HAPTOGLOBIN POLYMORPHISM AND CHRONIC HEPATITIS-C

Background/Aims: Haptoglobin (Hp) is a hemoglobin-binding acute phase protein characterized by a genetic polymorphism due to the existence o f two different alleles encoding for the alpha chain of the protein, T hree phenotypes have been described: Hp 1-1, Hp 2-1 and Hp 2-2. The la tter two forms are known to possess immunoglobulin-like properties and play a role in the immune response, Recently, it has been shown that in subjects suffering from hepatitis C, serum Hp concentrations were l ower than in the reference population. In the present study we examine d whether the haptoglobin phenotype distribution in chronic HCV patien ts was different from the reference population. We also looked for pos sible relationships between Hp phenotypes and hepatitis C virus types and response to interferon a therapy. Moreover, Hp concentrations were determined. Methods: The study population consisted of 239 Caucasian patients with proven hepatitis C. Hp phenotypes were determined using starch gel electrophoresis of hemoglobin-supplemented serum, followed by peroxidase staining, Serum Hp concentrations were assayed with an i mmunonephelometric method. Hepatitis C virus was genotyped accepted sy stem, Two hundred and twenty healthy Caucasian blood-donors served as the reference population. Results: In the reference population, 35 ind ividuals (15.9%) had Hp 1-1, 106 persons (48.2%) had Hp 2-1 and 79 had Hp 2-2 (35.9%), resulting in an Hp 1 allele frequency of 0.400, which is in agreement with the Hardy-Weinberg equilibrium, Hp phenotype dis tributions and Hp allele frequencies in the chronic hepatitis C virus patient group differed significantly from those obtained in the refere nce population, In the patient population, 59 individuals (24.7%) had Hp 1-1, 112 persons (46.9%) had Hp 2-1 and 68 had Hp 2-2 (28.5%). This resulted in an Hp 1 allele frequency of 0.481, which is in agreement with the Hardy-Weinberg equilibrium, No statistically significant diff erences were found between Hp phenotype distribution and hepatitis C v irus types or response to interferon alpha therapy. Conclusions: The o bserved shift in Hp phenotype distribution in chronic hepatitis C may point to a role of Hp in the natural evolution of hepatitis C.