Pneumocystis jirovecii pneumonia in a baby with hyper-IgE syndrome

Trends in the Epidemiology of Pneumocystis Pneumonia in Immunocompromised Patients without HIV Infection

The increasing morbidity and mortality of life-threatening Pneumocystis pneumonia (PCP) in immunocompromised people poses a global concern, prompting the World Health Organization to list it as one of the 19 priority invasive fungal diseases, calling for increased research and public health action. In response to this initiative, we provide this review on the epidemiology of PCP in non-HIV patients with various immunodeficient conditions, including the use of immunosuppressive agents, cancer therapies, solid organ and stem cell transplantation, autoimmune and inflammatory diseases, inherited or primary immunodeficiencies, and COVID-19. Special attention is given to the molecular epidemiology of PCP outbreaks in solid organ transplant recipients; the risk of PCP associated with the increasing use of immunodepleting monoclonal antibodies and a wide range of genetic defects causing primary immunodeficiency; the trend of concurrent infection of PCP in COVID-19; the prevalence of colonization; and the rising evidence supporting de novo infection rather than reactivation of latent infection in the pathogenesis of PCP. Additionally, we provide a concise discussion of the varying effects of different immunodeficient conditions on distinct components of the immune system. The objective of this review is to increase awareness and knowledge of PCP in non-HIV patients, thereby improving the early identification and treatment of patients susceptible to PCP.

Murine models of Pneumocystis infection recapitulate human primary immune disorders

Despite the discovery of key pattern recognition receptors and CD4+ T cell subsets in laboratory mice, there is ongoing discussion of the value of murine models to reflect human disease. Pneumocystis is an AIDS-defining illness, in which risk of infection is inversely correlated with peripheral CD4+ T cell counts. Due to medical advances in the control of HIV, the current epidemiology of Pneumocystis infection is predominantly due to primary human immunodeficiencies and immunosuppressive therapies. To this end, we found that every human genetic immunodeficiency associated with Pneumocystis infection that has been tested in mice recapitulated susceptibility. For example, humans with a loss-of-function IL21R mutation are severely immunocompromised. We found that IL-21R, in addition to CD4+ T cell intrinsic STAT3 signaling, were required for generating protective antifungal class-switched antibody responses, as well as effector T cell-mediated protection. Furthermore, CD4+ T cell intrinsic IL-21R/STAT3 signaling was required for CD4+ T cell effector responses, including IL-22 production. Recombinant IL-22 administration to Il21r-/- mice induced the expression of a fungicidal peptide, cathelicidin antimicrobial peptide, which showed in vitro fungicidal activity. In conclusion, SPF laboratory mice faithfully replicate many aspects of human primary immunodeficiency and provide useful tools to understand the generation and nature of effector CD4+ T cell immunity.

Clinical Manifestations and Genetic Analysis of 17 Patients with Autosomal Dominant Hyper-IgE Syndrome in Mainland China: New Reports and a Literature Review

PURPOSE

Autosomal dominant hyper-IgE syndrome (AD-HIES) is a rare complicated primary immunodeficiency disease (PID). Signal transducer and activator of transcription 3 (STAT3) gene mutation is found to cause AD-HIES. The distribution of AD-HIES patients with STAT3 deficiency in the Chinese population is not clear. Herein, we retrospectively report 17 AD-HIES patients with STAT3 deficiency and demonstrate their clinical, immunological, and genetic features.

METHODS

Patients' clinical data were collected from their medical records. Routine laboratory testing results included lymphocyte subset analysis and immunoglobulin quantification. STAT3 mutations were investigated by sequencing of genomic DNA.

RESULTS

Among 575 patients with PID, 28 (4.87%) were clinically diagnosed as HIES. Among them, 17 (2.96%) were confirmed as STAT3 mutant AD-HIES. The ratio of male to female patients was 8:9. All of the 17 patients had NIH scores over 40 points. The mean ages at onset and diagnosis were 1.05 and 10.35 years, respectively. Three patients (17.65%, 3/17) died with a mean age of 13.33 years. Eczema, recurrent skin infection, and respiratory tract infection were the most common clinical symptoms and are present in all of the 17 patients in this study. Six patients (37.5%, 6/16) suffered complication from BCG vaccination. Noninfection symptoms are characteristic facial features in 17 patients (100%, 17/17), retention of primary teeth in 10 patients (90.91%, 10/11), and abnormal bone fractures in 7 patients (41.18%, 7/17). Eleven types of STAT3 mutations were identified in 17 patients, including 1 novel mutation.

CONCLUSIONS

We here retrospectively report the largest Chinese cohort of AD-HIES patients with STAT3 mutation. Unique features, when compared to existing literature reports, include (1) later age of diagnosis, (2) significantly higher rate of BCG complications, and (3) lower rate of candidiasis and chronic otitis media.

Hyper-IgE Syndrome in an Infant

BACKGROUND

Hyper-immunoglobulin E syndrome (HIES) is a rare primary immunodeficiency disorder that affects multiple systems. One of the early findings is a papulopustular rash, which has a wide differential diagnosis.

METHOD

The authors report the case of a male newborn diagnosed with HIES. He presented with papulopustular dermatitis on the scalp. The authors also present a review of current theory on the pathophysiology, clinical presentation, and management of HIES.

CONCLUSION

Although HIES is a multisystem disorder, many of the manifestations of HIES may present after the neonatal period. The cutaneous manifestations of HIES are usually present shortly after birth, and the presentation of pustules in a newborn may be one of the reasons a dermatologist would be asked to assess a patient in the neonatal period.

Variable clinical expressivity of STAT3 mutation in hyperimmunoglobulin E syndrome: genetic and clinical studies of six patients

BACKGROUND AND PURPOSE

Autosomal dominant Hyper IgE syndrome (AD-HIES) is a rare and complex primary immunodeficiency that affects multiple systems. Mutations in signal transducer and activator of transcription 3 (STAT3) gene cause AD-HIES. These mutations have a dominant-negative effect and the presence of such mutations is associated with a clinical phenotype. We aim to describe genetic and clinical characteristics of patients with AD-HIES in our clinic and to highlight the variability of clinical patterns in the same family.

METHODS

We describe six patients, four individuals of the same family and two unrelated patients. All patients were given a clinical score based on disease phenotype according to the National Institute of Health (NIH) score. Mutation analysis of STAT3 was done by PCR amplification of all coding exons followed by bidirectional sequencing using the BigDye kit v1.1 and an ABI3700 genetic analyzer (Applied Biosystems).

RESULTS

All six patients had DNA binding region point mutations: a proband and his three children with p.Phe384Leu mutation, a patient with p.Arg382Trp substitution and a patient with p.Arg382Gln mutation. All of these mutations were previously reported. Patients differed in infectious, immunologic and somatic features. We observed an extreme variability in disease phenotype within the reported family with one genetically affected patient displaying an 'unaffected' phenotype.

CONCLUSIONS

Although the genetic cause of AD-HIES is known, more studies are required to better understand the possible additional factors that may affect disease expressivity within families and the clinical diversity of the disease.

An update on the hyper-IgE syndromes

The hyper-IgE syndromes (HIES; originally named Job's syndrome) are a collection of primary immunodeficiency syndromes resulting in elevated serum IgE levels and typified by recurrent staphylococcal skin abscesses, eczema and pulmonary infections. The disorder has autosomal dominant and recessive forms. Autosomal dominant HIES has been shown to be mainly due to STAT3 mutations and additionally results in connective tissue, skeletal, vascular and dental abnormalities. Autosomal recessive HIES has been shown to be mainly due to mutations in DOCK8; these patients are more prone to viral skin infections instead. This review article discusses the common clinical features of the syndrome, the genetic mutations responsible and the pathogenesis of the disease, as well as treatments currently used.

Host defenses against bacterial lower respiratory tract infection

Bacterial pneumonia continues to be a significant cause of morbidity and mortality worldwide. Recent studies have shown that lung epithelia signal through pattern recognition receptors to initiate the innate immune response. Other mediators of innate immunity against bacterial pneumonia include transepithelial dendritic cells, alveolar macrophages, and innate produces of IL-17. CD4+ T cells and B cells play a key role in eliminating and preventing the development of bacterial pneumonias. B cell development and maturation can be modulated by the lung epithelia through BAFF and APRIL, furthering our current understanding of the role of epithelial cells in the immune response.

Hyper-IgE syndrome update

Autosomal dominant hyper-IgE syndrome (AD-HIES) or Job's syndrome is a primary immunodeficiency with a wide array of clinical features caused by dominant negative mutations in STAT3. In recent years, not only the clinical phenotype of the disease has been expanded with recognition of features such as arterial aneurysms, but also our understanding of the pathogenesis of the disease has greatly improved.

Reduced expression of chemoattractant receptors by polymorphonuclear leukocytes in Hyper IgE Syndrome patients

Hyper IgE Syndrome (HIES) is a rare genetic disorder, characterized by elevated serum IgE levels and reduced inflammatory responses to bacterial infections. This leads to dermatitis, recurrent lung infections and "cold abscesses". Recently, progress was made in HIES research, when mutations in STAT3 were found in the autosomal dominant form of HIES, and impaired responses of T helper 17 cells were reported. However, the causes for reduced inflammatory responses in these patients were not fully elucidated. In view of studies that indicated that polymorphonuclear leukocytes (PMN) of HIES patients are defective in their chemotactic properties, we asked if the PMN of these patients have reduced expression of receptors for chemoattractants. To analyze this possibility, we focused on fMLP and ELR(+)-CXC chemokines - which are essential for mounting acute inflammatory responses - and determined the coding sequences and expression levels of their corresponding receptors: FPR (for fMLP) as well as CXCR1 and CXCR2 (the receptors for ELR(+)-CXC chemokines). The analyses of these receptors in HIES patients indicated that their coding sequences were intact and normal. However, the percentages of PMN that expressed FPR, CXCR1 and CXCR2 were significantly lower in HIES patients. In addition, lower expression levels per cell were denoted for CXCR1 in PMN of the patients. A cumulative score that was calculated for the three chemoattractant receptors together indicated that in some of the patients there were prominent reductions, of up to approximately 50% in the overall expression of the receptors (indicated by % positive cells and mean expression levels per cell). In addition, we asked whether deregulation of PMN activities in HIES may result from binding of IgE to corresponding receptors on HIES PMN. Our findings indicate that this is probably not the case, because similarly to normal PMN, the cells of HIES patients did not express notable levels of the IgE receptors FcvarepsilonRI and FcvarepsilonRII. Together, these results provide novel information on the expression of key determinants in PMN migration in HIES, suggesting that a defect in the expression of chemoattractant receptors may lead to impaired chemotaxis found in HIES patients, and to decreased inflammatory responses.