This study aimed to describe clinical and laboratory.characteristics of a population of patients with asthma and to investigate the potential role of FLCs as quantitative and objective serum biomarkers.FLC-κ levels were significantly increased in the asthmatic population, compared to the control group.FLC-λ levels displayed a significant negative correlation with the FEV1 value and were significantly decreased in patients treated with OCS.Abbreviations: ACT, Asthma Control Test; ACQ-5, Asthma Control Questionnaire 5; FeNo, Fractional Exhaled Nitric Oxide; FEV1; forced expiratory volume in the first second; FLC, free light chain; Ig, immunoglobulin; OCS, oral corticosteroids; SNOT-22, Sino-nasal Outcome Test 22.

Patients with chronic spontaneous urticaria (CSU) have higher numbers of CD117⁺ CD34⁺FcεRI⁺ progenitors in peripheral blood. Higher numbers of CD117⁺CD34⁺FcεRI⁺ progenitors are associated with a more rapid response to anti-immunoglobulin E therapy in CSU patients. Single-cell RNA sequencing shows the CD117⁺CD34⁺ cells contain mast cell precursors but also related immature FcεRI⁻ and FcεRI⁺ progenitors.Abbreviations: AUC, area under the curve; CSU, chronic spontaneous urticaria, IgE, immunoglobulin E.

Increased levels of circulating Gal-9⁺ eosinophils and Gal-9⁺ basophils in CSU lined to high disease activity, markers of non-autoimmune CSU, and good response to omalizumab treatment. Elevated serum TNF-α levels led to an increase in Gal-9 expression in CSU patients. The rates of Gal-9⁺ eosinophils and basophils were negatively linked to levels of TIM-3⁺ TH17 cells, suggesting that Gal-9 via TIM-3 protect CSU patients from type IIb autoimmunity.Abbreviations: BAT, basophil activation test; CSU, chronic spontaneous urticaria; Gal-9, Galectin-9; IgE, immunoglobulin E; OMA, omalizumab; TIM-3, T cell immunoglobulin-and mucin-domain-containing molecule-3 (Gal-9 ligand); TNF, tumor necrosis factor.

We conducted a prospective, multicentric, observational study, including 153 patients diagnosed with chonic urticaria and starting omalizumab. Twenty percent of patients at M3 were updosed, and 27% during the 9-month follow-up. Practitioners mainly chose to increase the frequency of injections (66%). At baseline, the updosed patients were more likely, to have inducible urticaria, severe urticaria, lower IgE and lymphocyte count.

In this multicenter study, we have demonstrated that clonal mast cell disease and HαT are more prevalent among individuals who need VIT; one or both was found in 27% of individuals overall. Both diagnoses were highly concentrated among individuals with severe anaphylaxis. Higher KIT p.D816V allelic burden was associated with more severe reactions. Abbreviations: BMM, bone marrow mastocytosis; BST, basal serum tryptase; HαT, hereditary alpha tryptasemia; ISM, indolent systemic mastocytosis; MMAS, monoclonal mast cell activation syndrome; PBL, peripheral blood leukocytes; VIT, venom immunotherapy.

HR are mainly triggered by Hymenoptera venoms in patients with CM and ISM and by drugs in patients with advSM. Tryptase levels <90 ng/mL, mast cell bone marrow infiltration <15%, and WHO category ISM are predictors of HR. New HR occur in 4.8% of all patients within 4 years.Abbreviations: advSM, advanced systemic mastocytosis; ASM, aggressive systemic mastocytosis; CI, confidence interval; HR, hypersensitivity reaction; ISM, indolent systemic mastocytosis; MCL, mast cell leukemia; MCPM, maculopapular cutaneous mastocytosis; MIS, mastocytosis in the skin; OR, odds ratio; SM-AHN, systemic mastocytosis with associated hematological neoplasm; SSM, smoldering systemic mastocytosis; WHO, World Health Organization.

COVID-19 leads to a sustained reduction of immune cells of the myeloid and lymphoid cell lineages even 10 months after the first infection. Ten months after the first infection, S- and RBD-specific IgG responses declined below the detection limit in almost 18% and in more than 80% in subjects, respectively. Anti-NC antibodies remained positive in all subjects 10 m after the first infection. A shift towards a Th2 cytokine pattern in serum accompanied by an inversion of the IFN-γ/IL-4-ratio was found between the time point 10 weeks and 10 months after infection.Abbreviations: CD, cluster of differentiation; COVID-19, coronavirus disease 2019; IL, interleukin; IFN, interferon; NC, nucleocapsid protein; NK, natural killer; RBD, receptor binding domain; RTE, recent thymic emigrants; S, spike protein; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.

We analyze some of the mechanisms underlying allergic reactions to COVID-19 mRNA vaccines. After performing hemolysis, indirect basophil activation, and single-cell multiome assays, we elucidated certain allergic reaction mechanisms. We found anti-PEG IgG correlates with vaccine-mediated complement activation and that epigenetic modulation of mononuclear phagocytes could influence vaccine reaction manifestations.Abbreviations: AP-1, activator protein 1; C1q, complement component 1q; C3, complement component 3; COVID-19, coronavirus disease 2019; CP, classical pathway; MAPK, mitogen-activated protein kinase; NF-κB, nuclear factor kappa-light-chain-enhancer; NLRP3, nucleotide-binding domain, leucine-rich–containing family, pyrin domain–containing-3; PEG, polyethylene glycol; siRNA seq, small interfering RNA sequencing; TLR, Toll-like receptor.