This week in Allergy & Immunology

Welcome to This Week in Allergy and Immunology. This week we're covering nine notable papers spanning type 2 inflammation and where biologics are being pushed next, new biology and biomarkers in atopic dermatitis, and the social and economic burden of allergic disease. Let's dive in.

We start with the growing question of what to do when one biologic isn't enough. In Allergy, a retrospective multicentre series from six centres in Germany, the Netherlands and Italy described thirty-four adults with severe uncontrolled chronic rhinosinusitis with nasal polyps who were treated with two type 2 biologics at the same time [1]. These were complex patients — nearly all had asthma, thirteen had eosinophilic granulomatosis with polyangiitis, five had hypereosinophilic syndrome, and most had already failed multiple treatment attempts. The commonest pairings were dupilumab with mepolizumab and benralizumab with dupilumab. At six months, sinonasal outcomes improved substantially compared with baseline on single-biologic therapy — the SNOT-22 score fell by nearly thirty-three points, polyp score fell by just over three points, and smell improved significantly, although the change in overall disease severity on a visual analogue scale did not quite reach statistical significance. Four patients had dual therapy withdrawn and all four needed it reinstated after losing control. Adverse reactions occurred in about one in eight patients and were mild. The authors are appropriately cautious: this is uncontrolled, off-label in several European countries, expensive, and the long-term safety is unknown. But it does tell you that for the small group of patients with overlapping type 2 syndromes, dual blockade is being used and appears to work.

Staying with type 2 disease, the Annals of Allergy, Asthma and Immunology published a study asking whether small airways physiology predicts asthma remission [4]. Two hundred and thirty-seven adults with severe asthma at a tertiary centre were studied retrospectively, one hundred and twenty-seven on add-on benralizumab, dupilumab or tezepelumab and one hundred and ten on standard care. Remission was defined three ways — no exacerbations, no maintenance oral steroids, and a controlled Asthma Control Questionnaire score — and then four ways, adding stable lung function. Just over half of biologic-treated patients hit three-component remission and about a third hit four-component remission, compared with roughly forty-three percent and twenty-five percent on standard care. What's interesting is the physiology. A baseline exhaled nitric oxide of twenty-five parts per billion or more predicted remission on biologics, and an improvement in the oscillometry-derived area under the reactance curve of at least the minimal clinically important difference roughly two-and-a-half-fold increased the odds of four-component remission. Conversely, in the standard-care group, worse baseline peripheral airway reactance made three-component remission substantially less likely — cutting the odds by about two-thirds. The message is that the small airways are not just a research curiosity; they behave like a treatable trait, and oscillometry may add information that spirometry misses.

Alongside that, a Chinese multi-omics study in the same journal reminds us that not all nasal polyp disease is type 2 [6]. Integrating transcriptomics and metabolomics on nasal tissue from one hundred and three subjects, the investigators found that about thirty-one percent of polyp patients carried a high-Th17 signature. Clinically these patients looked like type 2 disease, with similar IgE and eosinophil elevations, but biologically they had shifted toward aerobic glycolysis and pro-inflammatory lipid mediators, and this correlated with squamous metaplasia and barrier keratinisation rather than the classic oedematous phenotype. Notably, patients with concurrently high Th2 and Th17 signals had a higher postoperative disease control rate than the pure Th2 subgroup, forty-eight percent versus twenty-five percent. That's hypothesis-generating, and it cautions against assuming that eosinophils and IgE alone define the endotype.

Rounding out this theme, JACI In Practice reported the largest series yet of eosinophilic cellulitis, or Wells' syndrome — one hundred and fourteen biopsy-proven cases [5]. Presentation was usually papulonodular and on the legs, disabling itch affected eighty-three percent, and systemic symptoms were rare. A quarter had an identifiable trigger, most often arthropod bites, and a fifth had an associated condition — haematological malignancy, ANCA-negative eosinophilic granulomatosis with polyangiitis, or idiopathic hypereosinophilic syndrome. Topical and oral corticosteroids produced complete response in sixty-seven and eighty-two percent respectively, conventional DMARDs performed poorly, and type 2 biologics looked promising. The one independent predictor of a recurrent or persistent course was lesion size greater than five centimetres, which nearly quadrupled the odds. So biopsy, screen for an underlying eosinophilic or haematological disorder, and flag large lesions as likely to relapse.

Turning to atopic dermatitis, two papers in Allergy approach severity from different angles. The first is a microbiome substudy of the JADE MOA trial of abrocitinib [2]. Forty-three patients with moderate-to-severe disease were randomised to abrocitinib one hundred or two hundred milligrams or placebo for twelve weeks, with serial skin swabs. Alpha diversity rose significantly by week twelve on the higher dose, the treated groups separated from placebo on beta diversity as early as week two, and Staphylococcus and Staph aureus relative abundance fell in a dose-dependent way — with those microbial shifts tracking clinical improvement and immune marker changes. The point is mechanistic: you can restore the cutaneous microbiome by targeting JAK1 systemically, without an antimicrobial. The second paper used Olink proteomics on serum from sixty-seven adults, thirty-three mild and thirty-four severe [8]. Four hundred and sixty-nine proteins differed, heavily enriched for epithelial proteins, and machine learning converged on nine — including CCL17, CCL22 and IL-22 — that discriminated mild from severe disease with a cross-validated area under the curve of nearly zero point nine nine. That number is almost certainly optimistic in a cross-sectional cohort with no healthy controls and no external validation, which the authors acknowledge. Treat it as a promising signature, not a test you can order.

Finally, three papers on burden and access. A systematic review in the Annals looked at Pru p 3-based immunotherapy for lipid transfer protein food allergy, a phenotype common in Mediterranean populations and notorious for cofactor-dependent systemic reactions [3]. Across fifteen mostly observational studies, sublingual and less often oral immunotherapy appeared to raise the reaction threshold to peach and sometimes to other LTP-containing foods, with the expected specific IgE and IgG4 shifts. But heterogeneity was substantial and controlled trials few, so the certainty of evidence is low — promising for selected patients, not yet standard of care. From Allergology International, a nationwide Japanese claims analysis quantified the scale of seasonal allergic rhinitis: nearly thirteen million patients with spring disease alone, prescription costs of about one hundred and two billion yen a year, roughly three visits per season, and eighty-three percent managed in small outpatient clinics [9]. Across all seasons that's twenty-four point seven million patients and one hundred and eighty-three billion yen — and the authors call that a conservative floor. And in JACI In Practice, a nationally representative United States survey found that markers of household poverty explained up to thirty-eight percent of the excess risk of upper respiratory infection among Black children with asthma and eighteen percent among Mexican American children [7]. Since viral infection is the dominant exacerbation trigger, housing is not a side issue — it's part of asthma control.

If you only have time for one paper this week, make it the oscillometry and remission study in the Annals of Allergy, Asthma and Immunology [4]. It gives you a concrete, measurable physiological marker to track alongside symptoms and exhaled nitric oxide when you're deciding whether a biologic is truly delivering remission.

Here are the key takeaways from this week in Allergy and Immunology. Dual type 2 biologic therapy can rescue a small, carefully selected group of nasal polyp patients with overlapping eosinophilic syndromes, but it remains off-label, costly and unproven long term. Small airways dysfunction measured by oscillometry behaves as a treatable trait and its improvement tracks with four-component remission in severe asthma. Not all nasal polyp disease is type 2 — a mixed Th2/Th17 metabolic endotype exists and may explain surgical recalcitrance. In atopic dermatitis, JAK1 inhibition reduces Staph aureus and restores microbial diversity, while serum proteomics is beginning to define severity signatures that still need validation. And for Wells' syndrome, large lesions predict relapse, while corticosteroids remain first line and type 2 biologics look like reasonable second-line candidates. Finally, don't overlook the social and economic layer — housing conditions and out-of-pocket drug costs shape outcomes as much as prescriptions do.

That's your roundup for This Week in Allergy and 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.

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