Table 2.

Biological characteristics of patients with and without RI

	Total population	RI	Control group	P
	n = 153	n = 45	n = 108
Cryoglobulinaemia composition, n (%)
Type I cryoglobulinaemia	11 (7)	2 (4)	9 (8)	0.51
Type II cryoglobulinaemia	99 (65)	38 (84)	61 (57)	0.12
Type III cryoglobulinaemia	43 (28)	5 (11)	38 (35)	0.006
Presence of IgG cryoglobulin	141 (92)	44 (98)	97 (90)	0.11
Presence of IgA cryoglobulin	13 (8)	10 (22)	3 (3)	0.0003
Presence of IgM cryoglobulin	139 (91)	40 (89)	99 (92)	0.55
Cryoglobulin concentration (mg/L)
Total: median (IQR, min–max)	45 (140, 20–4006)	137 (875, 20–3792)	39 (75, 20–4006)	0.001
IgG: median (IQR, min–max)	17 (62, 0–1833)	44 (296, 0–1833)	14 (182, 0–1218)	0.001
IgA: median (IQR, min–max)	0 (0, 0–312)	0 (0, 0–130)	0 (0, 0–312)	<0.0001
IgM: median (IQR, min–max)	25 (79, 0–2523)	30 (360, 0–2408)	24 (33, 0–2523)	0.07
Monoclonal cryoglobulin, n (%)
Monoclonal IgGκ	29 (19)	10 (22)	7 (7)	0.005
Monoclonal IgGλ	16 (10)	4 (9)	7 (7)	0.73
Monoclonal IgA	12 (8)	5 (11)	1 (1)	0.009
Monoclonal IgMκ	103 (67)	27 (60)	46 (43)	0.050
Monoclonal IgMλ	22 (14)	4 (9)	14 (13)	0.48
Polyclonal cryoglobulin, n (%)
Polyclonal IgG	129 (84)	39 (87)	90 (83)	0.61
Polyclonal IgA	7 (5)	5 (11)	2 (2)	0.024
Polyclonal IgM	65 (42)	13 (29)	52 (48)	0.03
RF activity
Positive RF in cryoprecipitate, n (%)	45 (29)	19 (42)	26 (24)	0.03
Serum complement
Decreased C3 (<0.82 g/L), n (%)	27 (18)	8 (18)	19 (18)	0.98
Decreased C4 (<0.14 g/L), n (%)	82 (54)	23 (51)	59 (55)	0.69
Low CH50 (<41 UI/mL), n (%)	79 (52)	29 (64)	50 (46)	0.041
C3: median (g/L) (IQR, min–max)	1.04 (0.39, 0.13–1.74)	1.05 (0.40, 0.13–1.62)	1.03 (0.35, 0.35–1.74)	0.78
C4: median (g/L) (IQR, min–max)	0.15 (0.16, 0.01–0.50)	0.16 (0.27, 0.01–0.50)	0.15 (0.13, 0.02–0.46)	0.85

IQR (min–max), interquartile range (minimum–maximum).