Detection of IgA antibody to EBV membrane antigen using Staphylococcus aureus preabsorbed sera is closely associated with nasopharyngeal carcinoma

Transforming growth factor beta 1 (TGF-β1) modulates Epstein-Barr virus reactivation in absence of Helicobacter pylori infection in patients with gastric cancer

BACKGROUND

Transforming growth factor-beta 1 (TGF-β1), a multifunctional cytokine, acts as a key factor for Epstein-Barr virus (EBV) reactivation. We investigated the role of TGF-β1 in latent and lytic stages of EBV in relation to Helicobacter pylori infection among patients with gastric cancer (GC) and peptic ulcer disease (PUD).

METHOD

Gastric mucosal TGF-β1 expression was determined in 95 EBV positive patients with gastroduodenal pathology [GC 40, PUD 19 and non-ulcer dyspepsia (NUD) 36] by quantitative real time PCR. Presence of H. pylori infection was diagnosed when either culture or any two of three tests (RUT, histopathology and specific ureA PCR) were positive. Serum level of TGF-β1 was detected among 60 patients using ELISA.

RESULTS

Mucosal TGF-β1 mRNA expression was detected in 85 of 95 EBV positive patients and it was significantly higher in patients with GC (p=0.042). TGF-β1 expression tended to be higher among H. pylori non-infected than infected patients (3.80±6.24 vs. 2.07±2.50, p=0.085). Both mRNA and serum level had significant association with lytic stage of EBV in absence of H. pylori infection when compared with its presence (5.21±4.00 vs. 2.29±2.89, p=0.040 and 842.00 [669.55] vs. 662.63 [628.76], p=0.049; respectively).

CONCLUSION

TGF-β1 expression was significantly associated with GC. TGF-β1 was higher both at expression and translational levels in lytic EBV infection without H. pylori suggests that H. pylori infection might play important role in preventing EBV reactivation through attenuated TGF-β1 expression. This might be a "wise host defense against EBV reactivation".

Elevated serum transforming growth factor beta1 levels in Epstein-Barr virus-associated diseases and their correlation with virus-specific immunoglobulin A (IgA) and IgM

Transforming growth factor beta (TGF-beta) is an immunosuppressive cytokine which can induce immunoglobulin A (IgA) switch and Epstein-Barr virus (EBV) replication in latently infected cells. Here we report elevated serum levels of TGF-beta in various EBV-associated diseases correlating positively with EBV-specific IgA titers and negatively with IgM titers, suggesting a role for this cytokine in the pathogenesis of these diseases.

The Epstein-Barr virus (EBV) major envelope glycoprotein gp350/220-specific antibody reactivities in the sera of patients with different EBV-associated diseases

gp350 of Epstein-Barr virus (EBV) induces a strong immune response in EBV-infected individuals, but relatively little is known about the clinical relevance of this response in patients with different EBV-associated malignancies and other diseases. Using our gp350-expressing cell clones, we studied gp350-specific humoral immune responses in the sera of individuals with nasopharyngeal carcinoma (NPC), chronic symptomatic EBV infection (CEI), Hodgkin's disease (HD), acute infectious mononucleosis (IM) and healthy EBV-seropositive individuals (HI). The titres of antibody-dependent cellular cytotoxicity (ADCC) antibodies were highest in HI followed by CEI, HD and NPC. EBV-neutralizing (NA) and gp350-specific IgG antibody profiles in these conditions were: CEI > HI > NPC > HD, whereas IgA titres were the highest in NPC sera followed by CEI and HD. The sera from IM patients were found to be negative for gp350-specific ADCC and IgA activities. Sera from HI were also negative for gp350-specific IgA. A significant positive correlation was found between serum gp350 IgA and viral capsid antigen IgA and a significant negative one between IgM and ADCC titres. High IgA titres were also found in CEI and EBV-genome positive HD in addition to NPC. Importantly, gp350-specific IgA titres were of prognostic value in NPC patients. Our data provide new insights about the clinical relevance of gp350-specific immune responses in these diseases.

DNA viruses and human cancer

This review examines some of the evidence which aetiologically implicates various DNA viruses (primarily papillomavirus, hepatitis B virus and Epstein-Barr virus) in certain human cancers (cervical carcinoma, primary liver cell carcinoma, Burkitt's lymphoma and nasopharyngeal carcinoma, respectively). The evidence includes: presence of viral DNA, RNA and proteins in tumours (and cell lines derived from them); occurrence of viruses with apparently different oncogenic potential; their ability to transform cell lines in vitro or cause tumours in animals; epidemiological and serological data. Factors which affect the progression to cancer are briefly considered as they illustrate that there are several stages in tumorigenesis. These factors include the immune system, irradiation, presence of other viruses or carcinogens and treatment. The lack of a single unique characteristic which defines a transformed cell would be expected from the multistep hypothesis and is related to the possible virus-cell interactions that can occur. These form a continuous spectrum ranging from productive infection of a permissive cell, through infection of a non-permissive cell, to the inability of a virus to infect a cell. This spectrum may reflect the absence of increasing numbers of cellular functions necessary for productive virus infection, with cell transformation occurring as a rare type of abortive infection. The evidence, especially for human papillomavirus, indicates that it is quite probable that particular DNA viruses are the causative agents for certain human cancers. Even so other factors can play decisive roles in tumorigenesis. Final aetiological proof will only be obtained when an anti-virus vaccine eradicates one form of human cancer.