Novel NLRC4 Mutation Causes a Syndrome of Perinatal Autoinflammation With Hemophagocytic Lymphohistiocytosis, Hepatosplenomegaly, Fetal Thrombotic Vasculopathy, and Congenital Anemia and Ascites.

Autoinflammatory diseases are caused by pathologic activation of the innate immune system. Primary hemophagocytic lymphohistiocytosis (HLH) is an aggressive syndrome of excessive immune activation caused by monogenic mutations resulting in cytotoxic cell defects and subsequent failure to eliminate activated macrophages. Secondary HLH is often diagnosed in cases without a known Mendelian inheritance. However, some cases of "secondary" HLH have been shown to harbor mutations with partial dysfunction of the cytotoxic system. Recently, macrophage intrinsic abnormalities caused by NLRC4 inflammasome mutations have been linked to autoinflammation and recurrent macrophage activation syndromes resembling a primary HLH. We report a case of a former 28-week preterm infant with congenital anemia, ascites, and a heavy edematous placenta with fetal thrombotic vasculopathy, who developed hepatosplenomegaly and unexplained systemic inflammation with laboratory features of HLH in the early postnatal course and died at 2 months of age. Postmortem examination confirmed the hepatosplenomegaly with marked sinusoidal hemophagocytosis, along with striking hemophagocytosis in the bone marrow and lymph nodes. There was extensive acute and chronic ischemic bowel disease with matted bowel loops, fibrous adhesions, and patchy necrotizing enterocolitis features. Whole exome sequencing analysis demonstrated a novel mosaic heterozygous NLRC4 512 C> T (p.Ser171Phe) de novo mutation predicated to cause a dominant, gain-of-function mutation resulting in a constitutively active protein. The assembly of NLRC4-containing inflammasomes via an induced self-propagation mechanism likely enables a perpetuating process of systemic macrophage activation, presumed to be initiated in utero in this patient.

A Newborn With Familial Hemophagocytic Lymphohistiocytosis Complicated With Transfusion Associated Graft Versus Host Disease.

Hemophagocytic lymphohistiocytosis (HLH) is characterized by activation of cytotoxic T and natural killer (NK) cells, and macrophages related to a spectrum of hyperinflammatory disorders. The clinical findings mainly include high fever, cytopenia, splenomegaly, phagocytosis, and proliferation of histiocytes in lymphoreticular tissue. To the best of our knowledge, transfusion-associated graft versus host disease (TA-GVHD) in a 13-day old male newborn with HLH is being reported first time in the literature. The aim of this report was to emphasize the importance of blood products irradiation in the prevention of the development of graft versus host disease especially among high-risk subjects such as newborns with HLH.

Congenital hemophagocytic lymphohistiocytosis presenting as thrombocytopenia in a newborn.

Hemophagocytic lymphohistiocytosis (HLH) is a disease caused by dysregulation and hyperactivation of the immune system, and can be familial or acquired. HLH presenting in infancy can be rapidly fatal if not promptly recognized and treated. Congenital HLH can be caused by various genetic mutations or part of immunodeficiency syndromes. We present an infant with Griscelli syndrome and familial HLH with atypical genetic mutations, presenting as thrombocytopenia on the first day of life, cured with chemotherapy and unrelated cord blood transplant.

Los trastornos de la secreción lisosomal en la sinapsis inmune y otros tejidos / Secretory lysosome disorders in the immune synapse and other tissues

Introducción: El síndrome hemofagocítico (SH) constituye una manifestación común a una serie de anomalías congénitas que afectan a la excreción lisosomal, interrumpiendo la vía citolítica gránulodependiente y desencadenando una disfunción de la sinapsis inmunológica. La presencia de manifestaciones características en otros tejidos puede orientar el diagnóstico etiológico. Pacientes y métodos: Presentamos los hallazgos clínicos y biológicos de dos hermanos diagnosticados de linfohistiocitosis hemofagocítica familiar tipo 3 (FHL-3), dos pacientes con síndrome de Griscelli tipo 2 (GS-2), y un síndrome de Chédiak-Higashi (CHS). Resultados: Los pacientes de FHL-3 aportaron un resultado positivo en el estudio mutacional de UNC13D indicado por un SH precoz en el primero de ellos. El primer diagnóstico de SG-2 se confirmó por la presencia de una mutación en el gen Rab27A en una paciente con SH en la que había un llamativo trastorno de la pigmentación. La misma mutación se detectó en una prima afecta también de trastornos de la pigmentación. El diagnóstico de SCH se realizó en un paciente que presentaba un SH con trastornos de la pigmentación y granulación atípica en células hematopoyéticas. El hallazgo de una mutación en el gen LYST confirmó el diagnóstico. Conclusiones: En los pacientes con SH primario es preciso atender a manifestaciones extra-inmunológicas características de ciertos trastornos de la secreción lisosomal. La curiosa relación entre albinismo e inmunidad ha jugado recientemente un papel decisivo en la identificación de los mecanismos moleculares involucrados en estos procesos(AU)

Introduction: Haemophagocytic syndrome (HS) is a common manifestation of several congenital disorders characterised by a disruption of lysosomal secretion, interrupting the cytolytic pathway and triggering a dysfunction in the immune synapse. In this situation, the recognition of certain extra-immunological manifestations may help in the diagnostic process. Patients and methods: We describe the clinical and biological features present in two brothers with familial haemophagocytic lymphohistiocytosis type 3 (FHL-3), two patients with Griscelli syndrome type 2 (GS-2) and one patient with Chédiak-Higashi syndrome (CHS). Results: Mutational assays at UNC13D were carried out on two brothers after diagnosing an early onset HS in the first one, yielding a positive result in both cases with a consequent diagnosis of FHL-3. The diagnosis of GS-2 was supported by positive results of mutational Rab27A studies in one patient with HS and abnormal pigmentation, and in her cousin who was affected by a similar abnormal pigmentation. The diagnosis of CHS was established in one patient with HS, abnormal pigmentation and atypical granules on cytological examination of a bone marrow smear. Diagnosis was confirmed in this patient by the finding of a homozygous LYST mutation. Conclusions: We point out the importance of recognising the presence of typical extra-immunological manifestations of certain congenital disorders of lysosome secretion in patients diagnosed with HS. The association of albinism and immunodeficiency has played a critical role in the recent identification of the molecular mechanism involved in these disorders(AU)

Congenital hemophagocytic lymphohistiocytosis in a preterm infant: cytokine profile and a review of the disease.

A preterm infant with very low birth weight was born with fetal onset familial hemophagocytic lymphohistiocytosis. Known gene abnormalities responsible for the disease were not identified in the patient. The infant died at 13 months of age owing to complications from cord blood stem cell transplantation. We found selectively elevated expression of interleukin-6 and chemokines in the cord blood of the patient. We also reviewed 7 other preterm cases of congenital hemophagocytic lymphohistiocytosis to highlight the significance of this condition, as it can cause ascites and hepatosplenomegaly in utero and be mistaken for congenital infection in the fetus.

Fulminant neonatal liver failure in siblings: probable congenital hemophagocytic lymphohistiocytosis.

Familial hemophagocytic lymphohistiocytosis (HLH) is an autosomal recessive disorder of immune regulation characterized by fever, splenomegaly, cytopenia, hypertriglyceridemia, hypofibrinogenemia, and hyperferritinemia. Although presentation usually occurs during the first 2 years of life, congenital presentation is rare. We report siblings with a presumptive diagnosis of familial HLH who presented with hydrops fetalis and severe hepatic involvement ultimately resulting in their deaths. This report emphasizes the difficulty of confirming the diagnosis of HLH. However, establishing the diagnosis has important implications for genetic counseling and family planning. HLH should be considered in the setting of perinatal liver failure. The immunologic basis of the disease is incompletely understood but testing for natural killer cell function, and perforin defects may be helpful in establishing a diagnosis. HLH can be treated with chemotherapy, immunotherapy, and stem cell transplantation.