The impact of mannose-binding lectin (MBL) deficiency on bronchiectasis in Alpha-1 Antitrypsin Deficiency

<bold>INTRODUCTION:</bold> Mannose-binding lectin (MBL) is an important component of the innate immune system. An association between low levels of MBL and increased susceptibility to infection remains unclear. Alpha-1 antitrypsin deficiency (AATD) patients have been reported to have higher frequency of bronchiectasis [1], and various mechanisms may be involved [2]. To our knowledge no previous studies have looked at the impact of MBL deficiency in a cohort already predisposed to bronchiectasis through AATD. <bold>METHODS:</bold> We evaluated a total of 604 patients with AATD participating in a National AATD Registry. We analysed bronchiectasis status with biochemical markers including MBL, IgG and IgE levels, Aspergillus titers and Pseudomonas colonization status in addition to clinical markers such as FEV1% predicted, frequency of exacerbation, mMRC and CAT scores. <bold>RESULTS:</bold> A subgroup of AATD patients were identified with MBL deficiency. Preliminary data shows a possible positive association between severe MBL deficiency and severe AATD. Further work will explore correlations with exacerbation frequency, severity of bronchiectasis and patient reported outcomes measures. <bold>CONCLUSION:</bold> MBL deficiency may play a role in the pathogenesis of bronchiectasis in AATD, and could be a potential target for treatment. References: [1] Chan ED, Wooten W.I., Hsieh E.W.Y., Johnston K.I., Shaffer M., Dandhaus R., van de Veerdonk F. Diagnostic evaluation of bronchiectasis. Respir. Med. X. 2019;1:10006 [2] Sanduzzi A, Ciasullo E, Capitelli L, Sanduzzi Zamparelli S, Bocchino M. Alpha-1-Antitrypsin Deficiency and Bronchiectasis: A Concomitance or a Real Association? Int J Environ Res Public Health. 2020 Mar 29;17(7):2294