This Week in Allergy & Immunology — May 21, 2026

Welcome to This Week in Allergy & Immunology. This week we're covering 5 notable papers spanning advances in biologic therapy for airway disease, the natural history and prevention of allergy, and the safety of venom immunotherapy in pregnancy. Let's dive in.

We'll start with two major studies on biologic therapies for chronic airway diseases, one for severe asthma and one for COPD, which show contrasting results. First, in The Journal of Allergy and Clinical Immunology, we have the TERESA study, a prospective, single-arm trial from Japan evaluating tezepelumab for achieving clinical remission in severe asthma [1]. The concept of clinical remission—moving beyond simple symptom control to a state of no exacerbations, no oral corticosteroids, good symptom scores, and stable lung function—is the new ambitious goal in severe asthma management. This study enrolled 107 patients, including a significant number who had previously been on other biologics.

The Study Patients with uncontrolled severe asthma received tezepelumab every four weeks for one year. The primary outcome was the rate of clinical remission at week 52.

Results Overall, about one-third of patients, or 34.6 percent, achieved clinical remission. However, the results differed dramatically based on prior treatment history. Among patients who were new to biologics, the remission rate was 47.4 percent, so nearly one in two. In contrast, for patients who were biologic-experienced, the rate was only 20 percent, or one in five. The study also found that a baseline blood eosinophil count of 300 cells per microliter or higher was a strong independent predictor of achieving remission.

Discussion For clinicians, this study provides important data for patient selection and counseling. Tezepelumab, which targets the upstream cytokine TSLP, shows it can induce a comprehensive state of disease control in a meaningful portion of patients. The key takeaway is that its benefits are most pronounced in biologic-naïve patients and those with eosinophilic inflammation, reinforcing its role in this phenotype but also showing its potential in a broader population.

Now, let's turn to COPD. While tezepelumab showed a clear signal in asthma, a different biologic targeting the IL-33 pathway had a more complex outcome in COPD. Published in The Lancet, a report details two pivotal trials, the Phase 2b ALIENTO and Phase 3 ARNASA trials, on astegolimab, an anti-ST2 antibody [5]. This drug blocks the receptor for IL-33, an alarmin implicated in both neutrophilic and eosinophilic inflammation in COPD exacerbations. The trials enrolled current or former smokers with a history of frequent exacerbations, regardless of their baseline blood eosinophil counts.

The Study In both randomized, double-blind trials, patients received subcutaneous astegolimab either every two weeks, every four weeks, or placebo for 52 weeks. The primary endpoint was the annualized rate of moderate or severe COPD exacerbations.

Results This is where it gets complicated. The results were inconsistent across the two trials. In the ALIENTO trial, the every-2-week dose led to a 15 percent reduction in the exacerbation rate compared to placebo, a result that was statistically significant. However, the every-4-week dose in that same trial was not significant. In the ARNASA trial, the findings were essentially flipped. The every-4-week dose showed an 18 percent reduction in exacerbations and was statistically significant, while the every-2-week dose showed a similar 15 percent reduction but failed to meet statistical significance, with a p-value of 0.068.

Discussion So, what does this mean for practice? Astegolimab demonstrated a consistent, modest reduction in exacerbations of around 15 to 18 percent at one of its doses in each trial. However, the lack of consistent significance for the same dose across both pivotal trials muddies the waters. The authors conclude that these findings suggest a potential role for targeting the ST2/IL-33 pathway in this hard-to-treat population, but it's not the clear-cut positive result seen with some asthma biologics. It highlights the challenge of treating a heterogeneous disease like COPD and leaves the clinical path forward for astegolimab uncertain for now.

Our next theme shifts from treating established disease to the concepts of prevention and understanding the long-term course of sensitization. We have two papers from the journal Allergy. The first study explores whether sublingual immunotherapy, or SLIT, can be used preventively in young children [2]. The idea is to intervene in children who are sensitized to an allergen but have not yet developed clinical symptoms, to see if it's possible to alter their immune trajectory. This randomized, placebo-controlled trial enrolled house dust mite-sensitized preschoolers, aged 3 to 5, who were asymptomatic. They received either house dust mite SLIT or a placebo for two years.

Results The primary goal was to see if SLIT could induce blocking antibodies, specifically IgG against the major dust mite allergen Der p 1. The answer was a clear yes. The group receiving HDM-SLIT had a significant increase in these blocking antibodies compared to placebo. Furthermore, the treatment group showed reduced reactivity on skin prick tests and basophil activation tests. Their sera were also able to block basophil activation in lab experiments. Perhaps most importantly, the treatment appeared to blunt the development of new sensitizations.

Conclusions This study provides compelling mechanistic evidence that preventive SLIT in allergy-prone, sensitized young children can induce favorable immunomodulatory effects early on. It supports the hypothesis that this approach could interfere with the development of clinical allergy, a concept that could reshape how we approach pediatric allergy in the future.

From preventing allergy, we now turn to understanding its natural course. A second paper in Allergy provides a long-term look at sensitization to the mold *Alternaria* and its link to asthma and rhinitis [4]. This study used data from the well-known Isle of Wight birth cohort, following participants from childhood to young adulthood, with assessments at ages 4, 10, 18, and 26.

The Study Researchers characterized the trajectories of *Alternaria* sensitization using skin prick testing, whole-extract specific IgE, and specific IgE to the major component, rAlt a 1. They then looked at how these sensitization patterns were associated with the persistence of asthma and rhinitis over time.

Results Most participants, about 84 percent, were never sensitized. However, about 5 percent of the cohort showed a 'Persistent' sensitization trajectory. This group with persistent *Alternaria* sensitization had the highest risk for also having persistent asthma and persistent rhinitis into adulthood. An important diagnostic finding emerged: in younger participants at ages 10 and 18, testing for the component rAlt a 1 was better at discriminating asthma risk than using the whole *Alternaria* extract IgE. By age 26, the two tests performed similarly.

Conclusions This study confirms that *Alternaria* sensitization often consolidates during adolescence and, when it persists, it tracks strongly with persistent respiratory allergic disease. For clinicians, this highlights that persistent mold sensitization is not a benign finding. The data also suggests that in children and adolescents, using component-resolved diagnostics like rAlt a 1 may offer a more precise way to stratify a patient's future asthma risk.

Finally, we'll cover a highly practical paper addressing a common clinical dilemma: the safety of venom immunotherapy, or VIT, during pregnancy. Published in Allergy, this prospective, multicenter study from Italy provides much-needed evidence on this topic [3]. Hymenoptera venom allergy poses a risk of life-threatening anaphylaxis, making VIT a critical treatment. However, clinicians and patients often have concerns about continuing it during pregnancy due to limited safety data.

The Study Researchers followed 68 women through 86 pregnancies while they were receiving maintenance VIT. They tracked rates of spontaneous abortion, preterm birth, and any adverse events related to the immunotherapy.

Results The findings are incredibly reassuring. The rate of spontaneous abortion was 12.8 percent, and the rate of preterm birth was 8.1 percent. Both of these figures are comparable to rates seen in the general population. Importantly, no characteristics related to the venom immunotherapy itself were found to be risk factors for these adverse pregnancy outcomes. During the 86 pregnancies, only one mild, self-limiting adverse event to a VIT injection occurred. Furthermore, five women experienced field stings during their pregnancy, and only one had a large local reaction, with no systemic reactions or adverse effects on the pregnancy.

Conclusions This study provides strong, prospective evidence that continuing well-tolerated maintenance venom immunotherapy during pregnancy is both safe and effective. It does not appear to increase the risk of abortion or preterm birth and maintains protection against stings. This data should give clinicians the confidence to recommend continuing this life-saving therapy, as the risk of anaphylaxis from an untreated allergy likely poses a far greater danger to both the mother and fetus.

If you only have time for one paper this week, make it the multicentre study on venom immunotherapy safety in pregnancy by Martini and colleagues in Allergy [3]. It provides clear, prospective data answering a common and high-stakes clinical question, giving clinicians confidence to continue this life-saving therapy in pregnant patients.

Here are the key takeaways from this week in Allergy & Immunology. First, in severe asthma, tezepelumab can induce clinical remission in about a third of patients, with much higher rates, approaching 50 percent, in those who are biologic-naïve and have high baseline eosinophils [1].

Second, for COPD with frequent exacerbations, the anti-ST2 antibody astegolimab showed inconsistent results across two major trials, suggesting a potential but not yet definitive role for targeting the IL-33 pathway [5].

Third, in sensitized but asymptomatic preschoolers, preventive house dust mite SLIT induces favorable immunologic changes, including blocking antibodies, supporting its potential to alter the natural history of allergy [2].

Fourth, for a common clinical dilemma, we now have strong prospective evidence that continuing maintenance venom immunotherapy during pregnancy is safe for the mother and fetus, with rates of adverse pregnancy outcomes similar to the general population [3].

And fifth, persistent *Alternaria* sensitization from childhood is a strong marker for persistent asthma and rhinitis in adulthood. In younger patients, testing for the component rAlt a 1 may be a better predictor of asthma risk than whole-extract IgE [4].

That's your roundup for This Week in Allergy & Immunology. The full transcript and references are available on the episode page in your AudioScholar library. This is an AI-curated summary — for clinical decisions, always consult primary sources and current guidelines. See you next week.

This is an automated summary generated by artificial intelligence, which can make mistakes. Always review the original source materials.