Urinary Leukotriene E4 as a Biomarker in NSAID-Exacerbated Respiratory Disease (N-ERD): a Systematic Review and Meta-analysis.

PURPOSE OF REVIEW: Non-steroidal exacerbated respiratory disease (N-ERD) currently requires aspirin challenge testing for diagnosis. Urinary leukotriene E4 (uLTE4) has been extensively investigated as potential biomarker in N-ERD. We aimed to assess the usefulness of uLTE4 as a biomarker in the diagnosis of N-ERD. RECENT FINDINGS: N-ERD, formerly known as aspirin-intolerant asthma (AIA), is characterised by increased leukotriene production. uLTE4 indicates cysteinyl leukotriene production, and a potential biomarker in N-ERD. Although several studies and have examined the relationship between uLTE4 and N-ERD, the usefulness of uLTE4 as a biomarker in a clinical setting remains unclear. FINDINGS: Our literature search identified 38 unique eligible studies, 35 were included in the meta-analysis. Meta-analysis was performed (i.e. pooled standardised mean difference (SMD) with 95% confidence intervals (95% CI)) and risk of bias assessed (implementing Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy (Cochrane DTA)). Data from 3376 subjects was analysed (1354 N-ERD, 1420 ATA, and 602 HC). uLTE4 was higher in N-ERD vs ATA (n = 35, SMD 0.80; 95% CI 0.72-0.89). uLTE4 increased following aspirin challenge in N-ERD (n = 12, SMD 0.56; 95% CI 0.26-0.85) but not ATA (n = 8, SMD 0.12; CI - 0.08-0.33). This systematic review and meta-analysis showed that uLTE4 is higher in N-ERD than ATA or HC. Likewise, people with N-ERD have greater increases in uLTE4 following aspirin challenge. However, due to the varied uLTE4 measurement and result reporting practice, clinical utility of these findings is limited. Future studies should be standardised to increase clinical significance and interpretability of the results.

Preschoolers with recurrent wheezing have a high prevalence of sleep disordered breathing.

Objective: Sleep-disordered breathing (SDB) is highly prevalent in school children with poorly-controlled asthma. However, this association has not been assessed in preschoolers with recurrent wheeze, nor in those at risk for asthma. We hypothesized that preschoolers with asthma risk (positive asthma predictive index [API]) have a higher prevalence of SDB and higher inflammatory biomarkers (blood-hsCRP and urinary-LTE4) levels than those with negative API.Method: Children 2 to 5 years of age with recurrent wheezing were classified as positive or negative API. SDB was determined by the pediatric sleep questionnaire (PSQ) and its subscale (PSQSub6). Demographic characteristics, spirometry, blood hsCRP and urinary LTE4 were assessed.Results: We enrolled 101 preschoolers: 70 completed all measurements, 55.4% were males, mean age 4.07 ± 0.87 years, 45% overweight or obese, 70% had positive API, 87.5% had rhinitis. The prevalence of SDB measured by PSQ was 40.8% and by PSQSub6 was 29.6%. However, the proportion of SDB was similar between positive and negative API groups. The hsCRP (mean ± SD) was higher in the positive than in negative API (3.58 ± 0.58 and 1.32 ± 0.36 mg/L, p = 0.69, respectively); moreover, no differences in urinary LTE4 were found between groups. No correlation of PSQ (+) or PSQSub6 (+) with hsCRP and uLTE4 was found. However, preschoolers with positive API had significantly more post-bronchodilator percentage change in FEF25-75 than negative API (24.14 ± 28.1 vs. 4.13 ± 21.8, respectively, p = 0.01).Conclusions: In preschoolers with recurrent wheezing, we should be investigating for the coexistence of SDB, using early screening methods for detecting those conditions.

Leucotrienos urinarios en pacientes pediátricos con trastorno respiratorio del sueño secundario a hiperplasia adenoamigdalina / Urinary leukotrienes in pediatric patients with sleep disordered breathing secondary to adenotonsillar hypertrophy

RESUMEN Introducción: El trastorno respiratorio del sueño (TRS) afecta al 2% a 3% de la población pediátrica, siendo la hiperplasia adenoamigdalina (HAA) su principal causa. Se ha observado un aumento en los niveles de leucotrienos excretados en orina (LTU) en estos pacientes, los cuales se correlacionarían con la severidad de la enfermedad. Objetivo: Determinar el nivel de LTU en niños con TRS e HAA antes y después de adenoamigdalectomía (AA), y en controles sanos. Correlacionar los niveles de LTU con los síntomas de TRS. Material y método: Estudio prospectivo. Se incluyeron pacientes con TRS e HAA (n =12) y controles sanos (n =12). Se determinó la concentración de LTU en ambos grupos de forma basal y un mes después de cirugía en el grupo con TRS. Resultados: No hubo diferencias en los niveles de LTU antes y después de AA. Tampoco existieron diferencias entre el grupo control y grupo TRS previo a la cirugía. No se encontró asociación entre LTU y la severidad de síntomas respiratorios. Conclusión: Los LTU no se encuentran elevados en pacientes con TRS e HAA, no disminuyen luego de AA y no se correlacionan con la severidad de los síntomas. La medición de LTU no sería una herramienta útil en la evaluación de pacientes con TRS. Nuevos estudios son necesarios para evaluar el rol de los leucotrienos en esta enfermedad.

ABSTRACT Introduction: Sleep disorder breathing (SDB) affects 2%-3% of the pediatric population, being adenotonsillar hyperplasia (ATH) its main cause. An increase in the levels of urinary leukotrienes (ULT) has been measured in these patients, which could be correlated with the severity of the disease. Aim: To determine the level of ULT in children with SDB and ATH before and after adenotonsillectomy, and healthy controls. To correlate the levels of ULT with symptoms of SDB. Material and method: prospective study. SDB and ATH patients (n =12) and healthy controls (n =12) were included. The concentration of ULT in both groups was determined, before surgery and after a month of surgery. Results: There were no differences in the levels of ULT before and after tonsillectomy in the studied group. There were also no differences between the control group and the SDB group. No association was observed between the level of ULT and the severity of respiratory symptoms. Conclusions: ULT are not elevated in patients with SDB and ATH and they do not decrease after adenotonsillectomy. ULT are not correlated with the severity of the symptoms of SDB. The measurement of ULT would not be a useful tool in the evaluation of patients with SDB. New studies are needed to assess the role of the role of leukotrienes in this disease.