HLA-B*35:01 and Green Tea-Induced Liver Injury

BACKGROUND AND AIMS

Herbal supplements, and particularly multi-ingredient products, have become increasingly common causes of acute liver injury. Green tea is a frequent component in implicated products, but its role in liver injury is controversial. The aim of this study was to better characterize the clinical features, outcomes, and pathogenesis of green tea-associated liver injury.

APPROACH AND RESULTS

Among 1,414 patients enrolled in the U.S. Drug-Induced Liver Injury Network who underwent formal causality assessment, 40 cases (3%) were attributed to green tea, 202 to dietary supplements without green tea, and 1,142 to conventional drugs. The clinical features of green tea cases and representation of human leukocyte antigen (HLA) class I and II alleles in cases and control were analyzed in detail. Patients with green tea-associated liver injury ranged in age from 17 to 69 years (median = 40) and developed symptoms 15-448 days (median = 72) after starting the implicated agent. The liver injury was typically hepatocellular (95%) with marked serum aminotransferase elevations and only modest increases in alkaline phosphatase. Most patients were jaundiced (83%) and symptomatic (88%). The course was judged as severe in 14 patients (35%), necessitating liver transplantation in 3 (8%), but rarely resulting in chronic injury (3%). In three instances, injury recurred upon re-exposure to green tea with similar clinical features, but shorter time to onset. HLA typing revealed a high prevalence of HLA-B*35:01, found in 72% (95% confidence interval [CI], 58-87) of green tea cases, but only 15% (95% CI, 10-20) caused by other supplements and 12% (95% CI, 10-14) attributed to drugs, the latter rate being similar to population controls (11%; 95% CI, 10.5-11.5).

CONCLUSIONS

Green tea-related liver injury has distinctive clinical features and close association with HLA-B*35:01, suggesting that it is idiosyncratic and immune mediated.

EGCG induces G-CSF expression and neutrophilia in experimental sepsis

A major green tea component, epigallocatechin-3-gallate (EGCG), has been proven protective against lethal sepsis in experimental setting, but its protective mechanisms remain incompletely understood. Here, we provide evidence to support EGCG's capacities in stimulating G-CSF production and neutrophilia in vivo. In an animal model of sepsis, EGCG significantly elevated peritoneal levels of G-CSF and several chemokines (e.g., MCP-1/CCL2 and MIP-1γ/CCL9), and consequently increased peritoneal neutrophil numbers (neutrophilia) at a late stage. In vitro, EGCG divergently affected HMGB1-mediated production of several chemokines: reducing CXCL15 and RANTES/CCL5, but elevating G-CSF and MIP-1α/CCL3 production by peritoneal macrophages. Similarly, it significantly induced the expression and secretion of G-CSF and MIP-1α/CCL3 in human peripheral blood mononuclear cells. Based on our preliminary data, it may be important to search for anti-inflammatory and G-CSF-stimulating agents for the clinical management of inflammatory diseases.

Immunomodulatory effects of decaffeinated green tea (Camellia sinensis) on the immune system of rainbow trout (Oncorhynchus mykiss)

In order to study the immunomodulatory effects of decaffeinated green tea extract on rainbow trout, a study with a 30-day feeding trial was conducted. Commercial diets with graded levels of decaffeinated green tea extract, 20 mg (T1), 100 mg (T2), 500 mg (T3) per kg feed were prepared. 120 rainbow trout (35 ± 3 g) were randomly assigned to 4 groups in triplicates and fed one of the 3 experimental diets formulated or control diet. After feeding trial, 12 fish from each group were sampled for analysis of some immunological parameters. Remaining fish were injected with 0.5 ml of chicken red blood cell (C-RBC) suspension (2%) intraperitoneally on days 5 and 15 after feeding trial. Results of the current study showed that the inclusion of 20 mg kg-1 green tea (T1) in fish diet enhanced the serum bactericidal activity against Yersinia ruckeri, while significant elevation of lysozyme activity was shown in T2 group. Anti-trypsin activity due to α1-antiprotease was significantly higher in T1 and T2 groups while peroxidase content showed significant increase in all treatment groups compared to control group. Hemagglutination antibody titer against C-RBC was significantly higher in fish administered with 100 mg kg(-1) green tea (T2). Our findings showed that decaffeinated green tea in lower doses of administration could be optimum to enhance the immunity of rainbow trout.

Influence of diet enriched with green tea on innate humoral and cellular immune response of kelp grouper (Epinephelus bruneus) to Vibrio carchariae infection

Effect of diet enriched with green tea at 0, 0.01, 0.1 or 1.0% levels on immune responses such as non-specific humoral (lysozyme, antiprotease and complement) and cellular (myeloperoxidase content, production of reactive oxygen, and nitrogen species) and disease resistance on week 1, 2 or 4 in kelp grouper Epinephelus bruneus challenged with Vibrio carchariae (2.47 × 10(8) CFU ml(-1)) was quantified. At all doses green tea supplementation significantly enhanced the serum lysozyme activity from weeks 1 to 4. On the other hand, after week 2 the serum hemolytic complement activity, leucocyte myeloperoxidase content and reactive nitrogen species protection significantly increased in groups fed with 0.01 and 0.1% green tea supplementation diets. The serum antiprotease activity significantly increased in group fed with at 1.0% green tea from week 1 to 4. However, all diets except at 0.01% level resulted in a significant decrease in reactive oxygen species protection during the experimental period. Challenged groups fed with green tea enriched diet at 0.01 and 0.1% level had a higher relative percent survival than with 1.0% diet on week 1, 2 or 4. The results suggest that dietary administration of green tea supplementation at a concentration of 0.01 and 0.1% level positively enhances the non-specific humoral and cellular immune responses and disease resistance of kelp grouper E. bruneus to V. carchariae.

Chemical profiling and gene expression profiling during the manufacturing process of Taiwan oolong tea "Oriental Beauty"

Oriental Beauty, which is made from tea leaves infested by the tea green leafhopper (Jacobiasca formosana) in Taiwan, has a unique aroma like ripe fruits and honey. To determine what occurs in the tea leaves during the oolong tea manufacturing process, the gene expression profiles and the chemical profiles were investigated. Tea samples were prepared from Camellia sinensis var. sinensis cv. Chin-shin Dah-pang while the tea leaves were attacked by the insect. The main volatile compounds, such as linalool-oxides, benzyl alcohol, 2-phenylethanol, and 2,6-dimethylocta-3,7-diene-2,6-diol, increased during manufacture. The gene expression profiles during manufacture were analyzed by differential screening between fresh leaves and tea leaves of the first turn over. Many up-regulated transcripts were found to encode various proteins homologous to stress response proteins. Accordingly, the endogenous contents of abscisic acid and raffinose increased during manufacture. Thus the traditional manufacturing method is a unique process that utilizes plant defense responses to elevate the production of volatile compounds and other metabolites.

Levels of common antigens in determining pathogenicity of Curvularia eragrostidis in different tea varieties

AIMS

Pathogenicity of Curvularia eragrostidis, a foliar fungal pathogen of tea was studied in 24 commercially cultivated tea varieties by analysing the antigenic patterns of host and pathogen with the help of immunoserological techniques.

METHODS AND RESULTS

Initial testing by cut shoot inoculation technique followed by whole plant inoculation technique showed that among the varieties tested, TV12 was the most susceptible and TV25 most resistant. Antigen preparations from tea varieties, fungal pathogens (C. eragrostidis and Lasiodiplodia theobromae) and a nonpathogen (Gliocladium virens) were compared by immunodiffusion, immunoelectrophoresis and indirect ELISA to detect common antigens shared by host and pathogen. Common antigens were detected by immunodiffusion and immunoelectrophoresis only among susceptible varieties and the pathogens. Such antigens were not found between the pathogens and the resistant varieties and also between nonpathogens and tea varieties. However, ELISA revealed the presence of low level of common antigens between all combinations. A certain minimum level of antigens was present for compatible host-pathogen interaction. Indirect labelling of antibodies with fluorescein isothiocyanate (FITC) showed that cross-reactive antigens were found to be concentrated mainly in the epidermal cells and also spread throughout the cortical cells.

CONCLUSION

Pathogenicity of C. eragrostidis to different varieties of tea was found to be related to the level of common antigens present between host and pathogen.

SIGNIFICANCE AND THE IMPACT OF THE STUDY

Indirect ELISA proved to be valuable in screening commercially cultivated varieties of tea for their susceptibility to C. eragrostidis.

Human gamma delta T cells recognize alkylamines derived from microbes, edible plants, and tea: implications for innate immunity

Approximately 4% of peripheral blood T cells in humans express a T cell receptor with markedly restricted germline gene segment usage (V gamma 2 V delta 2). Remarkably, these T cells expand 2- to 10-fold (8%-60% of all circulating T cells) during many microbial infections. We show here that these T cells recognize a family of naturally occurring primary alkylamines in a TCR-dependent manner. These antigenic alkylamines are secreted to millimolar concentrations in bacterial supernatants and are found in certain edible plants. Given the large numbers of memory V gamma 2 V delta 2 T cells in adult humans, recognition of alkylamine antigens offers the immune system a response of the magnitude of major superantigens for alpha beta T cells and may bridge the gap between innate and adaptive immunity.

Allergy to natural honeys and camomile tea

Precipitation of food allergy reactions is well known in some patients with pollinosis when they consume natural food, such as honey or camomile tea. We present 9 patients with hay fever, with or without asthma, who experienced systemic allergic reactions after ingestion of natural honeys from two local areas (Andujar and Granada) and/or camomile tea. Pollen analysis showed a high level in sunflower pollen (23.6% of pollen grains) in the honey from Andujar but not in that from Granada. The diagnosis of food and respiratory allergy was based on history, skin prick tests and specific IgE activity against pollen from Compositae. Conjunctival challenge with camomile extract also gave positive results. The above allergological tests and the inhibition studies carried out, suggest that pollen of Compositae may be responsible for allergic reactions to certain natural foods and that the reactions are mediated by an IgE-related mechanism.