CD79A and immune system disorder: In addition, reduced IgA levels are closely related to immune dysfunction in children with severe pneumonia, and once their IgA expression is abnormal, their respiratory mucosal barrier function is directly affected (29, 30) In response, clinical attention should be paid to the monitoring of IgA levels in children with severe pneumonia, with timely and effective measures been taken for intervention to improve airway clearance in children with severe pneumonia.