Citations

Purpose of review Norovirus infection is an emerging chronic infection in immunocompromised hosts. The aim of this review is to discuss the pathophysiology of Norovirus infection and explore mechanistic models for chronic infection/shedder state, especially in patients with immune deficiency diseases. Recent findings Chronic Norovirus infection is increasingly associated with enteropathy associated with both primary and secondary immune deficiency diseases. There is an ongoing debate in the immune deficiency community whether it is truly a causative agent for the enteropathy or it is an innocent bystander. We describe the historic aspects of Norovirus infection, its immunology and viral structure and the basis for preventive and vaccination strategies. We also postulate in this review a disease model in immune deficiency subjects which creates a milieu for it to become a chronic and explore newer frontiers for disease modification and prevention. Summary Norovirus is the most common cause of acute gastroenteritis in general population but the factors that lead to its persistence in patients with immune deficiency need further holistic studies. This should include host assessment, microbiome signatures, and viral pathogenic factors assessment.

The term disappearing HDL syndrome refers to development of severe high density lipoprotein cholesterol (HDL-C) deficiency in noncritically ill patients with previously normal HDL-C and triglyceride levels. Autoimmune lymphoproliferative syndrome (ALPS) is a disorder of the immune system due to an inability to regulate lymphocyte homeostasis resulting in lymphadenopathy and hepatosplenomegaly. We describe a 17-year-old boy who was evaluated in the lipid clinic for history of undetectable or low HDL-C and low density lipoprotein cholesterol (LDL-C) levels. Past medical history was significant for ALPS IA diagnosed at 10 years of age when he presented with bilateral cervical adenopathy. He was known to have a missense mutation in one allele of the FAS protein extracellular domain consistent with ALPS type 1A. HDL-C and LDL-C levels had been undetectable on multiple occasions, though lipids had not been measured prior to the diagnosis of ALPS. He had been receiving sirolimus for immunosuppression. The HDL-C and LDL-C levels correlated with disease activity and improved to normal levels during times when the activity of ALPS was controlled. This case highlights the importance of considering ALPS as a cause of low HDL-C and LDL-C levels in a child with evidence of lymphoproliferation.

If untreated, most children with severe combined immunodeficiency disorder (SCID) will die of complications of infection within the first 2 years of life. Early hematopoietic stem cell transplant (HSCT) is the current standard of care for this disease. Although potentially lifesaving, prognosis of HSCT in SCID is variable depending on a number of host and donor factors. Of the survivors, many develop secondary problems such as chronic graft-versus-host disease or even second malignancies. Posttransplant care is complex and requires great effort from parents to adhere to difficult treatment regimens. In this article, we address the difficult ethical question of what to do if parents choose not to have their child with SCID undergo HSCT but prefer palliative care.

We present here a novel case of an atypical Omenn syndrome (OS) phenotype due to mutations in theADAgene encoding adenosine deaminase. This case is noteworthy for a significant increase in circulating CD56brightCD16- cytokine-producing NK cells after treatment with steroids for skin rash.