Group A | Group B | Group C | Group C1 | Group C2 | |
---|---|---|---|---|---|
No of patients | 272 | 228 | 425 | 173 | 252 |
Mean age (SD) | 62.8 (11.8) | 58.4 (15.4) | 56.0 (16.8) | 58.3 (17.8) | 54.5 (16.0) |
Sex (M/F) | 72/200 | 72/156 | 118/307 | 63/110 | 55/197 |
Cryo type I (%) | 5 (1.8) | 1 (0.4) | – | – | – |
Cryo type II (%) | 194 (71.3) | 40 (17.5) | – | – | – |
Cryo type III (%) | 32 (11.8) | 110 (48.2) | – | – | – |
Cryo not typifiable (%) | 41 (15.1) | 77 (33.8) | – | – | – |
Rheumatoid factor positivity (%) | 85.8 | 46.3 | 25.2 | 12.4 | 33.9 |
Low C4 (%) | 69.6 | 25.5 | 9.2 | 1.9 | 14.4 |
M component (%) | 82.7 | 27.2 | 3.7 | 2.8 | 4.4 |
Truly essential cryo (%) | 9 (3.3) | 7 (3.1) | – | – | – |
HCV infection (%)* | 230 (84.6) | 153 (67.1) | 31 (7.3) | – | 31 (12.3) |
SS (%) | 39 (14.4) | 34 (14.9) | 52 (12.2) | – | 52 (20.6) |
Other CTDs† (%) | 5 (1.8) | 30 (13.2) | 89 (20.9) | – | 89 (35.3) |
Other vasculitis‡ (%) | – | – | 173 (40.7) | 173 (100) | – |
Other diseases‡(%) | 10 (3.7) | 8 (3.5) | 80 (18.8) | – | 80 (31.7) |
↵* HCV infection could be also concomitant with SS or with other connective tissue diseases.
↵† Systemic lupus erythematosus, systemic sclerosis, poly/dermatomyositis, undifferentiated connective tissue disease, mixed connective tissue disease, antiphospholipid syndrome.
↵‡ In groups A and B, positivity for the hepatitis B virus surface antigen was noticed in 10 and in eight cases, respectively; see text for other diseases included in group C, to be differentiated from CV.
CTDs, connective tissue diseases; CV, cryoglobulinaemic vasculitis; F, female; HCV, hepatitis C virus; M, male; SS, Sjögren's syndrome.