Significance: Chronic mucocutaneous candidiasis (CMC) is defined as persistent or recurrent infections of the skin and/or mucosae by commensal fungi of the Candida genus. It is often seen in patients with T-cell deficiencies, whether inherited or acquired, who typically suffer from multiple infectious diseases. Rare patients are otherwise healthy and display isolated CMC, which often segregates as a Mendelian trait. In 2011, we described the first genetic cause of isolated CMC, with autosomal recessive (AR), complete IL-17 receptor A (IL-17RA) deficiency, in a single patient. We report here 21 patients from 12 unrelated kindreds, homozygous for 12 different mutant alleles that underlie AR IL-17RA deficiency. All patients have isolated CMC and their cells do not respond to IL-17A, -17F, and -17E/IL-25.

Primary immunodeficiency disorders associated with autoimmunity are poorly understood. Central nervous system (CNS) vasculitis can complicate the courses of such entities, but it is underappreciated. Deletion of the dedicator of cytokinesis 8 (DOCK8) gene is considered to be the autosomal recessive form of hyperimmunoglobulin E syndrome which is a rare type of primary immunodeficiency disease characterized by elevated levels of IgE antibody, eczema, and recurrent staphylococcal infections. DOCK8 deletion is associated with fatal CNS vasculitis. However, descriptions of such cases and their outcomes are scarce in the literature. This report describes a young female with a DOCK8 gene deletion presenting acutely with squint, fatigue and visual hallucinations. The patient was diagnosed as having neuritis of the third oculomotor nerve and encephalitis, which were thought to be related to her underlying immune deficiency, however, she subsequently was diagnosed with CNS vasculitis based on brain magnetic imaging and magnetic resonance angiography findings. We provide here a comprehensive description of the patient’s clinical outcome and outline an effective treatment approach that may be useful for similar patients and includes the use of steroids and mycophenolate mofetil (MMF). The treatment was well tolerated and enabled the patient to recover most of her neurological deficits. However, despite the initial improvement, she later developed stroke. To the best of our knowledge, this is the first report in the literature of a case of primary immunodeficiency complicated by CNS vasculitis demonstrating a successful outcome. Our observations indicate that the combination of MMF and steroids is an effective treatment for CNS vasculitis associated with DOCK8 deficiency. However, lack of awareness of the neurological comorbidities associated with primary immunodeficiencies and the delay in diagnosis likely contributed to the development of acute cerebral infarction. Early treatment and aggressive control of the disease’s initial inflammation is essential for preventing catastrophic stroke.

Children with a history of recurrent, severe, or unusual infections present a diagnostic challenge. It is important to maintain a high index of suspicion for the diagnosis of immunodeficiency, for early diagnosis and treatment can improve outcome. Differentiation between infections caused by common risk factors, or immune dysfunction should be based on a detailed history and physical examination and, if indicated, followed by appropriate laboratory studies. This paper aims at providing guidelines for the evaluation of children with recurrent infections. It provides an overview of the diagnostic approach including important details required from the history, physical examination, and an appropriate choice of screening test to be ordered.

Inherited deficiency of the RNA lariat–debranching enzyme 1 (DBR1) is a rare etiology of brainstem viral encephalitis. The cellular basis of disease and the range of viral predisposition are unclear. We report inherited DBR1 deficiency in a 14-year-old boy who suffered from isolated SARS-CoV-2 brainstem encephalitis. The patient is homozygous for a previously reported hypomorphic and pathogenic DBR1 variant (I120T). Consistently, DBR1 I120T/I120T fibroblasts from affected individuals from this and another unrelated kindred have similarly low levels of DBR1 protein and high levels of RNA lariats. DBR1 I120T/I120T human pluripotent stem cell (hPSC)–derived hindbrain neurons are highly susceptible to SARS-CoV-2 infection. Exogenous WT DBR1 expression in DBR1 I120T/I120T fibroblasts and hindbrain neurons rescued the RNA lariat accumulation phenotype. Moreover, expression of exogenous RNA lariats, mimicking DBR1 deficiency, increased the susceptibility of WT hindbrain neurons to SARS-CoV-2 infection. Inborn errors of DBR1 impair hindbrain neuron–intrinsic antiviral immunity, predisposing to viral infections of the brainstem, including that by SARS-CoV-2.