Food-specific immunoglobulin A does not correlate with natural tolerance to peanut or egg allergens

ImmunoglobulinA (IgA) is the predominant antibody isotype in the gut, where it regulates commensal flora and neutralizes toxins and pathogens. The function of food-specific IgA in the gut is unknown but is presumed to protect from food allergy. Specifically, it has been hypothesized that food-specific IgA binds ingested allergens and promotes tolerance by immune exclusion; however, the evidence to support this hypothesis is indirect and mixed. Although it is known that healthy adults have peanut-specific IgA in the gut, it is unclear whether children also have gut peanut-specific IgA. We found in a cohort of non-food-allergic infants (n = 112) that there is detectable stool peanut-specific IgA that is similar to adult quantities of gut peanut-specific IgA. To investigate whether this peanut-specific IgA is associated with peanut tolerance, we examined a separate cohort of atopic children (n = 441) and found that gut peanut-specific IgA does not predict protection from development of future peanut allergy in infants nor does it correlate with concurrent oral tolerance of peanut in older children. We observed higher plasma peanut-specific IgA in those with peanut allergy. Similarly, egg white-specific IgA was detectable in infant stools and did not predict egg tolerance or outgrowth of egg allergy. Bead-based epitope assay analysis of gut peanut-specific IgA revealed similar epitope specificity between children with peanut allergy and those without; however, gut peanut-specific IgA and plasma peanut-specific IgE had different epitope specificities. These findings call into question the presumed protective role of food-specific IgA in food allergy.

Bayesian hierarchical evaluation of dose-response for peanut allergy in clinical trial screening

Risk-based labeling based on the minimal eliciting doses (EDs) in sensitized populations is a potential replacement for precautionary allergen labeling of food allergens. We estimated the dose-response distribution for peanut allergen using data from double-blind placebo-controlled food challenges (DBPCFCs) conducted in the US at multiple sites, testing a population believed to be similar to the general U.S. food allergic population. Our final (placebo-adjusted) dataset included 548 challenges of 481 subjects. Bayesian hierarchical analysis facilitated model fitting, and accounted for variability associated with various levels of data organization. The data are best described using a complex hierarchical structure that accounts for inter-individual variability and variability across study locations or substudies. Bayesian model averaging could simultaneously consider the fit of multiple models, but the Weibull model dominated so strongly that model averaging was not needed. The ED01 and ED05 (and 95% credible intervals) are 0.052 (0.021, 0.13) and 0.49 (0.22, 0.97) mg peanut protein, respectively. Accounting for challenges with severe reactions at the LOAEL, by using the dose prior to the LOAEL as the new LOAEL, the ED01 drops to 0.029 (0.014, 0.074) mg peanut protein. Our results could aid in establishing improved food labeling guidelines in the management of food allergies.

Early epitope-specific IgE antibodies are predictive of childhood peanut allergy

BACKGROUND

Peanut allergy is characterized by the development of IgE against peanut antigen.

OBJECTIVE

We sought to evaluate the evolution of epitope-specific (es)IgE and esIgG₄ in a prospective cohort of high-risk infants to determine whether antibody profiles can predict peanut allergy after age 4 years.

METHODS

The end point was allergy status at age 4⁺ years; samples from 293 children were collected at age 3 to 15 months and 2 to 3 and 4⁺ years. Levels of specific (s)IgE and sIgG₄ to peanut and component proteins, and 50 esIgE and esIgG₄ were quantified. Changes were analyzed with mixed-effects models. Machine learning algorithms were developed to identify a combination of antigen- and epitope-specific antibodies that using 3- to 15-month or 2- to 3-year samples can predict allergy status at age 4⁺ years.

RESULTS

At age 4⁺ years, 38% of children were Tolerant or 14% had Possible, 8% Convincing, 24% Serologic, and 16% Confirmed allergy. At age 3 to 15 months, esIgE profiles were similar among groups, whereas marked increases were evident at age 2 and 4⁺ years only in Confirmed and Serologic groups. In contrast, peanut sIgE level was significantly lower in the Tolerant group at age 3 to 15 months, increased in Confirmed and Serologic groups but decreased in Convincing and Possibly Allergic groups over time. An algorithm combining esIgEs with peanut sIgE outperformed different clinically relevant IgE cutoffs, predicting allergy status on an "unseen" set of patients with area under the curves of 0.84 at age 3 to 15 months and 0.87 at age 2 to 3 years.

CONCLUSIONS

Early epitope-specific plus peanut-specific IgE is predictive of allergy status at age 4⁺ years.

Clinical factors associated with peanut allergy in a high-risk infant cohort

BACKGROUND

Prognostication of peanut allergy (PNA) is relevant for early interventions. We aimed to determine baseline parameters associated with the development of PNA in 3- to 15-month-olds with likely egg and/or milk allergy, and/or moderate to severe atopic dermatitis (AD) and a positive egg/milk skin prick test (SPT), but no known PNA.

METHODS

The primary endpoint was PNA [confirmed/convincing diagnosis or last classified as serologic PNA (<2 years, ≥5 kUA/L, otherwise ≥14 kUA/L, peanut IgE)] among 511 participants (median follow-up, 7.3 years). Associations were explored with univariate logistic regression; factors with P < 0.15 were analyzed by stepwise multiple logistic regression, using data stratified by PNA status and randomly assigned to development and validation datasets.

RESULTS

205/511 (40.1%) had PNA. Univariate factors associated with PNA (P < 0.01) included increased AD severity, larger egg and peanut SPT, greater egg, milk, peanut, Ara h1-h3 IgE, higher peanut IgG and IgG4, and increased pregnancy peanut consumption. P-values were between 0.01 and 0.05 for younger age, non-white race, lack of breastfeeding, and increased lactation peanut consumption. Using a development dataset, the multivariate model identified younger age at enrollment, greater peanut and Ara h2 IgE, and lack of breastfeeding as prognosticators. The final model predicted 79% in the development and 75% in the validation dataset (AUC = 0.83 for both). Models using stricter or less strict PNA criteria both found Ara h2 as predictive.

CONCLUSIONS

Key factors associated with PNA in this high-risk population included lack of breastfeeding, age, and greater Ara h2 and peanut-specific IgE, which can be used to prognosticate outcomes.

A Randomized, Double-Blind, Placebo-Controlled Trial to Assess the Utility of Tacrolimus (FK506) for the Prevention of Erectile Dysfunction Following Bilateral Nerve-Sparing Radical Prostatectomy

INTRODUCTION

Radical prostatectomy (RP) is associated with erectile dysfunction, largely mediated through cavernous nerve injury. There are robust pre-clinical data supporting a potential role for neuromodulatory agents in this patient population. This study assessed tacrolimus in improving erectile function recovery rates after RP (ClinicalTrials.gov number, NCT00106392).

AIM

To define the utility of oral tacrolimus in improving erectile function recovery after nerve sparing radical prostatectomy.

METHODS

A randomized, double-blind trial compared tacrolimus 2-3 mg daily and placebo in men undergoing RP. Patients had localized prostate cancer and excellent baseline erectile function, underwent bilateral nerve-sparing RP, and were followed up for at least 18 months after RP. Patients received study drug for 27 weeks and completed the International Index of Erectile Function erectile function domain (EFD) questionnaire at baseline and serially after surgery.

MAIN OUTCOME MEASURES

International Index of Erectile Function erectile function domain score.

RESULTS

Data were available for 124 patients (59 tacrolimus, 65 placebo); mean age was 54.6 ± 6.2 years. No patient experienced permanent creatinine or potassium elevation. At baseline, mean EFD scores were 28.6 ± 2.1 (tacrolimus group) and 29 ± 1.5 (placebo group). By week 5, mean EFD scores had dropped to 8 ± 9.4 (tacrolimus) and 9 ± 10.7 (placebo). At 18 months, mean EFD scores were 16.0 ± 11.3 (tacrolimus) and 20.2 ± 9.0 (placebo) (P = .09). Tacrolimus failed to meet significance (hazard ratio = 0.83; P = .50), with no difference in: (i) percentage of patients achieving normal spontaneous erectile function (EFD score ≥24), (ii) time to normalization of EFD score (≥24), (iii) percentage of patients capable of intercourse in response to phosphieserase type 5 inhibitor (PDE5i), and (iv) time to achieve response to PDE5i.

CLINICAL IMPLICATIONS

Despite positive animal data, oral tacrolimus as used in this trial failed to improve erectile function after nerve sparing radical prostatectomy.

STRENGTHS & LIMITATIONS

The study is limited by a high attrition rate. The strengths include a randomized, placebo controlled design, extensive patient monitoring, use of medication diaries and a validated instrument as the primary outcome measure.

CONCLUSION

Despite supportive animal data, tacrolimus used in this fashion in the RP population failed to demonstrate any superiority over placebo. Mulhall JP, Klein EA, Slawin K, et al. A Randomized, Double-Blind, Placebo-Controlled Trial to Assess the Utility of Tacrolimus (FK506) for the Prevention of Erectile Dysfunction Following Bilateral Nerve-Sparing Radical Prostatectomy. J Sex Med 2018;15:1293-1299.

Multicenter, randomized, double-blind, placebo-controlled clinical trial of vital wheat gluten oral immunotherapy

BACKGROUND

Wheat is a common food allergen that can cause anaphylaxis.

OBJECTIVE

We sought to determine the efficacy and safety of vital wheat gluten (VWG) oral immunotherapy (OIT).

METHODS

After baseline double-blind, placebo-controlled food challenge (DBPCFC), 46 patients with wheat allergy (median age, 8.7 years; range, 4.2-22.3 years) were randomized 1:1 to low-dose VWG OIT or placebo, with biweekly escalation to 1445 mg of wheat protein (WP). After a year 1 DBPCFC, active subjects continued low-dose VWG OIT for another year and underwent a year 2 DBPCFC and, if passed, a subsequent off-therapy DBPCFC. Placebo-treated subjects crossed over to high-dose VWG OIT (maximum, 2748 mg of WP).

RESULTS

The median baseline successfully consumed dose (SCD) was 43 mg of WP in both groups. At year 1, 12 (52.2%) of 23 low-dose VWG OIT-treated and 0 (0%) of 23 placebo-treated subjects achieved the primary end point of an SCD of 4443 mg of WP or greater (P < .0001); median SCDs were 4443 and 143 mg, respectively. At year 2, 7 (30.4%) of 23 low-dose VWG OIT-treated subjects were desensitized to an SCD of 7443 mg of WP; 3 (13%) achieved sustained unresponsiveness 8 to 10 weeks off therapy. Among placebo-treated subjects who crossed over to high-dose VWG OIT, 12 (57.1%) of 21 were desensitized after 1 year (median SCD, 7443 mg of WP; nonsignificant vs low-dose VWG OIT). At year 1, skin prick test responses and wheat- and omega-5 gliadin-specific IgE levels did not differ between groups; the low-dose VWG OIT median specific IgG₄ level was greater than placebo (wheat, P = .0005; omega-5 gliadin, P = .0001). Year 1 SCDs correlated with wheat-specific (rho = 0.55, P = .0003) and omega-5 gliadin-specific (rho = 0.51, P = .001) IgG₄ levels in all subjects. Among 7822 low-dose VWG OIT doses in year 1, 15.4% were associated with adverse reactions: 0.04% were severe, and 0.08% subjects received epinephrine. Among 7921 placebo doses, 5.8% were associated with adverse reactions; none were severe.

CONCLUSIONS

Low- and high-dose VWG OIT induced desensitization in about one half of the subjects after 1 year of treatment. Two years of low-dose VWG OIT resulted in 30% desensitization, and 13% had sustained unresponsiveness.

Phenotypic Characterization of Eosinophilic Esophagitis in a Large Multicenter Patient Population from the Consortium for Food Allergy Research

BACKGROUND

Eosinophilic esophagitis (EoE) is increasingly common, but data on phenotypic aspects are still incomplete.

OBJECTIVES

To describe the clinical, endoscopic, and histopathologic features of a large number of children and adults with EoE across the United States.

METHODS

This was a multisite single visit registry enrolling subjects aged 6 months to 65 years with EoE. Participants provided responses regarding their medical history, with verification of the diagnosis and history by the study teams.

RESULTS

A total of 705 subjects were analyzed (median [interquartile range] age at enrollment 11.2 [6.7-17.7] years, 68.2% male, 87.9% whites). Of these, 67 subjects had concurrent gastrointestinal eosinophilia, with gastric mucosa most common. An age- and race-dependent time gap was present between symptom onset and time of diagnosis (adults and whites with longer gap). Food allergy and atopic dermatitis were associated with a decrease in this gap. Symptoms varied with age (more dysphagia and food impaction in adults) and with race (more vomiting in non-whites). Esophageal rings and strictures at diagnosis were more common in adults, although esophageal eosinophilia was comparable among age groups. Concomitant allergic disease (91%), infectious/immunologic disorders (44%), neurodevelopmental disorders (30%), and failure to thrive (21%) were common. Depression/anxiety increased with age. EoE was reported in 3% of parents and 4.5% of siblings.

CONCLUSIONS

Gastrointestinal eosinophilia is present in approximately 10% of patients with EoE; the symptom-diagnosis time gap is influenced by age, race, food allergy, and atopic dermatitis; symptoms vary with race; concurrent infectious/immunologic disorders and mental health disorders are common; and the level of esophageal eosinophils is comparable in patients with and without fibrostenotic features.

Egg-specific IgE and basophil activation but not egg-specific T-cell counts correlate with phenotypes of clinical egg allergy

BACKGROUND

Egg allergy is phenotypically heterogeneous. A subset of patients with egg allergy can tolerate egg in an extensively heated form. Inclusion of baked egg (BE) into the diet accelerates resolution of egg allergy. Conversely, BE reactivity is associated with persistent disease. The immune basis of this clinical heterogeneity is unknown.

OBJECTIVES

We sought to study egg-specific antibody, basophil, and T-cell responses in children with reactivity or tolerance to BE.

METHODS

All participants underwent double-blind, placebo-controlled challenges to BE, and those who tolerated BE were challenged with unheated egg white protein to confirm clinical egg reactivity. Laboratory studies included serum antibody measurements, basophil activation tests, and CD154-based detection of egg-responsive T cells by using flow cytometry.

RESULTS

Of the 129 children studied, BE-reactive participants had significantly greater levels of egg-, ovalbumin-, and ovomucoid-specific IgE; lower ratios of egg-specific IgG₄/IgE; and increased basophil activation in response to egg. Among all participants, CD154-based profiling revealed egg-responsive T cells producing IL-4 and IL-13 but little IL-10 or IFN-γ, as well as the presence of egg-responsive Foxp3⁺CD25⁺CD127^low regulatory T cells. Egg-responsive T cells expressed CCR4, CCR6, and CXCR5, indicating capacity for homing to the skin, mucosa, and B-cell follicles. However, neither the frequency nor phenotype of egg-responsive T cells was different in those with tolerance or reactivity to BE.

CONCLUSIONS

Egg-specific antibody and basophil responses, but not T-cell responses, are greater in those with reactivity versus tolerance to BE. Egg-specific antibody and T-cell responses were highly heterogeneous in this cohort. The clinical implications of this immune heterogeneity will need to be studied longitudinally.

Epicutaneous immunotherapy for the treatment of peanut allergy in children and young adults

BACKGROUND

Peanut allergy is common, life-threatening, and without therapeutic options. We evaluated peanut epicutaneous immunotherapy (EPIT) by using Viaskin Peanut for peanut allergy treatment.

OBJECTIVE

We sought to evaluate the clinical, safety, and immunologic effects of EPIT for the treatment of peanut allergy.

METHODS

In this multicenter, double-blind, randomized, placebo-controlled study, 74 participants with peanut allergy (ages 4-25 years) were treated with placebo (n = 25), Viaskin Peanut 100 μg (VP100; n = 24) or Viaskin Peanut 250 μg (VP250; n = 25; DBV Technologies, Montrouge, France). The primary outcome was treatment success after 52 weeks, which was defined as passing a 5044-mg protein oral food challenge or achieving a 10-fold or greater increase in successfully consumed dose from baseline to week 52. Adverse reactions and mechanistic changes were assessed.

RESULTS

At week 52, treatment success was achieved in 3 (12%) placebo-treated participants, 11 (46%) VP100 participants, and 12 (48%) VP250 participants (P = .005 and P = .003, respectively, compared with placebo; VP100 vs VP250, P = .48). Median change in successfully consumed doses were 0, 43, and 130 mg of protein in the placebo, VP100, and VP250 groups, respectively (placebo vs VP100, P = .014; placebo vs VP250, P = .003). Treatment success was higher among younger children (P = .03; age, 4-11 vs >11 years). Overall, 14.4% of placebo doses and 79.8% of VP100 and VP250 doses resulted in reactions, predominantly local patch-site and mild reactions (P = .003). Increases in peanut-specific IgG₄ levels and IgG₄/IgE ratios were observed in peanut EPIT-treated participants, along with trends toward reduced basophil activation and peanut-specific T_H2 cytokines.

CONCLUSIONS

Peanut EPIT administration was safe and associated with a modest treatment response after 52 weeks, with the highest responses among younger children. This, when coupled with a high adherence and retention rate and significant changes in immune pathways, supports further investigation of this novel therapy.

Long-term treatment with egg oral immunotherapy enhances sustained unresponsiveness that persists after cessation of therapy

BACKGROUND

We previously reported the results of a randomized placebo-controlled study of egg oral immunotherapy (eOIT) in which 27.5% of subjects achieved sustained unresponsiveness (SU) after 2 years. Here we report the results of treatment through 4 years and long-term follow-up.

OBJECTIVE

We sought to evaluate the efficacy and safety of eOIT in participants treated up to 4 years.

METHODS

Children with egg allergy (5-18 years old) received eOIT (n = 40) for up to 4 years or placebo (n = 15) for 1 year or less. The key outcome was the percentage of subjects achieving SU by year 4. Safety and immunologic assessments were performed, and long-term follow-up questionnaires (LFQs) were administered after study conclusion (LFQ-1) and 1 year later (LFQ-2).

RESULTS

Of 40 eOIT-treated subjects, 20 (50.0%) of 40 demonstrated SU by year 4. For those subjects still dosing during years 3 and 4, mild symptoms were present in 12 (54.5%) of 22 subjects. At the time of the LFQ, more subjects receiving eOIT (LFQ-1, 23/34 [68%]; LFQ-2, 21/33 [64%]) were consuming unbaked and baked egg versus placebo (LFQ-1, 2/11 [18%], P = .006; LFQ-2, 3/12 [25%], P = .04). Of subjects achieving SU, 18 (90%) of 20 completed the LFQ, with 18 (100%) of 18 reporting consumption of all forms of egg. When compared with subjects not achieving SU, subjects achieving SU had higher IgG4 values (P = .001) and lower egg skin prick test scores (P = .0002) over time and a lower median baseline ratio of egg-specific IgE to total IgE (1.1% vs 2.7%, P = .04).

CONCLUSIONS

SU after eOIT is enhanced with longer duration of therapy and increases the likelihood of tolerating unbaked egg in the diet.

A randomized, double-blind, placebo-controlled study of omalizumab combined with oral immunotherapy for the treatment of cow's milk allergy

BACKGROUND

Although studies of oral immunotherapy (OIT) for food allergy have shown promise, treatment is frequently complicated by adverse reactions and, even when successful, has limited long-term efficacy because benefits usually diminish when treatment is discontinued.

OBJECTIVE

We sought to examine whether the addition of omalizumab to milk OIT reduces treatment-related reactions, improves outcomes, or both.

METHODS

This was a double-blind, placebo-controlled trial with subjects randomized to omalizumab or placebo. Open-label milk OIT was initiated after 4 months of omalizumab/placebo with escalation to maintenance over 22 to 40 weeks, followed by daily maintenance dosing through month 28. At month 28, omalizumab was discontinued, and subjects passing an oral food challenge (OFC) continued OIT for 8 weeks, after which OIT was discontinued with rechallenge at month 32 to assess sustained unresponsiveness (SU).

RESULTS

Fifty-seven subjects (7-32 years) were randomized, with no significant baseline differences in age, milk-specific IgE levels, skin test results, or OFC results. At month 28, 24 (88.9%) omalizumab-treated subjects and 20 (71.4%) placebo-treated subjects passed the 10-g "desensitization" OFC (P = .18). At month 32, SU was demonstrated in 48.1% in the omalizumab group and 35.7% in the placebo group (P = .42). Adverse reactions were markedly reduced during OIT escalation in omalizumab-treated subjects for percentages of doses per subject provoking symptoms (2.1% vs 16.1%, P = .0005), dose-related reactions requiring treatment (0.0% vs 3.8%, P = .0008), and doses required to achieve maintenance (198 vs 225, P = .008).

CONCLUSIONS

In this first randomized, double-blind, placebo-controlled trial of omalizumab in combination with food OIT, we found significant improvements in measurements of safety but not in outcomes of efficacy (desensitization and SU).

New-Onset Diabetes After Transplantation: Results From a Double-Blind Early Corticosteroid Withdrawal Trial

New-onset diabetes after transplantation (NODAT) is an important complication following kidney transplantation. Data from the 5-year early steroid withdrawal double-blind randomized trial were analyzed to determine if steroid avoidance reduced the NODAT risk. Incidence, timing and risk factors for NODAT were evaluated using eight definitions. By American Diabetes Association definition, 36.3% of patients on chronic corticosteroids (CCS) and 35.9% on early corticosteroid withdrawal (CSWD) were diagnosed with NODAT by 5 years. The definition combining fasting blood glucose ≥126 mg/dL on two occasions or treatment identified slightly more cases of NODAT: CCS (39.3%) and CSWD (39.4%). Through 5 years posttransplant, the proportion of NODAT patients requiring treatment were similar (CSWD 22.5% vs. CCS 21.5%); however, insulin therapy was lower with CSWD (3.7% vs. 11.6%; p = 0.049). By multivariate analysis, only age, but not corticosteroid use, was a significant risk factor for NODAT for more than one definition. Numerical, but not statistically significant trends toward lower NODAT rates with CSWD were observed through 5 years for insulin use, HbA1c ≥6.0% and ≥6.5% on two occasions. This prospective, randomized trial of CSWD indicates that CSWD has a limited impact in reducing NODAT when compared to low-dose prednisone (5 mg/day from month 6 to 5 years).

Sublingual immunotherapy for peanut allergy: Long-term follow-up of a randomized multicenter trial

BACKGROUND

We previously reported the initial results of the first multicenter, randomized, double-blind, placebo-controlled clinical trial of peanut sublingual immunotherapy (SLIT), observing a favorable safety profile associated with modest clinical and immunologic effects in the first year.

OBJECTIVE

We sought to provide long-term (3-year) clinical and immunologic outcomes for our peanut SLIT trial. Key end points were (1) percentage of responders at 2 years (ie, could consume 5 g of peanut powder or a 10-fold increase from baseline), (2) percentage reaching desensitization at 3 years, (3) percentage attaining sustained unresponsiveness after 3 years, (4) immunologic end points, and (5) assessment of safety parameters.

METHODS

Response to treatment was evaluated in 40 subjects aged 12 to 40 years by performing a 10-g peanut powder oral food challenge after 2 and 3 years of daily peanut SLIT therapy. At 3 years, SLIT was discontinued for 8 weeks, followed by another 10-g oral food challenge and an open feeding of peanut butter to assess sustained unresponsiveness.

RESULTS

Approximately 98% of the 18,165 doses were tolerated without adverse reactions beyond the oropharynx, with no severe symptoms or uses of epinephrine. A high rate (>50%) discontinued therapy. By study's end, 4 (10.8%) of 37 SLIT-treated participants were fully desensitized to 10 g of peanut powder, and all 4 achieved sustained unresponsiveness. Responders at 2 years showed a significant decrease in peanut-specific basophil activation and skin prick test titration compared with nonresponders.

CONCLUSIONS

Peanut SLIT induced a modest level of desensitization, decreased immunologic activity over 3 years in responders, and had an excellent long-term safety profile. However, most patients discontinued therapy by the end of year 3, and only 10.8% of subjects achieved sustained unresponsiveness.

Sublingual immunotherapy for peanut allergy: a randomized, double-blind, placebo-controlled multicenter trial

BACKGROUND

There are presently no available therapeutic options for patients with peanut allergy.

OBJECTIVE

We sought to investigate the safety, efficacy, and immunologic effects of peanut sublingual immunotherapy (SLIT).

METHODS

After a baseline oral food challenge (OFC) of up to 2 g of peanut powder (approximately 50% protein; median successfully consumed dose [SCD], 46 mg), 40 subjects, aged 12 to 37 years (median, 15 years), were randomized 1:1 across 5 sites to daily peanut or placebo SLIT. A 5-g OFC was performed after 44 weeks, followed by unblinding; placebo-treated subjects then crossed over to higher dose peanut SLIT, followed by a subsequent crossover Week 44 5-g OFC. Week 44 OFCs from both groups were compared with baseline OFCs; subjects successfully consuming 5 g or at least 10-fold more peanut powder than the baseline OFC threshold were considered responders.

RESULTS

After 44 weeks of SLIT, 14 (70%) of 20 subjects receiving peanut SLIT were responders compared with 3 (15%) of 20 subjects receiving placebo (P < .001). In peanut SLIT responders, median SCD increased from 3.5 to 496 mg. After 68 weeks of SLIT, median SCD significantly increased to 996 mg (compared with Week 44, P = .05). The median SCD at the Week 44 Crossover OFC was significantly higher than baseline (603 vs 71 mg, P = .02). Seven (44%) of 16 crossover subjects were responders; median SCD increased from 21 to 496 mg among responders. Of 10,855 peanut doses through the Week 44 OFCs, 63.1% were symptom free; excluding oral-pharyngeal symptoms, 95.2% were symptom free.

CONCLUSIONS

Peanut SLIT safely induced a modest level of desensitization in a majority of subjects compared with placebo. Longer duration of therapy showed statistically significant increases in the SCD.

Effect of corticosteroid withdrawal on tacrolimus and mycophenolate mofetil exposure in a randomized multicenter study

As corticosteroid-sparing protocols are increasingly utilized in kidney transplant recipients, it is crucial to understand potential drug interactions between tacrolimus (TAC) and the effect of corticosteroid withdrawal as well as to characterize dose adjustments of mycophenolate mofetil (MMF) in this setting. This prospective, multicenter, randomized, double-blind study included 397 patients who were randomized on posttransplant day 8 to receive either placebo (CSWD) or corticosteroid continuance (CCS). TAC trough levels at week two posttransplant were significantly greater in the CSWD group whereas TAC doses were comparable to the CCS group. This interaction was not observed in the African American subgroup. Higher serum creatinine and potassium levels were also observed in the CSWD group. MMF dose was significantly reduced in the CSWD group by the investigators because of decreased WBC counts, mostly outside of study protocol criteria, despite similar incidence of neutropenia and reported cytomegalovirus infection. Understanding TAC and MMF exposure in the context of corticosteroid-sparing protocols should allow for improved dosing of immunosuppressants and better management of posttransplant patients.

The natural history of milk allergy in an observational cohort

OBJECTIVE

There are few studies on the natural history of milk allergy. Most are single-site and not longitudinal, and these have not identified a means for early prediction of outcomes.

METHODS

Children aged 3 to 15 months were enrolled in an observational study with either (1) a convincing history of egg allergy, milk allergy, or both with a positive skin prick test (SPT) response to the trigger food and/or (2) moderate-to-severe atopic dermatitis (AD) and a positive SPT response to milk or egg. Children enrolled with a clinical history of milk allergy were followed longitudinally, and resolution was established by means of successful ingestion.

RESULTS

The cohort consists of 293 children, of whom 244 were given a diagnosis of milk allergy at baseline. Milk allergy has resolved in 154 (52.6%) subjects at a median age of 63 months and a median age at last follow-up of 66 months. Baseline characteristics that were most predictive of resolution included milk-specific IgE level, milk SPT wheal size, and AD severity (all P < .001). Baseline milk-specific IgG4 level and milk IgE/IgG4 ratio were not predictive of resolution and neither was expression of cytokine-inducible SH2-containing protein, forkhead box protein 3, GATA3, IL-10, IL-4, IFN-γ, or T-bet by using real-time PCR in CD25-selected, casein-stimulated mononuclear cells. A calculator to estimate resolution probabilities using baseline milk IgE level, SPT response, and AD severity was devised for use in the clinical setting.

CONCLUSIONS

In this cohort of infants with milk allergy, approximately one half had resolved over 66 months of follow-up. Baseline milk-specific IgE level, SPT wheal size, and AD severity were all important predictors of the likelihood of resolution.

Oral immunotherapy for treatment of egg allergy in children

BACKGROUND

For egg allergy, dietary avoidance is the only currently approved treatment. We evaluated oral immunotherapy using egg-white powder for the treatment of children with egg allergy.

METHODS

In this double-blind, randomized, placebo-controlled study, 55 children, 5 to 11 years of age, with egg allergy received oral immunotherapy (40 children) or placebo (15). Initial dose-escalation, build-up, and maintenance phases were followed by an oral food challenge with egg-white powder at 10 months and at 22 months. Children who successfully passed the challenge at 22 months discontinued oral immunotherapy and avoided all egg consumption for 4 to 6 weeks. At 24 months, these children underwent an oral food challenge with egg-white powder and a cooked egg to test for sustained unresponsiveness. Children who passed this challenge at 24 months were placed on a diet with ad libitum egg consumption and were evaluated for continuation of sustained unresponsiveness at 30 months and 36 months.

RESULTS

After 10 months of therapy, none of the children who received placebo and 55% of those who received oral immunotherapy passed the oral food challenge and were considered to be desensitized; after 22 months, 75% of children in the oral-immunotherapy group were desensitized. In the oral-immunotherapy group, 28% (11 of 40 children) passed the oral food challenge at 24 months and were considered to have sustained unresponsiveness. At 30 months and 36 months, all children who had passed the oral food challenge at 24 months were consuming egg. Of the immune markers measured, small wheal diameters on skin-prick testing and increases in egg-specific IgG4 antibody levels were associated with passing the oral food challenge at 24 months.

CONCLUSIONS

These results show that oral immunotherapy can desensitize a high proportion of children with egg allergy and induce sustained unresponsiveness in a clinically significant subset. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00461097.).

Allergic reactions to foods in preschool-aged children in a prospective observational food allergy study

OBJECTIVE

To examine circumstances of allergic reactions to foods in a cohort of preschool-aged children.

METHODS

We conducted a prospective, 5-site observational study of 512 infants aged 3 to 15 months with documented or likely allergy to milk or egg, and collected data prospectively examining allergic reactions.

RESULTS

Over a median follow-up of 36 months (range: 0-48.4), the annualized reaction rate was 0.81 per year (367/512 subjects reporting 1171 reactions [95% confidence interval: 0.76-0.85]). Overall, 269/512 (52.5%) reported >1 reaction. The majority of reactions (71.2%) were triggered by milk (495 [42.3%]), egg (246 [21.0%]), and peanut (93 [7.9%]), with accidental exposures attributed to unintentional ingestion, label-reading errors, and cross-contact. Foods were provided by persons other than parents in 50.6% of reactions. Of 834 reactions to milk, egg, or peanut, 93 (11.2%) were attributed to purposeful exposures to these avoided foods. A higher number of food allergies (P < .0001) and higher food-specific immunoglobulin E (P < .0001) were associated with reactions. Of the 11.4% of reactions (n = 134) that were severe, 29.9% were treated with epinephrine. Factors resulting in undertreatment included lack of recognition of severity, epinephrine being unavailable, and fears about epinephrine administration.

CONCLUSIONS

There was a high frequency of reactions caused by accidental and nonaccidental exposures. Undertreatment of severe reactions with epinephrine was a substantial problem. Areas for improved education include the need for constant vigilance, accurate label reading, avoidance of nonaccidental exposure, prevention of cross-contamination, appropriate epinephrine administration, and education of all caretakers.

A 32 kb critical region excluding Y402H in CFH mediates risk for age-related macular degeneration

Complement factor H shows very strong association with Age-related Macular Degeneration (AMD), and recent data suggest that multiple causal variants are associated with disease. To refine the location of the disease associated variants, we characterized in detail the structural variation at CFH and its paralogs, including two copy number polymorphisms (CNP), CNP147 and CNP148, and several rare deletions and duplications. Examination of 34 AMD-enriched extended families (N = 293) and AMD cases (White N = 4210 Indian = 134; Malay = 140) and controls (White N = 3229; Indian = 117; Malay = 2390) demonstrated that deletion CNP148 was protective against AMD, independent of SNPs at CFH. Regression analysis of seven common haplotypes showed three haplotypes, H1, H6 and H7, as conferring risk for AMD development. Being the most common haplotype H1 confers the greatest risk by increasing the odds of AMD by 2.75-fold (95% CI = [2.51, 3.01]; p = 8.31×10(-109)); Caucasian (H6) and Indian-specific (H7) recombinant haplotypes increase the odds of AMD by 1.85-fold (p = 3.52×10(-9)) and by 15.57-fold (P = 0.007), respectively. We identified a 32-kb region downstream of Y402H (rs1061170), shared by all three risk haplotypes, suggesting that this region may be critical for AMD development. Further analysis showed that two SNPs within the 32 kb block, rs1329428 and rs203687, optimally explain disease association. rs1329428 resides in 20 kb unique sequence block, but rs203687 resides in a 12 kb block that is 89% similar to a noncoding region contained in ΔCNP148. We conclude that causal variation in this region potentially encompasses both regulatory effects at single markers and copy number.

Genome-wide association identifies SKIV2L and MYRIP as protective factors for age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly in the developed world. We conducted a genome-wide association study in a series of families enriched for AMD and completed a meta-analysis of this new data with results from reanalysis of an existing study of a late-stage case-control cohort. We tested the top findings for replication in 1896 cases and 1866 controls and identified two novel genetic protective factors for AMD. In addition to the complement factor H (CFH) (P=2.3 × 10⁻⁶⁴) and age-related maculopathy susceptibility 2 (ARMS2) (P=1.2 × 10⁻⁶⁰) loci, we observed a protective effect at rs429608, an intronic SNP in SKIV2L (P=5.3 × 10⁻¹⁵), a gene near the complement component 2 (C2)/complement factor B (BF) locus, that indicates the protective effect may be mediated by variants other than the C2/BF variants previously studied. Haplotype analysis at this locus identified three protective haplotypes defined by the rs429608 protective allele. We also identified a new potentially protective effect at rs2679798 in MYRIP (P=2.9 × 10⁻⁴), a gene involved in retinal pigment epithelium melanosome trafficking. Interestingly, MYRIP was initially identified in the family-based scan and was confirmed in the case-control set. From these efforts, we report the identification of two novel protective factors for AMD and confirm the previously known associations at CFH, ARMS2 and C3.

Mitochondrial DNA variants of respiratory complex I that uniquely characterize haplogroup T2 are associated with increased risk of age-related macular degeneration

Background

Age-related macular degeneration (AMD), a chronic neurodegenerative and neovascular retinal disease, is the leading cause of blindness in elderly people of western European origin. While structural and functional alterations in mitochondria (mt) and their metabolites have been implicated in the pathogenesis of chronic neurodegenerative and vascular diseases, the relationship of inherited variants in the mitochondrial genome and mt haplogroup subtypes with advanced AMD has not been reported in large prospective cohorts.

Methodology/Prinicipal Findings

We examined the relationship of inherited mtDNA variants with advanced AMD in 1168 people using a three-stage design on samples from 12-year and 10-year prospective studies on the natural history of age-related eye disease. In Stage I we resequenced the entire genome in 99 elderly AMD-free controls and 215 people with advanced AMD from the 12-year study. A consistent association with AMD in 14 of 17 SNPs characterizing the mtDNA T haplogroup emerged. Further analysis revealed these associations were driven entirely by the T2 haplogroup, and characterized by two variants in Complex I genes (A11812G of MT-ND4 and A14233G of MT-ND6). We genotyped T haplogroups in an independent sample of 490 cases and 61 controls from the same study (Stage II) and in 56 cases and 246 controls from the 10-year study (Stage III). People in the T2 haplogroup were approximately 2.5 times more likely to have advanced AMD than their peers (odds ratio [OR] = 2.54, 95%CI 1.36–4.80, P≤0.004) after considering the totality of evidence. Findings persisted after considering the impact of AMD-associated variants A69S and Y402H (OR = 5.19, 95%CI 1.19–22.69, P≤0.029).

Conclusion

Loci defining the mtDNA T2 haplogroup and Complex I are reasonable targets for novel functional analyses and therapeutic research in AMD.

Complement factor H polymorphism in age-related macular degeneration

Age-related macular degeneration (AMD) is a major cause of blindness in the elderly. We report a genome-wide screen of 96 cases and 50 controls for polymorphisms associated with AMD. Among 116,204 single-nucleotide polymorphisms genotyped, an intronic and common variant in the complement factor H gene (CFH) is strongly associated with AMD (nominal P value <10(-7)). In individuals homozygous for the risk allele, the likelihood of AMD is increased by a factor of 7.4 (95% confidence interval 2.9 to 19). Resequencing revealed a polymorphism in linkage disequilibrium with the risk allele representing a tyrosine-histidine change at amino acid 402. This polymorphism is in a region of CFH that binds heparin and C-reactive protein. The CFH gene is located on chromosome 1 in a region repeatedly linked to AMD in family-based studies.

Prospective, randomized trial of the effect of antibody induction in simultaneous pancreas and kidney transplantation: three-year results

BACKGROUND

Historically, antibody induction has been used because of the higher immunologic risk of graft loss or rejection observed in simultaneous pancreas and kidney (SPK) transplantation compared with kidney transplantation alone. This trial was designed to assess the effect of antibody induction in SPK transplant recipients receiving tacrolimus, mycophenolate mofetil, and corticosteroids. Induction agents included T-cell-depleting and interleukin-2 receptor antibodies.

METHODS

A total of 174 SPK transplant recipients were enrolled in a prospective, open-label, multi-center study. They were randomized to induction (n=87) or non-induction (n=87) groups and followed for 3 years.

RESULTS

At 3 years, actual patient (94.3% and 89.7%) and pancreas (75.9% and 75.9%) survivals were similar between the induction and non-induction groups, respectively. Actual kidney survival was similar at 1 and 2 years, but at 3 years, it was significantly better in the induction group compared with the non-induction group (92% vs. 81.6%; P =0.04). At 3 years, median serum creatinine and hemoglobin A1C were similar between the induction and non-induction groups (1.35 mg/dL and 1.20 mg/dL, 5.4% and 5.5%, respectively). Three-year cumulative incidence of biopsy-confirmed, treated acute kidney rejection in the induction and non-induction groups was 19.5% and 27.5% (P =0.14), respectively, with odds 4.6 times greater in African Americans regardless of treatment (P =0.004). Significantly higher rates of cytomegalovirus (CMV) viremia and CMV syndrome occurred in those receiving T-cell-depleting antibody induction (36.1%) when compared with those receiving anti-interleukin-2 receptor antibodies (2%) and non-induction (8.1%) (P <0.0001).

CONCLUSIONS

Tacrolimus, mycophenolate mofetil, and corticosteroids resulted in excellent safety and efficacy in SPK transplant recipients. Actual 3-year kidney survival was significantly better in the induction group; however, CMV viremia and CMV syndrome rates were significantly higher in the T-cell-depleting antibody group. African Americans demonstrated a significantly greater risk of acute rejection despite antibody induction. Decisions regarding the use of induction therapy must weigh the risk of kidney graft loss or rejection against the risk of infection.

Prospective, randomized, multi-center trial of antibody induction therapy in simultaneous pancreas-kidney transplantation

A randomized, multicenter, prospective study was conducted at 18 pancreas transplant centers in the United States to determine the role of induction therapy in simultaneous pancreas-kidney (SPK) transplantation. One hundred and 74 recipients were enrolled: 87 recipients each in the induction and noninduction treatment arms. Maintenance immunosuppression consisted of tacrolimus, mycophenolate mofetil, and corticosteroids. There were no statistically significant differences between treatment groups for patient, kidney, and pancreas graft survival at 1-year. The 1-year cumulative incidence of any treated biopsy-confirmed or presumptive rejection episodes (kidney or pancreas) in the induction and noninduction treatment arms was 24.6% and 31.2% (p = 0.28), respectively. The 1-year cumulative incidence of biopsy-confirmed, treated, acute kidney allograft rejection in the induction and noninduction treatment arms was 13.1% and 23.0% (p = 0.08), respectively. Biopsy-confirmed kidney allograft rejection occurred later post-transplant and appeared to be less severe among recipients that received induction therapy. The highest rate of Cytomegalovirus (CMV) viremia/syndrome was observed in the subgroup of recipients who received T-cell depleting antibody induction and received organs from CMV serologically positive donors. Decisions regarding the routine use of induction therapy in SPK transplantation must take into consideration its differential effects on risk of rejection and infection.