Diagnostic evaluation of paediatric autoimmune lymphoproliferative immunodeficiencies (ALPID): a prospective cohort study.

BACKGROUND: Lymphoproliferation and autoimmune cytopenias characterise autoimmune lymphoproliferative syndrome. Other conditions sharing these manifestations have been termed autoimmune lymphoproliferative syndrome-like diseases, although they are frequently more severe. The aim of this study was to define the genetic, clinical, and immunological features of these disorders to improve their diagnostic classification. METHODS: In this prospective cohort study, patients were referred to the Center for Chronic Immunodeficiency in Freiburg, Germany, between Jan 1, 2008 and March 5, 2022. We enrolled patients younger than 18 years with lymphoproliferation and autoimmune cytopenia, lymphoproliferation and at least one additional sign of an inborn error of immunity (SoIEI), bilineage autoimmune cytopenia, or autoimmune cytopenia and at least one additional SoIEI. Autoimmune lymphoproliferative syndrome biomarkers were determined in all patients. Sanger sequencing followed by in-depth genetic studies were recommended for patients with biomarkers indicative of autoimmune lymphoproliferative syndrome, while IEI panels, exome sequencing, or genome sequencing were recommended for patients without such biomarkers. Genetic analyses were done as decided by the treating physician. The study was registered on the German Clinical Trials Register, DRKS00011383, and is ongoing. FINDINGS: We recruited 431 children referred for autoimmune lymphoproliferative syndrome evaluation, of whom 236 (55%) were included on the basis of lymphoproliferation and autoimmune cytopenia, 148 (34%) on the basis of lymphoproliferation and another SoIEI, 33 (8%) on the basis of autoimmune bicytopenia, and 14 (3%) on the basis of autoimmune cytopenia and another SoIEI. Median age at diagnostic evaluation was 9·8 years (IQR 5·5-13·8), and the cohort comprised 279 (65%) boys and 152 (35%) girls. After biomarker and genetic assessments, autoimmune lymphoproliferative syndrome was diagnosed in 71 (16%) patients. Among the remaining 360 patients, 54 (15%) had mostly autosomal-dominant autoimmune lymphoproliferative immunodeficiencies (AD-ALPID), most commonly affecting JAK-STAT (26 patients), CTLA4-LRBA (14), PI3K (six), RAS (five), or NFκB (three) signalling. 19 (5%) patients had other IEIs, 17 (5%) had non-IEI diagnoses, 79 (22%) were unresolved despite extended genetics (ALPID-U), and 191 (53%) had insufficient genetic workup for diagnosis. 16 (10%) of 161 patients with a final diagnosis had somatic mutations. Alternative classification of patients fulfilling common variable immunodeficiency or Evans syndrome criteria did not increase the proportion of genetic diagnoses. INTERPRETATION: The ALPID phenotype defined in this study is enriched for patients with genetic diseases treatable with targeted therapies. The term ALPID might be useful to focus diagnostic and therapeutic efforts by triggering extended genetic analysis and consideration of targeted therapies, including in some children currently classified as having common variable immunodeficiency or Evans syndrome. FUNDING: Deutsche Forschungsgemeinschaft under Germany's Excellence Strategy. TRANSLATION: For the German translation of the abstract see Supplementary Materials section.

Melanoma of the central nervous system based on neurocutaneous melanocytosis in childhood: A rare but fatal condition.

BACKGROUND: Melanomas of the central nervous system (CNS) based on neurocutaneous melanocytosis (NCM) are exceptionally rare in childhood and have been described only sporadically. Rapidly progressive disease may represent a major challenge for treating physicians, especially given the limited knowledge about this condition. This analysis aimed to increase knowledge about the occurrence and treatment of these malignancies. PROCEDURE: Data on diagnosis, treatment, and outcome of patients aged 0-18 years with CNS melanoma based on NCM recorded in the German Registry for Rare Pediatric Tumors (STEP registry) were analyzed. Additionally, published case reports on this condition were analyzed. RESULTS: In STEP, five patients with leptomeningeal melanoma based on NCM were identified, with a median age at melanoma diagnosis of 3.7 years. Various multimodal treatments were performed: (partial) resection (n = 4), irradiation (n = 2), trametinib (n = 3), different cytostatics (n = 2), and anti-GD2 immunotherapy (n = 1). All patients died between 0.3 and 0.8 years after diagnosis. Including published case reports, 27 patients were identified with a median age of 2.8 years at melanoma diagnosis (range: 0.2-16.6). Fourteen of 16 cases with reported data had a NRAS alteration (88%), particularly NRAS p.Q61K (85%). In the expanded cohort, no patient survived longer than 1 year after diagnosis despite multimodal therapy (including trametinib; n = 9), with a median survival of 0.4 years (range 0.1-0.9). CONCLUSIONS: CNS melanomas based on NCM in childhood are aggressive malignancies without curative treatment to date. Therapeutic approaches must be individualized. Genetic tumor sequencing is essential to improve understanding of tumorigenesis and potentially identify new therapeutic targets.

Feasibility of peripheral blood stem cell collection from sickle cell trait donors with an intensified G-CSF regimen.

OBJECTIVES: Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment for SCD and bone marrow from an HLA-matched sibling is currently the standard of care. Haploidentical HSCT from a family donor with a TCR αß/CD19 depleted graft (T-haplo) is an increasingly successful alternative, which requires the generation of G-CSF stimulated peripheral stem cell (PBSC) from haploidentical relatives. These sickle cell trait (SCT) donors reported to develop SCD-related complications in conditions of severe stress. METHODS: In this retrospective analysis, we compared the safety and efficacy of PBSC mobilization with a G-CSF intensified mobilization regimen in SCT donors with a conventional G-CSF mobilization regimen in healthy donors. RESULTS: The reported adverse events were similar during intensified G-CSF mobilization, apheresis, and shortly after stem cell apheresis in SCT and control donors. In SCT and control donors, we were able to mobilize high yields of CD34+ stem cells and the harvested CD34+ cell count was comparable with control donors. CONCLUSIONS: Peripheral stem cell mobilization using an intensified G-CSF regimen is safe, and well tolerated among SCT donors. SCT donors are a valid alternative for collection of peripheral CD34+ stem cells for T-cell-depleted haploidentical stem cell transplantation.

Clinical outcome of pediatric medulloblastoma patients with Li-Fraumeni syndrome.

BACKGROUND: The prognosis for Li-Fraumeni syndrome (LFS) patients with medulloblastoma (MB) is poor. Comprehensive clinical data for this patient group is lacking, challenging the development of novel therapeutic strategies. Here, we present clinical and molecular data on a retrospective cohort of pediatric LFS MB patients. METHODS: In this multinational, multicenter retrospective cohort study, LFS patients under 21 years with MB and class 5 or class 4 constitutional TP53 variants were included. TP53 mutation status, methylation subgroup, treatment, progression free- (PFS) and overall survival (OS), recurrence patterns, and incidence of subsequent neoplasms were evaluated. RESULTS: The study evaluated 47 LFS individuals diagnosed with MB, mainly classified as DNA methylation subgroup "SHH_3" (86%). The majority (74%) of constitutional TP53 variants represented missense variants. The 2- and 5-year (y-) PFS were 36% and 20%, and 2- and 5y-OS were 53% and 23%, respectively. Patients who received postoperative radiotherapy (RT) (2y-PFS: 44%, 2y-OS: 60%) or chemotherapy before RT (2y-PFS: 32%, 2y-OS: 48%) had significantly better clinical outcome then patients who were not treated with RT (2y-PFS: 0%, 2y-OS: 25%). Patients treated according to protocols including high-intensity chemotherapy and patients who received only maintenance-type chemotherapy showed similar outcomes (2y-PFS: 42% and 35%, 2y-OS: 68% and 53%, respectively). CONCLUSIONS: LFS MB patients have a dismal prognosis. In the presented cohort use of RT significantly increased survival rates, whereas chemotherapy intensity did not influence their clinical outcome. Prospective collection of clinical data and development of novel treatments are required to improve the outcome of LFS MB patients.

Biomodulatory therapy induces durable remissions in multi-system Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is rare hematological neoplasia originating from the aberrant proliferation of CD207-positive dendritic cells. Refractory multi-system LCH is difficult to treat necessitating the continuous development of different salvage therapies. At our medical center, eleven patients (age 11 months to 77 years) with multi-system LCH were treated on a compassionate use basis with metronomic biomodulation therapy (MBT) involving the daily oral application of low-dose trofosfamide, etoricoxib, pioglitazone and low-dose dexamethasone. Overall, four patients including two heavily pretreated pediatric patients achieved ongoing complete remission. Moreover, partial disease remission was observed in three patients, and four patients attained stable disease. MBT demonstrated high activity against multi-system LCH even in patients, refractory to multiple systemic chemotherapies. Further confirmation of efficacy should be systematically evaluated in prospective trials.

Clinical evidence for a biological effect of epigenetically active decitabine in relapsed or progressive rhabdoid tumors.

BACKGROUND: Refined therapy has helped to improve survival rates in rhabdoid tumors (RT). Prognosis for patients with chemoresistant, recurrent, or progressive RT remains dismal. Although decitabine, an epigenetically active agent, has mainly been evaluated in the management of hematologic malignancies in adults, safety in children has also been demonstrated repeatedly. MATERIALS AND METHODS: A retrospective series of patients who received decitabine upon relapse or progression following therapy according to the EU-RHAB regimen is presented. Due to the retrospective nature of analyses, response was defined as measurable regression of at least one lesion on imaging. 850k methylation profiling was done whenever tumor tissue was available. RESULTS: A total of 22 patients with RT of any anatomical localization were included. Most patients (19/22) presented with metastases. All received low-dose decitabine with or preceding conventional chemotherapy. Patients received a median of two (1-6) courses of decitabine; 27.3% (6/22) demonstrated a radiological response. Molecular analyses revealed increased methylation levels in tumors from responders. No excessive toxicity was observed. Clinical benefits for responders included eligibility for early phase trials or local therapy. Responders showed prolonged time to progression and overall survival. Due to small sample size, statistical correction for survivorship bias demonstrated no significant effect on survival for responders. CONCLUSIONS: Patients with RT demonstrate promising signs of antitumor activity after multiagent relapse therapy including decitabine. Analyses of methylation data suggest a specific effect on an epigenetic level. We propose to consider decitabine and other epigenetic drugs as candidates for further clinical investigations in RT.

Alternative donor: αß/CD19 T-cell-depleted haploidentical hematopoietic stem cell transplantation for sickle cell disease.

Sickle cell disease (SCD) is an inherited disorder; despite significant improvements in supportive care, SCD continues to cause substantial morbidity, mortality, and reduced life expectancy. Allogeneic hematopoietic stem cell transplantation (HSCT) is currently the only widely available curative therapy for SCD, which is offered as a standard of care for patients with a matched sibling donor (MSD). Donor availability is limited to a minority of patients. Thus, αß/CD3-depleted haploidentical HSCT, as an efficient means for depletion of graft-versus-host disease (GvHD)-mediating T cells, can be offered as an alternative curative therapy, particularly for nonmalignant diseases such as SCD. Out of 38 patients with advanced stage SCD, 25 were transplanted with CD3/CD19- or T-cell receptor αß/CD19 T-cell-depleted peripheral stem cell grafts (T-haplo-HSCT group), whereas 13 transplanted from MSD (MSD group); both groups received an almost identical conditioning regimen. Engraftment was achieved in all. However, in the T-haplo-HSCT group, three patients succumbed to an uncontrolled cytomegalovirus pneumonitis, a macrophage activation syndrome, and a major blood group incompatibility with a late graft failure and multiorgan failure. The overall survival was 88% and 100% in T-haplo-HSCT and MSD groups, respectively. None of our patients developed a Glucksberg Grade III-IV acute GvHD. Four patients (16%) in the T-haplo-HSCT group and two patients (15%) in the MSD group developed a steroid-sensitive, mild-to-moderate chronic GvHD that resolved within 18 months posttransplant. These results are encouraging and demonstrate the feasibility, safety, and efficacy of T-haplo-HSCT in advanced stage SCD in children and adults, thus offering a curative alternative to majority of patients.

Hemophagocytic lymphohistiocytosis in imported pediatric visceral leishmaniasis in a nonendemic area.

OBJECTIVES: To describe characteristics of visceral leishmaniasis-associated hemophagocytic lymphohistiocytosis (HLH) with focus on diagnostic clues and pitfalls, including the frequency of central nervous system (CNS) involvement, and to determine the efficacy of liposomal amphotericin B (L-AmB). STUDY DESIGN: We retrospectively analyzed clinical and laboratory features, diagnostic procedures, and treatment of 13 patients with HLH with imported visceral leishmaniasis, reported to the German HLH reference center (1999-2012). RESULTS: The spectrum of presentations was indistinguishable from patients with hereditary HLH or with acquired HLH because of infections with other pathogens. In 8 patients, disease onset occurred before the age of 2 years, coinciding with the typical age of manifestation of primary HLH. Two patients had mild nonspecific CNS findings. Misleading antiviral IgM (n = 6) and autoantibodies (n = 2) led to inaccurate interpretation of the etiology of HLH, sometimes with inappropriate therapeutic consequences. False negative results for Leishmania were obtained by initial bone marrow microscopy in 6/13, serology in 1/12, bone marrow culture in 2/5, and polymerase chain reaction of peripheral blood in 1/3 patients, and all bone marrow samples tested were Leishmania-positive by polymerase chain reaction (n = 7). L-AmB was administered to 12 patients, 5 of whom had no prior HLH-directed immunosuppressive therapy; sodium stibogluconate was administered to 1 patient. Persistent remission was achieved in 11 cases. Two patients required repeated or prolonged L-AmB therapy. CONCLUSIONS: Awareness of diagnostic pitfalls may save patients from unnecessary toxic treatment. CNS involvement is rare. L-AmB shows efficacy in visceral leishmaniasis-associated HLH.

Wiskott-Aldrich syndrome presenting with a clinical picture mimicking juvenile myelomonocytic leukaemia.

BACKGROUND: Wiskott-Aldrich syndrome (WAS) is a rare X-linked immunodeficiency caused by defects of the WAS protein (WASP) gene. Patients with WAS typically demonstrate micro-thrombocytopenia. PROCEDURES: The report describes seven male infants with WAS that initially presented with leukocytosis, monocytosis, and myeloid and erythroid precursors in the peripheral blood (PB) and dysplasia in the bone marrow (BM), which was initially indistinguishable from juvenile myelomonocytic leukaemia (JMML). RESULTS: The median age of affected patients was 1 month (range, 1-4 months). Splenomegaly was absent in four of these patients, which was unusual for JMML. A mutation analysis of genes in the RAS-signalling pathway did not support a diagnosis of JMML. Non-haematological features, such as eczema (n = 7) and bloody stools (n = 6), ultimately led to the diagnosis of WAS at a median age of 4 months (range, 3-8 months), which was confirmed by absent (n = 6) or reduced (n = 1) WASP expression in lymphocytes by flow cytometry (FCM) and a WASP gene mutation. Interestingly, mean platelet volume (MPV) was normal in three of five patients and six of seven patients demonstrated occasional giant platelets, which was not compatible with WAS. CONCLUSIONS: These data suggest that WAS should be considered in male infants presenting with JMML-like features if no molecular markers of JMML can be detected.

No evidence for germ-line transmission following prenatal and early postnatal AAV-mediated gene delivery.

BACKGROUND: Recombinant adeno-associated viruses have been used successfully in a number of pre-clinical and clinical gene therapy studies. Since there is a broad consensus that gene therapy must not lead to germ-line transmission, the potential of such vectors for inadvertent gene transfer into germ cells deserves special attention. This applies in particular to pre- or perinatal vector application which has been considered for diseases presenting with morbidity already at birth. METHODS: AAV serotype 2 derived vectors carrying a beta-galactosidase reporter gene or human clotting factor IX cDNA were injected intraperitoneally or via a yolk sac vein into mouse fetuses or administered intravascularly to newborn mice. Tissue samples of the treated animals including the gonads as well as sperm DNA, obtained by differential lysis of one testis of each male animal, and the offspring of all treated mice were investigated for the presence of vector DNA by nested PCR. In positive samples, the copy number of the vector was determined by quantitative real-time PCR. RESULTS: AAV vectors administered intraperitoneally or intravascularly to fetal or newborn mice reached the gonads of these animals and persisted there for time periods greater than one year. Intravascular injection of the vector resulted more frequently in gene transfer to the gonads than intraperitoneal injection. Vector copy numbers in the gonads ranged from 0.3 to 74 per 10(4) cell equivalents. However, neither in isolated sperm DNA from the treated animals nor in their offspring were vector sequences detectable. CONCLUSIONS: These data suggest the risk of inadvertent germ-line transmission following prenatal or early postnatal AAV type 2 mediated gene delivery to be very low.