HEPATITIS-C SEROTYPES IN NONALCOHOLIC AND ALCOHOLIC PATIENTS

Genotyping of the hepatitis C virus (HCV) RNA can be performed by a va riety of methods following polymerase chain reaction amplification of a stable RNA portion of the genome. The gold standard is amplification of the RNA from the NS5 region, followed by direct sequencing and hom ology comparison. This method is extremely labor intensive. In this st udy, we compared an immunoblot serotyping technique (HCV STA) to a rev erse-hybridization line-probe assay (LiPA) for genotype classification among non-alcoholic HCV infected patients. We then compared and contr asted the response in this cohort to a population of alcoholic patient s with HCV infection. To validate the serotype assay, sera from 110 pa tients with chronic HCV infection was utilized. Serotyping (Chiron SIA ) and genotyping by the LiPA (Line Probe Assay, Innogenetics) reverse- hybridization technique was performed. Additionally, both methods were compared to sequence-derived genotyping in 26 patients based on PCR a mplification of the NS5 region. After the validation phase, sera from 105 alcoholic patients was genotypically classified by the serologic m ethod. The nonalcoholic and alcoholic groups were then compared with r egard to serotype, demographics, and frequency of untypable test resul ts. Among typable pairs, the overall concordance rate between serotypi ng and LiPA-based genotyping was 93.75%. Patients with genotype 1 by r everse hybridization demonstrated a 95.8% concordance with serotype. U ntypable samples were present for both techniques, but since they occu rred in different patients, the techniques were complementary Alcoholi c patients were significantly more likely to be infected with untypabl e serotypes than those without a pattern of alcohol abuse. These patie nts were also more likely to be HCV RNA negative than sera from typabl e patients. Serotype 1 was associated with high HCV RNA titer and poor interferon treatment response among both nonalcoholic and alcoholic p atients. An immunoblot method for the evaluation of genotype classific ation was rapid and easily performed compared to sequence-based genoty ping. There was a high degree of concordance compared to reverse-hybri dization and sequence-based genotype characterization methods, Failure to detect HCV RNA in the serum is associated with a higher likelihood of classification failure. This problem was particularly prevalent in the alcoholic population HCV RNA titers and treatment outcomes were s trongly associated with serotype classification results, demonstrating clinical utility of this assay technique.