Evaluating the implementation of a multi-level mHealth study to improve hydroxyurea utilization in sickle cell disease

Background

Sickle Cell Disease (SCD) is a progressive genetic disease that causes organ damage and reduces longevity. Hydroxyurea is an underutilized evidence-based medication that reduces complications and improves survival in SCD. In a multi-site clinical trial, part of the NIH-funded Sickle Cell Disease Implementation Consortium (SCDIC), we evaluate the implementation of a multi-level and multi-component mobile health (mHealth) patient and provider intervention to target the determinants and context of low hydroxyurea use. Given the complexity of the intervention and contextual variability in its implementation, we combined different behavioral and implementation theories, models, and frameworks to facilitate the evaluation of the intervention implementation. In this report, we describe engagement with stakeholders, planning of the implementation process, and final analytical plan to evaluate the implementation outcomes.

Methods

During 19 meetings, a 16-member multidisciplinary SCDIC implementation team created, conceived, and implemented a project that utilized Intervention Mapping to guide designing an intervention and its evaluation plan. The process included five steps: (1) needs assessment of low hydroxyurea utilization, (2) conceptual framework development, (3) intervention design process, (4) selection of models and frameworks, and (5) designing evaluation of the intervention implementation.

Results

Behavioral theories guided the needs assessment and the design of the multi-level mHealth intervention. In designing the evaluation approach, we combined two implementation frameworks to best account for the contextual complexity at the organizational, provider, and patient levels: (1) the Consolidated Framework for Implementation Research (CFIR) that details barriers and facilitators to implementing the mHealth intervention at multiple levels (users, organization, intervention characteristics, broader community), and (2) the Technology Acceptance Model (TAM), a conceptual model specific for explaining the intent to use new information technology (including mHealth). The Reach Effectiveness Adoption Implementation and Maintenance (RE-AIM) framework was used to measure the outcomes.

Discussion

Our research project can serve as a case study of a potential approach to combining different models/frameworks to help organize and plan the evaluation of interventions to increase medication adherence. The description of our process may serve as a blueprint for future studies developing and testing new strategies to foster evidence-based treatments for individuals living with SCD.

A new sickling variant 'Hb S-Wake β[(Glu6Val-Asn139 Ser)]' found in a compound heterozygote with Hb S β(Glu6Val) coinherited with homozygous α-thalassemia-2: phenotype and molecular characteristics

We report the case of a 14-year-old African-American boy who was diagnosed with sickle cell disease. Laboratory tests showed that the patient was a compound heterozygote for a novel Hb variant with a double mutation detected on β(S) allele, Hb S βGlu6Val, and βAsn139Ser substitution, i.e. a β-chain variant named 'Hb S-Wake'. The patient also carried a single Hb S mutation in trans allele, leading to Hb SS-Wake disease. He had coinherited homozygous α(+)-thalassemia (-α(3.7)/-α(3.7)) simultaneously which resulted in multiple globin gene abnormalities.

Fetal hemoglobin in sickle cell anemia: genetic determinants of response to hydroxyurea

The increase in fetal hemoglobin (HbF) in response to hydroxyurea (HU) varies among patients with sickle cell anemia. Twenty-nine candidate genes within loci previously reported to be linked to HbF level (6q22.3-q23.2, 8q11-q12 and Xp22.2-p22.3), involved in metabolism of HU and related to erythroid progenitor proliferation were studied in 137 sickle cell anemia patients treated with HU. Three-hundred and twenty tagging single nucleotide polymorphisms (SNPs) for genotyping were selected based on HapMap data. Multiple linear regression and the nonlinear regression Random Forest method were used to investigate the association between SNPs and the change in HbF level after 2 years of treatment with HU. Both methods revealed that SNPs in genes within the 6q22.3-23.2 and 8q11-q12 linkage peaks, and also the ARG2, FLT1, HAO2 and NOS1 genes were associated with the HbF response to HU. Polymorphisms in genes regulating HbF expression, HU metabolism and erythroid progenitor proliferation might modulate the patient response to HU.

Transcranial Doppler ultrasonography in adults with sickle cell disease

BACKGROUND

Transcranial Doppler (TCD) is used to select children with sickle cell disease (SCD) for primary stroke prevention using regular blood transfusion. Whether it can also identify high stroke risk in adults with SCD is not known.

METHODS

The authors examined 112 adult patients from two convenience population samples with SCD and 53 healthy control subjects to compare velocities in adults to those reported in children with SCD and to evaluate the influence of age and hematocrit on TCD.

RESULTS

Adults with SCD had a higher mean time-averaged maximum mean velocity (110.9 +/- 25.7 cm/s) compared with healthy controls (71.1 +/- 12.0 cm/s), and the difference is approximately proportional to their anemia. No cases with velocities >/=200 cm/s (the threshold used in children for prophylactic treatment) were found in this sample.

CONCLUSIONS

Transcranial Doppler velocities in adults with sickle cell disease (SCD) are lower than those in children with SCD. Velocity criteria used in children cannot be used to stratify risk of stroke in adults.

The influence of uridine diphosphate glucuronosyl transferase 1A promoter polymorphisms, beta-globin gene haplotype, co-inherited alpha-thalassemia trait and Hb F on steady-state serum bilirubin levels in sickle cell anemia

PURPOSE

Homozygosity for the (AT)7 allele of uridine diphosphate glucuronosyl transferase 1A (UGT1A1) gene polymorphism is associated with increased bilirubin levels in sickle cell anemia (SCA). In the present study, in addition to UGT1A1 promoter genotype, serum bilirubin level was related to other genetic modifiers -beta(S)-globin gene haplotype, Hb F, co-inherited alpha-thal trait, age and gender.

METHODS

The patients were randomly selected from the sickle cell clinic, Medical College of Georgia. UGT1A1 promoter polymorphisms were determined using automated sequencing. Other investigations were with standard techniques.

RESULTS

There were 67 SCA patients (41 males and 26 females), aged 2-44 yr (mean of 20.6 +/- 10.7). Ten (14.9%) patients were homozygous for the (AT)6 UGT1A1 allele, 35 (52.2%) were heterozygous for (AT)6 and (AT)7 alleles while 22 (32.8%) were homozygous for (AT)7. Serum bilirubin was significantly higher in the homozygous (AT)7 group (3.7 +/- 1.5, 3.8 +/- 2.3 and 5.6 +/- 2.4 mg/dL, respectively). It was also significantly higher in males than females and in patients aged >10 yr. There was a significant negative linear correlation (r = -0.304, P = 0.016) of serum bilirubin with Hb F. The beta-globin haplotype and co-existing alpha-thal trait did not have any significant influence on serum bilirubin levels. Patients on hydroxyurea were older, had lower Hb F, but higher mean serum bilirubin. The latter also was signifcantly higher among those with UGT1A1 (AT)7 homozygosity.

CONCLUSIONS

Apart from UGT1A1 (AT)7 homozygosity, Hb F, age and gender are the other factors that significantly influence serum bilirubin level in SCA.

Postmortem molecular diagnosis of sickle beta thalassaemia

This report describes a case in which the diagnosis of sickle cell disease (SCD) was established after death. The diagnosis of sickle cell syndrome was made in a 68 year old black patient who was found to have sickled red blood cells in many organs at necropsy although the disease had not been diagnosed during her lifetime. DNA was isolated from a peripheral blood smear obtained on the day of the patient's death. The beta globin gene was polymerase chain reaction amplified and sequenced, revealing that the patient had S-beta(+) thalassaemia. This study shows that blood smears are a suitable source for retrospective DNA analysis studies. This case illustrates that relatively "mild" forms of SCD can be overlooked, despite symptomatology suggestive of a sickle syndrome, and demonstrates the feasibility of the postmortem molecular diagnosis of haemoglobinopathies in such cases.

Polymorphisms near a chromosome 6q QTL area are associated with modulation of fetal hemoglobin levels in sickle cell anemia

In patients with sickle cell anemia, fetal hemoglobin (HbF) concentrations vary by 2 orders of magnitude. This variance may be a result of heterogeneity in gene regulatory elements; accordingly, we searched for single nucleotide polymorphisms (SNPs) that might identify this variation. More than 180 SNPs were studied in 38 genes in 280 sickle cell anemia patients. The strongest association with HbF was found with SNPs near a QTL previously localized on chromosome 6q22.3-q23.2. Initially, two SNPs were identified in intergenic portions of this QTL and were associated with about a 20% difference in percent HbF. Subsequently, we genotyped 44 additional SNPs in the genomic region between 136.1 Mb and 137.5 Mb on chromosome 6q. Twelve SNPs, associated with a 20%-30% difference in HbF concentrations, were located in the introns of four genes, PDE7B, MAP7, MAP3K5 and PEX7. In K562 cells, the p38-MAPK pathway has been associated with the activation of gamma-globin gene expression by histone deacetylase inhibitors. Haplotypes C-T-T-T in MAP7 and T-C-C in PEX7 were significantly associated with increases in concentration of HbF, both showing strong dominance. Genetic elements abutting the 6q22.3-q23.2 QTL, may harbor trans-acting elements that help modulate baseline HbF level in sickle cell anemia.

Exercise in sickle cell anemia: effect on inflammatory and vasoactive mediators

The aim of this study was to determine the response of inflammatory and vasoactive mediators to 3 consecutive days of exercise in African-American women with and without sickle cell anemia (SCA). Circulating inflammatory mediators [C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha)] were measured before, and vasoactive mediators [endothelin-1 (ET-1), nitric oxide metabolites (NOx)] before and after each exercise bout in ten subjects with SCA and ten controls. Exercise did not affect ET-1, IL-6 or CRP concentrations (p >.05). TNFalpha was higher in SCA than controls (p < or = .0005) at all times; however, the response pattern was similar for the groups: no change from day 1 to day 2, but a decrease from day 2 to day 3 (p < or = .05). NOx increased significantly after exercise (p < or = .0001) but returned to baseline by 24 h afterward. On the 3rd day, NOx increased after exercise in SCA but not in the controls (p < or = .05). In conclusion, exercise did not cause a harmful inflammatory response in these individuals with SCA. However, NOx increased after exercise on all 3 days in SCA but appeared attenuated after 2 days in controls.

Purified poloxamer 188 for treatment of acute vaso-occlusive crisis of sickle cell disease: A randomized controlled trial

CONTEXT

Sickle cell disease (SCD) can cause severe painful episodes that are often thought to be caused by vaso-occlusion. The current therapy for these uncomplicated painful episodes includes hydration, oxygen, and analgesics. Purified poloxamer 188 may increase tissue oxygenation and thereby reduce inflammation, pain, and the overall duration of such painful episodes in patients with SCD.

OBJECTIVE

To compare the duration of painful episodes in patients with SCD treated with purified poloxamer 188 to that of similar episodes experienced by patients who receive a placebo.

DESIGN AND SETTING

Randomized, double-blind, placebo-controlled, intention-to-treat trial conducted between March 1998 and October 1999 in 40 medical centers in the United States.

PARTICIPANTS

Two hundred fifty-five patients with SCD (aged 9-53 years) who had a painful episode sufficiently severe to require hospitalization and narcotic analgesics.

INTERVENTION

Patients were randomly assigned to receive an intravenous infusion of purified poloxamer 188, 100 mg/kg for 1 hour followed by 30 mg/kg per hour for 47 hours (n = 127), or a matching volume of saline placebo (n = 128).

MAIN OUTCOME MEASURE

Duration of the painful episode, from randomization to crisis resolution.

RESULTS

Mean (SD) duration of the painful episodes was 141 (42) hours in the placebo group compared with 133 (41) hours in those treated with purified poloxamer 188, a 9-hour reduction (P =.04). Subset analyses indicated an even more pronounced purified poloxamer 188 effect in children aged 15 years or younger (21 hours; P =.01) and in patients who were receiving hydroxyurea (16 hours; P =.02). Finally, the proportion of patients achieving crisis resolution was increased by purified poloxamer 188 (65/126 [52%] vs 45/123 [37%]; P =.02). Similar results were observed in children aged 15 years or younger (22/37 [60%] vs 10/36 [28%]; P =.009) and in patients who were also receiving hydroxyurea (12/26 [46%] vs 4/28 [14%]; P =.02).

CONCLUSIONS

A decrease in the duration of painful episodes and an increase in the proportion of patients who achieved resolution of the symptoms were observed when the purified poloxamer 188-treated patients were compared with the patients receiving placebo. However, the difference between these groups was significant but relatively small. In subgroup analysis, a more significant effect on both parameters was observed in children and in patients who were receiving concomitant hydroxyurea. It is important to confirm both of these observations in further prospective trials.

Cytogenetic and morphological abnormalities in paroxysmal nocturnal haemoglobinuria

Paroxysmal nocturnal haemoglobinuria (PNH) is characterized by the expansion of a haematopoietic stem cell clone with a PIG-A mutation (the PNH clone) in an environment in which normal stem cells are lost or failing: it has been hypothesized that this abnormal marrow environment provides a relative advantage to the PNH clone. In patients with PNH, generally, the karyotype of bone marrow cells has been reported to be normal, unlike in myelodysplastic syndrome (MDS), another clonal condition in which cytogenetic abnormalities are regarded as diagnostic. In a retrospective review of 46 patients with a PNH clone, we found a karyotypic abnormality in 11 (24%). Upon follow-up, the proportion of cells with abnormal karyotype decreased significantly in seven of these 11 patients. Abnormal morphological bone marrow features reminiscent of MDS were common in PNH, regardless of the karyotype. However, none of our patients developed excess blasts or leukaemia. We conclude that in patients with PNH cytogenetically abnormal clones are not necessarily malignant and may not be predictive of evolution to leukaemia.

Body composition in women with sickle cell disease

INTRODUCTION

Adults with sickle cell disease (SCD) have increased morbidity and low perceived health status, similar to patients with other chronic conditions. These patients may be sedentary due to exercise intolerance, physical incapacity due to sickle cell-related complications or medical conservatism. Obesity is an indicator of low health status and overall well-being in the general population, and we hypothesize that adults with SCD will have a high total body fat (%BF). The purpose of this study was to assess body composition in women with SCD using dual-energy X-ray absorptiometry (DXA).

METHODS

Baseline medical examination, laboratory assessments, and seven-day activity recall to estimate energy expenditure (EE) were obtained for 22 women with SCD. BMI was calculated and whole body DXA was performed [fat mass (FM), fat-free soft tissue (FFST), and bone mineral content (BMC)]. Descriptive statistics were obtained and associations between body composition indices, total hemoglobin (Hb), treatment with hydroxyurea (HU), and EE were determined.

RESULTS

Patient age was 30.5+/-9.3 years and total Hb was 8.85+/-1.92 g/dL (mean+/-SD). Mean body mass index (BMI) (22.6 kg/m2) was in the 'acceptable' range, while DXA measurement of mean % fat (32.6%) indicated obesity. Fat-free mass (FFM) was 40.0+/-5.62 and bone mineral density (BMD) was 1.13+/-0.14 g/cm2 (mean+/-SD). There were no correlations between body composition indices and total Hb, HU, or EE.

CONCLUSIONS

This is the first report of high levels of adiposity, low FFM, and low BMD in normal weight women with SCD. The findings were not affected by total Hb, EE, HU. Further studies are needed to better define body composition, body composition determinants, and their impact on overall health status in adults with SCD.

The methylene tetrahydrofolate reductase (C677T) mutation as a potential risk factor for avascular necrosis in sickle cell disease

Avascular necrosis (AVN) of the humeral and femoral heads is a frequent and debilitating complication of sickle cell disease. Some of the risk factors for AVN are alpha-thalassemia and age. Recently, newly discovered thrombophilia mutations have been associated with AVN in patients without sickle cell disease. We studied the frequency of the thermolabile methylene tetrahydrofolate reductase (MTHFR) variant (C677T) in adult sickle cell patients with and without AVN. The frequency of the MTHFR mutation was 35.6% in patients with AVN and 12.9% in those without AVN (p = 0.006). These data suggest that the thermolabile MTHFR variant may be a contributing risk factor for AVN in some populations with sickle cell disease.

Frequency of the 677 C-->T mutation of the methylenetetrahydrofolate reductase gene among Kuwaiti sickle cell disease patients

Sickle cell disease (SCD) is relatively mild among Kuwaiti Arabs. However, an atypical subset of patients exists with frequent, severe vaso-occlusive crisis and osteonecrosis. The thermolabile variant of MTHFR, resulting from a C-->T mutation at nucleotide 677, has been shown to be associated with hyperhomocysteinemia, which is an important risk factor for premature vascular disease. We have screened an unselected group of 41 Kuwaiti SCD patients (33 SS and 8 Sbeta(0)-thal) attending the Hematology Clinic of Kuwait University Teaching Hospital for the MTHFR mutation, using a PCR-RFLP method. The patients were aged 2-41 years (mean of 12.8 +/- 8.6). One (2.4%) individual was homozygous for the mutation while 15 (36.6%) were heterozygous, giving an allele frequency of 20.7%. Twenty-one patients (14 SS and 7 Sbeta(0)-thal) were screened for osteonecrosis using MRI of the hip (spin-echo T1- and T2-weighted images). Seven (33.3%) had varying degrees of osteonecrosis, among whom the frequency of the 677 C-->T allele was 21.4%. The frequency was identical among those without osteonecrosis. Although the allele frequency is higher among our patients compared to American SS patients, our results do not suggest an association with osteonecrosis.

Sickle cell disease telemedicine network for rural outreach

The Medical College of Georgia (MCG) Sickle Cell Center in Augusta, Georgia, USA, provides consultation and (in some cases) primary-care services to more than 1000 patients with sickle cell disease (SCD). Three SCD telemedicine clinic sites were established in rural areas of middle and southern Georgia, based on clinical need; a fourth site had been proposed. Over a 36-month study period, 77 telemedicine SCD clinics were held. There was a mean of 6.1 (SD 2.5) encounters per clinic and 466 total encounters among 128 SCD patients. By using telemedicine, the productivity of the MCG adult sickle cell clinic increased from 1413 to 1889 encounters a year, with an increase in rural outreach activity from 271 to 745 encounters a year. This was accomplished with the addition of a single physician assistant during the last 12 months of the study period; otherwise provider staffing was unchanged. A formal cost-benefit analysis now needs to be carried out.

Autoimmune thrombocytopenia following autologous hematopoietic cell transplantation: review of literature and treatment options

Autoimmune thrombocytopenia after high-dose chemotherapy and autologous bone marrow/peripheral blood stem cell transplantation occurs infrequently and only six cases meeting the criteria have been reported in the literature. All six of these patients had either acute myelogenous leukemia (AML) or lymphoblastic lymphoma (LBL). Immune thrombocytopenia following autologous transplantation in solid tumors has not been reported. We report the first case of autoimmune thrombocytopenia after high-dose chemotherapy and peripheral blood stem cell transplantation in a patient with breast cancer. A review of the literature has been conducted and treatment options are discussed. In two patients the condition resolved with treatment and in a third patient it improved. Immune-mediated thrombocytopenia in the post-transplant period is one of the causes of a low platelet count. It should be recognized promptly and treated.

Sickle cell telemedicine and standard clinical encounters: a comparison of patient satisfaction

OBJECTIVES

To determine patient satisfaction with telemedicine encounters among adults with sickle cell disease and compare their scores with SCD patients who have standard medical encounters (as controls).

METHODS

Adults patients were recruited from a list of participants in sickle cell telemedicine clinics and prospectively at the time of clinic encounter. Patients were assigned to telemedicine or standard encounter groups. Demographic and pertinent clinical data were obtained for all subjects, and the Client Satisfaction Questionnaire (CSQ-8) was administered. Patients were also asked for open-ended comments regarding their satisfaction with the service. Their responses were recorded verbatim.

RESULTS

Patients with telemedicine (n = 60) and standard encounters (n = 60) were comparable in gender, genotype, education, employment, and mean number of sickle cell disease-related complications. Patients in the telemedicine group were younger (p< 0.005), more likely to have Medicaid insurance (p = 0.009), and more likely be taking hydroxyurea (p = 0.003) than patients in the control encounter group. Mean CSQ scores for the telemedicine group were high (total: 28.82+/-3.06), and there was no difference for any item between encounter groups (p = 0.389). Patients in the standard encounter group were more likely to provide positive open-ended comments regarding the encounter (95% vs. 70%; p = 0.001). Negative comments were generally in the area of confidentiality.

CONCLUSIONS

While some patients expressed concern about confidentiality with telemedicine, the benefits of improved access and continuity of care were recognized, and overall satisfaction with telemedicine was high. These findings support the use of telemedicine as an acceptable health care delivery option for rural, underserved populations with sickle cell disease.

Helicobacter pylori infection in sickle cell disease

Abdominal pain is a common presenting symptom in adults with sickle cell disease (SCD). One case of Helicobacter pylori gastritis has been reported in a child with sickle cell anemia. H. pylori-induced peptic ulcer disease (PUD) has not previously been reported in adults with SCD. We report eight cases of H. pylori infection in adult sickle cell patients presenting with acute or recurrent abdominal pain and/or gastrointestinal bleeding. In all cases, H. pylori serology (IgG) was positive, and three patients had gastric or duodenal ulcer by endoscopic examination. All patients responded to H. pylori treatment with complete resolution of symptoms by 4 weeks. The prevalence of H. pylori infection in SCD is unknown, but patients may be at increased risk for H. pylori-induced PUD and complications due to pre-existing anemia, increased nonsteroidal anti-inflammatory drug use, and alloimmunization which may delay necessary transfusion. It is important that the differential diagnosis of abdominal pain in adults with SCD include nonsickle cell-related disorders such as PUD. When confirmed, a definitive etiology of PUD must be determined so that appropriate treatment strategies can be initiated promptly and excess morbidity avoided.

Predicting the effectiveness of hydroxyurea in individual sickle cell anemia patients

The study described in this paper was undertaken to develop the ability to predict the response of sickle-cell patients to hydroxyurea (HU) therapy. We analyzed the effect of HU on the values of 23 parameters of 83 patients. A Student's t-test was used to confirm (Rodgers GP, Dover GJ, Noguchi CT, Schechter AN, Nienhuis AW. Hematologic responses of patients with sickle cell disease to treatment with hydroxyurea, N Engl J Med 1990;322;1037-44) at the 0. 001 level that treatment with HU increases the proportion of fetal hemoglobin (HbF), and the average corpuscular volume (MCV) of the red blood cells. Correlation analysis failed to establish a statistically significant relationship between any of the 23 parameters and the HbF response. Linear regression analysis also failed to predict a patient's response to HU. On the other hand, artificial neural network (ANN) pattern-recognition analysis of the 23 parameters predicts, with 86.6% accuracy, those patients that respond positively to HU and those that do not. Furthermore, we have found that the values of only 10 of the 23 parameters (listed in the body of this paper) are sufficient to train ANNs to predict which patients will respond to HU.

Primary-care delivery for sickle cell patients in rural Georgia using telemedicine

BACKGROUND

Advances in newborn screening and pediatric management of sickle cell disease have resulted in patients living well into adulthood. For adults, preventive care and medication monitoring are crucial for optimal health maintenance. The Medical College of Georgia (MCG) in Augusta provides consultative services and comprehensive medical care to about 1200 sickle cell patients residing in middle and southern Georgia. An increase in the demand for clinical services in this patient population has resulted in expansion of sickle cell outreach efforts throughout the state.

OBJECTIVE

A telemedicine clinic for adult sickle cell patients was established in order to meet the growing clinical demands.

METHODS

An on-site outreach clinic was introduced in the target area. After 10 months of operation, a monthly telemedicine clinic was offered to patients as an option for routine medical follow-up. A clinic model was used, with scheduled appointments and a public health nurse assisting at the remote site. Phlebotomy and laboratory services enhanced the telemedicine encounter.

RESULTS

Over a 12-month period, 52 encounters for 28 patients from 17 medically underserved counties were completed. All patients were African-American, and 89. 3% had Medicaid or Medicare insurance coverage or both. The clinic encounter time was 24 +/- 7.9 minutes (mean +/- SD), comparable to that for all telemedicine clinic encounters during the same period.

CONCLUSIONS

The adult sickle cell population in rural Georgia accepts innovative health care delivery using telemedicine. Thus, the telemedicine sickle cell clinic has increased access to care for rural patients in underserved areas. For providers, it has allowed greater clinical productivity and diminished travel time to outreach clinics.

Identification of the Chinese IVS-II-654 (C-->T) beta-thalassemia mutation in an immigrant Turkish family: recurrence or migration?

In this study we describe the Chinese IVS-II-654 (C-->T) beta-thalassemia mutation for the first time in an immigrant Turkish family living in Istanbul and originating from Xanthe, Greece. Four members of the family, representing 3 generations, are heterozygous for this mutation. A detailed family history demonstrated a Greek origin for members of 5 generations with no records of migration or consanguineous marriages. Analysis of polymorphic nucleotides located at the 5' end of the beta-globin chromosomes bearing the IVS-II-654 mutation in the family described carried the (AT)9(T)5 type of microsatellite sequence and the ACATCCCCA haplotype. These 2 haplotype components favor a non-Eastern Asian origin for this chromosome, hence suggesting an independent origin for the IVS-II-654 mutation described in this family.

Viral burden and disease progression in HIV-1-infected patients with sickle cell anemia

The spleen and lymph nodes are major sites of human immunodeficiency virus type 1 (HIV-1) replication, mutation, and genetic variation in vivo. If a major portion of the lymphatic tissue, such as the spleen, is removed or otherwise is unavailable for invasion by the HIV-1 virus, will the course of the infection be altered, resulting in a prolonged symptom-free interval or even increased survival? The spleen of most adults with sickle cell anemia (SS) is nonfunctional due to recurrent episodes of microinfarction. If autosplenectomized SS patients are exposed to HIV-1, they may be ideal candidates to examine the question of whether absence of splenic function at the time of infection will positively alter the course of HIV-1-related disease. All SS patients with a diagnosis of HIV-1 infection at five university sickle cell centers were included in the patient cohort. Patients in active treatment or in follow-up (group A, n = 11) underwent a series of quantitative viral studies to determine their HIV-1 viral burden. The studies included the branched-DNA signal amplification assay, quantitative DNA-polymerase chain reaction (PCR), quantitative reverse transcription (RT)-initiated-PCR, and in situ PCR. All patients who died of the complications of the acquired immunodeficiency syndrome (AIDS) or of SS, lost to follow-up, or were otherwise unavailable for study (Group B: n = 7) were included in the total patient group. None of the patients in group B underwent quantitative viral studies. In addition, a control population (group C, n = 36) of HIV-1-infected African Americans without SS, of similar age and gender to the SS patients, were compared with the study population for outcomes. In eight of 11 active patients (group A), the CD4+ T-lymphocyte counts were normal and viral burdens were low for an average of 10.25 years following diagnosis. These eight patients all from group A were the only long-term nonprogressors (44%) among a total of 18 SS patients (groups A and B). In group C (control), only five patients of 36 were long-term nonprogressors (13.9%). Five patients (28%) of the total SS group (groups A and B) succumbed to AIDS. One of the five was from Group A. The evaluation of a limited number of adult individuals suggests that a significant proportion of HIV-1-seropositive SS patients (44%) may be asymptomatic long-term nonprogressors. In these patients, the CD4+ T-lymphocyte counts remained high and their viral burdens were remarkably lower than in non-SS HIV-1-seropositive individuals. Whereas this study does not prove an "autosplenectomy" hypothesis, it suggests that in patients with both SS and HIV-1 infection, the retroviral disease may be ameliorated by host factors of which absence of splenic function prior to HIV-1 infection may be one.

Hb Hammersmith [beta 42(CD1) Phe-->Ser]: occurrence as a de novo mutation in black monozygotic twins with multiple congenital anomalies

PURPOSE

To present the occurrence of Hb Hammersmith as a de novo mutation in African-American twins with multiple congenital anomalies.

METHODS

Standard hematologic methods were used. The presence of an unstable Hb variant was confirmed by brilliant cresyl blue staining and an isopropanol stability test. Hb Hammersmith was confirmed by the sequencing of polymerase chain reaction-amplified beta-globin gene.

RESULTS

The presence of Hb Hammersmith was confirmed in female monozygotic twins of African-American origin with congenital Heinz body hemolytic anemia and multiple congenital anomalies. The variant occurred as a de novo mutation in the twins.

CONCLUSION

This report describes the occurrence of Hb Hammersmith [B42(CD1)Phe-->Ser] in African-American twins. As with the other reported cases, both twins were female. In addition to Heinz body hemolytic anemia, a low arterial O2 saturation in the proposita was shown by pulse oximetry. Multiple congenital anomalies involving various systems were also found in both twins.

Inhibition of gene expression by the Ggamma 5' flanking region of the Bantu beta(s) chromosome

Beta(s)-chromosome haplotypes are peculiar to specific regions of Africa and Asia and are associated with the occurrence of different fetal hemoglobin (Hb) levels in sickle cell patients. Among these haplotypes, beta(s)-chromosomes found in the Senegal and the Arab-India regions are associated with relatively high levels of HbF expression, whereas those around the Benin, Bantu, and the Cameroon regions show low levels of HbF expression. The roles of 5'HS2 and the 5' flanking (promoter region) region in the expression of globin genes are well documented. Haplotype specific variations are found in these regions and have been postulated to be involved in the regulation of HbF expression. In this study, we have analyzed the effect of sequence variations in regulatory regions of the Bantu 5'HS2 and 5' flanking region of the Ggamma gene on CAT expression. A diminution was observed in K562 cells when the promoter originated from the Bantu beta(s) chromosome. The decreased expression was independent of the origin of the 5'HS2 sequence--combinations of the Bantu promoter were measured with the Benin, Bantu, or Senegal 5'HS2 sequences in K562 cells. However, expression of the same plasmids in murine erythroleukemic (MEL) cells showed no difference in CAT expression among the various sequence combinations studied.

Prevention of a first stroke by transfusions in children with sickle cell anemia and abnormal results on transcranial Doppler ultrasonography

BACKGROUND

Blood transfusions prevent recurrent stroke in children with sickle cell anemia, but the value of transfusions in preventing a first stroke is unknown. We used transcranial Doppler ultrasonography to identify children with sickle cell anemia who were at high risk for stroke and then randomly assigned them to receive standard care or transfusions to prevent a first stroke.

METHODS

To enter the study, children with sickle cell anemia and no history of stroke had to have undergone two transcranial Doppler studies that showed that the time-averaged mean blood-flow velocity in the internal carotid or middle cerebral artery was 200 cm per second or higher. The patients were randomly assigned to receive standard care or transfusions to reduce the hemoglobin S concentration to less than 30 percent of the total hemoglobin concentration. The incidence of stroke (cerebral infarction or intracranial hemorrhage) was compared between the two groups.

RESULTS

A total of 130 children (mean [+/-SD] age, 8.3+/-3.3 years) were enrolled; 63 were randomly assigned to receive transfusions and 67 to receive standard care. At base line, the transfusion group had a slightly lower mean hemoglobin concentration (7.2 vs. 7.6 g per deciliter, P=0.001) and hematocrit (20.4 vs. 21.7 percent, P=0.002). Ten patients dropped out of the transfusion group, and two patients crossed over from the standard-care group to the transfusion group. There were 10 cerebral infarctions and 1 intracerebral hematoma in the standard-care group, as compared with 1 infarction in the transfusion group -- a 92 percent difference in the risk of stroke (P<0.001). This result led to the early termination of the trial.

CONCLUSIONS

Transfusion greatly reduces the risk of a first stroke in children with sickle cell anemia who have abnormal results on transcranial Doppler ultrasonography.

Stroke prevention trial in sickle cell anemia

Stroke occurs in 7-8% of children with Sickle Cell Disease (Hb SS) and is a major cause of morbidity. Rates of recurrence have been reduced from 46-90% to less than 10% through chronic blood transfusions. Prevention of first stroke, however, would be preferable because even one stroke can cause irreversible brain injury. Transcranial Doppler (TCD) ultrasound can detect arterial blood flow rates associated with subsequent stroke risk. By combining TCD screening and a potentially effective treatment, first stroke may be prevented. The Stroke Prevention Trial in Sickle Cell Anemia (STOP) is the first stroke prevention trial in Hb SS and the first randomized, controlled use of transfusion in Hb SS. This multi-center trial is designed to test whether reducing sickle hemoglobin to 30% or less with periodic blood transfusions will reduce first-time stroke by at least 70% compared to standard care. Primary endpoints will be clinically evident symptoms of cerebral infarction with consistent findings on Magnetic Resonance Imaging and Angiography (MRI/MRA) or symptomatic intracranial hemorrhage. Secondary endpoints will be asymptomatic brain lesions detected by MRI in brain areas not involved in primary endpoints. The design calls for a 6-month start-up interval, 18 months of TCD screening and randomization, and observation for stroke from entry through month 54. Key features of the trial are standardized TCD and MRI/MRA protocols interpreted blindly, and blinded adjudication of endpoints. The sample size (60 per treatment group) is based on prospective data relating TCD velocity to risk of stroke. A time-averaged mean velocity of > or = 200 cm/sec is associated with a 46% risk of cerebral infarction over 39 months. The sample size is sufficient to detect 70% reduction in the primary endpoint at 90% power. This trial will determine if transfusion is effective in the primary prevention of stroke. Secondary aims may further the understanding of the effects of transfusion on the brain and guide future research into cerebrovascular disease in Hb SS.

Reverse dot-blot detection of the African-American beta-thalassemia mutations

DNA-based diagnosis of the beta thalassemias provides accuracy to newborn screening genetic counseling, and prenatal diagnosis. However, the use of polymerase chain reaction (PCR)-based methods is challenged by the great number of different-beta-thalassemia mutations that exist even within defined ethnic groups. In this regard, the reverse dot-blot method offers a means of screening for several mutations with a single hybridization reaction. We have applied the reverse dot-blot method to the detection of the beta-thalassemia mutations of African-Americans. We used two biotin-labeled primer pairs in a duplex reaction to amplify and label two beta-globin target DNA fragments that encompass all known African-American beta-thalassemia mutations. The PCR products were denatured and hybridized to polyT-tailed, membrane-fixed, allele-specific probe pairs for the hemoglobin (Hb) S, Hb C, and 14 beta-thalassemia mutations and their corresponding wild-type sequences. Seven common mutations plus Hb S and Hb C were included on one diagnostic strip, and seven less common beta-thalassemia mutations were included on another strip. Carefully controlled, high stringency hybridization allowed accurate distinction of these alleles. Reverse dot-blot diagnosis of the less common beta-thalassemia mutations precludes the need for alternative, more technically challenging methods. This method provides a rapid, accurate method for diagnosis of beta thalassemia among African-Americans and other ethnic groups in which beta thalassemia occurs.

Alpha thalassemia and stroke risk in sickle cell anemia

In an effort to identify possible risk factors for stroke in Sickle Cell Anemia (Hb SS), we analyzed the distribution of alpha-globin gene deletions in a group of Hb SS patients with and without stroke. The group with stroke consisted of 44 patients, (27 male, 17 female) with a mean of 7.5 years at time of stroke. The control group (non-stroke) had 256 Hb SS patients (126 male, 130 female) with a mean age of 7.7 years. There were 9 patients with heterozygous alpha-thalassemia in the stroke group (20.5%). In the control group, there were 93 patients with heterozygous alpha-thalassemia and 5 with homozygous alpha-thalassemia. The incidence of alpha-thalassemia in Hb SS patients without stroke (38%) was comparable to that reported for the African-American population in general. The incidence in the stroke population (20.5%) was significantly lower (P = 0.02) These results indicate that alpha-thalassemia is associated with a lower risk of stroke in Hb SS. This observation should be confirmed in studies involving larger numbers of patients. Possible protective effects of alpha-thalassemia are unknown but may be related to decreased hemolysis and more favorable rheologic properties of red blood cells.

Prenatal diagnosis of sickle cell anemia using PCR and restriction enzyme Dde I

Prenatal diagnosis of sickle cell anemia was carried out in four fetuses using DNA technology. Fetal chorionic villus specimen were obtained at the 10th week of pregnancy from women at risk of giving birth to children with sickle cell anemia. Whole cellular DNA was obtained and the part of the DNA presumed to have a mutation increased after PCR was performed. After the application of Dde I restriction enzyme, mini gel electrophoresis was performed. The study of the electrophoretic patterns of the DNA indicated that one of the four fetuses was unaffected, one was a carrier and the remaining two were affected.

Case report: alpha G-Philadelphia, beta O-Arab, and beta C globins present in a single patient

The case of a 7-month-old Nigerian child who presented with anemia and microcytosis is described. Hemoglobin electrophoresis studies revealed a band with pronounced cathodic mobility. This represented a heterohybrid hemoglobin tetramer composed of an alpha-globin mutant, G-Philadelphia (alpha GPhil), and two variant beta-globin chains, beta C and beta O-Arab. The absolute amounts of alpha GPhil found in the propositus were less than expected for an alpha 2-globin gene product. It has not been established whether alpha G-Philadelphia interacting with beta O-Arab and beta C globin chains is the cause of the microcytosis.

Usefulness of HPLC methodology for the characterization of combinations of the common beta chain variants Hbs S, C, and O-Arab, and the alpha chain variant Hb G-Philadelphia

We have analyzed the blood samples from seven members of two families that contained mixtures of different hemoglobin types due to the simultaneous presence of different beta chain variants and the alpha chain variant Hb G-Philadelphia. The methods used were isoelectrofocusing and cation exchange high performance liquid chromatography for the separation of the hemoglobin components, and reversed phase high performance liquid chromatography for that of the various alpha and beta chains; the chromatographic procedures also provided quantitative data. Application of these fast and simple high performance liquid chromatographic methods greatly aided in defining the different hemoglobinopathies that were present in these persons, including an additional alpha-thalassemia-2 heterozygosity or homozygosity.

Molecular characterization of Hb S(C) beta-thalassemia in American blacks

An extension of previous reports describing the molecular defects and hematological abnormalities in black patients with Hb S(C) beta-thalassemia living in the Southeastern United States is presented. As many as 58 patients with Hb S-beta(+)-thalassemia, 16 with Hb C-beta(+)-thalassemia and 12 with Hb S-beta(0) -thalassemia have been studied. Patients with Hb S(C) beta(+)-thalassemia type 2 (high Hb A values) were most common; the thalassemia was due to mutations in the promoter of the beta-globin gene [-88 (C----T) and -29 (A----G)] or at the polyadenylation signal (T----C). Two patients with lower Hb A values (type 1) carried a mutation in the first intron of the beta-globin gene (IVS-1-5: G----T). The simultaneous presence of an alpha-thalassemia -2(-alpha/) resulted in some modifications of the hematological parameters, but had a minimal effect on the clinical condition. Patients with Hb S-beta (0) thalassemia had lower hemoglobin values, lower number of red blood cells, and lower MCHC values and suffered more frequently from complications than the patients with Hb S-beta(+)-thalassemia. A total of 17 different beta-thalassemia mutations were observed in 128 chromosomes; two mild beta(+)-thalassemia mutations [-88(C----T) and -29(A----G)] account for more than 80% of the thalassemic chromosomes.

The linkage of Hb Valletta [alpha 2 beta 287(f3)Thr----Pro] and Hb F-Malta-I [alpha 2G gamma 2117(G19)His----Arg] in the Maltese population

We have identified a new stable abnormal hemoglobin called Hb Valletta, which is characterized by a Thr----Pro substitution at position 87 of the beta chain. This mutation was found to be linked to that of the gamma chain variant Hb F-Malta-I with a His----Arg mutation at position 117 of the G gamma chain. Both variants were detected in the blood samples of 34 Maltese and two Italian newborn babies with isoelectrofocusing and reversed phase high performance liquid chromatography. Similar analyses of cord blood from 388 additional Maltese newborns failed to identify either one of these two variants. Additional analyses of 353 Maltese adults (including 39 beta-thalassemia heterozygotes) resulted in the detection of two adult Hb Valletta heterozygotes. Dot-blot hybridization analyses of amplified DNA with a probe specific for the G gamma-F-Malta-I variant showed that both also carried that mutation. These results show close linkage of the mutant forms of the G gamma- and beta-globin genes, 27-28 kb apart, and a failure to identify chromosomes with either the Hb F-Malta-I mutation alone or with the Hb Valletta mutation alone, indicating a low recombination frequency.

The detection of hemoglobin variants by isoelectrofocusing using EDTA-collected and filter paper-dried cord blood specimens

A comparative study was conducted aimed at the detection of abnormal hemoglobin conditions (mainly AS, SS, AC, CC, SC, AE, AD, Hb Bart's or gamma 4) by isoelectrofocusing of cord blood samples stored as liquid blood and as dried hemoglobin on filter paper. Analyses were made within four to six days after the collection of the samples; storage conditions mimicked those of testing programs using liquid blood samples (as in Georgia) or dried blood filter paper samples (as in several other states). During analysis of hemoglobin solutions extracted from dried blood samples, considerable difficulties were encountered in detecting significant hemoglobinopathies such as SS and SC, whereas even simple abnormalities such as AS, AC, AD, and AE were also often not diagnosed. Detection of the fast-moving variant Hb Bart's or gamma 4 was not possible. These results again cause doubt regarding the general use of dried blood filter paper samples in newborn hemoglobin testing programs. Perhaps special precautions--such as speed in analyzing the samples, storage at -20 degrees C (or perhaps 4 degrees C) instead of at room temperature, and removal of unstable hemoglobin from the filter paper extract by centrifugation--might eliminate some of the problems that were observed.

Chinese in west Malaysia: the geography of beta thalassaemia mutations

The overseas Chinese in West Malaysia are almost exclusively from the south-eastern provinces of China-Kwangtung, Fukien, and Kwangsi. To institute a comprehensive thalassaemia control programme for this region we have characterised the beta thalassaemia mutations in 16 Chinese patients from West Malaysia: 4 beta thalassaemia mutations were seen: a) an A----G substitution in the TATA box [-28 base pairs (bp)], an A----T substitution in codon 17 [17 A----T], c) a 4 base pairs - TCTT deletion in codon 41-42 [frameshift mutation (FSC 41-42)], and d) a C----T substitution at the second intervening sequence (IVS 11) position 654. Similar mutations have been described in patients from the south-eastern provinces of China. The delineation of the specific mutations present will enable effective prenatal diagnosis for beta thalassaemia of ethnic Chinese in West Malaysia to be instituted.

Fetal hemoglobin in normal adults and beta-thalassemia heterozygotes

A recently developed high performance liquid chromatographic (HPLC) procedure using a weak cation exchanger (PolyCAT) in columns of different sizes was used to quantify fetal hemoglobin (HbF) in blood of normal adults and beta-thalassemia (beta-thal) heterozygotes with ten different types of mutations. Preparative PolyCAT-HPLC greatly facilitated the characterization of isolated HbF, i.e., the determination of the relative quantities of the G gamma and A gamma chains. The method is accurate and allows quantitation of Hb F at the 0.5% level; preparative PolyCAT-HPLC allows isolation of (nearly) pure Hb F from blood samples with low (less than 1%) Hb F. Adult Hb F levels were determined in 69 normal adults (including 24 diabetics); Hb F levels fell below 1% except for subjects with abnormal -- G gamma -- G gamma -- arrangement and a C----T mutation at position -158 relative to the Cap site of both G gamma genes. The effect of the same mutation in the normal -- G gamma -- A gamma-arrangement was variable. Certain beta-thal mutations (namely, those at positions -29; -88; IVS-I-1; IVS-II-1) were associated with high Hb F levels in heterozygotes, while those at nucleotide (nt) positions IVS-I-6; IVS-I-110; codon 24; codon 39; codons 41/42; IVS-II-745 were not. G gamma values varied and often fell into two groups (high G gamma and low G gamma); high G gamma values were not associated with high Hb F values. The chromatographic procedure is ideally suited for Hb A2 quantitation. Average values of Hb A2 in beta-thal heterozygotes with any one of nine of the ten mutations were twice that of normals; the one exception was the beta-thal heterozygote with the IVS-I-6 (T----C) mutation with an average low Hb A2 value of 3.6%.

Hemoglobin Birmingham and hemoglobin Galicia: two unstable beta chain variants characterized by small deletions and insertions

Two unstable hemoglobins (Hbs) causing rather severe hemolytic anemia have been characterized. The beta chain of Hb Birmingham, found in an adult black man, is characterized by the loss of -Leu-Ala-His-Lys- at positions 141, 142, 143, and 144 and their replacement by one Gln residue. These changes are the result of a deletion of nine nucleotides, namely two base pairs (bp) of codon 141, all of codons 142 and 143, and one bp of codon 144; the remaining CAG triplet (C from codon 141 and AG from codon 144) codes for the inserted glutamine. In the beta chain of Hb Galicia from a Spanish patient, His and Val at positions 97 and 98 are replaced by one Leu residue. This is due to an ACG deletion in codons 97 and 98, which causes the removal of one His and one Val residue, while the remaining CTG triplet (C from codon 97 and TG from codon 98) codes for the inserted leucine residue. Two mechanisms, namely slipped mispairing in the presence of short repeats, and misreading by DNA polymerase due to a local distortion of the DNA helix, are considered in explaining the origin of the small deletions.

Molecular characterization of beta-thalassaemia in 174 Greek patients with thalassaemia major

The mutations producing beta-thalassaemia in 174 Greek patients with thalassaemia major were investigated by dot-blot hybridization of oligonucleotide probes to genomic DNA amplified by the polymerase chain reaction procedure, by direct sequencing of amplified DNA, and by gene mapping. beta-thalassaemia in Greeks was found to be very heterogeneous at the molecular level as 17 different mutations were observed: 86.6% of the beta-thalassaemic genes, however, could be identified with five probes: IVS-I-110 (G----A) (42.5%), codon 39 (C----T) (17%), IVS-I-1 (G----A) (13.2%), IVS-I-6 (T----C) (7.2%) and IVS-II-745 (C----G) (6.9%). Several mutations which had not previously been reported in the Greek population and which occurred at an incidence of 2% or lower were observed in this study. The information obtained will facilitate the prenatal diagnosis of beta-thalassaemia in Greece.