Human RELA dominant-negative mutations underlie type I interferonopathy with autoinflammation and autoimmunity.

Inborn errors of the NF-κB pathways underlie various clinical phenotypes in humans. Heterozygous germline loss-of-expression and loss-of-function mutations in RELA underlie RELA haploinsufficiency, which results in TNF-dependent chronic mucocutaneous ulceration and autoimmune hematological disorders. We here report six patients from five families with additional autoinflammatory and autoimmune manifestations. These patients are heterozygous for RELA mutations, all of which are in the 3' segment of the gene and create a premature stop codon. Truncated and loss-of-function RelA proteins are expressed in the patients' cells and exert a dominant-negative effect. Enhanced expression of TLR7 and MYD88 mRNA in plasmacytoid dendritic cells (pDCs) and non-pDC myeloid cells results in enhanced TLR7-driven secretion of type I/III interferons (IFNs) and interferon-stimulated gene expression in patient-derived leukocytes. Dominant-negative mutations in RELA thus underlie a novel form of type I interferonopathy with systemic autoinflammatory and autoimmune manifestations due to excessive IFN production, probably triggered by otherwise non-pathogenic TLR ligands.

[Reversible central pontine myelinolysis without hyponatremia in a child with acute lymphoblastic leukemia: a case report]. / Myélinolyse centropontine réversible sans hyponatrémie chez un enfant atteint de leucémie aigüe lymphoblastique: à propos d'un cas.

Central pontine myelinolysis is a demyelinating disorder mainly affecting the central pons. In some cases, it is associated with extrapontine myelinolysis. It is usually caused by rapid correction of hyponatremia and osmotic shock. We here report the case of a 3.5-year-old girl diagnosed with acute lymphoblastic leukemia admitted to our Oncology Unit with neutropenic fever and diarrhea. Laboratory tests showed mild neutropenia, normochromic normocytic anemia. Electrolyte tests were normal without hyponatremia. She received antibiotic therapy with Metronidazole. Five days later, she developed flaccid quadriparesis with mutism. Computerized tomography (CT) scan was normal, cerebrospinal fluid (CSF) examination was normal (there was no evidence of leukemic cells) and ophthalmological examination did not show any abnormalities. Brain MRI found hyperintense signal in the pons. The child improved without specific treatment, and clinical and complete neurological recovery was noted. This case highlights that myelinolysis can occur under some circumstances not related with hyponatremia such as malignancy, chemotherapy.

Posterior mediastinal teratoma presenting as an abdominal mass in a child: A case report.

We report the case of a 2.5-year-old child admitted for abdominal distension, whose imaging revealed a large posterior mediastinal cystic mass, with a tissue component, a calcification, and a minimal fat component. The ultrasound- guided biopsy led to the diagnosis of a benign extragonadal germ cell tumor, also called mature teratoma or dermoid cyst, whose mediastinal localization is rare, often localized in the anterior mediastinum, and rarely in the posterior mediastinum. The mainstay of treatment is complete surgical excision.

Intracranial bifocal germinoma.

Primary intracranial germ cell tumors are rare, often affecting children and young patients. Germinomas are the most common type of germ cell tumors. We present the case of a 10-year-old child, who was admitted with decreased visual acuity, asthenia, polyuro-polydipsic syndrome, and gait disorder. His biological assessment showed an hypocortisolemia and diabetes insipidus. Imaging found a bifocal process in the suprasellar and pineal region, suggestive of a bifocal germinoma. Imaging data and the positivity of human chorionic gonadotrophin in the cerebrospinal fluid were in favor of the diagnosis of bifocal germinal tumor confirmed by biopsy. Currently the patient is hospitalized in pediatric oncology department. The diagnosis of germ cell tumors is based on imaging, tumor marker assays, and biopsy. They are treated by radiation therapy alone or in combination with reduction chemotherapy, and surgery for tumor residues. The location of the tumor usually makes surgery difficult.

Clinical and Immunological Features of 96 Moroccan Children with SCID Phenotype: Two Decades' Experience.

Severe combined immunodeficiency (SCID) is a heterogeneous group of primary immunodeficiency diseases (PIDs) characterized by a lack of autologous T lymphocytes. This severe PID is rare, but has a higher prevalence in populations with high rates of consanguinity. The epidemiological, clinical, and immunological features of SCIDs in Moroccan patients have never been reported. The aim of this study was to provide a clinical and immunological description of SCID in Morocco and to assess changes in the care of SCID patients over time. This cross-sectional retrospective study included 96 Moroccan patients referred to the national PID reference center at Casablanca Children's Hospital for SCID over two decades, from 1998 to 2019. The case definition for this study was age < 2 years, with a clinical phenotype suggestive of SCID, and lymphopenia, with very low numbers of autologous T cells, according to the IUIS Inborn Errors of Immunity classification. Our sample included 50 male patients, and 66% of the patients were born to consanguineous parents. The median age at onset and diagnosis were 3.3 and 6.5 months, respectively. The clinical manifestations commonly observed in these patients were recurrent respiratory tract infection (82%), chronic diarrhea (69%), oral candidiasis (61%), and failure to thrive (65%). The distribution of SCID phenotypes was as follows: T-B-NK+ in 44.5%, T-B-NK- in 32%, T-B+NK- in 18.5%, and T-B+NK+ in 5%. An Omenn syndrome phenotype was observed in 15 patients. SCID was fatal in 84% in the patients in our cohort, due to the difficulties involved in obtaining urgent access to hematopoietic stem cell transplantation, which, nevertheless, saved 16% of the patients. The autosomal recessive forms of the clinical and immunological phenotypes of SCID, including the T-B-NK+ phenotype in particular, were more frequent than those in Western countries. A marked improvement in the early detection of SCID cases over the last decade was noted. Despite recent progress in SCID diagnosis, additional efforts are required, for genetic confirmation and particularly for HSCT.

[Macrophage activation syndrome revealing subcutaneous T-cell lymphoma in a 16-year old adolescent]. / Syndrome d'activation macrophagique révélant un lymphome T sous-cutané chez un adolescent de 16 ans.

Macrophage activation syndrome (MAS) is a multisystemic disorder resulting from an over-activation of the immune system leading to a more or less diffuse macrophagic infiltration into the tussues. Clinical signs including fever, hepatosplenomegaly, adenopathy are associated with abnormal values in laboratory test results (bi or pancytopenia, hepatic cytolysis, elevated LDH levels, coagulopathy) and hemophagocytosis. In children, it can be primary or secondary to several disorders. We report the case of a 16-year old patient admitted to the Department of Pediatrics with febrile leukopenia associated with impaired general condition and circular erythematous lesions spread to the lower limbs. The diagnosis of macrophage activation syndrome was retained based on clinical signs, laboratory test results and cytological results. Skin biopsy of these lesions showed subcutaneous panniculitis-like T-cell lymphoma. The purpose of this study is to insists on the peculiarities of this clinical case given the rarity of this type of subcutaneous T-cell lymphoma, much more in this age group. We want to highlight the importance of suspecting subcutaneous T-cell lymphoma in patients with MAS associated with subcutaneous erythematous lesions because this could be life threatening.

Hodgkin's Lymphoma Revealed by Hemophagocytic Lymphohistiocytosis in a Child.

Hemophagocytic lymphohistiocytosis (HLH) is a severe life-threatening disorder, responsible for extensive phagocytosis of hematopoietic cells and causing a multisystem organ failure. If lymphomas are common causes of HLH, the association with Hodgkin's lymphoma is rarely described in children. We report a case of a 9-year-old boy presenting with HLH as an initial manifestation of Hodgkin's lymphoma. He has been suffering from persistent high fever, asthenia, weight loss, and hepatosplenomegaly with no lymphadenopathy. The diagnosis of HLH secondary to infectious disease was initially worn. The patient received high-dose intravenous immunoglobulin with broad-spectrum antibiotics. However, his state got worse with the onset of dry cough and pleural effusion. Histopathologic examination of pleural fluid showed the presence of Reed-Sternberg cells. The outcome was favorable after treatment by corticosteroid and chemotherapy. Hodgkin's lymphoma revealed by HLH is a source of delayed diagnosis and should be borne in mind in children.