Omenn's syndrome: differential diagnosis in infants with erythroderma and immunodeficiency

[Relevant cutaneous manifestations as indications for inborn errors of immunity]

Inborn errors of immunity (IEI) can affect different parts of the immune system and manifest especially through pathological infection susceptibility and immune dysregulation. Cutaneous manifestations of IEI can hint at the underlying immunodeficiency and the tendency for infection and inflammation. These manifestations can present as recurring eczema, erythema, abscesses, and hair loss with poor response to therapy. Cutaneous manifestations can be specific for certain IEI, or rather unspecific. Together with clinical course and severity, they can indicate the diagnosis. Early and accurate recognition, diagnosis, and treatment are crucial for optimizing patient outcomes. The diagnosis can be determined through a detailed patient history, clinical examination, and immunological diagnostics. Collaboration between immunologists and dermatologists is vital for comprehensive care and improvement of life quality.

Atopic Dermatitis-like Genodermatosis: Disease Diagnosis and Management

Eczema is a classical characteristic not only in atopic dermatitis but also in various genodermatosis. Patients suffering from primary immunodeficiency diseases such as hyper-immunoglobulin E syndromes, Wiskott-Aldrich syndrome, immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome, STAT5B deficiency, Omenn syndrome, atypical complete DiGeorge syndrome; metabolic disorders such as acrodermatitis enteropathy, multiple carboxylase deficiency, prolidase deficiency; and other rare syndromes like severe dermatitis, multiple allergies and metabolic wasting syndrome, Netherton syndrome, and peeling skin syndrome frequently perform with eczema-like lesions. These genodermatosis may be misguided in the context of eczematous phenotype. Misdiagnosis of severe disorders unavoidably affects appropriate treatment and leads to irreversible outcomes for patients, which underlines the importance of molecular diagnosis and genetic analysis. Here we conclude clinical manifestations, molecular mechanism, diagnosis and management of several eczema-related genodermatosis and provide accessible advice to physicians.

Proposal for a 6-step-approach for differential diagnosis of neonatal erythroderma

The broad differential diagnosis of neonatal erythroderma often poses a diagnostic challenge. Mortality of neonatal erythroderma is high due to complications of the erythroderma itself and the occasionally severe and life-threatening underlying disease. Early correct recognition of the underlying cause leads to better treatment and prognosis. Currently, neonatal erythroderma is approached by a case by case basis. The purpose of this scoping review was to develop a diagnostic approach in neonatal erythroderma. After a systematic literature search in Embase (January 1990 - May 2020, 74 cases of neonatal erythroderma were identified, and 50+ diagnoses could be extracted. Main causes were the ichthyoses (40%) and primary immunodeficiencies (35%). Congenital erythroderma was present in 64% (47/74) of the cases, predominantly with congenital ichthyosis (11/11; 100%), Netherton syndrome (12/14, 86%), and Omenn syndrome (11/23, 48%). Time until diagnosis ranged from 102 days to 116 days for cases of non-congenital erythroderma and congenital erythroderma respectively. Among the 74 identified cases a total of 17 patients (23%) died within a mean of 158 days and were related to Omenn syndrome (35%), graft versus host disease (67%), and Netherton syndrome (18%). Disease history and physical examination are summarized in this paper. Age of onset and a collodion membrane can help to narrow the differential diagnoses. Investigations of blood, histology, hair analysis, genetic analysis and clinical imaging are summarized and discussed. A standard blood investigation is proposed and the need for skin biopsies with Lympho-Epithelial Kazal-Type related Inhibitor-staining is highlighted. Overall, this review shows that diagnostic procedures narrow the differential diagnosis in neonatal erythroderma. A 6-step flowchart for the diagnostic approach for neonatal erythroderma during the first month of life is proposed. The approach was made with the support of expert leaders from international multidisciplinary collaborations in the European Reference Network Skin-subthematic group Ichthyosis.

An infant with omenn syndrome: A case report

Background

Omenn syndrome is a rare, autosomal recessive disorder. It is a disorder that stems from severe combined immunodeficiency in an affected individual. The disease is also of rare occurrence in children in Pakistan because this is the age where this disease usually presents, after having developed in the child. This case report will explore all the reasons that lead to the occurrence of this syndrome while also reflecting on the management profile of the child.

Case presentation

This case report deals with the discussion of one such child who was diagnosed with Omenn Syndrome after being diagnosed with several other diseases, which were being mistaken for being the actual problem and disease, but the reality was that the child was suffering from Omenn syndrome.

Discussion

The child is only 3 months old and his symptoms pose a great risk to his overall health status while also making him predisposed to develop several complications and nutritional deficiencies as a result, all of which keep on adding to the burden of diseases that the child faced. In Omenn syndrome, there is an increased susceptibility to develop infections of the skin, lungs, joints, as well as sepsis. Usually, the death of the patient ensues due to pneumonia and septicemia or septic shock.

Conclusion

Omenn syndrome is a rare disease caused by missense mutations in the recombinase activating genes. It can be treated by bone marrow transplantation or lymphocytic stimulation depending on the severity of the presenting underlying immunodeficiency.

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Omenn syndrome is severe combined immune deficiency syndrome which is rare in children.

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Omenn syndrome are caused by missense mutations in the recombinase activating genes (RAG-1 and RAG-2). Mutations in these genes cause dysregulation in the B and T-cell functions.

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This case report deals with the discussion of one such child diagnosed with Omenn’ Syndrome who was mistakenly diagnosed with other disease, but the reality was that the child was suffering from Omenn syndrome.

Diagnosing Omenn syndrome

Omenn syndrome is a rare combined immunodeficiency mostly associated with RAG1 and RAG2 mutations; the clinical manifestations are well-described and include neonatal erythroderma. Mortality due to opportunistic infections is a serious risk, and a timely diagnosis with a skin biopsy is an important part of the diagnostic workup. We wish to highlight key clinical features of Omenn syndrome and discuss the relevance of a skin biopsy.

Cutaneous barrier leakage and gut inflammation drive skin disease in Omenn syndrome

Background

Severe early-onset erythroderma and gut inflammation, with massive tissue infiltration of oligoclonal activated T cells are the hallmark of Omenn syndrome (OS).

Objective

The impact of altered gut homeostasis in the cutaneous manifestations of OS remains to be clarified.

Methods

We analyzed a cohort of 15 patients with OS and the 129Sv/C57BL/6 knock-in Rag2^R229Q/R229Q (Rag2^R229Q) mouse model. Homing phenotypes of circulating lymphocytes were analyzed by flow cytometry. Inflammatory cytokines and chemokines were examined in the sera by ELISA and in skin biopsies by immunohistochemistry and in situ RNA hybridization. Experimental colitis was induced in mice by dextran sulfate sodium salt.

Results

We show that memory/activated T cells from patients with OS and from the Rag2^R229Q mouse model of OS abundantly express the skin homing receptors cutaneous lymphocyte associated antigen and CCR4 (Ccr4), associated with high levels of chemokine C-C motif ligands 17 and 22. Serum levels of LPS are also elevated. A broad T_h1/T_h2/T_h17 inflammatory signature is detected in the periphery and in the skin. Increased Tlr4 expression in the skin of Rag2^R229Q mice is associated with enhanced cutaneous inflammation on local and systemic administration of LPS. Likewise, boosting colitis in Rag2^R229Q mice results in increased frequency of Ccr4⁺ splenic T cells and worsening of skin inflammation, as indicated by epidermal thickening, enhanced epithelial cell activation, and dermal infiltration by T_h1 effector T cells.

Conclusions

These results support the existence of an interplay between gut and skin that can sustain skin inflammation in OS.

Hyper-IgE in the allergy clinic--when is it primary immunodeficiency?

The 2017 International Union of Immunological Societies (IUIS) classification recognizes 3 hyper-IgE syndromes (HIES), including the prototypic Job's syndrome (autosomal dominant STAT3-loss of function) and autosomal recessive PGM3 and SPINK5 syndromes. Early diagnosis of PID can direct life-saving or transformational interventions; however, it remains challenging owing to the rarity of these conditions. This can result in diagnostic delay and worsen prognosis. Within increasing access to "clinical-exome" testing, clinicians need to be aware of the implication and rationale for genetic testing, including the benefits and limitations of current therapies. Extreme elevation of serum IgE has been associated with a growing number of PID syndromes including the novel CARD11 and ZNF341 deficiencies. Variable elevations in IgE are associated with defects in innate, humoral, cellular and combined immunodeficiency syndromes. Barrier compromise can closely phenocopy these conditions. The aim of this article was to update readers on recent developments at this important interface between allergy and immunodeficiency, highlighting key clinical scenarios which should draw attention to possible immunodeficiency associated with extreme elevation of IgE, and outline initial laboratory assessment and management.

Laboratory diagnosis of primary immunodeficiencies

Primary immune deficiency disorders represent a highly heterogeneous group of disorders with an increased propensity to infections and other immune complications. A careful history to delineate the pattern of infectious organisms and other complications is important to guide the workup of these patients, but a focused laboratory evaluation is essential to the diagnosis of an underlying primary immunodeficiency. Initial workup of suspected immune deficiencies should include complete blood counts and serologic tests of immunoglobulin levels, vaccine titers, and complement levels, but these tests are often insufficient to make a diagnosis. Recent advancements in the understanding of the immune system have led to the development of novel immunologic assays to aid in the diagnosis of these disorders. Classically utilized to enumerate lymphocyte subsets, flow cytometric-based assays are increasingly utilized to test immune cell function (e.g., neutrophil oxidative burst, NK cytotoxicity), intracellular cytokine production (e.g., TH17 production), cellular signaling pathways (e.g., phosphor-STAT analysis), and protein expression (e.g., BTK, Foxp3). Genetic testing has similarly expanded greatly as more primary immune deficiencies are defined, and the use of mass sequencing technologies is leading to the identification of novel disorders. In order to utilize these complex assays in clinical care, one must have a firm understanding of the immunologic assay, how the results are interpreted, pitfalls in the assays, and how the test affects treatment decisions. This article will provide a systematic approach of the evaluation of a suspected primary immunodeficiency, as well as provide a comprehensive list of testing options and their results in the context of various disease processes.

Dyschromia related to severe combined immunodeficiency

Severe combined immunodeficiency includes a group of diseases characterized by different inherited immunological defects. A 4-month-old girl diagnosed with Omenn syndrome, a subtype of severe combined immunodeficiency presenting with generalized erythroderma, was referred to our hospital for an allogeneic stem cell transplantation. Days before transplantation, she developed hyperpigmented macules that increased in number in the following months. As the erythroderma resolved after transplantation, diffuse hypopigmentation was simultaneously noted together with the expansion of hyperpigmented lesions. Cutaneous biopsy samples were taken at different moments, showing features of Omenn syndrome at first, and 2 months later changes consistent with hypopigmentation and repigmentation were observed. Although pigmentary disorders are rarely described in this context, these must be taken into account as a possible alternative diagnosis to graft-versus-host disease and toxicoderma in immunosuppressed patients.

Neonatal erythroderma

PURPOSE OF REVIEW

Neonatal erythroderma is a potentially life-threatening condition in neonates less than 1 month old. During the first month of life, erythroderma is generally a presentation of genodermatosis, primary immune deficiency, or, more exceptionally, severe psoriasis, metabolic disease or infection. Atopic erythroderma is observed later in life, usually after the age of 1 month. Rapid determination of the underlying cause is crucial for better management. However, the diagnosis is often a challenge for the clinician and is frequently delayed due to the nonspecific nature of the clinical signs. We summarize the different causes of neonatal erythrodermas and list their clinical, biological, histological, and sometimes genetic characteristics.

RECENT FINDINGS

Severe erythroderma, typified by early onset, skin induration, severe alopecia and failure to thrive, is immediately suggestive of immunodeficiency or Netherton syndrome. In such cases, an early skin biopsy may be particularly of use in allowing accurate differentiation between these two disorders.

SUMMARY

This review outlines the clinical and histological features of these disorders and suggests an approach to their differential diagnosis and management.

Early skin biopsy is helpful for the diagnosis and management of neonatal and infantile erythrodermas

BACKGROUND

Erythrodermas are often life-threatening conditions in infants. Determination of the underlying cause is crucial. Microscopic changes in adult erythroderma lack specificity.

OBJECTIVE

To determine if an early skin biopsy is helpful for the diagnosis of neonatal and infantile erythroderma.

METHODS

Seventy-two patients admitted for erythroderma in the first year of life were retrospectively included. One hundred and eleven skin biopsies (12-year period) were examined by 3 pathologists blinded to the clinical diagnosis, and classified into atopic dermatitis, immunodeficiency (ID), psoriasis, Netherton syndrome (NS), ichthyosis, other. From year 2000, LEKTI antibody was performed when NS was suspected. Pathological diagnosis was then compared with clinical diagnosis.

RESULTS

The final diagnosis was made in 69.3% of the cases. In 57.6%, pathological diagnosis was in accordance, and in 11.7%, it was in accordance, but other diagnosis had also been proposed. For ID, sensitivity and specificity were 58.5 and 98.5%, respectively. Before year 2000, NS was frequently misdiagnosed with psoriasis, but with the use of LEKTI antibody, sensitivity and specificity were 100%.

CONCLUSION

Skin biopsy is helpful for etiologic diagnosis of early erythroderma of infancy, particularly in ID and NS, the most severe diseases. Consequently, these results justify an early systematic skin biopsy for a better and earlier management.

Omenn syndrome: inflammation in leaky severe combined immunodeficiency

Omenn syndrome (OS) was reported until recently as a distinct form (phenotype and genotype) of severe combined immunodeficiency (SCID). Similar to other patients with SCID, patients with OS present early in infancy with viral or fungal pneumonitis, chronic diarrhea, and failure to thrive. Unlike typical SCID, patients with OS have enlarged lymphoid tissue, severe erythroderma, increased IgE levels, and eosinophilia. The inflammation observed in these patients is believed to be triggered by clonally expanded T cells, which are predominantly of the T(H)2 type. These abnormal T cells, in the absence of proper regulation by other components of the immune system, secrete a host of cytokines that promote autoimmune as well as allergic inflammation. The emergence of these T-cell clones occurs in patients with hypomorphic mutations in recombination activating gene 1 or 2, but not in patients with deleterious mutations in these enzymes which render them inactive. Recently, OS was also identified in a growing list of other leaky SCIDs with mutations in RNA component of mitochondrial RNA processing endoribonuclease, adenosine deaminase, IL-2 receptor gamma, IL-7 receptor alpha, ARTEMIS, and DNA ligase 4. This new information revealed OS is a distinct inflammatory process that can be associated with genetically diverse leaky SCIDS.

Omenn's syndrome: lessons from a red baby

Exfoliative dermatitis and erythroderma in infancy are rare. Clinicians need to be alert to the possible diagnosis of Omenn's syndrome (OS), a rare form of combined immunodeficiency in infants presenting with exfoliative dermatitis, erythroderma, recurrent infections, eosinophilia and raised IgE. OS is fatal unless treated by bone-marrow transplantation (BMT). We describe a 3-week-old girl who presented with a widespread scaly erythematous rash and stomatitis, and was initially treated for presumed atopic eczema and primary herpes stomatitis. Aged 3 months, she developed erythroderma, diarrhoea and hepatosplenomegaly associated with eosinophilia, raised serum IgE and low IgG, IgA and IgM levels, abnormal lymphocyte populations and skin histology, consistent with a diagnosis of OS. She remains well 16 months after a human leucocyte antigen-matched bone-marrow transplant from an unrelated donor.

Primary Immunodeficiencies

Primary immunodeficiencies (PIDs), once considered to be very rare, are now increasingly recognized because of growing knowledge in the immunological field and the availability of more sophisticated diagnostic techniques and therapeutic modalities [161]. However in a database of >120,000 inpatients of a general hospital for conditions suggestive of ID 59 patients were tested, and an undiagnosed PID was found in 17 (29%) of the subjects tested [107]. The publication of the first case of agammaglobulinemia by Bruton in 1952 [60] demonstrated that the PID diagnosis is first done in the laboratory. However, PIDs require specialized immunological centers for diagnosis and management [33]. A large body of epidemiological evidence supports the hypothesis of the existence of a close etiopathogenetic relation between PID and atopy [73]. In particular, an elevated frequency of asthma, food allergy (FA), atopic dermatitis and enteric pathologies can be found in various PIDs. In addition we will discuss another subject that is certainly of interest: the pseudo-immunodepressed child with recurrent respiratory infections (RRIs), an event that often requires medical intervention and that very often leads to the suspicion that it involves antibody deficiencies [149].

LEKTI demonstrable by immunohistochemistry of the skin: a potential diagnostic skin test for Netherton syndrome

BACKGROUND

Netherton syndrome (NS) is a rare autosomal recessive condition characterized by ichthyosiform erythroderma, trichorrhexis invaginata and atopic manifestations. Confirming the diagnosis may be difficult in the early stages. Mutations in the SPINK5 gene which encodes for the serine protease inhibitor LEKTI are associated with NS. These mutations create premature termination codons which result in absent or abnormal expression of LEKTI in patients with NS.

OBJECTIVES

To investigate the expression of LEKTI in the skin of patients with NS in comparison with normal controls and patients with other skin conditions, namely atopic dermatitis, psoriasis and nonbullous ichthyosiform erythroderma.

METHODS

Immunohistochemistry was performed on skin sections from four patients with NS, four normal controls, four with atopic dermatitis, two with psoriasis and two with nonbullous ichthyosiform erythroderma, using a primary rabbit polyclonal antibody against LEKTI.

RESULTS

LEKTI was localized to the stratum granulosum in normal skin. All four skin sections from patients with NS showed absent or very reduced staining for LEKTI. Staining in the other disorders showed positive LEKTI expression in varying patterns.

CONCLUSIONS

NS can be difficult to diagnose especially in the early stage, which can lead to inappropriate treatments particularly if it is misdiagnosed as atopic dermatitis. Immunohistochemistry of skin with an antibody against LEKTI is a potentially useful diagnostic test for NS.