Monoclonal protein (M-protein) may play a role in assessing the survival of patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) who have renal involvement, according to a study conducted by researchers at Xinqiao Hospital, Army Medical University in China.

“Testing M-protein and rigorous diagnosing of the significance of the presence of M-protein may be helpful for assessing the survival of AAV patients with renal involvement,” the researchers wrote in International Urology and Nephrology.

Patients with AAV who tested positive for M-protein had a higher risk of all-cause mortality than those who tested negative (median follow-up, 33 months; follow-up rate, 85.7%).

Moreover, when considering only patients who were not dependent on dialysis at diagnosis, M-protein-positive patients had a higher risk of overall death than M-protein-negative patients. On the other hand, overall survival was similar for dialysis-dependent patients, regardless of the M-protein test result.

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Patients with AAV who tested positive for M-protein also had lower mean corpuscular hemoglobin concentration and hemoglobin, serum albumin, and complement 3 levels than those who tested negative.

These patients also showed higher platelet count and an increased incidence of pulmonary infection compared with M-protein-negative patients.

The study enrolled 91 patients with AAV (median age at diagnosis, 59 years; 58.2% male). Of those, 12 patients had acute kidney injury and 45 patients were diagnosed with chronic kidney disease. Twenty-nine patients were dependent on dialysis at diagnosis, and 16 patients tested positive for M-protein.

M-protein is a type of immunoglobulin produced by B lymphocytes that is commonly found in elderly individuals. It has been described as a potential outcome indicator for several conditions and diseases, including multiple myeloma, infection, fractures, and thrombosis.


Wang Y, Yang K, Yu Z, et al. The clinical value of monoclonal protein in ANCA-associated vasculitis with renal involvement. Int Urol Nephrol. Published online April 3, 2023. doi:10.1007/s11255-023-03579-0