Absolute Reticulocyte Count Acts as a Surrogate for Fetal Hemoglobin in Infants and Children with Sickle Cell Anemia.

Hemoglobin switching is largely complete in humans by six months of age. Among infants with sickle cell anemia (HbSS, SCA), reticulocytosis begins early in life as fetal hemoglobin (HbF) is replaced by sickle hemoglobin (HbS). The objective of this study was to determine if absolute reticulocyte count (ARC) is related to HbF levels in a cohort of pediatric SCA patients. A convenience sample of 106 children with SCA between the ages of 1 month and 20 years who were not receiving hydroxyurea or monthly blood transfusions were enrolled in this observational study. Hematologic data, including ARC and HbF levels, were measured at steady state. F-cells were enumerated by flow cytometry. Initial studies compared infants with ARC greater than or equal to 200 K/μL (ARC ≥ 200) based upon the previously reported utility of this threshold as a predictive marker for SCA severity. Mean HbF and F-cell levels were significantly lower in the ARC ≥ 200 group when compared to the ARC \u3c 200 group. Both HbF and F-cell percentages were negatively correlated to ARC in infants and in children between the ages of 1 and 9 years. However, the inverse relationship was lost after the age of 10 years. Overall, decreased expression and distribution of HbF during childhood SCA is well-correlated with increased reticulocyte production and release into the peripheral blood. As such, these data further support the clinical use of reticulocyte enumeration as a disease severity biomarker for childhood sickle cell anemia

Examination of Reticulocytosis among Chronically Transfused Children with Sickle Cell Anemia.

Sickle cell anemia (SCA) is an inherited hemolytic anemia with compensatory reticulocytosis. Recent studies have shown that increased levels of reticulocytosis during infancy are associated with increased hospitalizations for SCA sequelae as well as cerebrovascular pathologies. In this study, absolute reticulocyte counts (ARC) measured prior to transfusion were analysed among a cohort of 29 pediatric SCA patients receiving chronic transfusion therapy (CTT) for primary and secondary stroke prevention. A cross-sectional flow cytometric analysis of the reticulocyte phenotype was also performed. Mean duration of CTT was 3.1 ± 2.6 years. Fifteen subjects with magnetic resonance angiography (MRA) -vasculopathy had significantly higher mean ARC prior to initiating CTT compared to 14 subjects without MRA-vasculopathy (427.6 ± 109.0 K/μl vs. 324.8 ± 109.2 K/μl,

Examination of Reticulocytosis among Chronically Transfused Children with Sickle Cell Anemia.

Sickle cell anemia (SCA) is an inherited hemolytic anemia with compensatory reticulocytosis. Recent studies have shown that increased levels of reticulocytosis during infancy are associated with increased hospitalizations for SCA sequelae as well as cerebrovascular pathologies. In this study, absolute reticulocyte counts (ARC) measured prior to transfusion were analysed among a cohort of 29 pediatric SCA patients receiving chronic transfusion therapy (CTT) for primary and secondary stroke prevention. A cross-sectional flow cytometric analysis of the reticulocyte phenotype was also performed. Mean duration of CTT was 3.1 ± 2.6 years. Fifteen subjects with magnetic resonance angiography (MRA) -vasculopathy had significantly higher mean ARC prior to initiating CTT compared to 14 subjects without MRA-vasculopathy (427.6 ± 109.0 K/μl vs. 324.8 ± 109.2 K/μl,

Increased reticulocytosis during infancy is associated with increased hospitalizations in sickle cell anemia patients during the first three years of life

Objective Among older children with sickle cell anemia, leukocyte counts, hemoglobin, and reticulocytosis have previously been suggested as disease severity markers. Here we explored whether these blood parameters may be useful to predict early childhood disease severity when tested in early infancy, defined as postnatal ages 60–180 days. Study Design Data from fifty-nine subjects who were followed at Children’s National Medical Center’s Sickle Cell Program for at least three years was retrospectively analyzed. Comparisons were made between white blood cell counts, hemoglobin and reticulocyte levels measured at ages 60–180 days and the clinical course of sickle cell anemia during infancy and childhood. Results A majority of subjects had demonstrable anemia with increased reticulocytosis. Only increased absolute reticulocyte levels during early infancy were associated with a significant increase in hospitalization during the first three years of life. Higher absolute reticulocyte counts were also associated with a markedly shorter time to first hospitalizations and a four-fold higher cumulative frequency of clinical manifestations over the first three years of life. No significant increase in white blood cell counts was identified among the infant subjects. Conclusions These data suggest that during early infancy, increased reticulocytosis among asymptomatic SCA subjects is associated with increased severity of disease in childhood

Cervical screening in general practice - Strategies for improving participation

National cervical screening rates have plateaued at around 60%. Each method of recruitment has an upper limit to uptake and the benefits of multiple strategies are additive. There is debate about reallocating Pap testing to nurses in general practice.To assess the effects on cervical screening rates in one small general practice.An audit of the effect of: updating Pap test details in electronic records; active recruitment by letter; follow up telephone call if no appointment made; altering the letter to invite women to separate themselves into Pap test 'plus other issues' or 'screening test only'; and the offer of a Pap test for the 'Pap test only' group to be performed by a nurse.Over 18 months there was a 27% improvement from a biannual screening rate of 53% at baseline to 67.5% at the end of the audit. Over the past 6 months, 49% of women elected for the 'screening only' test provided by a nurse.All four strategies are feasible and associated with a considerable increase in screening rates. Patients can choose to have their test performed by a nurse in general practice. This study suggests that each strategy's improvement in uptake is independently additive

Patterns of youth injury: a comparison across the northern territories and other parts of Canada

Background: Injury is the leading cause of death for young people in Canada. For those living in the northern territories (Yukon, Nunavut, and the Northwest Territories), injury represents an even greater problem, with higher rates of injury for people of all ages in northern areas compared with the rest of Canada; however, no such comparative studies have focussed specifically on non-fatal injury in youth. Objective: To profile and examine injuries and their potential causes among youth in the northern territories as compared with other parts of Canada. Design: Cross-sectional data from the 2009/2010 Health Behaviour in School-aged Children survey (youth aged 11–15 years) were examined for the Canadian northern territories and the provinces (n=26,078). Individual survey records were linked to community-level data to profile injuries and then study possible determinants via multilevel regression modelling. Results: The prevalence of injury reported by youth was similar in northern populations and other parts of Canada. There were some minimal differences by injury type: northern youth experienced a greater percentage of neighbourhood (p<0.001) and fighting (p=0.02) injuries; youth in the Canadian provinces had a greater proportion of sport-related injuries (p=0.01). Among northern youth, female sex (RR=0.87, 95% CI 0.81–0.94), average (RR=0.88, 95% CI 0.80–0.97) or above-average affluence (RR=0.84, 95% CI 0.76–0.91), not being drunk in the past 12 months (RR=0.77, 95% CI 0.69–0.85), not riding an all-terrain vehicle (RR=0.81, 95% CI 0.68–0.97) and not having permanent road access (RR=0.89, 95% CI 0.80–0.98) were protective against injury; sport participation increased risk (RR=1.45, 95% CI 1.33–1.59). Conclusions: Patterns of injury were similar across youth from the North and other parts of Canada. Given previous research, this was unexpected. When implementing injury prevention initiatives, individual and community-level risk factors are essential to understand; however, specific positive safety assets that might exist in different community contexts must also be considered

HMGA2 Moderately Increases Fetal Hemoglobin Expression in Human Adult Erythroblasts.

Induction of fetal hemoglobin (HbF) has therapeutic importance for patients with beta-hemoglobin disorders. Previous studies showed that let-7 microRNAs (miRNAs) are highly regulated in erythroid cells during the fetal-to-adult developmental transition, and that targeting let-7 mediated the up-regulation of HbF to greater than 30% of the total globin levels in human adult cultured erythroblasts. HMGA2 is a member of the high-mobility group A family of proteins and a validated target of the let-7 family of miRNAs. Here we investigate whether expression of HMGA2 directly regulates fetal hemoglobin in adult erythroblasts. Let-7 resistant HMGA2 expression was studied after lentiviral transduction of CD34(+) cells. The transgene was regulated by the erythroid-specific gene promoter region of the human SPTA1 gene (HMGA2-OE). HMGA2-OE caused significant increases in gamma-globin mRNA expression and HbF to around 16% of the total hemoglobin levels compared to matched control transductions. Interestingly, no significant changes in KLF1, SOX6, GATA1, ZBTB7A and BCL11A mRNA levels were observed. Overall, our data suggest that expression of HMGA2, a downstream target of let-7 miRNAs, causes moderately increased gamma-globin gene and protein expression in adult human erythroblasts

Iron dose-dependent differentiation and enucleation of human erythroblasts in serum-free medium

Improvements in ex vivo generation of enucleated red blood cells are being sought for erythroid biology research, toward the ultimate goal of erythrocyte engineering for clinical use. Based upon the high levels of iron-saturated transferrin in plasma serum, it was hypothesized that terminal differentiation in serum-free media may be highly dependent on the concentration of iron. Here adult human CD34+ cells were cultured in a serum-free medium containing dosed levels of iron-saturated transferrin (holo-Tf, 0.1–1.0 mg/ml). Iron in the culture medium was reduced, but not depleted, with erythroblast differentiation into haemoglobinized cells. At the lowest holo-Tf dose (0.1 mg/ml), terminal differentiation was significantly reduced and the majority of the cells underwent apoptotic death. Cell survival, differentiation and enucleation were enhanced as the holo-Tf dose increased. These data suggest that adequate holo-Tf dosing is critical for terminal differentiation and enucleation of human erythroblasts generated ex vivo in serum-free culture condition