Rheumatoid factor levels indicate cryoglobulinemia severity in hepatitis B e antigen-negative hepatitis B virus carriers: a 7-year prospective cohort study

Background The phenotype of cryoglobulinemia in hepatitis B virus (HBV) carriers remains elusive. Methods A 7-year prospective cohort of 648 hepatitis B e antigen (HBeAg)-negative Taiwanese HBV carriers [males: 344 (53%)] was conducted. Results Among 648, 189 (29.2%) had cryoglobulinemia, and 26 (4.0%) had cryoglobulinemic syndrome (CS). More females; higher levels of rheumatoid factor (RF), immunoglobulin M (IgM) and fibrosis-4 indices; higher proportions of proteinuria, hematuria and hepatocellular carcinoma; and lower levels of quantitative HBsAg, C3, C4 and eGFR were noted in patients with than in those without cryoglobulinemia. The associations were RF levels with cryoglobulinemia (cutoff > 12.55 IU/mL), and RF levels and baseline autoimmune diseases with CS. CS patients, symptomless cryoglobulinemia patients and patients without cryoglobulinemia had the highest, moderate, and lowest RF levels, respectively. A greater percentage of mixed cryoglobulins [IgG (2 +), IgM (2 +) and IgA (1 +)] was noted in cryoglobulinemia patients with than in those without CS (11.5% vs. 0.81%, p = 0.002). Among the 7 CS patients treated with nucleos(t)ide analogues (Nucs), cryoglobulinemia disappeared in 3 and symptoms improved in 5 during therapy. The CS prevalence was highest (6%) in patients with a baseline age of 31-40 years. Among the 26 CS patients, 23 (88.5%), 20 (76.9%), and 16 (61.5%) had peripheral neuropathy, articular and skin involvement, respectively. The cumulative incidences of major outcomes and mortality did not differ between patients with and without cryoglobulinemia. Conclusions The prevalence rates of cryoglobulinemia and CS in HBeAg-negative HBV carriers were 29.2% and 4.0%, respectively. RF levels correlate with cryoglobulinemia severity. Mixed cryoglobulins of IgG (2 +), IgM (2 +) and IgA (1 +) are likely linked to CS, which might be alleviated by Nucs in some patients. The impact of cryoglobulinemia on long-term outcomes might be negligible.