Differential Reactivity to IMPDH2 by Anti-rods/rings Autoantibodies and Unresponsiveness to Pegylated Interferon-alpha/Ribavirin Therapy in US and Italian HCV Patients
- 419 Downloads
Autoantibodies to cytoplasmic structures called rods and rings (RR) are primarily specific to patients with hepatitis C virus (HCV) infection treated with pegylated interferon-alpha/ribavirin (IFN/R). Our aim is to examine anti-RR antibodies specificity and correlation with the response to IFN/R therapy in two independent cohorts (US and Italy) of HCV patients.
Sera from the US cohort (n = 47) and the Italian cohort (n = 46) pre-selected for anti-RR antibodies were analyzed by immunofluorescence and radioimmunoprecipitation. The prevalence and titers of anti-RR were analyzed for correlation with the response to IFN/R therapy.
In the US cohort, anti-RR antibodies were more frequently non-responders to IFN/R (71 % vs 29 % responders). Titers in responder patients (n = 11) were ≤1:3200, whereas titers in non-responder patients (n = 27) reached 1:819,200 (p = 0.0016). In the Italian cohort, anti-RR titers ranged from 1:200 to >1:819,200 and only relapsers had the highest anti-RR titers. Radioimmunoprecipitation demonstrated that anti-RR autoantibodies were mainly anti-inosine monophosphate dehydrogenase 2 (IMPDH2) - 96 % in the Italian cohort vs. 53 % in the US cohort.
In the two cohorts analyzed, the anti-IMPDH2 response as a component of the anti-RR response is much more prominent in the Italian cohort. The reason for the difference between the US and Italian cohorts is unclear but it possibly illustrates the heterogeneity in response and the overall negative correlation between the production of these autoantibodies and response to IFN/R therapy. Patients with high titer anti-RR antibodies are either relapsers (Italian) or non-responders/relapsers (US).
KeywordsIMPDH2 hepatitis C autoantibody
Cytidine triphosphate synthetase 1
Hepatitis C virus
Inosine monophosphate dehydrogenase 2
Rods and rings
Sustained virological response
Natasha Deming, Pabina Dhawan, and Jennifer R. Bess are acknowledged for the early work helping in the screening of HCV patient sera for anti-RR positive samples.
The authors declare that they have no conflicts of interest.
- 22.Gatselis NK, Georgiadou SP, Koukoulis GK, Tassopoulos N, Zachou K, Liaskos C, et al. Clinical significance of organ- and non-organ-specific autoantibodies on the response to anti-viral treatment of patients with chronic hepatitis C. Aliment Pharmacol Ther. 2006;24:1563–73.PubMedCrossRefGoogle Scholar