Successful treatment with bortezomib for refractory cryoglobulinemic vasculitis triggered by ischemic non-obstructive coronary artery disease.

Type I and mixed cryoglobulinemic vasculitis differ in pathophysiology, clinical presentation, and therapeutic response. We report a case of refractory cryoglobulinemic vasculitis diagnosed following ischemic non-obstructive coronary artery disease (INOCA). The patient presented with dyspnea, as well as abdominal pain due to ischemic enteritis, purpura, and renal failure requiring dialysis. Despite the patient's IgG λ-type monoclonal gammopathy of undetermined significance (MGUS) and negative hepatitis C virus, the presence of rheumatoid factor (RF) activity and the possibility of IgM involvement were suggested by cryoglobulin analysis and strong glomerular IgM deposition. The condition was diagnosed as mixed cryoglobulinemia, and various immunomodulatory treatments, including methylprednisolone, rituximab and plasmapheresis, were administered without achieving cryoglobulin negativity. However, treatment with bortezomib and dexamethasone ultimately led to cryoglobulin negativity and clinical improvement although the patient was not weaned off dialysis, resulting in remission of the cryoglobulinemic vasculitis. This case suggests that bortezomib, a proteasome inhibitor, may be a promising treatment for refractory cryoglobulinemic vasculitis.