High circulating levels of N-terminal pro-brain natriuretic peptide and interleukin 6 in patients with mixed cryoglobulinemia

Many patients with mixed cryoglobulinemia and chronic HCV infection experience symptoms, such as dyspnea, which sometimes do not seem to indicate the involvement of the liver but rather the symptoms of heart failure. To our knowledge, there has been no other study evaluating the serum levels of N-terminal pro-brain natriuretic peptide (NTproBNP) and Interleukin 6 (IL-6) in such patients. Serum NTproBNP and IL-6 were assayed in 54 patients with mixed cryoglobulinemia and chronic HCV infection, and in 54 sex- and age-matched controls. Cryoglobulinemic-patients showed significantly higher mean NTproBNP and IL-6 levels than the controls (P = 0.005). By defining a high NTproBNP level as a value higher than 125 pg/ml (the single cut-off point for patients under 75 years of age), 30% of patients with mixed cryoglobulinemia and chronic HCV infection and 7% of controls had high NTproBNP (chi-square; P < 0.003). With a cut-off point of 300 pg/ml (used to rule out heart failure in patients under 75 years of age), 5/49 patients with mixed cryoglobulinemia and chronic HCV infection and 0/54 controls had high NTproBNP (chi-square; P < 0.04). With a cut-off point of 900 pg/ml (used for including heart failure in patients aged between 50 and 75, such as the patients in this study) 3/51 of patients with mixed cryoglobulinemia and chronic HCV infection and 0/54 controls had high NTproBNP (chi-square; P = 0.07). The study revealed high levels of circulating NTproBNP and IL-6 in patients with mixed cryoglobulinemia and chronic HCV infection. The increase in NTproBNP could indicate the presence of a subclinical cardiac dysfunction.