Hematopoietic stem cell transplantation (HSCT) is an established therapeutic procedure for several congenital and acquired disorders, both malignant and nonmalignant. Despite the great improvements in HSCT clinical practices over the last few decades, complications, such as graft vs. host disease (GVHD) and sinusoidal obstructive syndrome (SOS), are still largely unpredictable and remain the major causes of morbidity and mortality. Both donor and patient genetic background might influence the success of bone marrow transplantation and could at least partially explain the inter-individual variability in HSCT outcome. This review summarizes some of the recent studies on candidate gene polymorphisms in HSCT, with particular reference to pediatric cohorts. The interest is especially focused on pharmacogenetic variants affecting myeloablative and immunosuppressive drugs, although genetic traits involved in SOS susceptibility and transplant-related mortality are also reviewed.

Vaccines represent the best tool to prevent the severity course and fatal consequences of the pandemic by the new Coronavirus 2019 infection (SARS-CoV-2). Considering the limited data on vaccination of pediatric oncohematological patients, we developed a Consensus document to support the Italian pediatric hematological oncological (AIEOP) centers in a scientifically correct communication with families and patients and to promote vaccination. The topics of the Consensus were: SARS-CoV-2 infection and disease (COVID-19) in the pediatric subjects; COVID-19 vaccines (type, schedule); who and when to vaccinate; contraindications and risk of serious adverse events; rare adverse events; third dose and vaccination after COVID-19; and other general prevention measures. Using the Delphi methodology for Consensus, 21 statements and their corresponding rationale were elaborated and discussed with the representatives of 31 centers, followed by voting. A high grade of Consensus was obtained on topics such as the potential risk of severe COVID-19 outcome in pediatric oncohematological patients, the need for vaccination as a preventative measure, the type, schedule and booster dose of vaccine, the eligibility of the patients for vaccination, and the timing, definition, and management of contraindications and serious adverse events, and other general prevention measures. All 21 of the statements were approved. This consensus document highlights that children and adolescents affected by hematological and oncological diseases are a fragile category. Vaccination plays an important role to prevent COVID-19, to permit the regular administration of chemotherapy or other treatments, to perform control visits and hospital admissions, and to prevent treatment delays.

Background: Posaconazole is an antifungal medication used to treat invasive fungal infections (IFI) in pediatric onco-hematological patients. Its approval for pediatric use was recent, and limitations still apply. Despite limited data, the safety and efficacy profile appear generally favorable in children. This study describes how posaconazole is used across centers affiliated with the Associazione Italiana Ematologia e Oncologia Pediatrica (AIEOP). Methods: A national survey was conducted among physicians within the AIEOP network to evaluate current use of posaconazole in pediatric cancer patients, including those undergoing hematopoietic stem cell transplantation (HSCT). A 25-item web questionnaire was developed and distributed in June 2024. Data analysis involved descriptive statistics. Results: Twenty-one of thirty-one centers (68%) responded, reporting availability of various posaconazole formulations: oral suspension (76%), delayed-release tablets (95%), and intravenous solution (14%). Posaconazole was primarily used for prophylaxis in patients with acute lymphoblastic leukemia (ALL, 38%), acute myeloid leukemia (AML, 38%), and aplastic anemia (19%). It was also used as secondary prophylaxis against previous possible or probable IFI or as salvage therapy for probable or confirmed aspergillosis or mucormycosis, often combined with other treatments. Drug plasma level monitoring was common but varied in scheduling across centers. Most centers (74%) discontinued posaconazole if adverse events suspected drug–drug interactions, such as with vincristine. Conclusions: Posaconazole is widely used in AIEOP centers, though application varies significantly. This variability emphasizes the need for prospective studies to better define indications, dosing, and monitoring protocols for pediatric use of this antifungal.

Pneumocysis jirovecii pneumonia (PJP) is a type of pneumonia originating from the fungus Pneumocystis jiroveci and is a major cause of serious pneumonia in immunocompromised conditions. PJP typically appears as bilateral diffuse pulmonary infiltrates. Granulomatous PJP is an uncommon form of pneumocystis infection, occurring in only 3% to 5% of patients. Calcification is exceptional. We present a 9-month-old boy affected by Severe Combined Immunodeficiency (SCID) that has been diagnosed at the age of 7 months following a lung Pneumocystis jirovecii infection. He underwent a routine total-body magnetic resonance imaging (MRI) prior to an allogeneic hematopoietic stem cell transplantation (HSCT). The MRI showed significant alterations of the pulmonary parenchyma; hence, a computer tomography of the lung was performed showing the presence of 11 calcified granulomatous nodules. We report a unique case of calcified granulomatous PJP in a toddler affected by SCID. Awareness of this rare yet possible presentation in patients with SCID is important given the potential clinical implications when managing a patient undergoing HSCT and it further enhances the importance of advanced radiologic imaging prior to HSCT.