HCV E2 protein binds directly to thyroid cells and induces IL-8 production: a new mechanism for HCV induced thyroid autoimmunity

Navigating the passage between Charybdis and Scylla: recognizing the achievements of Noel Rose

This special edition of the Journal of Autoimmunity is dedicated to celebrate the enormous contributions of Dr. Noel Rose, a physician-scientist, someone that can be readily anointed as a gifted scientist who laid down the foundation and fundamental concepts of human autoimmunity. Dr. Rose performed a series of landmark studies that extend back more than 50 years and whose work is the cornerstone of the commonly used term "from the bench to the bedside." The studies included not only characterization of a normal immune response but, more importantly, defining the nature of not only the antigen, but also the aberrant response that results in organ, tissue specific reactions and immunopathology. These pioneering studies contributed to the biochemical nature of antigens, dissection of the immune repertoire, the recognition of the importance of genetics and environment, and the distinctions between a normal and an autoimmune response. Hence, this volume has been coined "Navigating the Passage Between Charybdis and Scylla: Recognizing the Achievements of Noel Rose."

The etiology of autoimmune thyroid disease: a story of genes and environment

Autoimmune thyroid diseases (AITDs), including Graves' disease (GD) and Hashimoto's thyroiditis (HT) are prevalent autoimmune diseases, affecting up to 5% of the general population. Autoimmune thyroid diseases arise due to complex interactions between environmental and genetic factors. Significant progress has been made in our understanding of the genetic and environmental triggers contributing to AITD. However, the interactions between genes and environment are yet to be defined. Among the major AITD susceptibility genes that have been identified and characterized is the HLA-DR gene locus, as well as non-MHC genes including the CTLA-4, CD40, PTPN22, thyroglobulin, and TSH receptor genes. The major environmental triggers of AITD include iodine, medications, infection, smoking, and possibly stress. Recent data on the genetic predisposition to AITD lead to novel putative mechanisms by which the genetic-environmental interactions may lead to the development of thyroid autoimmunity.

Prevalence of hepatitis C serum antibody in autoimmune diseases

OBJECTIVE

To evaluate the prevalence of serum antibodies against hepatitis C virus and other infectious agents in a large cohort of well-characterized patients with autoimmune diseases (AID).

METHODS

We utilized 1322 sera from patients with 18 different AID and 236 sera from healthy controls from the same countries and with similar age and sex distribution. All sera were tested for the presence of serum anti-hepatitis C virus (HCV) antibodies as well as antibodies directed at other infectious agents and autoantibodies.

RESULTS

Anti-HCV antibody was detected in 115/1322 (8.7%) of patients with AID and 0.4% of matched healthy controls (P < 0.0001). The prevalence of anti-HCV antibody was significantly higher in 7/18 different AID (i.e. cryoglobulinemia, mixed cryoglobulinemia pemphigus vulgaris, vasculitis, secondary anti-phospholipid syndrome, Hashimoto's thyroiditis, and inflammatory bowel disease) compared to controls. Patients with AID and serum anti-HCV positivity had an increased prevalence of antibodies against hepatitis B virus, Toxoplasma gondii and Cytomegalovirus as opposed to a lower frequency of serum autoantibodies.

CONCLUSIONS

The enhanced prevalence of anti-HCV serum antibodies in AID may suggest a role for HCV in tolerance to breakdown, similarly to its established role in mixed cryoglobulinemia. This immune mediated effect does not rule out the role of other infectious agents.

Persistent infection of a carcinoma thyroid cell line with coxsackievirus B

BACKGROUND

Viral infections are described as environmental factors that are implicated in various thyroid diseases. The role of enteroviruses (EV) in the pathogenesis of thyroid diseases has been suspected. Recently, we found that EV RNA could be detected in postoperative thyroid specimens. We decided to investigate the infection of a human thyroid cell line with coxsackievirus B4 (CVB4).

METHODS

The wild-type human thyroid carcinoma cells K1 were inoculated with CVB4E2 at 2.1 x 10(7) TCID50/mL. The titer of the virus progeny was determined every 3 days on HEp-2 cells. CVB replication at the molecular level was monitored by searching for intracellular viral genomes using reverse transcription (RT)-polymerase chain reaction (PCR). EV VP1 capsid protein was detected by indirect immunocytofluorescence staining. Cell viability was determined by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) absorbance, and the nuclear morphology was assessed by Hoechst Dye staining.

RESULTS

Infectivity assays with CVB4E2 revealed an increase in viral titers. Virus production decreased thereafter, but was not stopped by serial subculture for 24 days after infection. Detection of intracellular positive and negative viral RNA strands by RT-PCR was positive between days 1 and 14 postinfection (p.i.), and by semi-nested RT-PCR up to 24 days. K1 cell cultures infected with CVB4 were stained positively for EV VP1: the number of VP1-positive cells decreased rapidly within 6 days and remained low up to the end of culture. Compared with mock-infected cultures, viability in CVB4-infected cultures was around 100% up to 24 days. Cells with strongly fluorescent nuclei and/or fragmented nuclei were observed.

CONCLUSION

We demonstrate for the first time that CVB4 could replicate in thyroid cells and could persist, with predominance of viral negative RNA strands for up to 24 days p.i. without obvious cytopathic effect. Our results suggest that CVB4 may lead to thyroid cell apoptosis. Further studies are needed to determine whether CVB could play a role in thyroid pathologies.