Impaired immune function, chronic baseline inflammation, complement system over activation, and increased Angiotensin Converting Enzyme 2 (ACE-2) receptor expression have all been proposed as contributing factors.[31] Additionally, obese patients have altered pulmonary mechanics and physiology leading to reduced lung volumes, decreased lung compliance, and respiratory muscle insufficiency that predispose this patient population to respiratory failure after pulmonary insult.[31]. This evidence concerns the gene ACE2 and respiratory failure.