The impact of anti-IgE treatment on the airway microbiome in asthma

Introduction: Severe asthma accounts for 5-10% of asthmatics. Omalizumab is an effective add on therapy for the treatment of severe allergic IgE mediated asthma. Little is known as to its effect on the lung microbiome. Aims and Objectives: Our aim was to elucidate potential differences in microbial diversity in a cohort of well-defined severe asthmatics after treatment with omalizumab. Methods: 9 severe asthmatics underwent bronchoscopy with bronchoalveolar lavage (BAL) pre- and post-omalizumab treatment. Cell differentials and cytokine levels were determined and DNA extraction performed. BAL cell pellet (CP, phagocytosed bacteria) and bacteria pellet (BP, free bacteria) derived DNA underwent qPCR to determine the presence and identity of microbes pre- and post- omalizumab Results: Microbes such as Prevotella, Veillonella, N. bacilliformis and M. catharralis remained at consistent levels within the patient cohort irrespective of treatment. Following omalizumab therapy there was an increased detection of Bordetella (CP) (0% to 89%), C. pneumoniae (CP) (11% to 89%) and (BP) (22% to 67%), N. meningitidis (CP) (22% to 100%) and (BP) (11% to 78%), S. pneumoniae (CP) (33% to 89%), H. influenzae (CP) (44% to 100%) and S. aureus (BP) (0% to78%). A decrease in the detection of microbes such as Bordetella (BP) (56% to 22%), M. pneumonaie (BP) (44% to 22%) and H. influenzae (BP) (78% to 55%) was observed. Conclusions: These findings suggest monoclonal asthma treatments such as omalizumab may affect lung microbial diversity.