Cryoglobulins (CGs) are cold precipitating immunoglobulins, and hepatitis C virus (HCV) infection is its most common cause. The purpose of the study was to determine the contribution of HCV in a large cohort of CG. Biological characteristics and specificity of CGs in HCV patients were compared to non-HCV subjects. Cryoglobulin analysis included isotype, clonality, concentration, and rheumatoid factor (RF) in cryoprecipitate and serum complement and RF. This study is an extension of the study carried out on a cohort of 13,439 patients tested for CGs from all medical units, in which 1,675/13,439 (12.5%) patients had a CG, and 680/1,675 (40.6%) had HCV serology or viral load determination (HCV RNA). Among these 680 CG patients tested for HCV, 325 of 680 (47.8%) HCV patients (272 HCV RNA⁺ and 45 HCV RNA⁻ patients) were compared to 355/680 (52.2%) non-HCV subjects. After a positive detection of CG, HCV status was determined only for 37.7% (256/680) of patients, allowing the diagnosis of a previously unknown HCV infection for 39.8% (102/256). Concentration of HCV RNA⁺ CGs (median = 80.5 mg/L) was significantly higher than that of HCV RNA⁻ CG (median = 50.5 mg/L, p = 0.001) and HCV⁻ CG (median = 32 mg/L, p < 0.0001). There was no difference of median CG concentration between HCV RNA⁻ patients and non-HCV subjects. Rheumatoid factor titer was significantly higher in type II CG compared to type III CG in HCV RNA⁺ patients (254 ± 720 vs. 15 ± 21 IU/mL, p < 0.0001) and non-HCV subjects (333 ± 968 vs. 16.8 ± 26 IU/mL, p = 0.0004). Complement functional activity CH50 was lower in HCV RNA⁺ patients (36 ± 24 U/mL) and in HCV RNA⁻ patients (32 ± 21 U/mL) than in non-HCV subjects (50 ± 25 U/mL, p = 0.001 and p = 0.004). In conclusion, HCV infection and treatment influence CG characteristics. It is essential, and far from always tested, to determine the HCV status of patients with mixed CG, and conversely to search for CG in patients with HCV infection.

冰球蛋白（CGs）是冷沉淀的免疫球蛋白，丙型肝炎病毒（HCV）感染是其最常见的原因。该研究的目的是确定HCV在大量CG中的贡献。将HCV患者中CGs的生物学特性和特异性与非HCV患者进行了比较。冰球蛋白分析包括冷沉淀，血清补体和RF中的同种型，克隆性，浓度和类风湿因子（RF）。这项研究是对所有医疗单位的CG测试的13439名患者进行的研究的扩展，其中1,675 / 13,439（12.5％）患者患有CG，而680 / 1,675（40.6％）患者具有HCV血清学或病毒载量测定（HCV RNA）。在这680名HCV测试的CG患者中，680名（47.8％）HCV患者中的325名（272 HCV RNA ⁺和45 HCV RNA⁻患者）与355/680（52.2％）非HCV受试者进行了比较。CG阳性检测后，仅对37.7％（256/680）的患者确定了HCV状态，从而诊断出39.8％（102/256）的先前未知的HCV感染。HCV RNA ⁺ CGs（中位数= 80.5 mg / L）的浓度显着高于HCV RNA ^- CG（中位数= 50.5 mg / L，p= 0.001）和HCV ^- CG（中位数= 32 mg / L，p<0.0001）。有没有HCV RNA之间的中间CG浓度的差异^-患者非HCV科目和。在HCV RNA ⁺患者中，II型CG的类风湿因子滴度明显高于III型CG （254±720 vs. 15±21 IU / mL，p <0.0001）和非HCV受试者（333±968对16.8±26 IU / mL， p= 0.0004）。HCV RNA ⁺患者（36±24 U / mL）和HCV RNA ⁻患者（32±21 U / mL）的补体功能活性CH50低于非HCV受试者（50±25 U / mL，p = 0.001并且 p= 0.004）。总之，HCV感染和治疗会影响CG特征。确定混合型CG患者的HCV状况是至关重要的，而且远远没有经过测试，相反，对于HCV感染的患者要搜索CG。