Lynda C. Schneider

TACI is mutant in common variable immunodeficiency and IgA deficiency

The tumor necrosis factor receptor family member TACI (transmembrane activator and calcium-modulator and cyclophilin ligand interactor) mediates isotype switching in B cells. We found that 4 of 19 unrelated individuals with common variable immunodeficiency (CVID) and 1 of 16 individuals with IgA deficiency (IgAD) had a missense mutation in one allele of TNFRSF13B (encoding TACI). One of the four individuals with CVID had a single nucleotide insertion in the other TNFRSF13B allele. None of these mutations were present in 50 healthy subjects. TNFRSF13B mutations cosegregated with the phenotype of CVID or IgAD in family members of four index individuals that we studied. B cells from individuals with TACI mutations expressed TACI but did not produce IgG and IgA in response to the TACI ligand APRIL, probably reflecting impaired isotype switching. These results suggest that TACI mutations can result in CVID and IgAD.

Tight junction defects in patients with atopic dermatitis.

BACKGROUND Atopic dermatitis (AD) is characterized by dry skin and a hyperactive immune response to allergens, 2 cardinal features that are caused in part by epidermal barrier defects. Tight junctions (TJs) reside immediately below the stratum corneum and regulate the selective permeability of the paracellular pathway. OBJECTIVE We evaluated the expression/function of the TJ protein claudin-1 in epithelium from AD and nonatopic subjects and screened 2 American populations for single nucleotide polymorphisms in the claudin-1 gene (CLDN1). METHODS Expression profiles of nonlesional epithelium from patients with extrinsic AD, nonatopic subjects, and patients with psoriasis were generated using Illuminas BeadChips. Dysregulated intercellular proteins were validated by means of tissue staining and quantitative PCR. Bioelectric properties of epithelium were measured in Ussing chambers. Functional relevance of claudin-1 was assessed by using a knockdown approach in primary human keratinocytes. Twenty-seven haplotype-tagging SNPs in CLDN1 were screened in 2 independent populations with AD. RESULTS We observed strikingly reduced expression of the TJ proteins claudin-1 and claudin-23 only in patients with AD, which were validated at the mRNA and protein levels. Claudin-1 expression inversely correlated with T(H)2 biomarkers. We observed a remarkable impairment of the bioelectric barrier function in AD epidermis. In vitro we confirmed that silencing claudin-1 expression in human keratinocytes diminishes TJ function while enhancing keratinocyte proliferation. Finally, CLDN1 haplotype-tagging SNPs revealed associations with AD in 2 North American populations. CONCLUSION Collectively, these data suggest that an impairment in tight junctions contributes to the barrier dysfunction and immune dysregulation observed in AD subjects and that this may be mediated in part by reductions in claudin-1.

Rapid oral desensitization in combination with omalizumab therapy in patients with cow’s milk allergy

To the Editor: We conducted a pilot phase I study in 11 children (age, 7-17 years) with cow’s milk allergy by using omalizumab (anti-IgE mAb; Xolair; Genentech, South San Francisco, Calif) in combination with relatively rapid oral milk desensitization. We hypothesized that oral desensitization might occur rapidly and with few side effects when performed with omalizumab. Our primary objectives were to examine the safety of this approach and to determine whether subjects could be dosed up to 2000 mg milk within 7 to 11 weeks of initiating the desensitization. Eleven patients with a history of IgE-mediated milk allergy were enrolled in the study at 2 sites—Children’s Hospital Boston and Stanford University—under institutional review board and US Food and Drug Administration approval. All subjects had histories of acute clinical reactions to milk, including immediate reactions (urticaria, vomiting, and/or anaphylaxis) after ingestion of milk, as well as elevated milk-specific IgE (median, 50 kilounits of antibody (kUA)/L; range, 41.6-342 kUA/L; Table I). At entry, the median wheal/flare skin prick test to milk was 20/50 mm (wheal/erythema diameter; range, 11-45/20-52 mm), and the median total serum IgE was 349 kU/L (range, 148-2593 kU/L). The median age was 8 years (range, 7-17 years). Seven subjects had a diagnosis of asthma and/or eczema. For children with IgE levels 700 kU/L, the dose was 225 to 300 mg (approximately 0.016 mg/kg/IgE [U/ mL]) every 2 to 4 weeks. During the course of the study, subjects were asked to exclude all dairy products from their diets except what was given as the study milk dose. TABLE I Characteristics of enrolled subjects Nine weeks after the start of omalizumab treatment, oral cow’s milk desensitization was performed in 2 phases. Rush oral desensitization occurred on the first day of desensitization, starting with 0.1 mg of milk powder (dried nonfat powdered cow’s milk, Carnation Instant Milk; Nestle, San Francisco, Calif), with doses every 30 minutes to a maximum dose of 1000 mg (cumulative dose, 1992 mg). One subject (subject 7; Table I) voluntarily discontinued the study because of abdominal migraines; eosinophilic esophagitis and other allergic disorders were ruled out. Nine of the 10 remaining subjects reached the 1000-mg dose on the first day of desensitization. However, 1 subject, subject 5 (Table I), after administration of the 1000-mg dose, received epinephrine for nasal obstruction and generalized urticaria refractory to diphenhydramine and cetirizine. Subject 8 reacted at the 7-mg dose on the first day. Desensitization with daily doses of milk continued in the 10 subjects, with weekly increases in the dose of milk over the next 7 to 11 weeks (all dose increases were given in the clinical research unit, and if the dose was tolerated, the dose was then given daily at home). During the study, subjects were asked to take the study milk dose on a full stomach and to half the study milk dose during a viral infection. Nine of the 10 patients reached the maximum daily dose of 2000 mg milk (the primary end point of the study); the subject who received epinephrine during the rush phase of desensitization achieved a daily dose of 1200 mg when the omalizumab was stopped (end of the weekly dose escalation phase, week 16). Omalizumab treatment was then discontinued at week 16, whereas daily oral milk was continued at home. A double-blind, placebo-controlled food challenge (DBPCFC) was performed 8 weeks later (week 24 of the study). The DBPCFC consisted of 5 doses (milk or placebo, eg, rice or soy beverage) administered orally every 15 minutes: 500 mg, 750 mg, 1000 mg, 2000 mg, and 3000 mg (cumulative dose, 7250 mg, equivalent to 220 mL milk). Allergic reactions occurring during the protocol were scored by using the system developed by Bock et al.1 All 9 patients who had reached a daily dose of 2000 mg passed the DBPCFC and an open challenge (for subjects taking their oral food challenge on the same day of the DBPCFC [n = 4], 4000 mg was given as the open challenge; for subjects taking their open challenge on the day after the DBPCFC [n = 5], 8000 mg was given). All 9 patients continued with daily milk ingestion >8000 mg/d, which included different types of milk products. In terms of overall safety, the mean frequency for total reactions reported by week 24 was 1.6% (32 reactions of 2199 doses total for all 11 subjects; Table II). All patients experienced some adverse events, though most reactions were defined as mild1 (1%) and needed no treatment. There were moderate reactions (0.3%), and these included abdominal pain and vomiting, which responded within 1 hour to oral antihistamine dosing. Severe reactions (0.1%) included swelling of the tongue in 1 subject during the initial rush desensitization day, which responded to oral antihistamines. Another subject developed rhinitis and urticaria after the 1000-mg dose during the rush desensitization and responded to epinephrine. The most common types of reactions were local (mostly pruritus or urticaria) and/ or gastrointestinal (eg, abdominal pain), occurring with a frequency of 1%. No reactions occurred that involved the cardiovascular system or that failed to respond rapidly to treatment. There were 2 other subjects who were given epinephrine at home by their guardians during the maintenance phase of dosing. One received epinephrine for a moderate reaction that was manifested by upper lip swelling and urticaria (7.5 cm × 5cm) on the left upper leg; the second received epinephrine for urticaria (2.5 cm × 5 cm) on the right upper arm. In addition, this subject had wheezing, which began before the milk ingestion that day, and which most likely was a result of a viral infection. Overall, the reaction rate in our study was relatively low given the rapidity of the desensitization, although the rate of epinephrine use was similar to that in previous desensitization studies. All subjects tolerated omalizumab treatment with no signs of allergic reactions. TABLE II Overall safety data Previous studies of slow, deliberate oral milk desensitization in patients with cow’s milk allergy showed that desensitization can increase the amount of milk tolerated by many of the treated subjects.2-6 We now show that milk desensitization can be performed relatively rapidly with minimal hospitalization time when combined with omalizumab treatment. The limitations of our study include the small sample size, the lack of a placebo group, and lack of a baseline oral food challenge. In addition, it is possible that our desensitization protocol with omalizumab might be further optimized by limiting the number of milk doses during the rush phase; by extending the dose escalation phase over a longer period, beyond the 7 to 11 weeks used in our current protocol; and by performing the DBPCFC 12 or more weeks after discontinuation of omalizumab. In summary, we demonstrated that omalizumab treatment combined with oral milk desensitization in children with clinical reactions to cow’s milk permitted rapid milk dose escalation in the majority of subjects. This study is the first to use omalizumab in combination with oral desensitization and demonstrates a potential value of this approach for the treatment of food allergy, a major public health problem,7-9 although it must be first confirmed by future phase II and III trials. Nine of the 11 patients achieved the primary objective, tolerating desensitization to a dose of 2000 mg/d within a period of 7 to 11 weeks. Moreover, 9 of the 10 patients who completed the study passed a DBPCFC and an open challenge of milk without symptoms. Importantly, the 9 patients, after passing the DBPCFC, began tolerating almost normal amounts of milk in their diet (≥240 mL, equivalent to ≥8000 mg/d). The tenth patient is tolerating 4000 mg/d.

Deficient natural killer cell cytotoxicity in patients with IKK-γ/NEMO mutations

NF-κB essential modifier (NEMO), also known as IKK-γ, is a member of the I-κB kinase complex responsible for phosphorylating I-κB, allowing the release and activation of NF-κB. Boys with an expressed NEMO mutation have an X-linked syndrome characterized by hypohidrotic ectodermal dysplasia with immune deficiency (HED-ID). The immunophenotype resulting from NEMO mutation is highly variable, with deficits in both T and B cell responses. We evaluated three patients with NEMO mutations (L153R, Q403X, and C417R) and HED-ID who had evidence of defective CD40 signaling. All three patients had normal percentages of peripheral blood NK cells, but impaired NK cell cytotoxic activity. This was not due to a generalized defect in cytotoxicity because antibody-dependent cellular cytotoxicity was intact. This abnormality was partially reversed by in vitro addition of IL-2, which was also able to induce NF-κB activation. In one patient with recurrent cytomegalovirus infections, administration of IL-2 partially corrected the NK cell killing deficit. These data suggest that NEMO participates in signaling pathways leading to NK cell cytotoxicity and that IL-2 can activate NF-κB and partially overcome the NK cell defect in patients with NEMO mutations.

A pilot study of omalizumab to facilitate rapid oral desensitization in high-risk peanut-allergic patients

BACKGROUND Peanut allergy is a major public health problem that affects 1% of the population and has no effective therapy. OBJECTIVE To examine the safety and efficacy of oral desensitization in peanut-allergic children in combination with a brief course of anti-IgE mAb (omalizumab [Xolair]). METHODS We performed oral peanut desensitization in peanut-allergic children at high risk for developing significant peanut-induced allergic reactions. Omalizumab was administered before and during oral peanut desensitization. RESULTS We enrolled 13 children (median age, 10 years), with a median peanut-specific IgE level of 229 kU(A)/L and a median total serum IgE level of 621 kU/L, who failed an initial double-blind placebo-controlled food challenge at peanut flour doses of 100 mg or less. After pretreatment with omalizumab, all 13 subjects tolerated the initial 11 desensitization doses given on the first day, including the maximum dose of 500 mg peanut flour (cumulative dose, 992 mg, equivalent to >2 peanuts), requiring minimal or no rescue therapy. Twelve subjects then reached the maximum maintenance dose of 4000 mg peanut flour per day in a median time of 8 weeks, at which point omalizumab was discontinued. All 12 subjects continued on 4000 mg peanut flour per day and subsequently tolerated a challenge with 8000 mg peanut flour (equivalent to about 20 peanuts), or 160 to 400 times the dose tolerated before desensitization. During the study, 6 of the 13 subjects experienced mild or no allergic reactions, 5 subjects had grade 2 reactions, and 2 subjects had grade 3 reactions, all of which responded rapidly to treatment. CONCLUSIONS Among children with high-risk peanut allergy, treatment with omalizumab may facilitate rapid oral desensitization and qualitatively improve the desensitization process.

Filaggrin mutations that confer risk of atopic dermatitis confer greater risk for eczema herpeticum.

BACKGROUND Loss-of-function null mutations R501X and 2282del4 in the skin barrier gene, filaggrin (FLG), represent the most replicated genetic risk factors for atopic dermatitis (AD). Associations have not been reported in African ancestry populations. Atopic dermatitis eczema herpeticum (ADEH) is a rare but serious complication of AD resulting from disseminated cutaneous herpes simplex virus infections. OBJECTIVE We aimed to determine whether FLG polymorphisms contribute to ADEH susceptibility. METHODS Two common loss-of-function mutations plus 9 FLG single nucleotide polymorphisms were genotyped in 278 European American patients with AD, of whom 112 had ADEH, and 157 nonatopic controls. Replication was performed on 339 African American subjects. RESULTS Significant associations were observed for both the R501X and 2282del4 mutations and AD among European American subjects (P = 1.46 x 10(-5), 3.87 x 10(-5), respectively), but the frequency of the R501X mutation was 3 times higher (25% vs 9%) for ADEH than for AD without eczema herpeticum (EH) (odds ratio [OR], 3.4; 1.7-6.8; P = .0002). Associations with ADEH were stronger with the combined null mutations (OR, 10.1; 4.7-22.1; P = 1.99 x 10(-11)). Associations with the R501X mutation were replicated in the African American population; the null mutation was absent among healthy African American subjects, but present among patients with AD (3.2%; P = .035) and common among patients with ADEH (9.4%; P = .0049). However, the 2282del4 mutation was absent among African American patients with ADEH and rare (<1%) among healthy individuals. CONCLUSION The R501X mutation in the gene encoding filaggrin, one of the strongest genetic predictors of AD, confers an even greater risk for ADEH in both European and African ancestry populations, suggesting a role for defective skin barrier in this devastating condition.

DOCK8 functions as an adaptor that links TLR-MyD88 signaling to B cell activation

The adaptors DOCK8 and MyD88 have been linked to serological memory. Here we report that DOCK8-deficient patients had impaired antibody responses and considerably fewer CD27+ memory B cells. B cell proliferation and immunoglobulin production driven by Toll-like receptor 9 (TLR9) were considerably lower in DOCK8-deficient B cells, but those driven by the costimulatory molecule CD40 were not. In contrast, TLR9-driven expression of AICDA (which encodes the cytidine deaminase AID), the immunoglobulin receptor CD23 and the costimulatory molecule CD86 and activation of the transcription factor NF-κB, the kinase p38 and the GTPase Rac1 were intact. DOCK8 associated constitutively with MyD88 and the tyrosine kinase Pyk2 in normal B cells. After ligation of TLR9, DOCK8 became tyrosine-phosphorylated by Pyk2, bound the Src-family kinase Lyn and linked TLR9 to a Src–kinase Syk–transcription factor STAT3 cascade essential for TLR9-driven B cell proliferation and differentiation. Thus, DOCK8 functions as an adaptor in a TLR9-MyD88 signaling pathway in B cells.

Phenotype of Atopic Dermatitis Subjects with a History of Eczema Herpeticum

BACKGROUND A subset of subjects with atopic dermatitis (AD) are susceptible to serious infections with herpes simplex virus, called eczema herpeticum, or vaccina virus, called eczema vaccinatum. OBJECTIVE This National Institute of Allergy and Infectious Diseases-funded multicenter study was performed to establish a database of clinical information and biologic samples on subjects with AD with and without a history of eczema herpeticum (ADEH(+) and ADEH(-) subjects, respectively) and healthy control subjects. Careful phenotyping of AD subsets might suggest mechanisms responsible for disseminated viral infections and help identify at-risk individuals. METHODS We analyzed the data from 901 subjects (ADEH(+) subjects, n = 134; ADEH(-) subjects, n = 419; healthy control subjects, n = 348) enrolled between May 11, 2006, and September 16, 2008, at 7 US medical centers. RESULTS ADEH(+) subjects had more severe disease based on scoring systems (Eczema Area and Severity Index and Rajka-Langeland score), body surface area affected, and biomarkers (circulating eosinophil counts and serum IgE, thymus and activation-regulated chemokine, and cutaneous T cell-attracting chemokine) than ADEH(-) subjects (P < .001). ADEH(+) subjects were also more likely to have a history of food allergy (69% vs 40%, P < .001) or asthma (64% vs 44%, P < .001) and were more commonly sensitized to many common allergens (P < .001). Cutaneous infections with Staphylococcus aureus or molluscum contagiosum virus were more common in ADEH(+) subjects (78% and 8%, respectively) than in ADEH(-) subjects (29% and 2%, respectively; P < .001). CONCLUSION Subjects with AD in whom eczema herpeticum develops have more severe T(H)2-polarized disease with greater allergen sensitization and more commonly have a history of food allergy, asthma, or both. They are also much more likely to experience cutaneous infections with S. aureus or molluscum contagiosum.

Thymopentin therapy reduces the clinical severity of atopic dermatitis

One hundred patients with moderate to severe atopic dermatitis were entered into a two-center, double-blind trial. Patients were randomized to receive either thymopentin (Timunox, n = 48) or placebo (n = 52), administered as daily subcutaneous injections for 6 weeks. Clinical extent of disease and severity parameters were measured at baseline and at regular time intervals during the study. Both the placebo- and thymopentin-treated groups demonstrated a progressive and statistically significant (p less than 0.001) decline in the overall severity of their disease, but reduction in the clinical severity score was higher in the thymopentin-treated group and statistically significant (p = 0.04) in comparison with the placebo-treated group after 6 weeks of treatment. Of the individual symptoms comprising the total severity score, pruritus (p = 0.02) and erythema (p = 0.04) were reduced significantly when thymopentin therapy was compared to placebo therapy. In addition, both the extent of body involvement and severity index (a combined severity/extent index) were significantly reduced after 6 weeks in the thymopentin-treated group in comparison to the placebo-treated group (p = 0.04). There were no serious adverse experiences in either treatment group. We conclude that treatment with thymopentin is safe and offers significant therapeutic promise for atopic dermatitis.

Genetic variants in thymic stromal lymphopoietin are associated with atopic dermatitis and eczema herpeticum

computer instead of at the patient makes care impersonal.’’ Two respondents commented that training programs for clinicians need to be meaningful and efficient, that all clinicians (and not just hospitalists) need to have access to health information technology, and that quantity and diversity made currently available information online daunting to navigate. Do physician researchers have a different perspective on desirable features in an EMR system compared with those who spend their time exclusively in the clinic? This question was explored by comparing the responses of the 2 groups to the questions ‘‘How can informatics be used to make medical care more personalized?’’ and ‘‘How can informatics help translate bench findings to clinical practice?’’ Physician researchers included the following 2 choices in their top 6 more often than those who spent their time mainly in the clinic: (1) the ability to exploit bioinformatic/genetic information to improve care (50% vs 28%; P 5 .03, x) and (2) the need to improve informatics methods (60% vs 42%; but P 5 .09). On-the-field clinical providers are valuable resources to facilitate refinement of health informatics technology to personalize medicine. Actively involving practicing physicians in the design, selection, and deployment of EMR systems is necessary for meaningful adoption and consequent improvement in health care. Deendayal Dinakarpandian, MD, PhD, MS Arthur R. Williams, PhD, MA(Econ), MPA Chitra Dinakar, MD From the School of Computing and Engineering, University of Missouri–Kansas City; the Center for Health Outcomes and Health Services Research, Children’s Mercy Hospitals and Clinics and University of Missouri Medical School, Kansas City; and the Division of Allergy and Immunology, Children’s Mercy Hospitals and Clinics, University of Missouri–Kansas City, Kansas City, Mo. E-mail: cdinakar@cmh.edu. Disclosure of potential conflict of interest: C. Dinakar is Chair of the Health Outcomes, Education, Delivery and Quality (HEDQ) Interest Section of the American Academy of Allergy, Asthma & Immunology and is on the Programming Committee of the American College of Allergy, Asthma and Immunology. The rest of the authors have declared that they have no conflict of interest.