Thank you for your recent inquiry.
Diseases associated with elevated complement activity are those usually associated with chronic inflammation (1). Elevated complement components can be acute phase reactants and CH50 can reflect their elevation. When inflammation occurs in the absence of complement fixing circulating immune complexes, elevations in CH50 can occur. There are a number of conditions that do this. Examples taken from Reference 1 are listed below:
Thyroiditis, Typhoid fever, Acute rheumatic fever, Reiter syndrome, Periarteritis nodosum, Gout, Dermatomyositis, Scleroderma, Acute myocardial infarction, Juvenile rheumatoid arthritis, Ulcerative colitis ,Ankylosing spondylitis, Sarcoidosis ,Traumatic spinal cord injuries (1).
This is not an all inclusive list.
On occasion, such elevations in complement are found for no obvious reason, and workup fails to reveal any responsible disease.
The workup that one does would be directed at identifying a disease producing the chronic inflammation.
Thank you again for your inquiry and we hope this response is helpful to you.
1. Glovsky M, Ward P, and Johnson K. Complement determinations in human disease. Annals of Allergy, Asthma, and Immunology 2004; 93:513-523.
Phil Lieberman, M.D.