Broadly effective metabolic and immune recovery with C5 inhibition in CHAPLE disease

Complement hyperactivation, angiopathic thrombosis, and protein-losing enteropathy (CHAPLE disease) is a lethal disease caused by genetic loss of the complement regulatory protein CD55 leading to overactivation of complement and innate immunity together with immunodeficiency due to immunoglobulin (Ig) wasting in the intestine. We report in vivo human data that we accumulated using the complement C5 inhibitor eculizumab for the medical treatment of CHAPLE patients and observed cessation of gastrointestinal pathology together with restoration of normal immunity and metabolism. We found that patients rapidly renormalized Ig concentrations and other serum proteins as revealed by aptamer profiling, re-established a healthy gut microbiome, discontinued Ig replacement and other treatments, and exhibited catch-up growth. Thus, we show blockade of C5 by eculizumab effectively re-establishes the regulation of the innate immune complement system to substantially reduce the pathophysiological manifestations of CD55 deficiency in humans.