Determinants of blood eosinophil levels in the general population and patients with COPD: a population-based, epidemiological study.

BACKGROUND: Blood eosinophils are considered a biomarker for the treatment of chronic obstructive pulmonary disease (COPD). Population-based studies are needed to better understand the determinants of the blood eosinophil count (BEC) in individuals with and without COPD. METHODS: EPISCAN II is a multicentre, cross-sectional, population-based epidemiological study aimed at investigating the prevalence and determinants of COPD in Spain. Study subjects were randomly selected from the general population, and COPD was defined by a post-bronchodilator FEV1/FVC < 0.7. For the pre-specified outcomes related to BEC, the first 35 COPD and 35 non-COPD subjects were consecutively recruited in 12 of the participating centres with the objective of analysing 400 individuals in each group. Baseline BEC and its association with demographic, clinical and functional variables were analysed. RESULTS: A total of 326 COPD and 399 non-COPD subjects were included in the analysis. The mean age (standard deviation [SD]) was 63.2 years (11.0), 46.3% were male, and 27.6% were active smokers. BEC was significantly higher in individuals with COPD [192 cells/µL (SD: 125) vs. 160 cells/µL (SD: 114); p = 0.0003]. In a stepwise multivariate model, being male, active smoker and having a previous diagnosis of asthma were independently associated with having a higher BEC. CONCLUSIONS: This population-based study estimated the distribution of eosinophils in the healthy adult population and concluded that COPD patients have a significantly higher BEC. Male sex, active smoking and concomitant asthma were significantly associated with a higher BEC.

Circulating BAFF as novel biomarker in distinguishing chronic rhinosinusitis with nasal polyps endotypes and predicting postoperative recurrence.

BACKGROUND: B cell-activating factor (BAFF) is a proinflammatory cytokine involved in inflammatory and allergic diseases, but its role in chronic rhinosinusitis with nasal polyps (CRSwNP) remains unclear. This study aims to explore the predictive value of circulating BAFF in CRSwNP endotypes and postoperative recurrence. METHODS: We recruited 120 CRSwNP patients, including 68 non-eosinophilic CRSwNP (neCRSwNP) patients, 52 eosinophilic CRSwNP (CRSwNP) patients, and 60 healthy controls (HCs). Circulating BAFF levels of all participants were measured by enzyme-linked immunosorbent assay (ELISA), and receiver-operating characteristic (ROC) and logistic regression analyses were applied to assess the predictive ability of BAFF levels in distinguishing CRSwNP endotypes. All CRSwNP patients were followed for more than 3 years, and the predictive value of circulating BAFF for postoperative recurrence was evaluated. RESULTS: Serum BAFF levels were elevated in CRSwNP patients compared with the HCs (P < 0.01) and significantly higher in eCRSwNP patients. The increased serum BAFF concentrations positively correlated with blood eosinophil counts and percentages, tissue eosinophil counts, and serum total IgE (P < 0.05). The ROC curve showed that serum BAFF exhibited strong discriminative ability for eCRSwNP. Finally, 99 CRSwNP patients completed the follow-up schedule, 65 patients were classified into non-recurrence group and the other 34 patients were categorized into recurrence group. Serum BAFF levels were significantly higher in recurrence group than non-recurrence group (P < 0.001), and the ROC curve suggested a high predictive value of serum BAFF in predicting postoperative recurrence. Moreover, logistic regression and Kaplan-Meier curves showed that serum BAFF was an independent risk factor for postoperative recurrence (P < 0.05). CONCLUSION: Our data suggested that serum BAFF levels were upregulated in CRSwNP patients and correlated with mucosal eosinophil infiltration severity. Serum BAFF seemed to be a novel biomarker for preoperatively distinguishing CRSwNP endotypes and predicting postoperative recurrence.

Síndrome DRESS secundária ao uso de alopurinol: um relato de caso / DRESS syndrome secondary to the use of allopurinol: a case report

A Síndrome de DRESS (do inglês, Drug Rash with Eosinophilia and Systemic Symptoms) é uma patologia rara que consiste em uma severa reação medicamentosa mediada por células T. O presente relato de caso retrata uma paciente do sexo feminino, 59 anos, que apresentou icterícia, febre não termometrada, acolia, colúria, mialgia, placas hipercrômicas e lesões pruriginosas. Referiu uso recente de alopurinol, paracetamol e nimesulida, apresentando melhora importante e espontânea após a suspensão das medicações. A extensão do tempo de exposição ao medicamento agressor ocasiona um maior período de internação e risco de mortalidade. Além disso, os dados restritos sobre a Síndrome de DRESS impõe desafios ao seu diagnóstico. Sendo assim, este estudo busca destacar a importância do diagnóstico clínico precoce, a suspensão do medicamento agressor e a instituição da terapêutica adequada para um prognóstico favorável

The Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) Syndrome is a rare pathology that consists of a severe drug reaction mediated by T cells. The present case report depicts a female patient, 59 years old, who presented jaundice, non thermometered fever, acholia, choluria, myalgia, hyperchromic plaques and pruritic lesions. She mentioned recent use of allopurinol, paracetamol and nimesulide, showing significant and spontaneous improvement after discontinuation of medications. The extension of time of exposure to the offending drug causes a longer period of hospitalization and risk of mortality. In addition, the restricted data on DRESS Syndrome poses challenges to its diagnosis. Therefore, this study seeks to highlight the importance of early clinical diagnosis, suspension of the offending drug and the institution of appropriate therapy for a favorable prognosis

Incidence, aetiology and clinical features of eosinophilic pleural effusion: a retrospective study.

BACKGROUND: Eosinophilic pleural effusion (EPE) is a distinct entity among pleural effusions, but its diagnostic and prognostic significance is still controversial. This study aimed to evaluate the incidence and aetiological distribution of EPE in our institution and to assess the relationship between EPE and malignancy and other underlying diseases and the relevance of the percentage of eosinophils and other laboratory parameters. METHODS: A retrospective study was conducted by reviewing the medical records of 252 patients with PE from September 2017 to January 2021. RESULTS: EPE was found in 34 (13.49%) out of 252 patients. There were 20 (58.82%) males and 14 (41.18%) females in the EPE group. The mean percentage of eosinophils in EPE (21.7%, range (10.0-67.5%)) was significantly higher than the percentage of eosinophils in peripheral blood (5.65%, range (0-34.60%); p < 0.05). The most common cause of EPE was malignant disease (52.94%), followed by idiopathy (14.71%), parasites (8.82%), pneumonia (8.82%) and others (14.71%). Comparative analysis of patients with malignant versus nonmalignant EPE showed that patients with malignant EPE were significantly older, and had a lower white blood cell (WBC) count in the pleural fluid (1.8 vs 4.7 cells × 109/L, p < 0.05). However, the percentage of eosinophils in PE was not significantly different between malignant EPE and nonmalignant EPE (p = 0.66). There was no correlation between the percentage of eosinophils in PE and peripheral blood (r = 0.29; p = 0.09). CONCLUSIONS: Malignant disease ranks as the leading cause of EPE. The presence of EPE should not be considered as a predictive factor of benign conditions. Pleural parasitic infestation (PPI) should be emphasized in areas with a high incidence of parasitic disease.

Time-dependent blood eosinophilia count increases the risk of kidney allograft rejection.

BACKGROUND: Growing evidence suggest that type 2 immune effectors play a role in solid organ transplantation. The aim of this study was to evaluate the impact of blood count eosinophils (BCEo) on immunological outcomes in kidney transplant recipients with stable graft function after 3 months post-transplant. METHOD: We performed cause-specific Cox model considering BCEo, the use of calcineurin inhibitors and systemic corticoids as time-dependent explicative variables on a prospective cohort of 1013 kidney transplant patients who experienced kidney allograft rejection and/or the appearance of de novo donor specific antibodies after excluding common causes of increased BCEo.. FINDINGS: BCEo ≥ 0.3 G/L was associated with a 3-fold increased risk of rejection independent of immunosuppressive regimen after 3 months post-transplant in patients without pre-transplant DSAs and with CNI-based immunosuppression. No association between BCEo either with donor specific antibodies or graft survival was noticed. INTERPRETATION: These observations in this large cohort support the hypothesis of eosinophils in allo-immunity in human and claim for further mechanistic research. FUNDING: This study was supported by the French National Research Agency, The "Institut de Recherche en Santé Respiratoire des Pays de la Loire" and the University hospital of Nantes.

Plasma levels of D-dimer and fibrin degradation products correlate with bullous pemphigoid severity: a cross-sectional study.

Bullous pemphigoid (BP), the most frequent blistering dermatosis in the elderly, is associated with increased mortality. The severity of BP can be assessed by detecting the anti-BP180 immunoglobulin G (IgG) concentration, but the lab test is not available in many community clinics. BP patients are usually in a hypercoagulable state with increased levels of D-dimer and fibrin degradation products (FDPs). We aimed to evaluate the use of D-dimer and FDPs in assessing BP severity. We compared the levels of plasma D-dimer, plasma FDPs, eosinophil counts, eosinophil cationic protein, and serum anti-BP180 IgG concentration between 48 typical BP patients and 33 Herpes zoster (HZ) patients (control group). Correlational analyses were conducted to determine the relationships between the lab values and common BP severity markers. The plasma D-dimer and FDP levels were higher in BP patients than in HZ controls (D-dimer: 3297 ± 2517 µg/L vs. 569.70 ± 412.40 µg/L; FDP: 9.74 ± 5.88 mg/L vs. 2.02 ± 1.69 mg/L, respectively, P < 0.0001). Significant positive correlations were found between D-dimer/FDP levels and BP severity markers (i.e. anti-BP180 IgG concentration [D-dimer: r = 0.3928, P = 0.0058; FDP: r = 0.4379, P = 0.0019] and eosinophil counts [D-dimer: r = 0.3625, P = 0.0013; FDP: r = 0.2880, P = 0.0472]) in BP patients. We also found an association between FDP and urticaria/erythema lesions (r = 0.3016, P = 0.0372), but no other BPDAI components. In 19 BP patients with complete remission after systemic glucocorticoid treatment, D-dimer and FDP levels decreased post-therapy (D-dimer: 5559 ± 7492 µg/L vs. 1738 ± 1478 µg/L; P < 0.0001; FDP: 11.20 ± 5.88 mg/L vs. 5.13 ± 3.44 mg/L; P = 0.0003), whereas they did not in BP patients with treatment resistant. Plasma D-dimer and FDP are convenient markers to evaluate BP severity assistant on BPDAI and eosinophil counts. FDP is also helpful for inflammatory lesions in BP patients.

Rhinovirus C Infection Induces Type 2 Innate Lymphoid Cell Expansion and Eosinophilic Airway Inflammation.

Rhinovirus C (RV-C) infection is associated with severe asthma exacerbations. Since type 2 inflammation is an important disease mechanism in asthma, we hypothesized that RV-C infection, in contrast to RV-A, preferentially stimulates type 2 inflammation, leading to exacerbated eosinophilic inflammation. To test this, we developed a mouse model of RV-C15 airways disease. RV-C15 was generated from the full-length cDNA clone and grown in HeLa-E8 cells expressing human CDHR3. BALB/c mice were inoculated intranasally with 5 x 106 ePFU RV-C15, RV-A1B or sham. Mice inoculated with RV-C15 showed lung viral titers of 1 x 105 TCID50 units 24 h after infection, with levels declining thereafter. IFN-α, ß, γ and λ2 mRNAs peaked 24-72 hrs post-infection. Immunofluorescence verified colocalization of RV-C15, CDHR3 and acetyl-α-tubulin in mouse ciliated airway epithelial cells. Compared to RV-A1B, mice infected with RV-C15 demonstrated higher bronchoalveolar eosinophils, mRNA expression of IL-5, IL-13, IL-25, Muc5ac and Gob5/Clca, protein production of IL-5, IL-13, IL-25, IL-33 and TSLP, and expansion of type 2 innate lymphoid cells. Analogous results were found in mice treated with house dust mite before infection, including increased airway responsiveness. In contrast to Rorafl/fl littermates, RV-C-infected Rorafl/flIl7rcre mice deficient in ILC2s failed to show eosinophilic inflammation or mRNA expression of IL-13, Muc5ac and Muc5b. We conclude that, compared to RV-A1B, RV-C15 infection induces ILC2-dependent type 2 airway inflammation, providing insight into the mechanism of RV-C-induced asthma exacerbations.

Repeated exposure of house dust mite induces progressive airway inflammation in mice: Differential roles of CCL17 and IL-13.

We conducted a systematic evaluation of lung inflammation indued by repeated intranasal exposure (for 10 consecutive days) to a human aeroallergen, house dust mite (HDM) in BALB/c mice. Peak influx of neutrophils, monocytes/lymphocytes, and eosinophils was observed in bronchoalveolar lavage (BAL) on days 1, 7 and 11, respectively, and normalized to baseline by day 21. Peak elevations of Th2, myeloid-derived cytokines/chemokines and serum IgE were seen both in BAL and lung tissue homogenates between days 7 and 11, and declined thereafter; however, IL-33 levels remained elevated from day 7 to day 21. Airway hyperreactivity to inhaled methacholine was significantly increased by day 11 and decreased to baseline by day 21. The lung tissue showed perivascular and peribronchial cuffing, epithelial hypertrophy and hyperplasia and goblet cell formation in airways by day 11, and resolution by day 21. Levels of soluble collagen and tissue inhibitors of metalloproteinases (TIMP) also increased reflecting tissue remodeling in the lung. Microarray analysis demonstrated a significant time-dependent up-regulation of several genes including IL-33, CLCA3, CCL17, CD4, CD10, CD27, IL-13, Foxa3, IL-4, IL-10, and CD19, in BAL cells as well as the lung. Pre-treatment of HDM challenged mice with CCL17 and IL-13 antibodies reduced BAL cellularity, airway hyper-responsiveness (AHR), and histopathological changes. Notably, anti-IL-13, but not anti-CCL17 monoclonal antibodies (mAbs) reduced BAL neutrophilia while both mAbs attenuated eosinophilia. These results suggest that CCL17 has an overlapping, yet distinct profile versus IL-13 in the HDM model of pulmonary inflammation and potential for CCL17-based therapeutics in treating Th2 inflammation.

The association between eosinophilic exacerbation and eosinophilic levels in stable COPD.

BACKGROUND: Blood eosinophil count may predict treatment response in patients with chronic obstructive pulmonary disease (COPD) during acute exacerbations (AE). However, the ability and thresholds of blood eosinophil counts in stable status to predict eosinophilic AECOPD have not been completely investigated. METHODS: This was a retrospective multicenter study performed January 2010 to December 2014. COPD subjects hospitalized with exacerbations, were included. Blood samples were obtained at the time of AE and stable disease at outpatient clinic before or after admission. We identified a blood eosinophil count cut-off point at stable COPD, either taken as a percentage or as absolute value, for identification of eosinophilic exacerbation. RESULTS: There was significant positive correlation of eosinophil counts between stable COPD and AECOPD. The best cut-off value of blood eosinophil count in stable status for the prediction of eosinophilic COPD exacerbation based on blood eosinophil count ≥ 2% was 300 cells/µL (area under the ROC curve [AUC] 0.614, P = 0.001, 39% sensitivity, 83.8% specificity). When the eosinophilic COPD exacerbation was based on blood eosinophil count ≥ 300 cells/µL, the best cut-off value of blood eosinophil count in stable status for the prediction of eosinophilic COPD exacerbation was also 300 cells/uL (AUC 0.634, P = 0.046, 45.8% sensitivity, 80.9% specificity). CONCLUSIONS: We demonstrated association between blood eosinophil counts at stable COPD and those with AECOPD. The thresholds of blood counts at stable COPD to predict eosinophilic exacerbations was 300 cells/µL. Further and prospective studies in other populations should validate our results.

Allergy-Related Sialodochitis: A Preliminary Cohort Study.

OBJECTIVES/HYPOTHESIS: To explore the clinically feasible diagnosis criteria and treatment outcomes of allergy-related sialodochitis (ARS). STUDY DESIGN: Prospective Cohort Study. METHODS: Ninety-six consecutive patients were enrolled by the following criteria: 1) recurrent swelling of ≥2 large salivary glands that lasted for ≥3 months; 2) with mucus plug exudations; 3) with atopic diseases; 4) ductal stenosis and/or ectasia. Sixty-four patients with elevation of peripheral blood eosinophil (PBE) and/or serum IgE level comprised group A (highly-suspected ARS group), while the remaining 32 comprised group B (patients without confirmed evidence of ARS). These patients were treated with interventional endoscopy. A chronic obstructive sialadenitis symptom (COSS) questionnaire was used to quantify the treatment outcomes. RESULTS: In group A, Serum IgE was elevated in 84.4% of patients and PBE was elevated in 34.4% of patients. Percentage of submandibular gland involvement was higher in group A than group B (48.4% vs. 18.8%). On sialograms, the snowflake changes of branch ducts were seen in higher percentage of group A compared with group B (59% vs. 35% for parotid glands, 27% vs. 8% for submandibular glands, respectively). Mucus plug smears showed abundant eosinophils in 14 group A patients. Biopsy of five group A patients revealed significant eosinophil infiltration around the main and interlobular ducts. During follow-up, the COSS scores were significantly decreased in both groups, and group B was improved better than group A. CONCLUSION: PBE and serum IgE are important diagnostic indexes of ARS. Mucus plug smear or histopathology verifies the diagnosis. Interventional endoscopy is helpful for ARS cases. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2030-2035, 2021.

Clinical evaluation of type 2 disease status in a real-world population of difficult to manage asthma using historic electronic healthcare records of blood eosinophil counts.

BACKGROUND: Blood eosinophil measurement is essential for the phenotypic characterization of patients with difficult asthma and in determining eligibility for anti-IL-5/IL-5Rα biological therapies. However, assessing such measures over limited time spans may not reveal the true underlying eosinophilic phenotype, as treatment, including daily oral corticosteroid therapy, suppresses eosinophilic inflammation and asthma is intrinsically variable. METHODS: We interrogated the electronic healthcare records of patients in the Wessex AsThma CoHort of difficult asthma (WATCH) study (UK). In 501 patients being evaluated in this tertiary care centre for difficult to control asthma, all requested full blood count test results in a 10-year retrospective period from the index WATCH assessment were investigated (n = 11,176). RESULTS: In 235 biological therapy-naïve participants who had 10 or more measures in this time period, 40.3% were eosinophilic (blood eosinophils ≥300 cells/µl) at WATCH enrolment whilst an additional 43.1%, though not eosinophilic at enrolment, demonstrated eosinophilia at least once in the preceding decade. Persistent eosinophilia was associated with worse post-bronchodilator airway obstruction and higher Fractional exhaled Nitric Oxide (FeNO). In contrast, the 16.6% of patients who never demonstrated eosinophilia at this blood eosinophil threshold showed preserved lung function and lower markers of Type 2 inflammation. CONCLUSIONS: This highlights the central role that type 2 inflammation, as indicated by blood eosinophilia, has in difficult asthma and suggests that longitudinal electronic healthcare record analysis can be an important tool in clinical asthma phenotyping, providing insight that may help understand disease progression and better guide more specific treatment approaches.

Food allergy as an asthma comorbidity in children and adolescents: a practical approach through a real-world study

INTRODUCTION: Several studies have shown interactions between food allergy (FA) and asthma, but the influence of FA in asthma traits has been scarcely studied. METHODS: A real-world retrospective observational study was conducted among patients between 3 and 18 years old referred to our Asthma Clinic from November 2014 to November 2017. Data were obtained from daily clinical practice. Only patients properly diagnosed with asthma and FA were included. RESULTS: 815 patients were included: 483 asthmatics and 332 non-asthmatics and 180 FA and 635 no FA. Food allergy was statistically more prevalent among asthma patients (p = 0.014). In a high pollen exposure area, Madrid, among subjects with asthma (121 FA, 362 no-FA), sensitiza­tion to lipid transfer protein (LTP) (p = 0.016, OR: 3.064, RR: 2.512) and pollen (p = 0.016, OR: 3.064, RR: 2.512) are risk factors to have a concomitant FA diagnosis, whereas sensitization to profilin is not. Peripheral blood eosinophils were higher in subjects with asthma and FA (≥450 eos/μL) than in asthmatics without FA (≤300 eos/μL) (p = 0.031). Blood eosinophilia, using a cut-off >300 eos/μL, was only present in the FA group. Therefore, this trait should be considered when phenotyping a patient as eosinophilic asthma. Sex had an impact on several variables: height, weight, BMI, blood eosinophils count, sensitization profile, and early-onset asthma. CONCLUSIONS: Asthma and FA are closely related and the presence of FA should be investigated in every asthma patient. This study shows an association between asthma with concomitant FA and sensitization to pollen and LTP, blood eosinophilia, and growth alterations. Differences between boys and girls were also described, so a sex-specific approach is recommended

No disponible

Heart disease in eosinophilic granulomatosis with polyangiitis (EGPA) patients: a screening approach proposal.

OBJECTIVE: To define the pattern of cardiac involvement in eosinophilic granulomatosis and polyangiitis (EGPA) and propose an algorithm for heart disease screening. METHODS: This was a retrospective study of EGPA patients attending a specialized vasculitis clinic (1989-2016). Clinical characteristics and cardiovascular evaluation (CE) results (serum troponin, ECG, echocardiography and cardiac magnetic resonance) were collected and compared according to symptoms and inflammatory cardiac disease (ICD). RESULTS: A total of 131 EGPA patients were included, of whom 96 (73%) had undergone CE. The median (interquartile range) age was 50 (38-58) years and 36% showed ANCA+. Asthma preceded diagnosis by a median of 97 (36-240) months. Among the 96 patients who underwent CE, 43% were symptomatic, with dyspnea (47%) and chest pain (29%) being the predominant symptoms. In asymptomatic patients, CE reported abnormalities in 45% of cases, with a subsequent earlier diagnosis (4 vs 11 months). Overall, 27 patients had EGPA-related ICD (EGPA-rICD) that was already present at diagnosis in 20 cases, preceded it in 2 cases and developed later in 5 cases. EGPA-rICD patients were younger (46 vs 50 years; P = 0.04), had more frequently abnormal ECG (30.8 vs 2.1%; P < 0.001), negative ANCA (85 vs 69%; NS), higher BVAS score (3 vs 1; P = 0.005), higher eosinophil count (5.60 vs 1.60 × 109/l; P = 0.029) and higher CRP (52 vs 15 mg/l; P = 0.017). Overall, 11% of cases with EGPA-rICD were asymptomatic. CONCLUSION: In our study, 45% of asymptomatic patients had an abnormal baseline cardiac evaluation, which allowed an earlier diagnosis of cardiac disease. We recommend prompt cardiac screening in all EGPA patients, instead of a symptoms-guided algorithm.

Identification of a Novel CSNK2A1-PDGFRB Fusion Gene in a Patient with Myeloid Neoplasm with Eosinophilia.

Platelet-derived growth factor receptor beta (PDGFRB) rearrangements play an important role in the pathogenesis of eosinophilia-associated myeloid/lymphoid neoplasms. Up to now, more than 70 PDGFRB fusions have been identified. Here, a novel PDGFRB fusion gene CSNK2A1-PDGFRB has been identified in myeloproliferative neoplasm (MPN) with eosinophilia by RNA-sequencing, which has been verified by reverse transcription polymerase chain reaction and Sanger sequencing. The new PDGFRB fusion partner gene CSNK2A1 encoded one of the two catalytic subunit of casein kinase II (CK2). To our knowledge, this is the first report on the involvement of CSNK2A1 in fusion genes, especially fusion with another kinase PDGFRB in MPN. In addition, the CSNK2A1-PDGFRB fusion retained the entire kinase domain of PDGFRB and response to imatinib at low concentration. The patient with CSNK2A1-PDGFRB was sensitive to imatinib treatment and acquired sustained complete remission.

Blood eosinophils associate with reduced lung function growth in adolescent asthmatics.

BACKGROUND AND OBJECTIVE: Some children with asthma have low lung growth, putting them at increased risk for COPD later in life. However, it is currently not clear who will experience this adverse growth pattern. We therefore investigated the predictive role of blood eosinophils as a type 2 inflammation marker in lung growth, focusing on the presence and severity of asthma. METHODS: We investigated blood eosinophils and lung function growth (percentage of predicted values) using linear mixed models in children and adolescents from two longitudinal cohorts. One cohort was hospital-based and consisted of asthmatic children at their first outpatient clinic visit after referral by the general practitioner (n = 133, mean age 9.8), while the second was a general population-based birth cohort (PIAMA, asthma n = 52 and non-asthma n = 433, mean age 8.1). The hospital-based cohort had not been treated with inhaled corticosteroids (ICS) before referral. RESULTS: Subjects in the hospital-based asthma cohort had more severe asthma compared with the asthmatic subjects in the population-based cohort, defined by lower lung function levels and a higher prevalence of bronchial hyper-responsiveness. In the asthma cohort, higher blood eosinophil numbers were associated with less growth in FEV1 (estimated change in lung function per 1 unit increase in ln blood eosinophils (B): -0.66%/year (95% confidence interval (CI): -1.11 to -0.20, p < .01)) and FVC (B: -0.40%/year (95% CI: -0.75 to -0.05), p = .025)) during follow-up in adolescence (min 7, max 17 years). These associations were not observed in the general population-based birth cohort, regardless of asthma status during follow-up (age 8-16). CONCLUSIONS AND CLINICAL RELEVANCE: Blood eosinophil counts in children with asthma not treated with ICS at referral were predictive of lower growth in FEV1 and FVC during follow-up in adolescence. Our findings indicate that this association is dependent on the degree of asthma severity. Future studies should address whether anti-eosinophilic treatments preserve lung function growth in children with asthma.