Beverly A. Schaefer

Characteristics of a rapid, point‐of‐care lateral flow immunoassay for the diagnosis of sickle cell disease

Sickle cell disease (SCD) is a common and life‐threatening hematological disorder, affecting approximately 400,000 newborns annually worldwide. Most SCD births occur in low‐resource countries, particularly in sub‐Saharan Africa, where limited access to accurate diagnostics results in early mortality. We evaluated a prototype immunoassay as a novel, rapid, and low‐cost point‐of‐care (POC) diagnostic device (Sickle SCAN™) designed to identify HbA, HbS, and HbC. A total of 139 blood samples were scored by three masked observers and compared to results using capillary zone electrophoresis. The sensitivity (98.3–100%) and specificity (92.5–100%) to detect the presence of HbA, HbS, and HbS were excellent. The test demonstrated 98.4% sensitivity and 98.6% specificity for the diagnosis of HbSS disease and 100% sensitivity and specificity for the diagnosis of HbSC disease. Most variant hemoglobins, including samples with high concentrations of HbF, did not interfere with the ability to detect HbS or HbC. Additionally, HbS and HbC were accurately detected at concentrations as low as 1–2%. Dried blood spot samples yielded clear positive bands, without loss of sensitivity or specificity, and devices stored at 37°C gave reliable results. These analyses indicate that the Sickle SCAN POC device is simple, rapid, and robust with high sensitivity and specificity for the detection of HbA, HbS, and HbC. The ability to obtain rapid and accurate results with both liquid blood and dried blood spots, including those with newborn high‐HbF phenotypes, suggests that this POC device is suitable for large‐scale screening and potentially for accurate diagnosis of SCD in limited resource settings. Am. J. Hematol. 91:205–210, 2016.

Long‐term outcome for kaposiform hemangioendothelioma: A report of two cases

Kaposiform hemangioendothelioma (KHE) is a rare aggressive vascular tumor of skin and deep soft tissues that typically presents in infancy and may be associated with a potentially life‐threatening coagulopathy known as Kasabach–Merrit phenomenon (KMP). Recent advances in medical therapy have successfully treated many patients. However, our knowledge regarding the natural history of these lesions and optimum surveillance strategies remains rudimentary. We report two young women who had KHE with KMP treated in infancy and presented in adolescence with comorbidities related to their KHE tumor. This presentation supports the need for long‐term surveillance in these patients.

Genetic modifiers of white blood cell count, albuminuria and glomerular filtration rate in children with sickle cell anemia

Discovery and validation of genetic variants that influence disease severity in children with sickle cell anemia (SCA) could lead to early identification of high-risk patients, better screening strategies, and intervention with targeted and preventive therapy. We hypothesized that newly identified genetic risk factors for the general African American population could also impact laboratory biomarkers known to contribute to the clinical disease expression of SCA, including variants influencing the white blood cell count and the development of albuminuria and abnormal glomerular filtration rate. We first investigated candidate genetic polymorphisms in well-characterized SCA pediatric cohorts from three prospective NHLBI-supported clinical trials: HUSTLE, SWiTCH, and TWiTCH. We also performed whole exome sequencing to identify novel genetic variants, using both a discovery and a validation cohort. Among candidate genes, DARC rs2814778 polymorphism regulating Duffy antigen expression had a clear influence with significantly increased WBC and neutrophil counts, but did not affect the maximum tolerated dose of hydroxyurea therapy. The APOL1 G1 polymorphism, an identified risk factor for non-diabetic renal disease, was associated with albuminuria. Whole exome sequencing discovered several novel variants that maintained significance in the validation cohorts, including ZFHX4 polymorphisms affecting both the leukocyte and neutrophil counts, as well as AGGF1, CYP4B1, CUBN, TOR2A, PKD1L2, and CD163 variants affecting the glomerular filtration rate. The identification of robust, reliable, and reproducible genetic markers for disease severity in SCA remains elusive, but new genetic variants provide avenues for further validation and investigation.

Knowledge insufficient: the management of haemoglobin SC disease

Although haemoglobin SC (HbSC) accounts for 30% of sickle cell disease (SCD) in the United States and United Kingdom, evidence‐based guidelines for genotype specific management are lacking. The unique pathology of HbSC disease is complex, characterized by erythrocyte dehydration, intracellular sickling and increased blood viscosity. The evaluation and treatment of patients with HbSC is largely inferred from studies of SCD consisting mostly of haemoglobin SS (HbSS) patients. These studies are underpowered to allow definitive conclusions about HbSC. We review the pathophysiology of HbSC disease, including known and potential differences between HbSS and HbSC, and highlight knowledge gaps in HbSC disease management. Clinical and translational research is needed to develop targeted treatments and to validate management recommendations for efficacy, safety and impact on quality of life for people with HbSC.

Hemoglobin variants identified in the Uganda Sickle Surveillance Study

The Uganda Sickle Surveillance Study analyzed dried blood spots that were collected from almost 100 000 infants and young children from all 10 regions and 112 districts in the Republic of Uganda, with the primary objective of determining the prevalence of sickle cell trait and disease. An overall prevalence of 13.3% sickle cell trait and 0.7% sickle cell disease was recently reported. The isoelectric focusing electrophoresis technique coincidentally revealed numerous hemoglobin (Hb) variants (defined as an electrophoresis band that was not Hb A, Hb F, Hb S, or Hb C) with an overall country-wide prevalence of 0.5%, but with considerable geographic variability, being highest in the northwest regions and districts. To elucidate these Hb variants, the original isoelectric focusing (IEF) gels were reviewed to identify and locate the variant samples; corresponding dried blood spots were retrieved for further testing. Subsequent DNA-based investigation of 5 predominant isoelectric focusing patterns identified 2 α-globin variants (Hb Stanleyville II, Asn78Lys; Hb G-Pest, Asp74Asn), 1 β-globin variant (Hb O-Arab, Glu121Lys), and 2 fusion globin variants (Hb P-Nilotic, β31-δ50; Hb Kenya, Aγ81Leu-β86Ala). Compound heterozygotes containing an Hb variant plus Hb S were also identified, including both Hb S/O-Arab and HbS/Kenya. Regional differences in the types and prevalence of these hemoglobin variants likely reflect tribal ancestries and migration patterns. Algorithms are proposed to characterize these Hb variants, which will be helpful for emerging neonatal hemoglobinopathy screening programs that are under way in sub-Saharan Africa.

Genetic ancestry and population differences in levels of inflammatory cytokines in women: Role for evolutionary selection and environmental factors

Selection pressure due to exposure to infectious pathogens endemic to Africa may explain distinct genetic variations in immune response genes. However, the impact of those genetic variations on human immunity remains understudied, especially within the context of modern lifestyles and living environments, which are drastically different from early humans in sub Saharan Africa. There are few data on population differences in constitutional immune environment, where genetic ancestry and environment are likely two primary sources of variation. In a study integrating genetic, molecular and epidemiologic data, we examined population differences in plasma levels of 14 cytokines involved in innate and adaptive immunity, including those implicated in chronic inflammation, and possible contributing factors to such differences, in 914 AA and 855 EA women. We observed significant differences in 7 cytokines, including higher plasma levels of CCL2, CCL11, IL4 and IL10 in EAs and higher levels of IL1RA and IFNα2 in AAs. Analyses of a wide range of demographic and lifestyle factors showed significant impact, with age, education level, obesity, smoking, and alcohol intake, accounting for some, but not all, observed population differences for the cytokines examined. Levels of two pro-inflammatory chemokines, CCL2 and CCL11, were strongly associated with percent of African ancestry among AAs. Through admixture mapping, the signal was pinpointed to local ancestry at 1q23, with fine-mapping analysis refined to the Duffy-null allele of rs2814778. In AA women, this variant was a major determinant of systemic levels of CCL2 (p = 1.1e-58) and CCL11 (p = 2.2e-110), accounting for 19% and 40% of the phenotypic variance, respectively. Our data reveal strong ancestral footprints in inflammatory chemokine regulation. The Duffy-null allele may indicate a loss of the buffering function for chemokine levels. The substantial immune differences by ancestry may have broad implications to health disparities between AA and EA populations.

TFE3‐positive renal cell carcinoma occurring in three children with dysfunctional kidneys on immunosuppression

Pediatric RCC is a rare pediatric neoplasm and is distinctly different compared to adult RCC, often demonstrating translocation morphology evidenced by unique histopathological features and TFE3 or TFEB nuclear expression. We report three cases of pediatric TFE3 positive RCC (TFE3‐RCC) occurring in the setting of chronic kidney disease and long‐term pharmacological immunosuppression, including two cases that developed in the native kidney following kidney transplantation. Together, these cases suggest that the kidney microenvironment in combination with immune dysregulation is likely contributing factors in the pathogenesis of some pediatric RCC, warranting further study. Long‐term post‐transplant surveillance may warrant screening for RCC.

Risk factors for venous thromboembolic events in pediatric surgical patients: Defining indications for prophylaxis

BACKGROUND Venous thromboembolism (VTE) in pediatric surgical patients is a rare event. The risk factors for VTE in pediatric general surgery patients undergoing abdominopelvic procedures are unknown. STUDY DESIGN The American College of Surgeons National Surgical Quality Improvement Program-Pediatric (NSQIP-P) database (2012-2015) was queried for patients with VTE after abdominopelvic general surgery procedures. Patient and operative variables were assessed to identify risk factors associated with VTE and develop a pediatric risk score. RESULTS From 2012-2015, 68 of 34,813 (0.20%) patients who underwent abdominopelvic general surgery procedures were diagnosed with VTE. On multivariate analysis, there was no increased risk of VTE based on concomitant malignancy, chemotherapy, inflammatory bowel disease, or laparoscopic surgical approach, while a higher rate of VTE was identified among female patients. The odds of experiencing VTE were increased on stepwise regression for patients older than 15 years and those with preexisting renal failure or a diagnosis of septic shock, patients with American Society of Anesthesia (ASA) classification ≥ 2, and for anesthesia time longer than 2 h. The combination of age > 15 years, ASA classification ≥ 2, anesthesia time > 2 h, renal failure, and septic shock was included in a model for predicting risk of VTE (AUC = 0.907, sensitivity 84.4%, specificity 88.2%). CONCLUSION VTE is rare in pediatric patients, but prediction modeling may help identify those patients at heightened risk. Additional studies are needed to validate the factors identified in this study in a risk assessment model as well as to assess the efficacy and cost-effectiveness of prophylaxis methods. LEVEL OF EVIDENCE Level III, retrospective comparative study.

Subcutaneous diphtheria and tetanus vaccines in children with haemophilia: A pilot study and review of the literature.

Subcutaneous (SQ) vaccination has emerged as standard of care in children with severe bleeding disorders to reduce unnecessary factor exposure and avoid provoking an intramuscular bleed, but little is known about comparative immunogenicity to intramuscular (IM) vaccination.

Five-Year-Old Boy Presenting With Severe Back Pain, Swelling, and Refusal to Walk

A 5-year-old Caucasian male presented to the emergency room with sudden onset of severe back pain, swelling, and refusal to walk. Four days prior to presentation, he had a self-limited febrile illness with headache and malaise that lasted 48 hours. He was symptom free until the evening prior to admission, when he developed an erythematous rash on lower legs and buttocks. Rash consisted of multiple raised round erythematous, nonpruritic, painless papules. Later that evening, he complained of severe back pain, and he refused to walk. On arrival, he complained of back pain while sitting. Vital signs included the following: temperature 36.8°C, respirations 22 breaths/min, heart rate 103 beats/min, blood pressure 98/72 mm Hg, and weight 19 kg. Physical exam was notable for a well-developed 5-year-old child. His oropharynx was benign, with no lymphadenopathy. Cardiovascular and pulmonary exam were normal. Abdominal exam was soft, without tenderness or organomegaly. Genitourinary exam was normal. Back exam revealed normal thoracic spine, with significant symmetrical soft tissue swelling from L1 to sacrum, obscuring spinous processes and with loss of normal lumbar curve. There was tenderness to palpation over bony processes and paraspinous muscles. There were no overlying skin changes. He had normal lateral and backward bending but restricted range of motion with forward bending. All other joints had normal range of motion, without effusion or tenderness. Neurologic exam showed normal sensation, reflexes, and 5/5 strength in lower extremities. Skin exam revealed few petechiae on buttocks, posterior thighs, shoulders, and approximately 2 dozen subcentimeter raised erythematous smooth papules on bilateral lower extremities and dorsum of feet. The patient’s laboratory evaluation was significant for leukocytosis with white blood cell count of 20 400/ mm (normal 3600-11 800/mm), mild thrombocytosis with platelets of 442 000/mm (normal 150 000-400 000/mm), hemoglobin of 14.9 g/dL (normal 11.5-13.5 g/dL), and hematocrit of 44% (normal 34% to 40%). Erythrocyte sedimentation rate was 31 mm/h (normal 0-13 mm/h) and C-reactive protein was normal at 0.9 mg/dL (normal 0-0.9 mg/dL). Creatine phosphokinase was normal at 80 U/L (normal 30-150 U/L). Serum chemistries and liver function studies were all within normal limits, including an albumin of 4.4 g/dL (normal 3.8-5.4 g/dL). Urinalysis showed a specific gravity of 1.020 but was otherwise negative. Magnetic resonance imaging of the lumbar spine showed edema of the lumbosacral subcutaneous fascial planes, which demonstrated enhancement after contrast administration (Figures 1 and 2). No evidence of drainable fluid collection or discrete involvement of the underlying musculature, bony structures, or intervertebral discs. 511294 CPJXXX10.1177/0009922813511294Clinical PediatricsSchaefer and Soprano research-article2013