Neurologic Involvement in Primary Immunodeficiency Disorders

Clinical Reasoning: A 24-Year-Old Man With Gait Impairment, Hearing Loss, and Recurrent Fever

We present a case study of a 24-year-old man who reported mild balance and walking difficulties for 2 years. He had a history of recurrent fever, skin lesions, headache, and elbow pain, but most of these events resolved spontaneously. There was no significant family history. On examination, we observed frontal bossing, sensorineural hearing loss, and gait ataxia. This case underscores the significance of identifying clinical indicators in patients with neurologic symptoms, particularly recurrent fever, to establish a precise and thorough differential diagnosis.

Neurological involvement in patients with primary immunodeficiency

INTRODUCTION

Primary immunodeficiency diseases (PID) are defined by recurrent infections, allergies, autoimmunity, and malignancies. Neurologic symptoms are one of the major components of some immunodeficiency syndromes, such as Ataxia-Telangiectasia (AT), Nijmegen breakage syndrome (NBS), and Purine Nucleoside Phosphorylase (PNP) deficiency, which are considered as the primary involvement. Various pathological mechanisms, DNA repair disorders, metabolic abnormalities, and autoimmune phenomena have also been linked with neurological conditions.

MATERIALS AND METHOD

We retrospectively assessed the neurological involvement in 108 patients out of 6000 with PID in this study.

RESULTS

The female/male ratio of the cases was 49/59, and the median age was 13 years (min = 1; max = 60). Neurological problems were detected at a median age of 7 years (min = 0.5; max = 30). Di George Syndrome (DGS) and CVID (common variable immunodeficiency) were the most common diseases in our cohort (n = 31, 30% and n = 30, 27%, respectively). The most frequent outcomes were cognitive delay (n = 63, 58%), epilepsy (n = 25, 23%), and ataxia (n = 20, 18%). Central nervous system involvement was found in 99% of the patients (n = 107), and peripheral nervous system complication was found in only one patient with CVID and chronic inflammatory demyelinating polyneuropathy (CDIP). Cranial MRI was found to be abnormal in 74% (n = 80) of the patients. MRI findings included cerebellar atrophy (n = 33, 34%), white matter lesion (n = 27, 28.4%), cerebral atrophy (n = 21, 22.3%), gray matter lesion (n = 6, 6.3%), hydrocephalus (n = 5, 5,3%), and pituitary gland lesion (n = 3, 3.2%), intracranial hemorrhage (n = 3, 3%), intracranial vasculitis (n = 3, 2.7%), and arterio-venous malformation (n = 1, 0,9%). Primary involvement (a component of the disease) was 60% (n = 65), and secondary (infection or autoimmunity) and tertiary involvements (structural or incidental lesions) contributed 20% (n = 20) each in the patients.

CONCLUSION

In this study, we describe the various neurologic findings of patients with PID. The neurologic presentation may represent the initial manifestation of certain types of PID. Early diagnosis and treatment are essential to prevent or reduce further neurologic damages.

Central nervous system manifestations of LRBA deficiency: case report of two siblings and literature review

BACKGROUND

LPS-responsive beige-like anchor protein (LRBA) deficiency is a primary immunodeficiency disease (PID) characterized by a regulatory T cell defect resulting in immune dysregulation and autoimmunity. We present two siblings born to consanguineous parents of North African descent with LRBA deficiency and central nervous system (CNS) manifestations. As no concise overview of these manifestations is available in literature, we compared our patient's presentation with a reviewed synthesis of the available literature.

CASE PRESENTATIONS

The younger brother presented with enteropathy at age 1.5 years, and subsequently developed Evans syndrome and diabetes mellitus. These autoimmune manifestations led to the genetic diagnosis of LRBA deficiency through whole exome sequencing with PID gene panel. At 11 years old, he had two tonic-clonic seizures. Brain MRI showed multiple FLAIR-hyperintense lesions and a T2-hyperintense lesion of the cervical medulla.  His sister presented with immune cytopenia at age 9 years, and developed diffuse lymphadenopathy and interstitial lung disease. Genetic testing confirmed the same mutation as her brother. At age 13 years, a brain MRI showed multiple T2-FLAIR-hyperintense lesions. She received an allogeneic hematopoietic stem cell transplantation (allo-HSCT) 3 months later. Follow-up MRI showed regression of these lesions.

CONCLUSIONS

Neurological disease is documented in up to 25% of patients with LRBA deficiency. Manifestations range from cerebral granulomas to acute disseminating encephalomyelitis, but detailed descriptions of neurological and imaging phenotypes are lacking. LRBA deficiency amongst other PIDs should be part of the differential diagnosis in patients with inflammatory brain lesions. We strongly advocate for a more detailed description of CNS manifestations in patients with LRBA deficiency, when possible with MR imaging. This will aid clinical decision concerning both anti-infectious and anti-inflammatory therapy and in considering the indication for allo-HSCT.

Association of rare variants in genes of immune regulation with pediatric autoimmune CNS diseases

Background

There is a gap in the literature regarding genetic underpinnings of pediatric autoimmune CNS diseases. This study explored rare gene variants implicated in immune dysregulation within these disorders.

Methods

This was a single-center observational study of children with inflammatory CNS disorder who had genetic testing through next generation focused exome sequencing targeting 155 genes associated with innate or adaptive immunity. For in silico prediction of functional effects of single-nucleotide variants, Polymorphism Phenotyping v2, and Sorting Intolerant from Tolerant were used, and Combined Annotation Dependent Depletion (CADD) scores were calculated. Identified genes were analyzed using Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis.

Results

Of 54 patients, 42 (77.8%) carried variant(s), among which 12 (22.2%) had 3–8 variants. Eighty-eight unique single-nucleotide variants of 55 genes were identified. The most variants were detected in UNC13D, LRBA, LYST, NOD2, DOCK8, RNASEH2A, STAT5B, and AIRE. The majority of variants (62, 70.4%) had CADD > 10. KEGG pathway analysis revealed seven genes associated with primary immunodeficiency (Benjamini 1.40E − 06), six genes with NOD-like receptor signaling (Benjamini 4.10E − 04), five genes with Inflammatory Bowel Disease (Benjamini 9.80E − 03), and five genes with NF-kappa B signaling pathway (Benjamini 1.90E − 02).

Discussion

We observed a high rate of identification of rare and low-frequency variants in immune regulatory genes in pediatric neuroinflammatory CNS disorders. We identified 88 unique single-nucleotide variants of 55 genes with pathway analysis revealing an enrichment of NOD2-receptor signaling, consistent with involvement of the pathway within other autoinflammatory conditions and warranting further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-022-11325-2.

Progressive choreodystonia in X-linked hyper-IgM immunodeficiency: a rare but recurrent presentation

An association between movement disorders and immune‐system dysfunction has been described in the context of rare genetic diseases such as ataxia telangiectasia as well as infectious encephalopathies. We encountered a male patient who presented immunodeficiency of unknown etiology since childhood. A medication‐refractory, progressive choreodystonic movement disorder emerged at the age of 42 years and prompted an exome‐wide molecular testing approach. This revealed a pathogenic hemizygous variant in CD40LG, the gene implicated in X‐linked hyper‐IgM syndrome. Only two prior reports have specifically suggested a causal relationship between CD40LG mutations and involuntary hyperkinetic movements. Our findings thus confirm the existence of a particular CD40LG‐related condition, combining features of compromised immunity with neurodegenerative movement abnormalities. Establishing the diagnosis is crucial because of potential life‐threatening immunological complications.

Activated PI3Kδ syndrome, an immunodeficiency disorder, leads to sensorimotor deficits recapitulated in a murine model

The phosphoinositide-3-kinase (PI3K) family plays a major role in cell signaling and is predominant in leukocytes. Gain-of-function (GOF) mutations in the PIK3CD gene lead to the development of activated PI3Kδ syndrome (APDS), a rare primary immunodeficiency disorder. A subset of APDS patients also displays neurodevelopmental delay symptoms, suggesting a potential role of PIK3CD in cognitive and behavioural function. However, the extent and nature of the neurodevelopmental deficits has not been previously quantified. Here, we assessed the cognitive functions of two APDS patients, and investigated the causal role of the PIK3CD GOF mutation in neurological deficits using a murine model of this disease. We used p110δ^E1020K knock-in mice, harbouring the most common APDS mutation in patients. We found that APDS patients present with visuomotor deficits, exacerbated by autism spectrum disorder comorbidity, whereas p110δ^E1020K mice exhibited impairments in motor behaviour, learning and repetitive behaviour patterning. Our data indicate that PIK3CD GOF mutations increase the risk for neurodevelopmental deficits, supporting previous findings on the interplay between the nervous and the immune system. Further, our results validate the knock-in mouse model, and offer an objective assessment tool for patients that could be incorporated in diagnosis and in the evaluation of treatments.

Diverse clinical features and diagnostic delay in monogenic inborn errors of immunity: A call for access to genetic testing

BACKGROUND

Inborn errors of immunity (IEIs) are a group of conditions affecting immune system development and function. Due to their clinical heterogeneity and lack of provider awareness, patients suffer from long diagnostic delays that increase morbidity and mortality. Next-generation sequencing facilitates earlier diagnosis and treatment of IEIs, but too often patients are unable to see the benefit of this technology due to gaps in providers' knowledge regarding which patients to test and barriers to accessing sequencing.

METHODS

Here, we provide detailed clinical phenotyping and describe the impact of genetic sequencing on a cohort of 43 patients with monogenic IEIs seen in a tertiary care center from 2014 to 2019. Data were abstracted from a chart review, and a panel of clinical immunologists were consulted on the impact of genetic sequencing on their patients.

RESULTS

We found that our patients had significant diagnostic delays, averaging 3.3 years; had diverse manifestations of immune system dysfunction; and had demonstrated highly complex medical needs, with on average 7.9 subspecialties involved in their care and 4.9 hospitalizations prior to definitive treatment. Our results also demonstrate the benefits of genetic testing, as it provided the majority of our patients with a diagnosis, and positively impacted their treatment, follow-up, and prognosis.

CONCLUSION

This paper expands the paucity of literature on genetically confirmed IEIs in North America and supports the expansion of access to genetic testing for patients with clinical features suggesting IEI, such as those presented in our cohort.

Self-reported cognitive impairment in individuals with Primary Immunodeficiency Disease

Individuals with Primary Immunodeficiency Disease (PID) have increased risk for infection, autoimmune conditions, and inflammatory disorders. Cognitive impairment, also referred to as brain fog, has been recognized in other medical conditions and as a side-effect of treatments; however, it has not been previously reported in individuals with PID. The phenomenon of brain fog is recognized in other autoimmune or inflammatory conditions, including lupus, multiple sclerosis, chronic fatigue syndrome, and has resulted from chemotherapy treatment for cancer. This research investigates the self-reported memory function of individuals with a diagnosis of PID. Respondents completed a survey which used reliable and valid questionnaires: Memory Functioning Questionnaire, Beck’s Depression Inventory II, and Beck’s Anxiety Inventory. Of the 292 completed surveys, 133 did not report any comorbid neurological diagnosis or incident of concussion (both of which could influence perceived memory function). When compared to normative scores, the respondents in this study were found to have significantly greater perceived memory impairment. The respondents had a significant higher score for anxiety and depression as compared to non-anxious and non-depressed normative values. This study finds that individuals with a diagnosis of PID have a greater degree of perceived memory impairment, or brain fog, in addition to greater levels of anxiety and depression. Individuals with a diagnosis of PID would benefit from prospective surveillance through a comprehensive neuropsychological assessment to track cognitive status and implement corrective measures, should any decline be identified.

Primary immunodeficiency diseases treated with immunoglobulin and associated comorbidities

Background: Primary immunodeficiency diseases (PIDD) consist of a heterogeneous group of disorders characterized by various aspects of immune dysregulation. Although the most universally recognized manifestation of PIDD is an increased susceptibility to infections, there is a growing body of evidence that patients with PIDD often have a higher incidence of lung disease, autoimmunity, autoinflammatory disorders, and malignancy. Objective: The purpose of this study was to better understand the noninfectious complications of PIDD by determining the comorbid disease prevalence across various age groups, genders, and immunoglobulin replacement types compared with the general population. Methods: A large U.S. insurance claims database was retrospectively analyzed for patients who had a diagnosis of PIDD and who had received intravenous immunoglobulin (IVIG) or subcutaneous immunoglobulin (SCIG). The prevalences of 31 different comorbid conditions in the Elixhauser comorbidity index were compared among the 3125 patients in the PIDD population to > 37 million controls separated by gender and by 10-year age cohorts. Results: In the PIDD population, statistically significantly higher comorbid diagnoses included chronic obstructive pulmonary disease-asthma in 51.5%, rheumatoid disease in 14%, deficiency anemia in 11.8%, hypothyroidism in 21.2%, lymphoma in 16.7%, neurologic disorders in 9.7%, arrhythmias in 19.9%, electrolyte disorders in 23.6%, coagulopathies in 16.9%, and weight loss in 8.4%. Conclusion: PIDD that require immunoglobulin replacement are associated with an increased risk of numerous comorbid conditions that affect morbidity and mortality. Recognition and increased awareness of these noninfectious complications can allow for better monitoring, care coordination, targeted treatments, and improved prognosis.