Natural IgG autoantibodies are abundant and ubiquitous in human sera, and their number is influenced by age, gender, and disease

• Published in: PloS one Vol. 8; no. 4; p. e60726
• Main Authors: Nagele, Eric P, Han, Min, Acharya, Nimish K, DeMarshall, Cassandra, Kosciuk, Mary C, Nagele, Robert G
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 02-04-2013; Public Library of Science (PLoS)
• Subjects: Adult; Age Factors; Aged; Aged, 80 and over; Aging; Alzheimer's disease; Alzheimers disease; Animals; Antigens; Antigens - immunology; Antigens - metabolism; Autism; Autoantibodies; Autoantibodies - immunology; Autoantibodies - metabolism; Autoimmune diseases; Autoimmune Diseases - blood; Autoimmune Diseases - immunology; Biology; Biomarkers; Conservation; Dentistry; Development and progression; Diagnosis; Diagnostic systems; Evolutionary conservation; Female; Gender; Genetic aspects; Homeostasis; Human behavior; Humans; Immune clearance; Immune system; Immunoglobulin G; Immunoglobulin G - immunology; Immunoglobulin G - metabolism; Immunoglobulins; Immunological tolerance; Immunology; Livestock; Male; Medicine; Middle Aged; Organs; Osteopathic medicine; Parkinson disease; Parkinson's disease; Pathology; Physiological aspects; Protein Array Analysis; Protein arrays; Proteins; Rats; Sex Factors; Swine; Tissues; Ubiquitination; United States; United States > US; New Brunswick New Jersey
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0060726

The presence of self-reactive IgG autoantibodies in human sera is largely thought to represent a breakdown in central tolerance and is typically regarded as a harbinger of autoimmune pathology. In the present study, immune-response profiling of human serum from 166 individuals via human protein microarrays demonstrates that IgG autoantibodies are abundant in all human serum, usually numbering in the thousands. These IgG autoantibodies bind to human antigens from organs and tissues all over the body and their serum diversity is strongly influenced by age, gender, and the presence of specific diseases. We also found that serum IgG autoantibody profiles are unique to an individual and remarkably stable over time. Similar profiles exist in rat and swine, suggesting conservation of this immunological feature among mammals. The number, diversity, and apparent evolutionary conservation of autoantibody profiles suggest that IgG autoantibodies have some important, as yet unrecognized, physiological function. We propose that IgG autoantibodies have evolved as an adaptive mechanism for debris-clearance, a function consistent with their apparent utility as diagnostic indicators of disease as already established for Alzheimer's and Parkinson's diseases.