Is green tea a potential trigger for autoimmune hepatitis?

Abstract

A case of autoimmune liver hepatitis is reported: the onset was triggered by consumption of green tea infusion in a patient taking oral contraceptives and irbesartan.

We hypothesize that our patient, carrying genetic variant of hepatic metabolism making her particularly susceptible to oxidative stress, developed an abnormal response to a mild toxic insult, afforded by a combination of agents (oral contraceptives + irbesartan + green tea) that normally would not be able to cause damage. Her particular hepatic metabolism further increased the drugs’ concentration, favoring the haptenization of liver proteins, eventually leading to the development of an autoimmune hepatitis.

Introduction

Green tea (Camellia sinensis) is a worldwide consumed beverage, used for almost 50 centuries. Green tea's popularity recently increased with scientific evidences that demonstrate its beneficial health effects, such as reduced risk of cardiovascular and degenerative diseases, likely due to the antioxidant properties of polyphenols. Among them, catechins, and in particular epigallocatechin-3-gallate (EGCG), seem to be the most effective compound in exerting the beneficial effects of green tea (Boehm et al. 2009). Although EGCG has widely demonstrated an antioxidant effect and radical scavenging activity, recent data suggest also a pro-oxidant activity (Forester and Lambert 2011). This oxidative effect may also exert some benefit, inducing apoptosis in tumor cells and, at the same time, stimulating endogenous antioxidant systems in normal tissues, potentially exerting protection against carcinogenic insults (Forester and Lambert 2011). Despite its positive effects and its wide consumption, recently, some reports of suspected green tea-related hepatic reactions have also been published; those were generally observed in subjects taking high doses of dietary supplements containing concentrated or purified tea preparations, even if one case study reported hepatotoxicity after consumption of 6 cups/day of green tea infusion (Mazzanti et al. 2009). The potential hepatotoxicity of green tea could be related to EGCG-induced oxidative stress with the main evidences supporting an idiosyncratic or immune-mediated mechanism (Lambert et al. 2010). The major risk factors implicated in idiosyncratic drug induced liver injury are old age, female gender, high dose, drug interactions, cross-sensitizations, genetic factors, and hepatic metabolism of the compounds (Czaja 2011). In addition, as it happens with other herbal remedies, green tea molecules may act as triggers for an immune process and may lead to an autoimmune like hepatitis (AIH) according to the ‘hapten hypothesis’ (Czaja 2011).

Here we report a case of autoimmune liver hepatitis whose onset was triggered by consumption of green tea infusion in a patient taking oral contraceptives and irbesartan.