Hermansky-Pudlak Syndrome: Spectrum in Oman.

Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder, characterized by oculocutaneous albinism, a hemorrhagic diathesis secondary to storage pool-deficient platelets, and in some patients' pulmonary fibrosis, granulomatous colitis, and immunodeficiency. To date, 11 different types of Hermansky-Pudlak syndrome were identified. HPS type 2 is distinctively characterized by severe neutropenia and recurrent sinopulmonary infections. HPS is more common in Puerto Rico, and this is the first report deciphering the genotypic spectrum of HPS in Oman. Between 2001 and 2021, 8 Omani cases with HPS (3 HPS type 2, 1 HPS type 3, and 4 HPS type 6) had been suspected clinically and confirmed through genetic mutation analysis. Patients had mild hemorrhagic phenotype, and variable platelet aggregation defects with different platelet agonists. All patients had characteristic eye manifestations. In addition, patients with HPS type 2 had severe neutropenia. Novel mutations in AP3B1(c.205-1G>C, c.12_13delTA (p.Asn4Lysfs*6) and HPS6 (c.19_20delCT (p. Leu7Alafs*168) were not reported in population variant databases. Diagnosis of HPS had markedly improved in Oman; however, increased clinician awareness is needed. A high index of suspicion and early referral for diagnosis and initiation of proper treatment might help improve outcomes.

Outcome of Viral-associated Hemophagocytic Lymphohistiocytosis at a Tertiary Hospital.

BACKGROUND: Little is known about viral-associated hemophagocytic lymphohistiocytosis (HLH) in Oman. This study was done to assess the epidemiology, clinical features and outcome of viral-associated HLH in our setting. METHODS: We retrospectively reviewed children (0-18 years) managed for viral-associated HLH at the Sultan Qaboos University Hospital, Oman, over a 15-year period (2006-2020). Patients' medical records were used to describe their demographic, clinical and laboratory features, management and outcome. RESULTS: Fifty-six children were managed for HLH at Sultan Qaboos University Hospital over the last 15 years (2006-2020) of whom a third (19; 34%) had a viral trigger. The median age at the time of diagnosis of viral-associated HLH was 83 (13-96) months. Fever, cytopenia, hyperferritinemia and evidence of hemophagocytosis in bone marrow were the most consistent findings. Most of these children had either genetic predisposition to HLH (8/19; 42%) or underlying immunodeficiency secondary to malignant conditions or chemotherapy/hematopoietic stem cell transplantation (6/19; 32%). Epstein-Barr virus (9; 47%) followed by cytomegalovirus (6; 31%) was the most common viral trigger in our setting. Treatment included antivirals (8; 42%), HLH 2004 protocol (4; 21%), rituximab (4; 21%) and hematopoietic stem cell transplantation (3; 16%). Fourteen children (74%) had full recovery. CONCLUSIONS: In our small cohort, viral-associated HLH was more frequently encountered in children with genetic predisposition to HLH or children with underlying immunodeficiency. In addition, we found that the outcome is overall good for children who have no genetic predisposition to HLH and children with genetic predisposition who underwent hematopoietic stem cell transplantation.

Hematopoietic Stem Cell Transplantation for Patients with Autosomal Recessive Complete INF-λ Receptor 2 Deficiency: Experience in Oman.

Autosomal recessive complete INF-γ receptor-2 (IFN-γR2) deficiency is a rare, potentially fatal primary immune deficiency that predisposes to disseminated mycobacterial disease. Hematopoietic stem cell transplantation (HSCT) is currently the only curative treatment. Few patients have been reported so far. Here we report the outcomes of HSCT in 7 patients with IFNγ-R2 deficiency from 3 Omani families who underwent HSCT at Sultan Qaboos University Hospital in Oman. All patients were homozygous for the same mutation (c.-175_+102del) of INFGR2. Four patients underwent HLA-matched related donor (MRD) HSCT (3 siblings and 1 parent), and the other 3 underwent T cell-depleted (TCD) haploidentical HSCT from a family donor. The stem cell source was peripheral blood stem cells in 5 patients and bone marrow in 2 patients. Five patients received myeloablative conditioning, and 2 had reduced-intensity conditioning. The overall survival rate was 85.7%, and the event-free survival was 71.4%. One of the 7 patients died on day +31 with gram-negative sepsis, and the other 6 patients were cured from their original disease (median follow-up of 78.5 months). One patient had primary graft failure following a TCD-haploidentical transplantation and underwent successful retransplantation from another haploidentical relative. Three patients received a donor lymphocyte infusion for mixed chimerism. Our findings indicate that HSCT is curative for complete IFN-γR2 deficiency. In this cohort from Oman, 85.7% of the patients were cured with either an MRD or a TCD haploidentical transplantation. Genetic analysis at birth in children of high-risk couples permits early diagnosis, prevents the morbidity of BCG vaccination, and can enable safer and more successful transplantation outcomes.

Outcome of Early Hemostatic Intervention in Children With Sepsis and Nonovert Disseminated Intravascular Coagulation Admitted to PICU: A Randomized Controlled Trial.

OBJECTIVES: Evaluation of the outcome of early hemostatic management of disseminated intravascular coagulopathy in patients with severe sepsis/septic shock admitted to PICU, before the development of clinically overt disseminated intravascular coagulopathy. DESIGN: Prospective interventional, open label randomized controlled clinical trial. SETTING: PICU at Alexandria University Children's Hospital. PATIENTS: The study included 80 patients with proven severe sepsis/septic shock in nonovert disseminated intravascular coagulopathy stage. They were randomly assigned into two groups (group 1 and group 2). INTERVENTIONS: Specific intervention was applied for group 1 (plasma transfusion, low-dose unfractionated heparin, and tranexamic acid). MEASUREMENTS: All patients had assessment of Pediatric Index of Mortality 2 score, Pediatric Logistic Organ Dysfunction score, inotropic score, routine laboratory, and hemostatic tests including fibrin degradation products and d-dimers. Disseminated intravascular coagulopathy risk assessment scores were calculated on daily basis. RESULTS: Mortality rate was significantly higher in group 2. Progression to overt disseminated intravascular coagulopathy was significantly more common among group 2 patients than group 1 (45% and 10%, respectively) (p < 0.0001). Disseminated intravascular coagulopathyRisk Assessment Scores were significantly higher on the second and fifth days among group 2 patients. The initial specific hemostatic intervention was the only significant predictor of survival and prevention of progression to overt disseminated intravascular coagulopathy. CONCLUSIONS: Our results suggest that early use of a combination of fresh frozen plasma transfusion, low-dose heparin, and tranexamic acid in children with severe sepsis/septic shock in the "window of opportunity" before the development of overt disseminated intravascular coagulopathy stage was associated with better outcome for survival and prevention of progression to overt disseminated intravascular coagulopathy, with no increase in bleeding risk. Larger multicenter studies are needed to further prove this practice.

Preoperative transfusion versus no transfusion policy in sickle cell disease patients: a randomized trial.

BACKGROUND: Many children with sickle cell disease (SCD) indicated for adenotonsillectomy receive pre-operative transfusion therapy, either simple or exchange transfusion, in order to reduce surgical and sickle cell disease-related complications. SUBJECTS AND METHODS: This is a prospective randomized controlled clinical trial aiming to compare between preoperative simple transfusion and no transfusion in pediatric patients with sickle SCD admitted in Sultan Qaboos University Hospital, Muscat, Oman for adenotonsillectomy during the period from January 2014 through June 2018. They were randomly assigned into two arms (simple transfusion and no transfusion). RESULTS: Postoperative SCD-related complications have been encountered in 6 out of 138 patients (4.3%). There was no statistically significant difference between the two studied groups as regards the development of surgical or SCD-related complications (p = 0.6 and 0.8 respectively). The length of postoperative hospital stay was comparable in the two groups. (p = 0.607). SCD-related complications occurred exclusively in cases with homozygous sickle anemia (4 out of 81 = 4.9%). CONCLUSION: Sickle cell disease patients with a hemoglobin level above 7.5 g/dL do not need PRBCs transfusion prior to adenotonsillectomy. This approach did not increase the risk of postoperative surgical or SCD-related complications.

T Cell Depleted Haploidentical Hematopoietic Stem Cell Transplantation for Patients with Familial Hemophagocytic Lymphohistiocytosis Who Do Not Have Matched Family Donors: Experience in Oman.

Familial hemophagocytic lymphohistiocytosis (FHLH) is a potentially fatal disorder of immune regulation. Management includes chemotherapy followed by hematopoietic stem cell transplantation (HSCT). T cell depleted (TCD)-haploidentical HSCT could be an option for those patients who do not have HLA matching family donor. The objective of this study was to report on the outcome of TCD-haploidentical HSCT in patients with FHLH who underwent transplantation at Sultan Qaboos University Hospital (SQUH). This is a retrospective report on 12 patients with FHLH who received TCD- haploidentical HSCT at SQUH between August 2010 and December 2018. Epidemiologic characteristics and details on the transplantation procedures and complications were collected from patients' electronic records. Twelve patients with FHLH received TCD-haploidentical HSCT after a myeloablative conditioning regimen composed of treosulfan/thiotepa/fludarabine/anti-thymocyte globulin and rituximab. The mean age at transplantation was 11.67 ± 8 months. All patients had Perforin gene mutations, except 1 patient who had an UNC-13D mutation. Most patients received TCRαß+/CD19+ depleted grafts for faster immune reconstitution. Seven patients (58.3%) have been cured with a mean follow-up duration of 3.44 years. Four patients died of multiorgan failure secondary to gram-negative sepsis. One patient had primary graft failure, and 2 patients had mild graft-versus-host disease. Two patients had Pneumocystis carinii pneumonia, 2 had adenoviremia, and 9 patients had cytomegalovirus (CMV) viremia. Among patients with CMV viremia, 2 had evidence of disease (retinitis, enteritis). All patients with CMV viremia were treated successfully with foscarnet pre-engraftment and ganciclovir postengraftment, respectively. TCD-haploidentical HSCT could be a viable option for patients with FHLH who do not have HLA matching family donors. Infectious complications are the leading cause of death in that setting. CMV viremia was the most frequently encountered infectious complication.

Neutropenia and Life-threatening Agranulocytosis Among Children With ß-Thalassemia Treated With Oral Iron Chelators in a Community With Background of Ethnic Neutropenia.

INTRODUCTION: Neutropenia and agranulocytosis are rare side effects of deferiprone (DFP) in patients treated for iron overload. Unfortunately, no study directly addressed special risks in countries with a background of ethnic neutropenia, such as Oman. AIM: The aim of this study was to report the incidence of neutropenia in Omani children with ß-thalassemia treated with different iron chelators. METHODS/DESIGN: This was a retrospective study that included 179 Omani pediatric patients. For patients who developed neutropenia, demographic data, iron-chelating agent, clinical presentation, management, and outcome were recorded. Detailed clinical, laboratory±radiologic information was added for patients with agranulocytosis. RESULTS: Neutropenia was encountered in 43.6% of patients: severe neutropenia in 10 patients, moderate in 29, and mild in 69 patients. Severe and moderate neutropenia had similar incidence among DFP-exposed and DFP-naive patients (P=0.515 and 0.421, respectively), while mild neutropenia was common among DFP-naive patients (P=0.0001). A higher incidence of DFP-related agranulocytosis (4.1%) was noted compared with previous reports, but none had a fatal outcome. CONCLUSIONS: In a community with ethnic neutropenia, mild to moderate neutropenia is common. Higher incidence of severe neutropenia and agranulocytosis mandates careful monitoring and rational modification of iron-chelating agents to avoid life-threatening complications.

Premature ventricular contractions as a side effect of filgrastim in a child with B-thalassaemia.

Premature ventricular contractions are a rare side effect of filgrastim, reported mainly in elderly men. Here we report the case of a 9-year-old child with thalassaemia who developed frequent premature ventricular contractions after three doses of filgrastim were given for deferiprone-induced agranulocytosis. The arrhythmia resolved 3 weeks after discontinuation of filgrastim. Children treated with filgrastim should be carefully monitored for potentially serious arrhythmia.

Vincristine-induced neuropathy in pediatric patients with acute lymphoblastic leukemia in Oman: Frequent autonomic and more severe cranial nerve involvement.

BACKGROUND: Vincristine (VCR) induced peripheral neuropathy is a common complication in children with acute lymphoblastic leukemia (ALL). PROCEDURES: A retrospective data analysis over an interval of 10 years (2006-2016) of all children with ALL seen at Sultan Qaboos University Hospital was carried out. Electronic medical records of eligible patients were reviewed. Patients with clinical evidence of neuropathy and abnormal nerve conduction studies (NCSs) were included in the study. RESULTS: Nineteen (nine females and 10 males) out of 103 pediatric patients developed VCR-related neuropathy, and their age ranged between 2.5 and 14 years. Symptoms started after 2-11 doses of VCR. All 19 patients had documented peripheral neuropathy on NCSs. The autonomic nervous system and cranial nerves affection was relatively common in our patients; two presented with bradycardia, two patients with unexplained tachycardia, and five had abdominal pain and constipation, complicated by typhlitis in two patients. One patient developed unilateral hearing loss. Two patients developed severe life-threatening cranial nerve involvement with bilateral ptosis and recurrent laryngeal nerve involvement presented as vocal cord paralysis, hoarseness of voice, frequent chocking, and aspiration episodes. CONCLUSIONS: Peripheral neuropathy was the commonest form of VCR-related neuropathy. Autonomic neuropathy was relatively common in our patients. Cranial neuropathy is a serious side effect of VCR that can be severe, involving multiple cranial nerves and needs prompt recognition and management. Concomitant administration of pyridoxine and pyridostigmine does not seem to protect against further neurological damage in some patients.

Efficacy and Safety of Dapsone Versus Trimethoprim/Sulfamethoxazol for Pneumocystis Jiroveci Prophylaxis in Children With Acute Lymphoblastic Leukemia With a Background of Ethnic Neutropenia.

STUDY OBJECTIVE: To study dapsone in comparison with trimethoprim/sulfamethoxazole (TMP/SMX) for Pneumocystis jiroveci (PJP) prophylaxis in children with acute lymphoblastic leukemia (ALL). DESIGN: A retrospective study with a prospective follow-up. PATIENTS: Pediatric ALL patients diagnosed between May 2009 and May 2014, who are still receiving or have completed their maintenance chemotherapy. Patients who completed chemotherapy were prospectively followed up for neutropenia. METHODS: TMP/SMX was used as the initial PJP prophylaxis. An alternative drug was indicated if the patient remained cytopenic for >3 weeks. Average absolute neutrophilic count (ANC), average % of oral mercaptopurine (6-MP), and methotrexate doses were calculated over a period of 6 months before and after shifting to dapsone. RESULTS: Sixty-two ALL patients were eligible for analysis. Twenty-four patients (38.7%) received TMP/SMX for PJP prophylaxis, whereas 34 patients received Dapsone (54.8%). Only 3 patients received IV pentamidine (4.8%), whereas 1 patient (1.6%) received atovaquone. The incidence of prophylaxis failure was 1/1041 months on TMP/SMX and 1/528 months on dapsone. After shifting to dapsone, patients maintained significantly higher ANC (1.46±0.46 vs. 1.17±0.40, P=0.0053), and received significantly higher doses of 6-MP (62.61%±11.45 vs. 57.45±10.14, P=0.0081) and methotrexate (64.9%±14.29 vs. 56.5%±9.9, P=0.0176), with a significantly shorter duration of chemotherapy interruption (1.94±1.2 vs. 3.25±1.29 wk, P=0.0002). CONCLUSIONS: Dapsone for PJP prophylaxis in ALL allowed patients to maintain higher ANC and to receive higher doses of chemotherapy, while maintaining a low incidence of PJP breakthrough infection.