Life-Threatening Infectious Complications in Sickle Cell Disease: A Concise Narrative Review

Promoting penicillin allergy de-labeling for children attending a hematology clinic

BACKGROUND

Up to 10% of children are reported to be allergic to penicillin, but many allergy labels are unverified and may require formal testing. Inaccurate drug allergy labels are associated with a range of adverse clinical outcomes. Patients with hematological disorders may experience frequent and severe infections; those who have been incorrectly labeled penicillin allergic may benefit from allergy de-labeling (ADL) efforts to facilitate access to beta-lactam antibiotics. We developed a multidisciplinary, pharmacist-driven process that enabled non-allergist trained providers to assess and de-label penicillin allergies in a pediatric hematology center.

METHODS

Volunteers, including physicians, advanced practice providers, nurses, and pharmacists, were trained in skin testing and oral challenge procedures. Patients were identified by review of electronic medical records for penicillin or penicillin-derivative allergy. Patient and family interviews were conducted in cases where a true penicillin allergy was deemed uncertain based on chart review. If allergy could not be de-labeled by chart review or interview alone, patients were offered skin and/or oral challenge testing.

RESULTS

Fifty-nine patients were initially labeled as penicillin allergic. Allergy labels of 11 (19%) were removed by chart review only, and 15 (25%) after conducting interviews. A total of two (3%) patients were ineligible due to contraindications, and five (9%) declined participation. Twenty-six patients (44%) underwent allergy testing (50% skin testing, 50% oral challenge) of which 23 (88%) were negative.

CONCLUSIONS

ADL was possible in most patients previously identified as penicillin allergic. Testing was well tolerated with no serious adverse effects.

Managing gastrointestinal challenges: Diarrhea in sickle cell anemia

Sickle cell anemia (SCA), a hereditary hemoglobinopathy, is characterized by the presence of abnormal hemoglobin and has long been associated with a wide range of complications. While much attention has been given to the condition hematological aspects, gastrointestinal complications, particularly diarrhea, have been relatively understudied and often overlooked. This publication delves into the management of gastrointestinal challenges, with a focus on diarrhea, in individuals living with SCA. The pathophysiology of SCA is intrinsically linked to gastrointestinal complications, and diarrhea is a common manifestation of this condition. This abstract publication outlines the key elements discussed in the full-length work, which includes the clinical presentation of diarrhea in these patients, the diagnostic tools used to evaluate the condition, and various management strategies to alleviate symptoms and enhance the overall quality of life for affected individuals. The paper emphasizes the importance of patient education, offering healthcare professionals valuable insights into how to inform and support patients in managing their conditions effectively. It also highlights the need for continued research to further our understanding of gastrointestinal challenges in SCA and to identify potential areas for future therapeutic interventions. Ultimately, the comprehensive management of diarrhea in individuals with SCA is vital for their overall well-being. This publication serves as a valuable resource for healthcare providers, researchers, and caregivers in addressing the gastrointestinal challenges that accompany SCA, ultimately working toward a better quality of life for those affected by this condition.

Sickle cell disease in Australia: a snapshot from the Australian Haemoglobinopathy Registry

BACKGROUND

Sickle cell disease (SCD) is the most common monogenic disorder worldwide. In deoxygenated conditions, the altered beta chain (haemoglobin S [HbS]) polymerises and distorts the erythrocyte, resulting in pain crises, vasculopathy and end-organ damage. Clinical complications of SCD cause substantial morbidity, and therapy demands expertise and resources. Optimising care for patients and planning resource allocation for the future requires an understanding of the disease in the Australian population. The Australian Haemoglobinopathy Registry (HbR) is a collaborative initiative of specialist centres collating and analysing data on patients with haemoglobin disorders.

AIMS

To provide a snapshot of SCD in Australia over a 12-month period based on data from the HbR.

METHODS

Patients with a clinically significant sickling disorder across 12 clinical sites were included for analysis. Data include demographic and diagnostic details, as well as details of the clinical management of the condition over a 12-month period.

RESULTS

Data on 359 SCD patients demonstrate a shift in the demographic of patients in Australia, with a growing proportion of sub-Saharan African ethnicities associated with the HbSS genotype. Acute and chronic complications are common, and patients require significant outpatient and inpatient support. Prevalence of disease complications and therapeutic trends are in keeping with other high-income countries.

CONCLUSIONS

This study provides the first national picture of SCD in Australia, describing the characteristics and needs of SCD patients, elucidating demand for current and novel therapy and facilitating the planning of services for this vulnerable population.

Factors associated with adverse outcome among children with sickle cell disease admitted to the pediatric intensive care unit: an observational cohort

BACKGROUND

Sickle cell disease (SCD) is one of the most frequent inherited diseases in the world. Over the last decades, in high-income countries, an important decrease in mortality have been observed due to the improvement of care. However, children with SCD can become critically ill and require admission in Pediatric Intensive Care Units (PICU). The purpose of this study was to describe the epidemiology of children with SCD admitted to PICU for acute crisis and to identify factors associated with adverse outcome (AO).

METHODS

We conducted a retrospective study in a Tertiary Hospital in France including all consecutive children with SCD admitted to PICU between January 1st, 2009 and December 31, 2019. We collected baseline patient's characteristics, clinical and biological data as well as treatments and life sustaining therapies used in the PICU. Patients were defined as experiencing AO in case of death during stay and/or need for invasive mechanical ventilation (MV) and/or for non-invasive ventilation (NIV) for more than 3 days and/or need for vasopressors and/or need for renal replacement therapy.

RESULTS

We included 579 admissions in 395 patients, mainly of SS genotype (90%) with a median age of 9.2 years [5.5-13.4] and a median baseline hemoglobin of 8.0 g/dl (7.5-8.8). The two main reasons for admission were acute chest syndrome (ACS) (n = 331, 57%) and vaso-occlusive crisis refractory to first line therapy (n = 99, 17%). Half of patients required NIV and 47 (8%) required MV. The overall length of stay was 3 days [1-4] and seven (1%) patients died during PICU stay.There was a total of 113 (20%) admissions with AO and on multivariable analysis, baseline hemoglobin < 8 g/dL, history of bronchial obstruction and admission for ACS were associated with AO. There was no difference in the proportion of hydroxyurea treatment or exchange transfusion program between patients with AO and the other patients.

CONCLUSIONS

Baseline hemoglobin < 8 g/dL, history of bronchial obstruction and admission for ACS were the strongest risk factors for severe evolution in SCD children admitted to PICU. These factors could be taken into consideration when choosing the adequate therapeutic options.

[Syndromic approach in migrant patients: Fever, diarrhea, anemia, eosinophilia and chronic cough]

Migrant patients share the same diseases as natives, but biological or environmental differences may lead to distinct prevalence and manifestations of certain syndromes. Some common conditions in Primary Care stand out, such as fever, diarrhea, anemia, eosinophilia, and chronic cough, where it is important to have a special consideration. Fever may indicate a serious imported illness, and malaria should always be ruled out. Diarrhea is generally of infectious origin, and in most cases, management is outpatient. Anemia may indicate malnutrition or malabsorption, while eosinophilia may indicate a parasitic infection. Lastly, chronic cough may be a sign of tuberculosis, especially in immigrants from endemic areas. Family medicine holds a privileged position for the comprehensive, culturally sensitive, and person-centered approach to these conditions.

Antimicrobial and anti-diabetic efficiency of Polyalthia longifolia leaf extracts and major compounds characterization

This research was performed to investigate the bactericidal and fungicidal competence of extracts (methanol and petroleum ether extract) of Polyalthia longifolia leaf. Moreover, the major active compounds present in the effective crude extract (either methanol or petroleum ether extract) was determined through initially with UV-Vis spectra, FTIR, and GC-MS analyses. The methanol extract alone showed remarkable bactericidal and fungicidal activity against the bacterial (S. pyogenes > E. coli > S. aureus > S. pneumoniae > C. difficile > P. aeruginosa) and fungal (A. clavatus > C. albicans > A. niger > A. fumigatus > C. tropicalis > C. auris) pathogens at increased concentration (12.5 mg mL-1) than petroleum ether extract. The MIC and MBC values of methanol extract were found as 10-20 mg mL-1 and 30-40 mg mL-1 respectively. The MFC value of methanol extract was found as 10-20 mg mL-1. These MIC, MBC, and MFC values of methanol extract were considerably greater than petroleum ether extract. The FTIR and GC-MS characterization studies revealed that the presence of more acre functional groups belonging to bioactive compounds such as Z)-7-Hexadecenal, Aromandendrene, α-Curcumene, Caryophyllene, Methyl 14-methyl Pentadecanoat, Methyl trans-13-Octadecenoate, 9-Octadecenoic acid (Z)-, and 2-hydroxy-1- (hydroxymethyl)ethyl. As a result of these findings, it is possible that P. longifolia leaf methanol extract contains medicinally important bioactive substances with bactericidal and fungicidal properties.

Emergency Department Utilization by Pediatric Patients With Sickle Cell Disease in Basrah, Iraq

Background Patients with sickle cell disease (SCD) often present in the Emergency Department (ED) with acute and debilitating pain and other SCD-related complications. Objectives The objective is to analyze the causes of ED visits of pediatric patients with SCD, assess the burden of ED admission due to SCD in relation to other pediatric diseases, the treatment given, and the outcomes. Methods A prospective analytical study was conducted on children and adolescents with SCD, 1-14 years old who had been admitted to the ED at Basrah Maternity and Children Hospital over a six-month period. Patient's sociodemographic and clinical data, drug history, length of ED stay, complications, outcome, and readmissions were recorded.  Results A total of 422 patients with SCD were admitted to ED during the study period representing 4.10% of the total admitted cases; 276(65.40%) of them were recruited in this study, and their mean age was 7.84 ±3.47 years. The main cause for ED admission was pain (73.91%), followed by infection (10.14%) and hemolytic crisis (6.15%). The mean duration of stay at ED was 6.11±1.87 hours. All admitted SCD patients had received analgesia; non-steroidal anti-inflammatory drugs (NSAIDs) were the commonest (80.4%), followed by acetaminophen (39.5%), and opioid narcotic (18.5%). Readmission within 30-days was reported in 82(29.71%) patients and was associated with the number of ED visits/last year (B=0.151, P=0.023), length of stay at ED (B=0.140, P=0.034) and severe disease (B=0.253, P<0.001). Conclusions Acute painful episodes were the main cause of ED admission. Although most patients with pain did receive NSAIDs, only a small percentage of them did receive opioids. About one-third of patients have been readmitted within 30 days, and readmission was associated with the number of ED visits/last year, disease severity, and length of ED stay. These findings can help in establishing local guidelines for managing such patients in the ED especially pain management.

Chronic humeral osteomyelitis in an adult with sickle-cell disease

INTRODUCTION AND IMPORTANCE

The rising incidence of sickle-cell disease in European countries has led to an increase in associated complications. Osteomyelitis, a rare complication in non-traumatic adult cases, poses diagnostic challenges and presents treatment difficulties due to limited cases and studies.

CASE PRESENTATION

A 23-year-old woman diagnosed with sickle-cell disease presented with a six-day fever and painful swelling in the left upper extremity persisting for a fortnight. She had no history of trauma but had experienced a previous episode of bacteremia due to Salmonella, four years prior. Magnetic resonance imaging revealed an intramedullary bone injury with cortical rupture extending into soft tissues, forming a collection that raised clinical suspicion of osteomyelitis, despite negative blood and aspirate cultures. Empiric antibiotic therapy was initiated, followed by surgical debridement of infected tissues. The resulting dead space was filled with antibiotic-coated calcium phosphate beads and tissue grafting. Anatomopathological studies confirmed findings consistent with chronic osteomyelitis. Stabilization of the arm was achieved with an orthopedic brace, and antibiotic administration continued for 6 weeks post-surgery. The injury consolidated 4 months after treatment, and nearly two years later she has not suffered a recurrence.

CLINICAL DISCUSSION

The scarcity of literature implies the absence of clinical guidelines for treating osteomyelitis in these patients. Empirical antibiotic therapy combined with surgery when there are abscesses that need debridement can be an effective approach.

CONCLUSION

Humeral osteomyelitis in sickle-cell disease patients can be effectively managed using a pharmaco-surgical strategy, but it should be tailored to the patient's needs.

Guarding Health: A Comprehensive Review of Nosocomial Infections in Sickle Cell Anemia, a Multifaceted Approach to Prevention

This comprehensive review explores the complex dynamics of nosocomial infections in individuals with sickle cell anemia (SCA) and advocates for a collaborative strategy to enhance prevention. SCA patients, marked by compromised immunity and susceptibility to infections, face unique challenges that necessitate tailored preventive measures. The review underscores the importance of vaccination, antibiotic prophylaxis, education, and environmental hygiene in mitigating the risk of nosocomial infections. Addressing socioeconomic factors, healthcare system limitations, patient-related issues, and cultural considerations is imperative for effective prevention. The call to action emphasizes the pivotal roles of healthcare professionals, policymakers, researchers, and community engagement in implementing targeted interventions. By fostering a collective effort, this review envisions an improved landscape for infection prevention in SCA patients, enhancing their overall health outcomes and quality of life.

Nosocomial infections in sickle cell anemia patients: Prevention through multi-disciplinary approach: A review

Sickle cell anemia (SCA), a hereditary blood disorder characterized by the presence of abnormal hemoglobin, poses a unique set of challenges for both patients and healthcare providers. One of the most pressing issues in the care of these individuals is the persistent threat of nosocomial infections, which are infections acquired during hospitalization. This abstract provides a concise overview of the ongoing challenge of nosocomial infections in SCA patients, highlighting the factors contributing to their vulnerability and the preventive measures in place. SCA patients face increased susceptibility to nosocomial infections due to their compromised immune systems, frequent hospitalizations, prolonged stays, and the need for invasive medical interventions. The emergence of multidrug-resistant pathogens further complicates the management of these infections. To address this challenge, healthcare facilities have implemented infection control protocols, vaccination strategies, and antimicrobial stewardship, emphasizing the importance of patient education. Recognizing the gravity of this issue and adopting comprehensive preventive measures is crucial to improving the quality of care and patient outcomes in this vulnerable population. Further research and ongoing efforts are essential to reducing the burden of nosocomial infections in SCA patients and enhancing their overall healthcare experience.

Exploring the Link between Maternal Hematological Disorders during Pregnancy and Neurological Development in Newborns: Mixed Cohort Study

Maternal hematological disorders during pregnancy may pose a risk to the neurological development of newborns. To investigate the association between maternal hematological disorders during pregnancy and neurological outcomes in newborns, this mixed cohort study was conducted on 200 pregnant women diagnosed with hematological disorders during pregnancy. Some cases have been identified in the past who have completed the pregnancy in full, as well as cases in pregnancy. Currently, the children of all mothers have been followed up to evaluate the neurological outcomes of the children at the age of three months. Logistic regression analysis was used to determine the association between maternal hematological disorders and neurological outcomes in newborns. Children born to mothers with hematological disorders had a higher risk of developmental delays (OR = 1.50, 95% CI = 0.90-2.50), cognitive impairments (OR = 1.80, 95% CI = 1.20-2.70), and motor impairments (OR = 1.60, 95% CI = 1.00-2.50) compared to children born to mothers without hematological disorders. Hemophilia was associated with the highest risk of neurological outcomes (developmental delay: OR = 2.80, 95% CI = 1.60-4.90; cognitive impairment: OR = 3.20, 95% CI = 2.00-5.10; motor impairment: OR = 2.60, 95% CI = 1.50-4.60). Conclusion: Our study suggests that maternal hematological disorders during pregnancy may increase the risk of negative neurological consequences in newborns. Further research is needed to identify potential mechanisms and explore preventive measures.

Invasive Bacterial Infections in Children With Sickle Cell Disease: 2014-2019

BACKGROUND

Children with sickle cell disease (SCD) are at a high risk of invasive bacterial infections (IBI). Universal penicillin prophylaxis and vaccination, especially against Streptococcus pneumoniae, have deeply changed its epidemiology. Analysis of IBI in children with SCD in a post-13-valent pneumococcal vaccine era is limited.

METHODS

Twenty-eight pediatric hospitals from 5 European countries retrospectively collected IBI episodes in SCD children aged 1 month to 18 years between 2014 and 2019. IBI was defined as a positive bacterial culture or polymerase chain reaction from a normally sterile fluid: blood, cerebrospinal, joint, or pleural fluid and deep surgical specimen.

RESULTS

We recorded 169 IBI episodes. Salmonella spp. was the main isolated bacteria (n = 44, 26%), followed by Streptococcus pneumonia (Sp; n = 31, 18%) and Staphylococcus aureus (n = 20, 12%). Salmonella prevailed in osteoarticular infections and in primary bacteremia (45% and 23% of episodes, respectively) and Sp in meningitis and acute chest syndrome (88% and 50%, respectively). All Sp IBI occurred in children ≤10 years old, including 35% in children 5 to 10 years old. Twenty-seven (17%) children had complications of infection and 3 died: 2 because of Sp, and 1 because of Salmonella. The main risk factors for a severe IBI were a previous IBI and pneumococcal infection (17 Sp/51 cases).

CONCLUSIONS

In a post-13-valent pneumococcal vaccine era, Salmonella was the leading cause of bacteremia in IBI in children with SCD in Europe. Sp came second, was isolated in children ≤10 years old, and was more likely to cause severe and fatal cases.

A Review of the Relationship between the Immune Response, Inflammation, Oxidative Stress, and the Pathogenesis of Sickle Cell Anaemia

Sickle cell anaemia (SCD) is a life-threatening haematological disorder which is predominant in sub-Saharan Africa and is triggered by a genetic mutation of the β-chain haemoglobin gene resulting in the substitution of glutamic acid with valine. This mutation leads to the production of an abnormal haemoglobin molecule called haemoglobin S (HbS). When deoxygenated, haemoglobin S (HbS) polymerises and results in a sickle-shaped red blood cell which is rigid and has a significantly shortened life span. Various reports have shown a strong link between oxidative stress, inflammation, the immune response, and the pathogenesis of sickle cell disease. The consequence of these processes leads to the development of vasculopathy (disease of the blood vessels) and several other complications. The role of the immune system, particularly the innate immune system, in the pathogenesis of SCD has become increasingly clear in recent years of research; however, little is known about the roles of the adaptive immune system in this disease. This review examines the interaction between the immune system, inflammation, oxidative stress, blood transfusion, and their effects on the pathogenesis of sickle cell anaemia.

A case of hyperhemolysis syndrome in sickle cell disease and concomitant COVID-19

BACKGROUND

Hyperhemolysis syndrome (HHS) is an uncommon transfusion reaction described in several hematologic disorders, including sickle cell disease (SCD). HHS is characterized by a decline in hemoglobin (Hb) values below pre-transfusion levels following transfusion of red blood cells (RBCs), coupled with laboratory markers consistent with hemolysis. The proposed pathophysiologic mechanisms underlying HHS include increased phosphatidylserine expression, macrophage activation, and complement dysregulation. Many pathophysiologic mechanisms thought to contribute to HHS have been similarly described in cases of severe COVID-19.

CASE REPORT

A 28-year-old male with a history of HbSS presented with shortness of breath, right-sided chest pain, and a two-day history of fever. Polymerase chain reaction (PCR) detected SARS-CoV-2 infection with the omicron variant. The patient required an RBC transfusion (pre-transfusion hemoglobin [Hb]5.8 g/dL) with an immediate post-transfusion Hb of 6.3 g/dL. However, Hb rapidly declined to 1.7 g/dL, and lactate dehydrogenase (LDH) rose to 8701 u/L. The absolute reticulocyte count of 538 × 109/L correspondingly fell to 29 × 109/L. Despite additional RBC transfusions and initiation of immunosuppressive therapy, he expired on Day 9(D9).

CONCLUSION

Given the similarities in their proposed pathophysiology, patients with SCD and concomitant SARS-CoV-2 infection may be predisposed to developing HHS.

Cervical precancer screening with HPV DNA testing and mobile colposcopy in women with sickle cell disease in Accra, Ghana

Background

Worldwide, about 20-25 million people are affected by sickle cell disease (SCD), with 60% of patients living in sub-Saharan Africa. Despite recent therapeutic advancements resulting in improved life expectancy among SCD patients, the prevalence of high-risk human papillomavirus (hr-HPV) and cervical lesions have not been studied in women with SCD. We determined the prevalence of hr-HPV and cervical lesions among women with SCD and recommended strategies for reducing cervical cancer incidence in this cohort.

Methods

Through the mPharma 10,000 Women Initiative, women with SCD attending routine visits at the Ghana Institute of Clinical Genetics SCD clinic were screened by trained nurses. Screening was performed via concurrent MA-6000 hr-HPV DNA testing and enhanced visual assessment (EVA) mobile colposcopy from mobileODT.

Results

Among 168 participants screened (mean age, 43.0 years), the overall prevalence rates of hr-HPV infection and cervical lesions were 28.6% (95% CI, 21.7-35.4) and 3.6% (95% CI, 0.8-6.4), respectively. The hr-HPV prevalence rates stratified by haemoglobin genotype were 29.4% (95% CI, 19.7-39.1) and 28.6% (95% CI, 18.5-38.7) for genotypes SS and SC, respectively. None of the five women with the SF genotype tested hr-HPV positive, and the only patient with Sbthal genotype tested hr-HPV positive. Two women were EVA 'positive' but hr-HPV negative, whereas four were EVA positive and hr-HPV positive. Exploratory analysis revealed no significant associations between hr-HPV positivity and age, education level, marital status or parity.

Conclusion

In the absence of a comprehensive national cervical screening programme aimed at including women with SCD as a special population, cervical cancer may increase in frequency among SCD patients. Thus, there is a need to build capacity and expand the scope of screening services for women with SCD.

Impact of genotype on clinical course in sickle cell disease and the utility of neutrophil-lymphocyte ratio: a ten-year single-institution experience

BACKGROUND

Sickle cell disease (SCD) is a diverse group of blood disorders with significant global disease burden. Contemporary interest in the underlying inflammatory paradigm of SCD has emphasized the role of the neutrophil-lymphocyte ratio (NLR) as a prognostic inflammatory marker.

METHODS

We retrospectively reviewed 268 hospitalized patients with SCDs of different genotypes (HbSS, HbSβ0 thalassemia, HbSβ+ thalassemia, and HbSC), totaling 3329 hospital admissions over a 10-year period. Patients were stratified into SS/Sβ0 and Sβ+/SC groups for statistical analysis of parameters collected at steady state and at hospital admission.

RESULTS

At steady state, per unit increase of hemoglobin values was associated with reduced odds of ≥ 2 hospital admissions per year in SS/Sβ0 and Sβ+/SC groups; per unit increase in platelet count and white blood cell count was associated with increased odds only in the SS/Sβ0 group. The NLR had no association in either group. During admission, a cutoff of NLR = 3.5 discerned infection with a sensitivity of 60% and specificity of 57%. Performance improved when excluding patients on outpatient hydroxyurea therapy (cutoff of NLR = 3.5; sensitivity of 68% and specificity of 64%).

CONCLUSION

This study supports the utility of NLR as an accessible adjunctive clinical tool in SCD prognostication.

Case Fatality Rate and Severity of COVID-19 among Patients with Sickle Cell Disease: A Systematic Review and Meta-Analysis

The sickle cell disease (SCD) population has been considered particularly vulnerable to viral pandemics since the emergence of H1N1 in 2009. In this sense, the advance of the COVID-19 pandemic from 2020 has brought this group of patients to the center of concern. However, scientific knowledge about the susceptibility of patients with SCD to a severe COVID-19 pandemic is still insufficient, and efforts to establish a general profile of the disease in these patients, remain inadequate. The present study, therefore, sought to characterize the case fatality rate and severity of COVID-19 in patients with SCD throughout the world. A systematic review of Pubmed/MEDLINE, Scopus, Cochrane Library, and Virtual Health Library databases through December 2021 was then performed. Subsequently, the primary and secondary outcomes were used in the meta-analysis in RStudio® software. Seventy-two studies were included with 6,011 SCD patients confirmed to have SARS-CoV-2 infection between mid-2020 and early 2022. The mean age of patients was 27 years. During this period, 218 deaths caused by COVID-19 were reported in the studied population, corresponding to an overall case fatality rate of 3%. In addition, 10% of patients with SCD were admitted to the ICU after complications caused by COVID-19, and 4% of them required invasive ventilatory support. In conclusion, the high fatality rate, intensive care unit admission and need for mechanical ventilation due to COVID-19 in young patients with SCD indicate that this population is at high risk for severe disease progression.

Inflammatory status in pediatric sickle cell disease: Unravelling the role of immune cell subsets

Introduction: The mutation of the beta-globin gene that causes sickle cell disease (SCD) results in pleiotropic effects, such as hemolysis and vaso-occlusive crisis that can induce inflammatory mechanisms with deleterious consequences on the organism. Moreover, SCD patients display an increased susceptibility to infections. Few studies are currently available that evaluate a wide immunological profile in a pediatric population. This study proposes an evaluation of the immune profile in subjects with SCD in a pediatric population through a detailed analysis by flow cytometry. Methods and Materials: Peripheral blood samples from 53 pediatric patients with SCD (mean age 9.8 years, interquartile range 9 years) were obtained and then analyzed by flow cytometry, in order to evaluate changes in the immune populations compared to 40 healthy donors (mean age 7.3 years, interquartile range 9.5 years). Results: Our data showed an increase in neutrophils (with a reduction in the CD62L + subpopulation) and monocytes (with a decrease in HLA-DRlow monocytes) with normal values of lymphocytes in SCD patients. In the lymphocyte subpopulations analysis we observed lower values of CD4⁺ T cells (with higher number of memory and central memory T lymphocytes) with increased frequency of CD8⁺ T cells (with a predominant naive pattern). Moreover, we observed higher values of CD39⁺ Tregs and lower HLA-DR+ and CD39^- T cells with an increased Th17, Th1-17 and Th2 response. Conclusion: We observed immunological alterations typical of an inflammatory status (increase in activated neutrophils and monocytes) associated with a peculiar Treg pattern (probably linked to a body attempt to minimize inflammation intrinsic to SCD). Furthermore, we highlighted a T helper pathway associated with inflammation in line with other studies. Our data showed that immunological markers may have an important role in the understanding the pathophysiology of SCD and in optimizing targeted therapeutic strategies for each patient.

Correctly Establishing and Interpreting Oxygenation Status in Sickle Cell Disease

BACKGROUND

As hypoxemia and hypoxia are central elements of disease pathophysiology and disease-related morbidity and mortality in individuals affected by sickle cell disease (SCD), clinical management aims to optimize oxygenation.

CONTENT

Hypoxemia is primarily screened for with pulse oximetry. However, in SCD pulse oximetry can inaccurately reflect arterial saturation, posing the risk of undetected (occult) hypoxemia. Solely relying on pulse oximetry might therefore lead to misdiagnosis or mismanagement, with devastating effects on tissue oxygenation. The interpretation of oxygenation status is multifaceted, and "oxygen saturation" is often used as an umbrella term to refer to distinctly different measured quantities-estimated oxygen saturation (O2Sat), hemoglobin oxygen saturation (SO2) by either pulse oximetry or co-oximetry, and fractional oxyhemoglobin (FO2Hb). While in many clinical situations this ambiguous use is of little consequence, O2Sat, SO2, and FO2Hb cannot be used interchangeably in the setting of SCD, as dyshemoglobins, anemia, cardiopulmonary comorbidities, concomitant medications, and frequent transfusions need to be accounted for. This article describes the parameters that determine blood and tissue oxygen concentration, discusses laboratory method performance characteristics and the correct interpretation of currently available clinical laboratory testing, and reviews the literature on noninvasive vs invasive oxygenation measurements in SCD.

SUMMARY

By correctly establishing and interpreting oxygenation parameters, clinical and laboratory teams can ensure high-quality, equitable healthcare, counteracting systemic exacerbations of health disparities frequently experienced by individuals with SCD.

Numb Chin Syndrome in Sickle Cell Disease: A Systematic Review and Recommendations for Investigation and Management

Numb chin syndrome (NCS) is a rare sensory neuropathy resulting from inferior alveolar or mental nerve injury. It manifests as hypoesthesia, paraesthesia, or, rarely, as pain in the chin and lower lip. Several case reports suggest that sickle cell disease (SCD) could be a cause of NCS. However, information about NCS is scarce in this population. Our objectives were to synthesize all the available literature relevant to NCS in SCD and to propose recommendations for diagnosis and management based on the best available evidence. A systematic review was performed on several databases to identify all relevant publications on NCS in adults and children with SCD. We identified 73 publications; fourteen reports met the inclusion/exclusion criteria. These described 33 unique patients. Most episodes of NCS occurred in the context of typical veno-occlusive crises that involved the mandibular area. Radiological signs of bone infarction were found on some imaging, but not all. Neuropathy management was mostly directed toward the underlying cause. Overall, these observations suggest that vaso-occlusion and bone infarction could be important pathophysiological mechanisms of NCS. However, depending on the individual context, we recommend a careful evaluation to rule out differential causes, including infections, local tumors, metastatic disease, and stroke.

The relationship between anemia and obesity

INTRODUCTION

Obesity is linked to a variety of unfavourable outcomes, including anaemia, which is a serious global public health problem. The prevalence of obesity along with anaemia suggests a relationship between obesity and anaemia. Recent studies have demonstrated strong associations between anaemia and obesity, chronic diseases, ageing, hepato-renal impairment, chronic infection, autoimmune diseases, and widespread malignancy. Thus, the intersection point of obesity and anaemia is an important area of attention.

AREA COVERED

This paper reviews the pathophysiology of obesity and anaemia. Then, It deliberates the relationship between obesity and different types of anaemia and other clinical forms associated with anaemia.

EXPERT OPINION

Obesity, especially obesity-related to excessive visceral fat distribution, is accompanied by several disturbances at the endothelial, hormonal, and inflammatory levels. These disturbances induce activation of several mechanisms that contribute to the anaemic state. Over-weight patients with chronic anaemias are required to maintain the related vitamins and minerals at optimum levels and appropriate BMI. In addition, a regular clinical follow-up is essential to be scheduled to reduce the risk of complications associated with anaemia in obese patients.

Heme-stress activated NRF2 skews fate trajectories of bone marrow cells from dendritic cells towards red pulp-like macrophages in hemolytic anemia

Heme is an erythrocyte-derived toxin that drives disease progression in hemolytic anemias, such as sickle cell disease. During hemolysis, specialized bone marrow-derived macrophages with a high heme-metabolism capacity orchestrate disease adaptation by removing damaged erythrocytes and heme-protein complexes from the blood and supporting iron recycling for erythropoiesis. Since chronic heme-stress is noxious for macrophages, erythrophagocytes in the spleen are continuously replenished from bone marrow-derived progenitors. Here, we hypothesized that adaptation to heme stress progressively shifts differentiation trajectories of bone marrow progenitors to expand the capacity of heme-handling monocyte-derived macrophages at the expense of the homeostatic generation of dendritic cells, which emerge from shared myeloid precursors. This heme-induced redirection of differentiation trajectories may contribute to hemolysis-induced secondary immunodeficiency. We performed single-cell RNA-sequencing with directional RNA velocity analysis of GM-CSF-supplemented mouse bone marrow cultures to assess myeloid differentiation under heme stress. We found that heme-activated NRF2 signaling shifted the differentiation of bone marrow cells towards antioxidant, iron-recycling macrophages, suppressing the generation of dendritic cells in heme-exposed bone marrow cultures. Heme eliminated the capacity of GM-CSF-supplemented bone marrow cultures to activate antigen-specific CD4 T cells. The generation of functionally competent dendritic cells was restored by NRF2 loss. The heme-induced phenotype of macrophage expansion with concurrent dendritic cell depletion was reproduced in hemolytic mice with sickle cell disease and spherocytosis and associated with reduced dendritic cell functions in the spleen. Our data provide a novel mechanistic underpinning of hemolytic stress as a driver of hyposplenism-related secondary immunodeficiency.

Bacterial Meningitis in Children With Sickle Cell Disease in Angola

Sickle cell disease (SCD) was found in 10% of children with bacterial meningitis (BM) in Luanda, 5-fold more than in the general population. BM children with SCD versus BM children without SCD had higher inflammatory markers, more often had pneumococcal meningitis (71% vs. 39%), and either died (39% vs. 22%) or had a longer hospital stay (15 vs. 11 days).

Manifestations of Sickle Cell Disorder at Abdominal and Pelvic Imaging

Sickle cell disorder (SCD) refers to a spectrum of hematologic disorders that cause a characteristic clinical syndrome affecting the entire body. It is the most prevalent monogenetic hemoglobinopathy worldwide, with a wide range of focal and systemic expressions. Hemoglobin gene mutation leads to the formation of abnormal sickle-shaped red blood cells, which cause vascular occlusion and result in tissue and organ ischemia and infarction. Recurrent episodes of acute illness lead to progressive multisystem organ damage and dysfunction. Vaso-occlusion, hemolysis, and infection as a result of functional asplenia are at the core of the disease manifestations. Imaging plays an essential role in the diagnosis and management of SCD-related complications in the abdomen and pelvis. A thorough understanding of the key imaging findings of SCD complications involving hepatobiliary, gastrointestinal, genitourinary, and musculoskeletal systems is crucial to timely recognition and accurate diagnosis. The authors aim to familiarize the radiologist with the SCD spectrum, focusing on the detection and evaluation of manifestations that may appear at imaging of the abdomen and pelvis. The topics the authors address include (a) the pathophysiology of the disease, (b) the placement of SCD among hemoglobinopathies, (c) the clinical presentation of SCD, (d) the role of imaging in the evaluation and diagnosis of patients with SCD who present with abdominal and pelvic manifestations in addition to extraperitoneal manifestations detectable at abdominal or pelvic imaging, (e) imaging features associated with common and uncommon sequelae of SCD in abdominal and pelvic imaging studies, and (f) a brief overview of management and treatment of patients with SCD. Online supplemental material is available for this article. ^©RSNA, 2022.

Skeletal infections: microbial pathogenesis, immunity and clinical management

Osteomyelitis remains one of the greatest risks in orthopaedic surgery. Although many organisms are linked to skeletal infections, Staphylococcus aureus remains the most prevalent and devastating causative pathogen. Important discoveries have uncovered novel mechanisms of S. aureus pathogenesis and persistence within bone tissue, including implant-associated biofilms, abscesses and invasion of the osteocyte lacuno-canalicular network. However, little clinical progress has been made in the prevention and eradication of skeletal infection as treatment algorithms and outcomes have only incrementally changed over the past half century. In this Review, we discuss the mechanisms of persistence and immune evasion in S. aureus infection of the skeletal system as well as features of other osteomyelitis-causing pathogens in implant-associated and native bone infections. We also describe how the host fails to eradicate bacterial bone infections, and how this new information may lead to the development of novel interventions. Finally, we discuss the clinical management of skeletal infection, including osteomyelitis classification and strategies to treat skeletal infections with emerging technologies that could translate to the clinic in the future.

Transcranial doppler as screening method for sickling crises in children with sickle cell anemia: a latin America cohort study

Background

Sickle cell anemia (SCA) is the leading cause of childhood stroke. We aimed to evaluate whether altered cerebral flow velocities, as measured by transcranial Doppler (TCD), are associated with vaso-occlusive complications in addition to stroke in pediatric SCA patients.

Methods

We evaluated 37 children aged between 2 and 16 years with SCA who underwent screening for TCD between January 2012 and October 2018. Genotypic profiles and demographic data were collected, TCD examinations were performed during follow-up, and the presence of sickling crises was compared. Survival analyses were performed using simple frailty models, in which each predictor variable was analyzed separately in relation to the occurrence of a sickling crisis.

Results

The variables related to sickle cell crises in the univariate analysis were peak systolic velocity (PSV) in the middle cerebral artery (MCA), hazard ratio (HR) 1.01 (1.00—1.02) p = 0.04; end-diastolic velocity (EDV) in the MCA, HR 1.02 (1.01—1.04) p = 0.01; time average mean maximum velocity (TAMMV) in the basilar artery (BA), HR 1.02 (1.00—1.04) p = 0.04; hemoglobin, HR 0.49 (0.38—0.65) p < 0.001; hematocrit, HR 0.78 (0.71—0.85) p < 0.001; leukocyte counts, HR 1.1 (1.05—1.15) p < 0.001; platelets counts, HR 0.997 (0.994—0.999) p = 0.02; and reticulocyte numbers, HR 1.14 (1.06—1.23) p < 0.001.

Conclusions

Our results indicate PSV and EDV in the MCA and TAMMV in the BA as markers of risk for the occurrence of sickling crises in SCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03429-5.

The Effects of Sickle Cell Disease on the Quality of Life: A Focus on the Untold Experiences of Parents in Tanzania

Tanzania is among the top five countries with a high burden of sickle cell disease (SCD) in the world. Even though the effects of SCD on quality of life have been documented in other countries including Nigeria and the United States of America, few are known from Tanzania. Therefore, this study focused on evaluating the effects of SCD on the quality of life among children living with SCD and their parents. The study employed a qualitative approach to interview purposively selected parents of children who have lived with SCD and have used hydroxyurea (HU) for more than 3 years. The in-depth interviews were conducted with 11 parents of children with SCD at the Muhimbili University of Health and Allied Sciences (MUHAS) in Dar-es-salaam, Tanzania. A semi-structured interview guide was used. Interviews were audio-recorded, transcribed, and thematically analyzed. Three themes were generated including psycho-social effects: family conflicts and divorce, limited access to education, stress and fear; financial effects: Employment limitation, reduced efficiency and productivity, loss of job and lack of self-keeping expenses; and physical effects: physical disability and dependence, and burden of the frequent crisis. Children living with SCD and their parents suffer psycho-social, financial, and physical impacts of the disease. Appropriate interventions should be introduced to minimize the observed effects as ways of improving the quality of life of the individuals living with SCD and their caregivers.

In-Depth Immunological Typization of Children with Sickle Cell Disease: A Preliminary Insight into Its Plausible Correlation with Clinical Course and Hydroxyurea Therapy

Sickle cell disease (SCD) is a condition of functional hypo-/a-splenism in which predisposition to bacterial infections is only a facet of a wide spectrum of immune-dysregulation disorders forming the clinical expression of a peculiar immunophenotype. The objective of this study was to perform an in-depth immunophenotypical characterization of SCD pediatric patients, looking for plausible correlations between immunological biomarkers, the impact of hydroxyurea (HU) treatment and clinical course. This was an observational case−control study including 43 patients. The cohort was divided into two main groups, SCD subjects (19/43) and controls (24/43), differing in the presence/absence of an SCD diagnosis. The SCD group was split up into HU+ (12/19) and HU− (7/19) subgroups, respectively receiving or not a concomitant HU treatment. The principal outcomes measured were differences in the immunophenotyping between SCD patients and controls through chi-squared tests, t-tests, and Pearson’s correlation analysis between clinical and immunological parameters. Leukocyte and neutrophil increase, T-cell depletion with prevalence of memory T-cell compartment, NK and B-naïve subset elevation with memory and CD21low B subset reduction, and IgG expansion, significantly distinguished the SCD HU− subgroup from controls, with naïve T cells, switched-memory B cells and IgG maintaining differences between the SCD HU+ group and controls (p-value of <0.05). The mean CD4+ central-memory T-cell% count was the single independent variable showing a positive correlation with vaso-occlusive crisis score in the SCD group (Pearson’s R = 0.039). We report preliminary data assessing plausible clinical implications of baseline and HU-related SCD immunophenotypical alterations, which need to be validated in larger samples, but potentially affecting hypo-/a-splenism immuno-chemoprophylactic recommendations.

Clinical outcomes of COVID-19 in patients with sickle cell disease and sickle cell trait: A critical appraisal of the literature

Individuals with sickle cell disease (SCD) and sickle cell trait (SCT) have many risk factors that could make them more susceptible to COVID-19 critical illness and death compared to the general population. With a growing body of literature in this field, a comprehensive review is needed. We reviewed 71 COVID-19-related studies conducted in 15 countries and published between January 1, 2020, and October 15, 2021, including a combined total of over 2000 patients with SCD and nearly 2000 patients with SCT. Adults with SCD typically have a mild to moderate COVID-19 disease course, but also a 2- to 7-fold increased risk of COVID-19-related hospitalization and a 1.2-fold increased risk of COVID-19-related death as compared to adults without SCD, but not compared to controls with similar comorbidities and end-organ damage. There is some evidence that persons with SCT have increased risk of COVID-19-related hospitalization and death although more studies with risk-stratification and properly matched controls are needed to confirm these findings. While the literature suggests that most children with SCD and COVID-19 have mild disease and low risk of death, some children with SCD, especially those with SCD-related comorbidities, are more likely to be hospitalized and require escalated care than children without SCD. However, children with SCD are less likely to experience COVID-19-related severe illness and death compared to adults with or without SCD. SCD-directed therapies such as transfusion and hydroxyurea may be associated with better COVID-19 outcomes, but prospective studies are needed for confirmation. While some studies have reported favorable short-term outcomes for COVID-19 patients with SCD and SCT, the long-term effects of SARS-CoV-2 infection are unknown and may affect individuals with SCD and SCT differently from the general population. Important focus areas for future research should include multi-center studies with larger sample sizes, assessment of hemoglobin genotype and SCD-modifying therapies on COVID-19 outcomes, inclusion of case-matched controls that account for the unique sample characteristics of SCD and SCT populations, and longitudinal assessment of post-COVID-19 symptoms.

Caregivers’ experience of seeking care for adolescents with sickle cell disease in a tertiary care hospital in Bahrain

Objective

This study aimed to determine caregivers’ perspectives on difficulties encountered while seeking care for adolescents with sickle cell disease (SCD). It explored the social, emotional, and financial impact of caring for an adolescent with SCD on their caregivers.

Study design

A mixed-method study in a major tertiary care hospital in Bahrain was conducted between June and August 2019. Cross-sectional questionnaires and thematic analyzed interviews were performed with 101 and 18 Bahraini caregivers of adolescents with SCD (aged 10–18 years), respectively.

Results

Lack of parking lots (52.5%) and traffic jams (27%) were identified as the most common challenges in seeking hospital care for adolescents with SCD. These difficulties, including prolonged waiting in the emergency room, discouraged more than half of the caregivers who preferred to seek care from smaller healthcare centers. Most caregivers reported receiving a high degree of support from their families, who emotionally encouraged them to facilitate patient care (73.3%). Therefore, their relationships with their friends, colleagues, and relatives were not significantly affected. Catastrophic health expenditure occurred in 14.8% of caregivers. Qualitative themes that emerged were A) the intricacy of caring for adolescents with SCD, B) dissatisfaction with hospital facilities, and C) insufficient healthcare services, wherein caregivers reported adolescents’ experiences with services during hospital visits. Subthemes for the intricacy of caring for adolescents with SCD were 1) the psychological tragedy, summarizing the initial caregivers’ feelings after the confirmed diagnosis, 2) caregiving hardships that described the caregivers’ emotional and health burden while accepting and adjusting to the disease, and 3) the cost of care on families, which highlights the financial burden of the disease on families.

Conclusion

The caregivers of adolescents with SCD experienced several overwhelming challenges, including problems in accessing healthcare and receiving medical services, in addition to influences on the emotional, financial, and social aspects of their lives.

Strategies to increase access to basic sickle cell disease care in low- and middle-income countries

INTRODUCTION

Sickle cell disease (SCD) is the most common hemoglobinopathy in the world. Over 90% of those born with SCD live in low- and middle-income countries (LMICs), yet individuals in these settings have much poorer outcomes compared to those in high-income countries.

AREAS COVERED

This manuscript provides an in-depth review of the cornerstones of basic SCD care, the barriers to implementing these in LMICs, and strategies to increase access in these regions. Publications in English language, peer-reviewed, and edited from 2000 to 2021 were identified on PubMed. Google search was used for gray literature.

EXPERT OPINION

Outcomes for patients with SCD in high-income countries have improved over the last few decades due to the implementation of universal newborn screening programs and use of routine antimicrobial prophylaxis, increase in therapeutic and curative options, and the adoption of specific measures to decrease risk of stroke. This success has not translated to LMICs due to several reasons including resource constraints. A combination of several strategies is needed to increase access to basic SCD care for patients in these settings.

Carica papaya ameliorates thrombocytopenia through upregulation of Interleukin-11 and modulation of thrombopoietin in mouse model of carboplatin-induced myelosuppression

INTRODUCTION

Carica papaya L. (C. papaya) is used as a folk medicine for the treatment of various diseases throughout the world. Recently, papaya leaves decoction has been effectively used for the prevention and treatment of thrombocytopenia. The current study was undertaken to evaluate the thrombopoietic and immunomodulatory activities of C. papaya leaves in the mouse model of carboplatin induced myelosuppression.

METHODS

Myelosuppression was induced by a single intraperitoneal injection of carboplatin (125 mg/kg b. w.). Aqueous extract of C. papaya leaves (15 mg/kg b. w.) was given orally by feeding tube from day 0-18 to preventive group to see the preventive effect and from day 6-18 to treatment group for treatment effect.

RESULTS

The results showed that the C. papaya leaves extract significantly decreased the fall in platelet count in preventive and treatment groups. Extract significantly prevented the fall in total WBCs count on day 12 and 18 in the preventive group, whereas it significantly elevated the WBCs count in treatment group on day 18. Significantly increased RBCs count in both groups was observed on day 18 after treatment with C. papaya leaves extract. Treatment with C. papaya leaves extract significantly upregulated the mRNA expression levels of thrombopoietic cytokine IL-11 in both preventive and treatment groups. It is also observed that restoration of normal platelet count might have been resulted owing to the synergistic effect of upregulated IL-11 which ultimately led to a significantly diminished TPO expression.

CONCLUSION

Our data suggest that aqueous extract of C. papaya leaves possesses significant preventive and curative properties against thrombocytopenia.

Ulcerative colitis in patients with sickle cell disease: a rare but important co-morbidity

COVID-19: Coronavirus disease 2019; HIC: high-income countries; IBD: inflammatory bowel disease; LMIC: low- and middle-income countries; PUCAL: paediatric ulcerative colitis activity index; SCD: sickle cell disease; UC: ulcerative colitis.

Does Sickle Cell Disease Protect against HIV Infection: A Systematic Review

OBJECTIVE

The aim of this systematic review was to investigate whether sickle cell disease (SCD) protects against human immunodeficiency virus (HIV) infection by determining the association between SCD and the incidence and virulence of HIV infection.

METHODS

This is a systematic review that used MEDLINE, PubMed, CINAHL, and Academic Search Complete as data sources. Articles describing the relationship of SCD with HIV infection were included in this review. The effect measures were converted to correlation coefficients and synthesized accordingly to examine the putative protective role of SCD against HIV infection. Independent full-text screening and data extraction were conducted on all eligible studies. The risk of bias was assessed using the mixed methods appraisal tool. We employed a random-effects model of meta-analysis to estimate the pooled prevalence. We computed Cochrane's Q statistics, I2, and prediction interval to quantify effect size heterogeneity.

RESULTS

SCD reduces the risk of HIV infection by 75% (odds ratio [OR] = 0.25; r = -0.36, p < 0.001; I2 = 71.65). There was no publication bias (Egger's t value = 0.411; p = 0.721). Similarly, risk of HIV virulence was reduced by 77% (OR = 0.23; r = -0.38; p < 0.001; I2 = 63.07). The mechanisms implicated in the protective influence of SCD include autosplenectomy, reduced CCR5 expression, and increased expression of heme and iron-regulated genes.

CONCLUSIONS

SCD appears to protect against HIV infection and slows HIV progression.

Hematopoietic cell transplantation for sickle cell disease: updates and future directions

Excellent outcomes in hematopoietic cell transplantation (HCT) from HLA-identical siblings, improvements in conditioning regimens, novel graft-versus-host disease prophylaxis, and the availability of alternative donors have all contributed to the increased applicability and acceptability of HCT for sickle cell disease (SCD). In young children with symptomatic SCD with an available HLA-identical related donor, HCT should be carefully considered. HCT from alternative donors is typically undertaken only in patients with severe symptoms, causing or likely to cause organ damage, and in the context of clinical trials. Patients undergoing HCT for SCD require careful counseling and preparation. They require careful monitoring of unique organ toxicities and complications during HCT. Patients must be prospectively followed for a prolonged time to determine the long-term outcomes and late effects of HCT for SCD. Thus, there is a need for a universal, longitudinal clinical registry to follow patients after HCT for SCD in conjunction with individuals who do not receive HCT to compare outcomes. Antibody-based conditioning and ex-vivo umbilical cord blood expansion are likely to improve the availability and acceptability of HCT. In addition, new disease-modifying drugs and the emerging option of the autologous transplantation of gene-modified hematopoietic progenitor cells are likely to expand the available therapeutic options and make decision-making by patients, physicians, and caregivers even more complicated. Future efforts must also focus on determining the impact of socioeconomic status on access to and outcomes of HCT and the long-term impact of HCT on patients, families, and society.

Bordetella Holmesii: An Unusual Cause of Endogenous Endophthalmitis in a Patient With Sickle Cell Disease

PURPOSE

This case report describes a rare organism causing endogenous endophthalmitis in a patient with sickle cell disease.

METHODS

A case report was conducted.

RESULTS

A 41-year-old man with sickle cell disease presented with acute onset of blurry vision of the right eye. His visual acuity was counting fingers in the right eye and 20/20 in the left eye. He had ophthalmic findings of hypopyon and vitritis in the right eye, consistent with endophthalmitis. He was treated with intravitreal and systemic antibiotics. Vitreous cultures grew Bordetella holmesii. His visual acuity at follow-up visits improved to 20/40 in the setting of improved vitritis.

CONCLUSIONS

This is the first case describing B holmesii, a rare causative organism of endogenous endophthalmitis, in a patient with sickle cell disease. More studies are needed to improve the early detection and treatment of this unusual organism.

Systemic T Cell Subsets and Cytokines in Patients With Homozygous Sickle Cell Disease and Asymptomatic Urinary Tract Infections in Togo

Background: In sickle cell disease (SCD), cytokine expression influences the pivotal pathways that contribute to disease pathogenesis. Additional infection could affect the immune profile of patients with SCD and increase disease mortality. The aim of this study was to investigate the cytokines and T helper cells profile in patients with asymptomatic urinary tract infection and homozygous SCD (HbSS).

Methods: From July to September 2018, 22 HbSS subjects were recruited at Centre Hospitalier Universitaire Campus in Lomé, Togo, 12 of whom had urinary tract bacterial infections and 10 of whom were uninfected. Cytokines from plasma were measured by the enzyme-linked immunosorbent assay (ELISA) sandwich method, and immune cell profiles were performed by flow cytometry. The immunogenicity of bacteria-derived antigens isolated from the urine of HbSS subjects with asymptomatic urinary tract infections was studied in a cell culture system, and the induction of the cytokines was measured.

Results: The mean age of HbSS subjects with urinary tract infections was 20.33 ± 3.58 years, and the male/female ratio was 0.09 (1:11). HbSS subjects with asymptomatic urinary tract infections had elevated plasma levels of interferon gamma (IFN-γ) and interleukin (IL)-10. CD4⁺Tbet⁺IFN-γ⁺ and CD4⁺FoxP3⁺IL-10⁺ T cell populations were decreased in HbSS subjects with asymptomatic urinary tract infections. Bacterial antigens from HbSS subjects induced the production of IL-10 but not IFN-γ in uninfected volunteer donors (HbAA).

Conclusion: Our study demonstrated that patients with SCD and asymptomatic urinary tract infections had elevated IFN-γ and IL-10 levels. This chronic inflammatory condition could be a risk for this group of patients in terms of vaso-occlusive crisis. Systematic cytobacteriologic examination of the urine of HbSS subjects would be of interest.

Complement in Sickle Cell Disease: Are We Ready for Prime Time?

Sickle cell disease (SCD) is a widely spread inherited hemoglobinopathy that includes a group of congenital hemolytic anemias, all characterized by the predominance of sickle hemoglobin (HbS). Its features are anemia, predisposal to bacterial infections and complications such as vaso-occlusive crisis (VOC) or delayed hemolytic transfusion reaction (DHTR), which lead to increased rate of morbidity and mortality even in the era of hydroxyurea. The interaction between sickle cells, neutrophils, platelets or endothelial cells in small vessels results in hemolysis and has been considered the disease’s main pathophysiological mechanism. Complement activation has been reported in small cohorts of SCD patients, but the governing mechanism has not been fully elucidated. This will be important to predict the patient group that would benefit from complement inhibition. Until now, eculizumab-mediated complement inhibition has shown beneficial effects in DHTR, with limited reports in patients with VOC. In the meantime, several innovative agents are under clinical development Our state-of-the-art review summarizes current data on 1) complement activation in SCD both in steady state and crisis, 2) underlying mechanisms of complement over-activation for the clinician in the context of SCD, 3) actions of hydroxyurea and new therapeutic approaches including indirect involvement in complement activation, and 4) novel paradigms in complement inhibition.

Hemolysis inhibits humoral B-cell responses and modulates alloimmunization risk in patients with sickle cell disease

Red blood cell alloimmunization remains a barrier for safe and effective transfusions in sickle cell disease (SCD), but the associated risk factors remain largely unknown. Intravascular hemolysis, a hallmark of SCD, results in the release of heme with potent immunomodulatory activity, although its effect on SCD humoral response, specifically alloimmunization, remains unclear. Here, we found that cell-free heme suppresses human B-cell plasmablast and plasma cell differentiation by inhibiting the DOCK8/STAT3 signaling pathway, which is critical for B-cell activation, as well as by upregulating heme oxygenase 1 (HO-1) through its enzymatic byproducts, carbon monoxide and biliverdin. Whereas nonalloimmunized SCD B cells were inhibited by exogenous heme, B cells from the alloimmunized group were nonresponsive to heme inhibition and readily differentiated into plasma cells. Consistent with a differential B-cell response to hemolysis, we found elevated B-cell basal levels of DOCK8 and higher HO-1-mediated inhibition of activated B cells in nonalloimmunized compared with alloimmunized SCD patients. To overcome the alloimmunized B-cell heme insensitivity, we screened several heme-binding molecules and identified quinine as a potent inhibitor of B-cell activity, reversing the resistance to heme suppression in alloimmunized patients. B-cell inhibition by quinine occurred only in the presence of heme and through HO-1 induction. Altogether, these data suggest that hemolysis can dampen the humoral B-cell response and that B-cell heme responsiveness maybe a determinant of alloimmunization risk in SCD. By restoring B-cell heme sensitivity, quinine may have therapeutic potential to prevent and inhibit alloimmunization in SCD patients.

Thrombin generation in vivo and ex vivo in sickle cell disease patients

Activation of coagulation is an important hallmark of sickle cell disease (SCD) and it is believed that hypercoagulability plays a role to the disease pathophysiology. Studies have sought to identify how hemostatic biomarkers are expressed in SCD, however, the results are inconclusive. In this context, our objective was to evaluate the thrombin generation in vivo and ex vivo in SCD patients and the association between these biomarkers and the use of HU. This cross-sectional study was carried out with patients diagnosed with SCD, users or not of Hydroxyurea (HU), and healthy individuals as controls. D dimer (D-Di) was evaluated by ELISA and (TGT) thrombin generation test by CAT method. D-Di plasma levels were significantly higher in SCD patients when compared to the controls. TGT parameters such as peak, ETP and normalized ETP at low TF concentration and time-to-peak, peak, ETP and normalized ETP values at high TF concentration were lower in SCD patients than in controls. In contrast, the normalized activated protein C sensitivity ratio (nAPCsr) was higher in patients compared to controls, indicating resistance to the action of this natural anticoagulant. Regarding the use of HU, comparing users and non-users of this drug, no difference was observed in D-Di levels and in most TGT parameters. Our data analyzed together allow us to conclude that patients with SCD present a state of hypercoagulability in vivo due to the higher levels of D-Di and resistance to APC assessed ex vivo which is consistent with the coagulation imbalance described in SCD patients.

Analysis of Risk Factors Associated With Poor Outcome in Posterior Reversible Encephalopathy Syndrome After Treatment in Children: Systematic Review and Meta-Analysis

Objective: Chemotherapy and hematopoietic stem cell transplantation (HSCT) play important roles in clinical etiology, symptoms, signs, imaging findings, and biochemical parameters for inducing posterior reversible encephalopathy syndrome (PRES) in pediatric oncologic diseases. We aimed to evaluate various risk factors of pediatric oncologic diseases after conducting chemotherapy and HSCT to induce PRES for predicting the clinical prognosis frequency.

Methods: The literature was performed on PubMed, Web of Science, and Embase databases to recognize the qualified studies. The odds ratios (ORs) of related risk factors and their corresponding 95% confidence intervals (CIs) were used to compute the pooled assessments of the outcomes.

Results: Six studies were included in the meta-analysis, involving 828 records. The risk of female children has a significantly higher incidence than male children in oncologic age groups of PRES. Children over the age of 10 years old in oncologic age groups develop a significantly increased risk of PRES. Acute graft-versus-host disease (GVHD) has a significant promotion effect on the occurrence of PRES. Hypertension can promote the occurrence of PRES in children. The risk of PRES in immunodeficient children increases significantly. Children with sickle cell disease (SCD) have a significantly increased risk of PRES. The risk of PRES in children with T-cell leukemia rises considerably. The central nervous system (CNS) leukemia/involvement has a significant role in promoting the occurrence of PRES in children. The pooled OR for the factors male, ≥ 10 years old of age, acute GVHD, hypertension, immunodeficiency, SCD, T-cell leukemia, CNS leukemia/involvement was 0.66 (95% CI: 0.58, 0.76; P < 0.00001), 2.06 (95% CI: 1.23, 3.43; P < 0.006), 1.32 (95% CI: 1.14, 1.53; P < 0.0003), 8.84 (95% CI: 7.57, 10.32; P < 0.00001), 2.72 (95% CI: 1.81, 4.08; P < 0.00001), 2.87 (95% CI: 2.15, 3.83; P < 0.00001), 2.84 (95% CI: 1.65, 4.88; P < 0.0002), and 3.13 (95% CI: 1.43, 6.84; P < 0.004), respectively.

Conclusions: The result of this meta-analysis suggests that female children, age over 10 years old, acute GVHD, hypertension, immunodeficiency, SCD, T-cell leukemia, and CNS leukemia/involvement are likely to have the poor outcome in pediatric oncologic/hematologic diseases in PRES.