Targeted Gene Sanger Sequencing Should Remain the First-Tier Genetic Test for Children Suspected to Have the Five Common X-Linked Inborn Errors of Immunity

To address inborn errors of immunity (IEI) which were underdiagnosed in resource-limited regions, our centre developed and offered free genetic testing for the most common IEI by Sanger sequencing (SS) since 2001. With the establishment of The Asian Primary Immunodeficiency (APID) Network in 2009, the awareness and definitive diagnosis of IEI were further improved with collaboration among centres caring for IEI patients from East and Southeast Asia. We also started to use whole exome sequencing (WES) for undiagnosed cases and further extended our collaboration with centres from South Asia and Africa. With the increased use of Next Generation Sequencing (NGS), we have shifted our diagnostic practice from SS to WES. However, SS was still one of the key diagnostic tools for IEI for the past two decades. Our centre has performed 2,024 IEI SS genetic tests, with in-house protocol designed specifically for 84 genes, in 1,376 patients with 744 identified to have disease-causing mutations (54.1%). The high diagnostic rate after just one round of targeted gene SS for each of the 5 common IEI (X-linked agammaglobulinemia (XLA) 77.4%, Wiskott–Aldrich syndrome (WAS) 69.2%, X-linked chronic granulomatous disease (XCGD) 59.5%, X-linked severe combined immunodeficiency (XSCID) 51.1%, and X-linked hyper-IgM syndrome (HIGM1) 58.1%) demonstrated targeted gene SS should remain the first-tier genetic test for the 5 common X-linked IEI.

Treatment and outcomes of high-risk neuroblastoma in Southeast Asia: a single institution experience and review of the literature

INTRODUCTION

In Europe and Northern America, the majority of children with high-risk neuroblastoma survive the disease. Elsewhere, treatment outcomes are poor.

METHODS

A retrospective review of children treated for high-risk neuroblastoma in a single institution in Singapore from 2007 to 2019 was carried out. Treatment consisted of intensive chemotherapy, surgery aimed for gross total resection of residual disease after chemotherapy, consolidation with high-dose therapy followed by autologous stem cell rescue, radiotherapy to the primary and metastatic sites, followed by maintenance treatment with either cis-retinoic acid or anti-disialoganglioside (anti-GD2) monoclonoal antibody therapy. Survival data were examined on certain clinical and laboratory factors.

RESULTS

There were 57 children with 32 males treated for high-risk neuroblastoma. Their mean age was 3.9 (0.7-14.9) years. The median follow-up time was 5.5 (1.8-13.0) years for the surviving patients. There were 31 survivors with 27 surviving in first remission, and 5-year overall survival and event-free survival rates were 52.5% and 47.4%, respectively. On log-rank testing, only the group of 17 patients who were exclusively treated at our centre had a survival advantage. Their 5-year overall survival rate, compared with others whose initial chemotherapy was done elsewhere, was 81.6% versus 41.1% (p = 0.011), and that of event-free survival was 69.7% versus 36.1% (p = 0.032). Published treatment results were found from four countries in Southeast Asia with 5-year overall survival rates from 13.5%-28.2%.

CONCLUSION

Intensified medical and surgical treatment for high-risk neuroblastoma proved to be effective with superior survival rates compared with previous data from Southeast Asia.

A multicenter report on the safety and efficacy of plerixafor based stem cell mobilization in children with malignant disorders

BACKGROUND

Pleraxifor for peripheral blood stem cell (PBSC) mobilization in children with malignancies is often given following failure of standard mobilization (SM) rather than as a primary mobilizing agent.

STUDY DESIGN AND METHODS

In this retrospective multicenter study, we report the safety of plerixafor-based PBSC mobilization in children with malignancies and compare outcomes between patients who received plerixafor upfront with SM (Group A) with those who received plerixafor following failure of SM (Group B). In the latter pleraxifor was given either following a low peripheral blood (PB) CD34 (<20 cells/cu.mm) (Group B1) or as a second collection process due to an unsuccessful yield (CD34 + < 2 × 10⁶ /kg) (Group B2) following failed SM and first apheresis attempts.

RESULTS

The study cohort (n = 47) with a median age of 8 (range 0.6-21) year, comprised 19 (40%) Group A and 28 (60%) Group B patients (B1 = 12 and B2 = 16). Pleraxifor mobilization was successful in 87.2% of patients, similar between Groups A and B (84.2% vs 89.2%) and resulted in a median 4-fold increase in PB CD34. Median number of apheresis attempts was 2 in Groups A and B1 but 4 in Group B2. In Group B2, median total CD34+ yield post-plerixafor was 9-fold higher than after SM (P = .0013). Mild to moderate transient adverse events affected 8.5% of patients. Among patients who proceeded to autologous transplant (n = 39), all but one engrafted.

CONCLUSION

Plerixafor-based PBSC collection was safe and effective in our cohort and supports consideration as a primary mobilizing agent in children with malignancies.

Burkitt Lymphoma Presenting as Acute Pancreatitis: Report of 3 Cases and Review of the Literature

Acute pancreatitis is a rare presentation in Burkitt lymphoma (BL) and may lead to delayed medical or unnecessary surgical treatment. Three cases of BL presenting as acute pancreatitis in the authors' institutions were described. Similar cases reported in the medical literature were collected and described along with the authors' cases. There were 12 cases described in the medical literature and hence a total of 15 cases of BL presenting as acute pancreatitis. Fourteen cases were the first diagnosis, and the other presented at lymphoma relapse. Twelve cases occurred in children under 15 years. Twelve patients had extrapancreatic disease. Three children were treated with surgery before diagnosis. Two patients died. Six of the remaining had adequate follow-up and were surviving in remission 8 months to 16 years after diagnosis. Lymphoma should be included in the differential diagnosis of acute pancreatitis in children. Acute pancreatitis in combination with malignant infiltration on imaging is highly suggestive of BL, especially in the jaundiced child.

Management of thoracoabdominal neuroblastoma: a 13-year experience

Background

Thoracoabdominal neuroblastoma is a unique surgical challenge. We reviewed our experience focusing on disease patterns and corresponding surgical approaches.

Methods

Among 310 patients in our neuroblastoma database, 30 (9.7%) had thoracoabdominal neuroblastoma. Patients’ clinical charts were reviewed and analyzed. Two disease patterns were identified: solitary thoracoabdominal tumor (group A, n=15) and multifocal tumors in thorax and abdomen (group B, n=15). Operative approaches were categorized based on routes of surgical access.

Results

Thirty patients with average age of 4.1 (range 0.8–12.8) years were studied. All received preoperative chemotherapy. Among 15 group A patients, four were stage 3 intermediate risk (IR) and 11 were stage 4 high risk (HR). Surgical approaches included single-incision thoracoabdominal approach (n=10), laparotomy-cum-transdiaphragmatic approach (n=3), and laparotomy-cum-thoracotomy approach (n=2). One patient had 10% residual disease and the rest achieved gross total resection. Postoperative complications included chylous ascites (n=3), intestinal obstruction (n=3), pneumonia (n=1), spinal cord infarction (n=1) scoliosis (n=2) and thoracoabdominal nerves palsy (n=3). Among 15 group B patients, all were stage 4 with five IR and 10 HR. Thoracic components were found in the posterior mediastinum (n=7), superior mediastinum (n=4), middle mediastinum (n=1), parietal pleura (n=3) and lungs (n=3). Surgical approaches included multi-incision laparotomy-cum-thoracotomy (n=14) and laparotomy-cum-transdiaphragmatic approach (n=1). Gross total resection was achieved in all surgeries. Postoperative complications included chylous ascites (n=3). Overall, all nine IR patients survived without evidence of disease and 9 (42.8%) HR patients died of disease. There was no perioperative mortality.

Conclusion

Surgical resection of thoracoabdominal neuroblastoma is feasible and safe. Despite its complexity, thoracoabdominal neuroblastoma has comparable treatment outcomes when compared with single-compartmental disease.

Macropolycyte in Pediatrics

Macropolycytes are tetraploid neutrophils produced during accelerated myelopoiesis. They have been reported in adults with pernicious anemia, sepsis, and after cytotoxic chemotherapy. Two pediatric cases are reported, one after granulocyte colony-stimulating factor treatment and the other following Kawasaki disease, respectively.

Treatment of hepatic veno-occlusive disease in children with N-acetylcysteine

In our institution, hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) has been treated with N-acetylcysteine (NAC) since 2008-a loading dose of 150 mg/kg, followed by 12 doses of 70 mg/kg 6 hourly. Nine children were diagnosed with hepatic VOD/SOS. Hepatic VOD/SOS occurred in seven children after stem cell transplantation and two were receiving chemotherapy for Wilms tumor. Their clinical severity was classified as moderate in two and severe in seven by the European Society for Blood and Marrow Transplantation criteria. All children recovered and were discharged from 4 to 16 days after diagnosis. No side effects were observed. Intravenous NAC is an effective treatment for hepatic VOD/SOS.

Idiopathic Purpura With Gray Platelets: an Acquired Form of Gray Platelet Syndrome

An acquired, transient bleeding disorder that predominantly affects children in Southeast Asia has been reported for the last 4 decades. The condition has been named idiopathic purpura with gray platelets (IPGP) or acquired platelet dysfunction with eosinophilia. In a retrospective review from a private pediatric clinic over an 8-year period, 10 consecutive children were diagnosed as IPGP with a mean age of 8.4 (3.7 to 16.2) years. Eosinophilia (>0.5×10/L) was absent in 1, while gray platelets were consistently found in all cases with a mean proportion of 64.5% (40% to 80%). Platelet aggregation tests were performed in 9 patients with abnormal responses consistent with platelet storage pool defect. All children recovered completely and spontaneously from 1 to 4 months after diagnosis without specific therapy. In an otherwise well child who presents abruptly with easy bruising and a platelet count >100×10/L, IPGP can be readily recognized as an acquired form of gray platelet syndrome. Eosinophilia is common but not mandatory for diagnosis.

Isolated thrombocytopenia in childhood: what if it is not immune thrombocytopenia?

INTRODUCTION

Childhood immune thrombocytopenia (ITP) remains a diagnosis of exclusion when isolated thrombocytopenia is not part of another disease process. In practice, the diagnosis of ITP can only be confirmed when thrombocytopenia resolves or is excluded after the recognition of a primary cause.

METHODS

The records of 87 consecutive children with isolated thrombocytopenia seen over a nine-year period in a private paediatric haematology practice were reviewed retrospectively. Children in whom a primary cause was eventually found were the subjects of a further descriptive study.

RESULTS

9 (10%) children with isolated thrombocytopenia were not diagnosed with ITP because a primary disease was found. Of these nine cases, four had thrombocytopenia recognised during the neonatal period, consisting of perinatal cytomegalovirus infection (n = 2), meconium aspiration pneumonia (n = 1) and transient abnormal myelopoiesis associated with Down syndrome (n = 1). The remaining five children were each found to have familial thrombocytopenia, portal hypertension, cutaneous mastocytosis, May-Hegglin anomaly and systemic lupus erythematosus. Two of them had a history of failure of response to corticosteroid therapy.

CONCLUSION

Secondary thrombocytopenia is not uncommon in a tertiary paediatric specialty practice with adequate evaluation. Thrombocytopenia occurring during the newborn period and failure of steroid therapy are predictive of secondary cases.

Haematologist-reviewed peripheral blood smear in paediatric practice

Manual examination of the peripheral blood smear (PBS) is currently performed on a fraction of samples sent for automated complete cell count. 39 children (age range 0-16.2 years) referred to a private paediatric practice during a 16-month period were retrospectively reviewed. Clinical scenarios, haematological features, laboratory-initiated PBS review, haematologist's PBS review and final diagnosis were described. Clinical indications included isolated thrombocytopenia (n = 10), unexplained bruises (n = 5), acute febrile illnesses (n = 11), anaemia (n = 8) and others (n = 5). The laboratory reviewed the PBS in 30 cases according to preset criteria and made no conclusive remarks. All slides were reviewed by a haematologist and a diagnosis was made in 27 (69%) cases, including 7 (78%) of the nine slides the laboratory did not review. The practice of laboratory-initiated PBS review requires re-evaluation. Haematologist-reviewed PBS is an important diagnostic tool for children with anaemia, bleeding disorders and acute febrile illnesses.