestations of sickle-cell anemia, namely vaso-occlusive disease and hemorrhage without aneurysm formation. Pathological material from this series and data from the literature are presented to support this hypothesis.

Total hip arthroplasty in patients who have sickle-cell hemoglobinopathy.

Eleven patients who had a form of sickle-cell hemoglobinopathy had a total hip arthroplasty for avascular necrosis of the hip. Four patients had a revision and three had a resection arthroplasty. Four had a serious infection postoperatively. Both acute and late complications were numerous. We concluded that patients who have a sickle-cell hemoglobinopathy are at markedly increased risk for complications after total hip replacement arthroplasty, yet that over-all the results are favorable.

Sustained attention and inhibitory control in children with sickle cell syndrome.

Comparing sustained attention and inhibitory control among youth with sickle cell syndrome (SCS) and nondiseased sibling controls, this study found significant differences in multiple components of attention and inhibitory control as a function of chronological age. Older SCS youth were found to have increased attention and reflectivity. Although it has been argued that SCS youth without overt neurological impairments might evidence microvascular infarction, the present study, which employed commonly utilized neurocognitive and behavioral measures, does not lend support to the notion of generalized deficits in the absence of specific laboratory findings. Disease parameters including hemoglobin levels, days hospitalized, and emergency room visits were not significantly correlated with performance on any of the measures. Within the limitations of this particular study, results were interpreted to refute the notion of disease-related neurocognitive impairments for SCS youth. Further, the development of attentional skills for SCS youth is suggested to proceed similarly to that of normally developing youth.

Neurocognitive aspects of pediatric sickle cell disease.

Studies pertaining to the neurocognitive functioning and learning of children in whom sickle cell disease is diagnosed are reviewed, and findings suggest diffuse neurocognitive deficits, with much variability across subjects. A hypothesis is presented about the cumulative nature of such deficits in children who have not sustained cerebral vascular accidents. Important methodological shortcomings in the literature are identified and recommendations are made for future neurocognitive research with children in whom sickle cell disease has been diagnosed. Studies pertaining to the psychosocial development of these children are also reviewed, and it is concluded that behavioral problems, low self-esteem, and disturbances of body image are frequently characteristic of these children. Recommendations are made including early special education and psychosocial intervention programs for children with sickle cell disease.

Molecular basis of sickle cell-endothelial cell interactions.

Adherence of sickle erythrocytes to microvascular endothelium is posited to initiate or contribute to sickle cell vaso-occlusive pain episodes. Adherence and occlusion in vivo may depend on hemodynamics interacting with plasma, erythrocyte, and endothelial cell factors. Four receptor-mediated adherence pathways have been described to date: adherence mediated by high molecular weight von Willebrand factor multimers bridging glycoprotein lb-like and integrin receptors on sickle cells and similar receptors on endothelial cells; thrombospondin bridging CD36 on sickle reticulocytes and the alpha v beta 3 integrin on large-vessel endothelial cells or alpha v beta 3 and CD36 on microvascular endothelium; binding of sickle reticulocyte alpha 4 beta 1 receptors to vascular cell adhesion molecule 1 expressed on endothelial cells stimulated by cytokine or double-stranded RNA viruses; and binding of sickle cells to endothelial cell-associated fibronectin via sickle reticulocyte alpha 4 beta 1 activated by phorbol ester or interleukin-8. The significance of these adherence pathways in sickle cell vaso-occlusion is discussed.

Sickle erythrocyte adherence to large vessel and microvascular endothelium under physiologic flow is qualitatively different.

Complications in sickle syndromes are thought to result from regional disturbances of normal blood flow with subsequent ischemic damage. Adherence of sickle erythrocytes has been implicated in the pathophysiology of occlusive complications. Most previous studies have explored adherence of sickle erythrocytes to endothelial cells from large vessels, even though the majority of the pathophysiologic models implicate the microvascular system. To explore potential variation in endothelial interactions at low shear rates, adherence of sickle erythrocytes to large vessel umbilical vein endothelium and microvascular endothelium was compared under flow conditions in a parallel-plate flow chamber at a shear stress of 1.0 dyne/cm2. Autologous plasma promotes high levels of sickle red cell adherence to microvascular endothelial cells, but only low levels of adherence to human umbilical vein endothelium. On average, autologous plasma promotes sixfold more sickle cell red adherence to microvascular endothelial cells. In contrast to umbilical vein endothelium, high molecular von Willebrand factor does not elevate sickle cell adherence to microvascular endothelial cells, and the integrin receptor agonist peptide, RGD, does not inhibit adherence to microvascular endothelial cells. These results demonstrate that sickle erythrocyte adherence to large vessel and microvascular endothelium is quantitatively and qualitatively different and that plasma factors may have significant impact on sickle erythrocyte adherence to endothelium in the microvessels. Since microvascular occlusion has been suggested as an antecedent of ischemic damage in sickle syndromes, plasma enhanced adherence to microvascular endothelium may contribute to the pathophysiology of episodic occlusion in sickle cell anemia.

Inhibition of plasma-mediated adherence of sickle erythrocytes to microvascular endothelium by conformationally constrained RGD-containing peptides.

Adherence of sickle erythrocytes to vascular endothelium likely initiates or participates in microvascular occlusion, leading to ischemic tissue and organ damage characteristic of sickle-cell pain episodes. In vitro, sickle-cell adherence to endothelium involves adhesive plasma proteins and integrin and nonintegrin receptors on sickle cells and endothelial cells. The involvement of arginine-glycine-aspartic acid (RGD) sequences in adhesive plasma proteins and integrin receptors suggests that RGD-containing peptides may inhibit sickle-cell/endothelial-cell adherence. In the present study, inhibition of plasma-mediated sickle-erythrocyte adherence to endothelium using conformationally constrained RGD-containing peptides was quantified in vitro under continuous flow at a shear stress of 1.0 dyn/cm2. Two conformationally constrained RGD peptides were investigated: 6Z (which has high affinity for alpha5beta1, alpha(V)beta3, and alpha(IIIb)beta3 integrin receptors), and TP9201 (which preferentially binds to alpha(IIb)beta3). Peptide 6Z at 50 microM inhibited plasma-mediated sickle-cell adherence to microvascular endothelium 70% when incubated with sickle red cells, and 63% when incubated with endothelium. Under similar conditions, peptide TP9201 inhibited plasma-mediated sickle-cell adherence up to 85% at concentrations from 250 to 500 microM TP9201. The inhibition of plasma-mediated adherence by conformationally constrained RGD peptides, but not by linear or circular constructs, suggests that the tertiary structure of the peptide containing the binding sequence is important. Inhibition of plasma-mediated sickle-cell adhesion with these peptides in vitro suggests that such conformationally constrained RGD peptides could provide therapeutic interventions in the course of the disease by inhibiting receptor-ligand interactions.

Activation of vascular endothelial cell adhesion molecule expression by sickle blood cells.

Microvascular complications in sickle cell disease occur as a result of obstruction of small vessels by deoxygenated sickle cells. Cerebrovascular complications are also common and result from obstruction of large blood vessels by thrombosis with changes in vessels that have some similarity to those found in arteriosclerotic vascular disease. Endothelial damage and activation from sickle cell-endothelial interactions may contribute to both. We find that endothelial cells have increased expression of VCAM-1, E-selectin, and ICAM-1 when exposed to sickle blood cells. The concentration-dependent, sickle-induced, adhesion molecule expression is significantly greater than that promoted by normal cells. The time course of Cell Adhesion Molecule (CAM) expression is similar to that induced by TNF-alpha and IL1. Studies after white cell enrichment and reduction suggest leukocytes are the primary mediators. CAM expression by endothelial cells appears stimulated by soluble factors. Antibody inhibition studies support TNF-alpha and IL-1, produced by sickle leukocytes, as the primary soluble factors responsible for the observed CAM expression. Both the induction of endothelial CAM expression and subsequent endothelial adherence of sickle erythrocytes may play significant roles in the pathophysiology of sickle-related complications, and reduction in CAM expression may provide a new approach to treatment.

Alpha 4 beta 1-integrin expression on sickle reticulocytes: vascular cell adhesion molecule-1-dependent binding to endothelium.

Important complications in sickle cell anemia occur secondary to vascular occlusion, which is postulated to be initiated by interactions of erythrocytes with vascular endothelial cells. In patients with sickle cell anemia, up to 25% of reticulocytes express the alpha 4 beta 1-integrin complex. Furthermore, erythrocytes from patients with sickle cell anemia bind to endothelial cells activated by tumor necrosis factor alpha via (TNF alpha) via interactions between erythrocyte alpha 4 beta 1 and endothelial cell vascular cell adhesion molecule-1 (VCAM-1). Thus, binding of alpha 4 beta 1-expressing reticulocytes to cytokine-activated endothelial cells may initiate vascular complications in sickle cell anemia and perhaps other hemolytic anemias during episodes of infection and inflammation.

Effects of nonsteroidal antiinflammatory drugs on renal function in sickle cell anemia.

Renal hemodynamics and solute and water handling were evaluated in 19 sickle cell patients and 8 matched normal subjects during water diuresis, before and after acute oral administration of a nonsteroidal antiinflammatory drug (NSAID). Baseline GFR and RPF were higher in the patients compared to the normals. In contrast to normals, indomethacin and sulindac induced a 16% and 14% decrease in GFR, respectively. Indomethacin resulted in a slight increase in UOsm in normals, but a substantially greater rise in the patients. Following indomethacin a greater fall in FENa, fractional solute delivery to the diluting segment of the nephron [(CH2O + CNa + K)/GFR], fractional solute reabsorption in the diluting segment [CH2O/GFR] and the fraction of distally delivered solute reabsorbed [CH2O/(CH2O + CNa + K)] was observed in the sickle cell patients than in the normal subjects. A similar trend, but of significantly lesser magnitude than that induced by indomethacin, was observed following sulindac in the sickle cell patient. The data imply that the supranormal GFR observed in the sickle cell patients was prostaglandin-mediated. The effects of NSAID's on renal solute and water handling in the sickle cell patients are compatible with a prostaglandin-dependent decreased salt reabsorption in the medullary thick ascending limb of Henle, together with a hyperfunctioning proximal tubule. The data also imply an additional indomethacin-sensitive antinatriuretic effect in the diluting segment in these patients. Moreover, the results suggest that in sickle cell anemia sulindac may not have a "renal sparing" advantage over other NSAID's.

Double-stranded RNA induces sickle erythrocyte adherence to endothelium: a potential role for viral infection in vaso-occlusive pain episodes in sickle cell anemia.

Vaso-occlusive pain episodes in sickle cell anemia are hypothesized to be precipitated by adherence of sickle erythrocytes to vascular endothelium in the microcirculation. Febrile episodes, thought to be viral in etiology, are frequently associated with vaso-occlusion; however, a direct link between viral infection and vascular occlusion has not yet been established. Many pathogenic viruses contain double-stranded RNA or replicate through double-stranded RNA intermediates. Double-stranded RNA has been shown to induce vascular cell adhesion molecule-1 (VCAM-1) protein expression on endothelial cells. Recently, a new adhesion pathway has been described between VCAM-1 expressed on cytokine stimulated endothelium and the alpha 4 beta 1 integrin complex expressed on sickle reticulocytes. Based on these observations, the hypothesis was developed that viral infection, through double-stranded RNA intermediates, increases endothelial VCAM-1 expression leading to sickle erythrocyte adhesion to endothelium via an alpha 4 beta 1-VCAM-1--dependent mechanism. In support of this hypothesis, endothelial cells exposed to the synthetic double-stranded RNA poly(I:C) or the RNA virus parainfluenza 1 (Sendai virus) express increased levels of VCAM-1 and support increased sickle erythrocyte adherence under continuous flow at 1.0 dyne/cm2 shear stress as compared with unstimulated endothelium. Blocking antibodies directed against either VCAM-1 on the endothelium or alpha 4 beta 1 on sickle erythrocytes inhibit nearly all of the increased sickle cell adherence caused by poly(I:C) or Sendai virus. These results support the hypothesis that viruses, through double-stranded RNA elements, can induce sickle erythrocyte adherence to endothelium through alpha 4 beta 1-VCAM-1--mediated adhesion and provide a potential link between viral infection and microvascular occlusion precipitating sickle cell pain episodes.

Family functioning and social support in the adaptation of caregivers of children with sickle cell syndromes.

OBJECTIVE: To examine moderating effects of family functioning and social support on the relationship of child-related stressors to caregivers' psychological adaptation in a sample of caregivers of children with a chronic illness. METHOD: Participants were 67 caregivers of children and adolescents with sickle cell syndromes. We conducted MANOVAs and subsequent effect size calculations to determine if family functioning would buffer the effects of caring for difficult-to-manage children with this illness. RESULTS: Findings supported a moderator effect of family functioning on the association of children's externalizing behavioral problems to caregivers' symptoms of hostility. Greater levels of cohesive and adaptive family functioning buffered the potential detrimental effects of caring for children perceived as hard to manage. No significant associations were obtained between measures of caregivers' psychological adaptation and the severity of their children's disease. CONCLUSIONS: We make recommendations for family systems interventions, particularly for caregivers of children with behavior problems.