Estimating the serological underrecognition of patients with weak or partial RHD variants

BACKGROUND

For patients with weak or discrepant RhD RBC phenotypes, RHD genotyping is employed to determine need for RhD-negative management. However, many RHD variants are type D-negative or D-positive. Serological recognition rates (RRs) of weak and partial RHD variants are poorly characterized.

STUDY DESIGN AND METHODS

Four US studies employing RHD genotyping for weak or discrepant RhD phenotypes provided data for race/ethnicity-specific serological recognition. Three studies used microplate, and 1 used gel and tube; 2 had anti-D data. We obtained White and Hispanic/Latino allele frequencies (AFs) of weak D types 1, 2, and 3 single-nucleotide variants (SNVs) from the Genome Aggregation Database (gnomAD, v4.0.0) and devised Hardy-Weinberg-based formulas to correct for gnomAD's overcount of hemizygous RHD SNVs as homozygous. We compiled common partial RHD AF from genotyped cohorts of US Black or sickle cell disease subjects. From variant AF, we calculated hemizygous-plus-homozygous genetic prevalences. Serological prevalence: genetic prevalence ratios yielded serological RRs.

RESULTS

Overall RRs of weak D types 1-3 were 17% (95% confidence interval 12%-24%) in Whites and 12% (5%-27%) in Hispanics/Latinos. For eight partial RHD variants in Blacks, overall RR was 11% (8%-14%). However, DAR RR was 80% (38%-156%). Compared to microplate, gel-tube recognition was higher for type 2 and DAU5 and lower for type 4.0. Anti-D was present in 6% of recognized partial RHD cases, but only in 0.7% of estimated total genetic cases.

DISCUSSION

Based on AF, >80% of patients with weak or partial RHD variants were unrecognized serologically. Although overall anti-D rates were low, better detection of partial RHD variants is desirable.

Emergency department visits and hospitalizations among patients with sickle cell disease in illinois, 2016-2020

Sickle cell disease (SCD) state level surveillance data are limited. We performed a retrospective review of emergency department (ED) visits and hospitalizations from individuals with SCD in Illinois (2016-2020) using the Illinois Health and Hospital Association's Comparative Health Care and Hospital Data Reporting Services. There were 48,094 outpatient ED visits and 31,686 hospitalizations. Most visits (67%) occurred in Cook County, were covered by public insurance (77%) and were from individuals with medium high (40.3%) or high (36.1%) poverty levels. SCD healthcare utilization remains high and surveillance data may inform SCD program development and resource allocation at the state level.AbbreviationsCDCCenters for Disease Control and PreventionEDEmergency DepartmentFDAFood & Drug AdministrationICDInternational Classification of DiseasesILIllinoisSCDSickle cell disease.

RHD genotyping to resolve weak and discrepant RhD patient phenotypes

BACKGROUND

We instituted RHD genotyping in our transfusion service for obstetrical patients and transfusion candidates. We sought to examine how RHD genotyping resolved weak or discrepant automated microplate direct agglutination (MDA) RhD phenotypings and impacted needs for Rh Immune Globulin (RhIG) and D-negative RBCs.

STUDY DESIGN AND METHODS

We investigated RhD phenotypes with equivocal or reagent-discrepant automated MDA (Immucor, Norcross, GA), weak-2+ immediate-spin tube typings, historically discrepant RhD typings, or D+ typings with anti-D. We performed microarray RHD genotyping (RHD BeadChip, Immucor BioArray Solutions, Warren, NJ). Patients were managed as D+ with weak-D types 1, 2, and 3, and as D-negative with all other results.

RESULTS

Our weak-D prevalence was 0.14%. Among 138 patients (73 obstetrics, 65 transfusion candidates), 38% had weak-D types 1, 2 or 3, 25% weak partial type 4.0, 21% other partial-D variant alleles, and 15% no variant detected. One novel allele with weak partial type 4.0 variants plus c.150T>C (Val50Val) was discovered. Weak D types 1, 2 or 3 were identified in 66% (48/73) of Whites versus 3% (2/62) of diverse ethnic patients (p < .0001). RHD genotyping changed RhD management in 60 patients (43%) (49 to D+, 11 to D-negative), resulting in net conservation of D-negative RBCs (98 avoided, 14 given) and RhIG (8 avoided, 3 given).

CONCLUSION

In our patient population, equivocal or reagent-discrepant MDA RhD phenotypes were highly specific for weak-D or partial-D RHD genotypes. Resolution of RHD genotype status reduced our use of D-negative RBCs and RhIG.

Cerebral and skeletal muscle tissue oxygenation during exercise challenge in children and young adults with sickle cell anaemia

We used near-infrared spectroscopy to examine tissue oxygenation (StO₂₎ during exercise in 17 children and young adults with sickle cell anaemia (SCA) and 13 controls. Patients had lower cerebral StO₂ at all exercise stages and demonstrated significantly greater decreases in cerebral StO₂ later during exercise. Quadriceps StO₂ increased similarly in patients and controls during early exercise, but decreases from baseline were greater in patients during later exercise. At similar workloads, patients demonstrated lower cerebral StO₂ (69·2 ± 6·6 vs. 79·5 ± 5·3%, P < 0·001) and trended towards lower quadriceps StO₂ (67·7 ± 9·0 vs. 73·2 ± 7·9%, P = 0·09) . Further studies of tissue oxygenation during exercise in SCA are warranted.

Blood transfusion utilization in hospitalized COVID-19 patients

Background

The acute respiratory illness designated coronavirus disease 2019 (COVID‐19) was first reported in Wuhan, China, in December 2019 and caused a worldwide pandemic. Concerns arose about the impact of the COVID‐19 pandemic on blood donations and potential significant blood transfusion needs in severely ill COVID‐19 patients. Data on blood usage in hospitalized COVID‐19 patients are scarce.

Study Design and Methods

We performed a retrospective observational study of blood component transfusions in the first 4 weeks of COVID‐19 ward admissions. The study period began 14 days before the first COVID‐19 cohort wards opened in our hospital in March 2020 and ended 28 days afterward. The number of patients and blood components transfused in the COVID‐19 wards was tabulated. Transfusion rates of each blood component were compared in COVID‐19 wards versus all other inpatient wards.

Results

COVID‐19 wards opened with seven suspected patients and after 4 weeks had 305 cumulative COVID‐19 admissions. Forty‐one of 305 hospitalized COVID‐19 patients (13.4%) received transfusions with 11.1% receiving red blood cells (RBCs), 1.6% platelets (PLTs), 1.0% plasma, and 1.0% cryoprecipitate (cryo). COVID‐19 wards had significantly lower transfusion rates compared to non‐COVID wards for RBCs (0.03 vs 0.08 units/patient‐day), PLTs (0.003 vs 0.033), and plasma (0.002 vs 0.018; all p < 0.0001). Cryo rates were similar (0.008 vs 0.009, p = 0.6).

Conclusions

Hospitalized COVID‐19 patients required many fewer blood transfusions than other hospitalized patients. COVID‐19 transfusion data will inform planning and preparation of blood resource utilization during the pandemic.

A patient-centered medical home model for comprehensive sickle cell care in infants and young children

BACKGROUND

The patient-centered medical home (PCMH) has been proposed as a model for comprehensive care coordination and delivery for children with sickle cell disease (SCD), yet little is known regarding the implementation of PCMH core concepts on adherence to preventative care measures, health care utilization, and parent satisfaction.

PROCEDURE

We implemented the newborn cohort clinic (NCC) to explore the application of the PCMH model for infants and children with SCD from birth to age 3 years in 2011. In July 2017, we conducted a retrospective chart review to evaluate subjects currently or previously followed in the clinic. We surveyed parents in the NCC to assess their satisfaction with their experience.

RESULTS

A total of 112 patients have been managed in the NCC. All patients received penicillin prophylaxis, while 70% and 73% of patients, respectively, received the 23-valent pneumococcal vaccine and an initial transcranial Doppler by age 36 months. Most (92 of 112) of the subjects utilized the emergency department (569 encounters), with 86% of encounters for fever or other sickle cell-related complications. The majority of parents indicated satisfaction with the clinic, with 71% saying clinic providers always or usually spent enough time with their child, listened carefully to them (81%) and were sensitive to family values and customs (77%).

CONCLUSIONS

A comprehensive sickle cell clinic as a component of a PCMH is feasible and can achieve high levels of preventative care. Parents are largely satisfied with this model of care.