Anne K. Junker

Mutations in STAT3 and diagnostic guidelines for hyper-IgE syndrome

BACKGROUND The hyper-IgE syndrome (HIES) is a primary immunodeficiency characterized by infections of the lung and skin, elevated serum IgE, and involvement of the soft and bony tissues. Recently, HIES has been associated with heterozygous dominant-negative mutations in the signal transducer and activator of transcription 3 (STAT3) and severe reductions of T(H)17 cells. OBJECTIVE To determine whether there is a correlation between the genotype and the phenotype of patients with HIES and to establish diagnostic criteria to distinguish between STAT3 mutated and STAT3 wild-type patients. METHODS We collected clinical data, determined T(H)17 cell numbers, and sequenced STAT3 in 100 patients with a strong clinical suspicion of HIES and serum IgE >1000 IU/mL. We explored diagnostic criteria by using a machine-learning approach to identify which features best predict a STAT3 mutation. RESULTS In 64 patients, we identified 31 different STAT3 mutations, 18 of which were novel. These included mutations at splice sites and outside the previously implicated DNA-binding and Src homology 2 domains. A combination of 5 clinical features predicted STAT3 mutations with 85% accuracy. T(H)17 cells were profoundly reduced in patients harboring STAT3 mutations, whereas 10 of 13 patients without mutations had low (<1%) T(H)17 cells but were distinct by markedly reduced IFN-gamma-producing CD4(+)T cells. CONCLUSION We propose the following diagnostic guidelines for STAT3-deficient HIES. Possible: IgE >1000IU/mL plus a weighted score of clinical features >30 based on recurrent pneumonia, newborn rash, pathologic bone fractures, characteristic face, and high palate. Probable: These characteristics plus lack of T(H)17 cells or a family history for definitive HIES. Definitive: These characteristics plus a dominant-negative heterozygous mutation in STAT3.

Clinical and molecular profile of a new series of patients with immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome: Inconsistent correlation between forkhead box protein 3 expression and disease severity

BACKGROUND Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is an autoimmune genetic disorder caused by mutation of the forkhead box protein 3 gene (FOXP3), a key regulator of immune tolerance. OBJECTIVE We sought to provide clinical and molecular indicators that facilitate the understanding and diagnosis of IPEX syndrome. METHODS In 14 unrelated affected male subjects who were given diagnoses of IPEX syndrome based on FOXP3 gene sequencing, we determined whether particular FOXP3 mutations affected FOXP3 protein expression and correlated the molecular and clinical data. RESULTS Molecular analysis of FOXP3 in the 14 subjects revealed 13 missense and splice-site mutations, including 7 novel mutations. Enteropathy, generally associated with endocrinopathy and eczema, was reported in all patients, particularly in those carrying mutations within FOXP3 functional domains or mutations that altered protein expression. However, similar genotypes did not always result in similar phenotypes in terms of disease presentation and severity. In addition, FOXP3 protein expression did not correlate with disease severity. CONCLUSION Severe autoimmune enteropathy, which is often associated with increased IgE levels and eosinophilia, is the most prominent early manifestation of IPEX syndrome. Nevertheless, the disease course is variable and somewhat unpredictable. Therefore genetic analysis of FOXP3 should always be performed to ensure an accurate diagnosis, and FOXP3 protein expression analysis should not be the only diagnostic tool for IPEX syndrome.

Ataxia-telangiectasia: Identification and detection of founder-effect mutations in the ATM gene in ethnic populations

To facilitate the evaluation of ATM heterozygotes for susceptibility to other diseases, such as breast cancer, we have attempted to define the most common mutations and their frequencies in ataxia-telangiectasia (A-T) homozygotes from 10 ethnic populations. Both genomic mutations and their effects on cDNA were characterized. Protein-truncation testing of the entire ATM cDNA detected 92 (66%) truncating mutations in 140 mutant alleles screened. The haplotyping of patients with identical mutations indicates that almost all of these represent common ancestry and that very few spontaneously recurring ATM mutations exist. Assays requiring minimal amounts of genomic DNA were designed to allow rapid screening for common ethnic mutations. These rapid assays detected mutations in 76% of Costa Rican patients (3), 50% of Norwegian patients (1), 25% of Polish patients (4), and 14% of Italian patients (1), as well as in patients of Amish/Mennonite and Irish English backgrounds. Additional mutations were observed in Japanese, Utah Mormon, and African American patients. These assays should facilitate screening for A-T heterozygotes in the populations studied.

Recurrent varicella-zoster virus infections in apparently immunocompetent children.

Fourteen generally healthy children (5 females, 9 males, ages 18 months to 13 years) who have developed 2 to 5 attacks of chickenpox are described. Herpes zoster also occurred in 2 of 14 children. No case of chickenpox was severe or associated with complications. General studies of immunoglobulins, specific antibodies to immunization agents, complement and lymphocyte subpopulation number and function indicated that 1 of 14 had low serum IgA and 3 of 14 lacked antibody to 1 (n = 2) or 2 (n = 1) immunization agents. Varicella-zoster virus (VZV)-specific immune studies showed that the children developed VZV-antibody titers by enzyme-linked immunosorbent assay of 1:640 to 1:10 240. By immunoblot assay all appeared to develop a normal spectrum of antibodies to individual VZV proteins. All but one developed VZV cellular immune responses with stimulation indices ranging from 3.6 to 174. Sequential follow-up of 8 patients revealed 1 who became seronegative and 2 who lost VZV cell-mediated immune responses. Chickenpox may recur more frequently than is generally recognized. General and VZV-specific immune investigations are unlikely to indicate a reason.

Epstein-Barr Virus Shedding in Breast Milk

One hundred healthy women already donating to the Childrens Hospital Breast Milk bank consented to provide a sample of breast milk for this study. Using a DNA-DNA hybridization dot-blot assay Epstein-Barr virus (EBV) genome (Bam HIW region) was detected in cells shed into breast milk of 46 out of 100 women studied and in 60 out of 132 (46%) of samples donated overall. The prevalence of EBV shedding increased postnatally to a peak of 74% (26/35 positive samples) between 3 and 12 weeks postdelivery. Women delivering prematurely had an initially lower prevalence of shedding with only six out of 30 (20%) positive samples in the first week after delivery, compared to 16 out of 35 (46%) for women delivering at term. Of the 18 women donating more than one sample, 13 showed consistently positive (n = 8) or negative (n = 5) results, and the remaining five had intermittent shedding detected. Only seven out of 42 (17%) breast milk samples studied were EBV-IgG antibody positive, and none showed IgM or IgA-EBV antibodies. Further studies and prospective followup of infants are needed to confirm that breast milk is a significant source for early EBV infection of infants, as indicated by serologic studies.

Identification of WASP mutations, mutation hotspots and genotype-phenotype disparities in 24 patients with the Wiskott-Aldrich syndrome

Abstract The Wiskott-Aldrich syndrome (WAS), an X-linked immunodeficiency disease caused by mutation in the recently isolated gene encoding WAS protein (WASP), is known to be associated with extensive clinical heterogeneity. Cumulative mutation data have revealed that WASP genotypes are also highly variable among WAS patients, but the relationship of phenotype with genotype in this disease remains unclear. To address this issue we characterized WASP mutations in 24 unrelated WAS patients, including 18 boys with severe classical WAS and 6 boys expressing mild forms of the disease, and then examined the degree of correlation of these as well as all previously published WASP mutations with disease severity. By analysis of these compiled mutation data, we demonstrated clustering of WASP mutations within the four most N-terminal exons of the gene and also identified several sites within this region as hotspots for WASP mutation. These characteristics were observed, however, in both severe and mild cases of the disease. Similarly, while the cumulative data revealed a predominance of missense mutations among the WASP gene lesions observed in boys with isolated thrombocytopenia, missense mutations were not exclusively associated with milder WAS phenotypes, but also comprised a substantial portion (38%) of the WASP gene defects found in patients with severe disease. These findings, as well as the detection of identical WASP mutations in patients with disparate phenotypes, reveal a lack of phenotype concordance with genotype in WAS and thus imply that phenotypic outcome in this disease cannot be reliably predicted solely on the basis of WASP genotypes.

Abnormal antibody responses in patients with persistent generalized lymphadenopathy

Persistent, generalized lymphadenopathy (PGL) is a recognized component of human immunodeficiency virus (HIV) infection. We conducted longitudinal studies of B and T cell function in seven homosexual men with HIV infection and PGL. All seven had abnormal antibody-mediated immunity as studied by sequential assessment ofin vivo antibody responses after immunization with the T-dependent neoantigens bacteriophage γX 174 and key-hole limpet hemocyanin (KLH), the T-independent tetradecavalent pneumococcal polysaccharide vaccine, and the recall antigens diphtheria and tetanus toxoid. Compared to HIV-negative heterosexual controls, PGL patients responded with lower antibody titers and, following immunization with phage, failed to develop immunologic memory and to switch from IgM- to IgG-isotype antibody.In vitro antigen-induced antibody production was markedly diminished; and some patients showed depressed mitogen responses. There was a correlation between the degree of compromised immunity and the clinical condition; those with the most severe symptoms showed the most extensive immune deficiency. Yet despite obvious immunologic impairment, five of the seven men have remained clinically stable over a 3-year follow-up period.

Wild-type FOXP3 is selectively active in CD4+CD25hi regulatory T cells of healthy female carriers of different FOXP3 mutations

Forkhead box P3 (FOXP3) is constitutively expressed by CD4(+)CD25(hi) regulatory T cells (nTregs). Mutations of FOXP3 cause a severe autoimmune syndrome known as immune dysregulation polyendocrinopathy enteropathy X-linked, in which nTregs are absent or dysfunctional. Whether FOXP3 is essential for both differentiation and function of human nTreg cells remains to be demonstrated. Because FOXP3 is an X-linked gene subject to X-chromosome inactivation (XCI), we studied 9 healthy female carriers of FOXP3 mutations to investigate the role of wild-type (WT) versus mutated FOXP3 in different cell subsets. Analysis of active WT versus mutated (mut)-FOXP3 allele distribution revealed a random pattern of XCI in peripheral blood lymphocytes and in naive and memory CD4(+)T cells, whereas nTregs expressed only the active WT-FOXP3. These data demonstrate that expression of WT-FOXP3 is indispensable for the presence of a normal nTreg compartment and suggest that FOXP3 is not necessary for effector T-cell differentiation in humans.

Pigmented hypertrichotic dermatosis and insulin dependent diabetes : Manifestations of a unique genetic disorder?

Abstract:  A novel pigmented dermatosis was observed in four unrelated boys, three of whom had insulin‐dependent diabetes. Three patients were the offspring of consanguineous parents. All four boys had pigmented hypertrichotic patches or induration on the upper inner thighs, with variable involvement of the genitalia, trunk, and limbs. Two boys had episcleritis and orbital proptosis with similar facies and musculoskeletal abnormalities including clinodactyly, flat feet, and short stature. One child had paraaortic and inguinal lymphadenopathy and three patients had an enlarged liver and spleen. A large, swollen pancreas was observed on ultrasound imaging in one patient with insulin dependent diabetes who also had echocardiographic evidence of pericardial inflammation. Three boys had elevated laboratory markers of inflammation. Biopsy specimens from the skin and orbit showed a chronic inflammatory cell infiltrate composed of polyclonal lymphocytes, histiocytes, and plasma cells; fibrosis was observed in two patients, one of whom had previously received radiation therapy to the orbit. Two boys responded to treatment with subcutaneous interferon‐α, combined with a short course of oral prednisone in the child without diabetes. We believe these inflammatory pigmented skin lesions represent a unique dermatosis associated with diabetes mellitus and systemic disease. The pathogenesis is unknown. The presence of consanguinity in three of four families, and similar dysmorphic features in two boys, suggest a genetic disorder, possibly with autosomal recessive inheritance.

Transient immune deficiency in patients with acute Epstein-Barr virus infection

To study the effect of primary Epstein-Barr virus (EBV) infection on antigen-specific antibody production, we immunized 17 college students who had developed acute infectious mononucleosis with the T-cell dependent neoantigen bacteriophage phi X174. During the early phase of infectious mononucleosis, the proportion of peripheral blood lymphocytes displaying Ia and T8 (CD8) phenotypes was increased and the T helper/suppressor (T4/T8) ratio was decreased (less than 1). These abnormalities disappeared during the convalescent phase. Correlating with EBV-induced changes in T lymphocytes, we demonstrated depressed humoral immune responses to bacteriophage phi X174 both in vivo and in vitro. In vitro coculture experiments indicated that the Ia+ suppressor T cells could inhibit antibody production and isotype switch. Removal of T8+ lymphocytes from patient T cells normalized in vitro antibody synthesis. In addition, impaired B-cell function was shown to be in part responsible for deficient antibody production. These studies demonstrate that infection with EBV affects both B and T lymphocytes and causes a broad-based transient immune deficiency in patients with uncomplicated infectious mononucleosis.