BackgroundImmunoglobulin A is the most abundant isotype in secretions from mucosal surfaces of the gastrointestinal, respiratory and genitourinary tracts and in external secretions such as colostrum, breast milk, tears and saliva. The high concentration of human secretory IgA (hsIgA) in human colostrum strongly suggests that it should play an important role in the passive immune protection against gastrointestinal and respiratory infections.Materials and methodsHuman secretory IgA was purified from colostrum. The reactivity of hsIgA against mycobacterial antigens and its protective capacity against mycobacterial infection was evaluated.ResultsThe passive administration of hsIgA reduces the pneumonic area before challenge with M. tuberculosis. The intratracheal administration of M. tuberculosis preincubated with hsIgA to mice greatly reduced the bacterial load in the lungs and diminished lung tissue injury.ConclusionsHsIgA purified from colostrum protects against M. tuberculosis infection in an experimental mouse model.

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Background In March 2020 our Institution was designated a COVID-19 unit, since the start of 2021 conventional medical attention has been reinstalled and it became a hybrid hospital. Our objective was to compare the outcome of patients with Invasive Aspergillosis (IA) without COVID-19 during the COVID-19 pandemic, compared with past controls from a historical cohort, and describe their clinical characteristics. As a secondary objective, we described the characteristics of other Invasive Fungal Infections (IFI) in a similar patient group. Methods Retrospective and descriptive study. The information was obtained from the electronic file. For IFI diagnosis, the EORTC/MSG criteria for proven and probable infection were considered, including the AspiCU modified criteria. The main outcome was death at 6 weeks, time from symptom onset to diagnosis/treatment, and having received antifungal treatment as secondary outcomes. Outcomes were compared to historical IA controls (2:1) from a pre-COVID-19 cohort. The study was approved by the local research and ethics committee. Results From March 2020 to December 2021, 50 IFIs were diagnosed in non-COVID-19 patients, of which 27 (54%) were Invasive Aspergillosis, 10 (20%) Cryptococcosis, 8(16%) histoplasmosis, 4 (8%) mucormycosis, and 1 (2%) Fusariosis. The median age was 44 years (IQR 33-58) and 67% were men. Forty three percent (22/51) had immunosuppression and 35% (18/51) had hematological malignancy, the median time from symptom onset to IFI diagnosis was 30 days (IQR 11-90) and 38% died within 6 weeks. During the pandemic, in Invasive Aspergillosis non COVID-19 patients, the median number of days from symptom onset to start antifungal was 21 (IQR 6-68) vs 5 (IQR 3-10) of IA historic controls (p=0.0005), 81.5% (22/27) vs 93% (50/54) received antifungal treatment (OR 0.88 , 95% CI 0.72-1.0,p=0.13), and IA cases had a mortality of 44% (12/27) vs 41% (22/54) in the historical cohort (p=0.75). We show the IA characteristics in Table 1. Table 1.Clinical characteristics of Patients with Invasive aspergillosis without COVID-19 during COVID-19 pandemic vs historic controlsFigure 1.Invasive fungal infections in non-COVID-19 patients during COVID-19 pandemicFigure 2.Invasive aspergillosis diagnosis methods in non-COVID-19 patients during COVID-19 pandemic GM: Galactomannan antigen Conclusion During the COVID-19 pandemic, patients with IA withouth COVID-19 were diagnosed significantly later. Also, a trend towards increased mortality and lower proportion of antifungal treatment was observed. It is likely a consequence of hospital reconversion during the start of the pandemic. Disclosures All Authors: No reported disclosures.