Concomitant cryoglobulinaemic vasculitis alongside ANCA-associated vasculitis: concurrence or coincidental individual...

Cryoglobulinaemic vasculitis (CryoVas) and antineutrophil cytoplasmic antibody-associated vasculitis (AAV) share the common characteristic of being small vessel vasculitides but exhibit significant differences in pathologic findings. This study investigated the incidence rate of cryoglobulinaemia and the concurrence of AAV and CryoVas in AAV patients without chronic viral hepatitis or haematologic malignancies.

Among the 324 patients diagnosed with AAV, 136 with available cryoglobulin test results were included. Their clinical data were reviewed, and clinical and laboratory data, including AAV-specific indices at diagnosis, were recorded. Repeated cryoglobulinaemia was defined as cryoglobulin positivity in sera on at least two occasions separated by an interval of ≥ 12 weeks. The classification criteria for CryoVas were applied to all 136 patients with AAV.

The median age of the patients was 61.0 years (50.0-69.0), and 41.2% were male patients. Of the 136 patients, 75, 31, and 30 were diagnosed with microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), and eosinophilic GPA, respectively. Cryoglobulin was detected in sera of only two patients, yielding a detection rate of 1.5%. Both patients exhibited repeated cryoglobulinaemia and presented with red skin spots, constitutional symptoms, articular involvement, and vascular involvement; enabling their classification as having CryoVas alongside MPA. Additionally, one patient displayed peripheral neuropathy, reduced serum C4 levels, and rheumatoid factor positivity.

This study represents the first demonstration that the incidence rates of cryoglobulinaemia and CryoVas are 1.5% in patients with AAV without chronic viral hepatitis or haematologic malignancies.