Incidence and risk factors for osteonecrosis of the femoral head in five hundred and ten sickle cell disease paediatric patients

PURPOSE

Osteonecrosis of the femoral head (ONFH) is a degenerative and progressive disorder that mainly affects people with sickle cell disease (SCD). Herein, we aimed to search for a better understanding of markers that can act as risk factors for ONFH in patients with SCD.

METHODS

We conducted a retrospective study including 510 SCD patients followed over 23 years. Patients were divided into the ONFH group and the no-ONHF control group. Univariate and multivariate logistic regression analyses were performed to identify risk factors.

RESULTS

Among 510 SCD patients, 41(8%) were diagnosed with ONFH at a mean age of 167 months ± 64 (72-288). The cumulative incidence of ONHF increased from 2.3% at ten years to 18.3% at 20 years of age. The radiological grade 3 ONHF was predominant. No significant differences in sex, age at diagnosis of SCD, and Hb genotype were found between groups. The patient age and the time since diagnosis of SCD were statistically higher in patients with ONHF in univariate and multivariate analysis. ONHF was also associated with higher creatinine level (p = 0.001) lower LDH level (p = 0.006), and higher number of vaso-occlusive crisis (VOC)/patient/year (p < 0.001). The cumulative incidence of ONHF in patients having more than 3 VOC/year was significantly higher (43% versus 18.9% at 20 years, p < 0.001). In addition, infections, gallstones, growth delay, delayed initiation of hydroxyurea, and a higher transfusion rate were significantly associated with ONFH.

CONCLUSION

These findings confirm that ONFH is closely related to the age, severity, and duration of SCD. Better management of this disease prevents acute and chronic complications, and early screening of the ONFH as soon as the first signs of the severity of the disease are detected provides a better functional prognosis.

Clinical features and predictors of osteoarticular manifestations in common variable immunodeficiency

INTRODUCTION

This study aimed to assess osteoarticular manifestations in patients with common variable immunodeficiency (CIVD) and to identify the predictive factors.

METHODS

This was a retrospective and prognostic study conducted in the pediatrics: immuno-hematology and stem cell transplantation department, including patients who fit the definition of CVID. A Cox model analysis was used to identify predictive factors.

RESULTS

A total of 36 patients were enrolled. Osteoarticular involvement was noted in 15 patients (42%) with a cumulative incidence of 90% after a median follow-up of 25 years. Non-infectious manifestations were reported in 14 patients (39%). The cumulative risk of inflammatory or autoimmune osteoarticular etiology was 74%. Well-characterized rheumatic diseases were retained in six patients and unlabeled autoimmune or inflammatory mechanism in five cases. Bone mineral density revealed osteoporosis in six cases leading to a cumulative risk of degenerative complications of 72%. The cumulative incidence of infectious complications was 17%. In multivariate analysis, predictors of osteoarticular complications were low body weight (HR = 8.67, CI: 1.496-50.278, p = 0.01) and hepatomegaly at diagnosis (HR = 6.2, CI: 1.537-25.075, p = 0.01). Reduced CD4 cells rate < 600 cells/mm3 and hepatomegaly were predictors of autoimmune or inflammatory complications, while chronic diarrhea and iron deficiency were associated with degenerative manifestations.

CONCLUSIONS

Osteoarticular manifestations have emerged as a real health problem for CVID patients. Risk increases with low body weight, hepatomegaly, chronic diarrhea, iron deficiency, and CD4 cells rate under 600 cell/mm3. Elucidating the mechanisms of these complications in CVID is important for developing preventive strategies. Key Points • This retrospective and prognostic study described the clinical characteristics of osteoarticular manifestations in 36 patients with CVID to ensure better recognition and understanding of this association by clinicians. • Identification of predictive factors of osteoarticular complications according to its etiology is crucial to establish appropriate, optimal and early management of patients at risk.

Molecular characterization of a novel homozygous deletion in β-globin cluster causing (δβ)0-Thalassemia among Tunisian family

BACKGROUND

Deletions in the β-globin cluster are uncommon and cause thalassemia (thal) with hereditary persistence of fetal hemoglobin. They constitute a heterogenous group of disorders characterized by absent or reduced synthesis of adult hemoglobin (Hb A) and increased synthesis of fetal hemoglobin (Hb F). Although the clinical severity of these disorders are asymptomatic owing to the increased Hb F levels, the molecular basis is very heterogenous due to the large deletions in the β-globin cluster spanning both HBD and HBB genes. Here, we describe a Tunisian family carrying a novel deletion mutation causing (δβ)°-thalassemia.

METHODS

The amounts of hemoglobin fractions were measured by capillary electrophoresis of hemoglobin. Amplification and sequencing of different regions on the β-gene cluster were performed by Sanger method.

RESULTS

Family study and genetic analysis revealed a large deletion mutation in the β-globin cluster of 14.5 kb (NG_000,007.3:g. 58,253 to g.72837del14584) at the homozygous state in the patient and at heterozygous state at the other members of the family. This deletion removes the HBD and HBB genes.

CONCLUSIONS

In our knowledge, this new large deletion is described for the first time in the Tunisian population and in the world, designed Tunisian(δβ)⁰ in Ithanet database (IthaID: 3971). Therefore, it is important to identify the deletion leading to δβ-thalassemia carriers at the molecular level, to highlight the importance of recognizing the clinical features and implementing appropriate testing to clarify the diagnosis and manage the condition.

Diagnostic challenge in a series of eleven patients with hyper IgE syndromes

Hyper IgE syndromes (HIES) is a heterogeneous group of Inborn Errors of Immunity characterized by eczema, recurrent skin and lung infections associated with eosinophilia and elevated IgE levels. Autosomal dominant HIES caused by loss of function mutations in Signal transducer and activator of transcription 3 (STAT3) gene is the prototype of these disorders. Over the past two decades, advent in genetic testing allowed the identification of ten other etiologies of HIES. Although Dedicator of Cytokinesis 8 (DOCK8) deficiency is no more classified among HIES etiologies but as a combined immunodeficiency, this disease, characterized by severe viral infections, food allergies, autoimmunity, and increased risk of malignancies, shares some clinical features with STAT3 deficiency. The present study highlights the diagnostic challenge in eleven patients with the clinical phenotype of HIES in a resource-limited region. Candidate gene strategy supported by clinical features, laboratory findings and functional investigations allowed the identification of two heterozygous STAT3 mutations in five patients, and a bi-allelic DOCK8 mutation in one patient. Whole Exome Sequencing allowed to unmask atypical presentations of DOCK8 deficiency in two patients presenting with clinical features reminiscent of STAT3 deficiency. Our study underlies the importance of the differential diagnosis between STAT3 and DOCK8 deficiencies in order to improve diagnostic criteria and to propose appropriate therapeutic approaches. In addition, our findings emphasize the role of NGS in detecting mutations that induce overlapping phenotypes.

Prevalence and predictive factors of splenic sequestration crisis among 423 pediatric patients with sickle cell disease in Tunisia

This study was aimed to identify the predictors of splenic sequestration crisis (SSC) among pediatric patients with sickle cell disease (SCD). This prognosis study was carried out in the pediatric immuno-hematology unit, over 20 years (1998 to 2017), enrolling patients with SCD. The cox model was used in multivariate analysis. Among 423 patients with SCD (240 S/S phenotype, 128 S/B0, 30 S/B+, 14 S/O arab and 11 S/C), 150(35.4%) had at least one episode of SSC. The average age of patients at the first episode was 48.3 months ± 32.4(2-168). Recurrence of SSC was observed in 117 patients (78%). Spleen size ≥3 cm at baseline was the strongest predictor of SSC occurrence (HR = 7.27, CI: 4.01-13.20, p = 0.05) and recurrence (HR = 6.37, CI: 1,46-27.83, p = 0.01). Pallor revealing the disease, age at onset of symptoms <24 months and reticulocytosis ≥300,000/mm³ increased the risk of SSC. Pain crisis revealing the disease as well as neutrophilia was associated with a lower risk of SSC. In conclusion, this study confirmed the high prevalence of SSC in SCD and the high frequency of recurrence after a first episode. The SSC occurrence and recurrence were intimately linked to the presence of splenomegaly, chronic pallor revealing the disease as well as reticulocytosis.