Human T-cell leukemia virus type 1 is associated with dysthyroidism in the French Amazon.

Background: Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus known to cause two major diseases: adult T-cell leukemia/lymphoma and a progressive neuromyelopathy-tropical spastic paraparesis. Many viruses may be involved in the pathogenesis of thyroiditis; however, few studies have focused on the role of HTLV-1. We aimed to investigate the association between HTLV-1 and biological thyroid dysfunction. Methods: We included 357 patients with a positive HTLV-1 serology and thyroid-stimulating hormone assay data between 2012 and 2021 in a hospital in French Guiana; we compared the prevalence of hypothyroidism and hyperthyroidism in this group with that in an HTLV-1-negative control group (722 persons) matched for sex and age. Results: The prevalence of hypothyroidism and hyperthyroidism in patients with HTLV-1 infection was significantly higher than that in the control group (11% versus 3.2% and 11.3% versus 2.3%, respectively; p < 0.001). Conclusion: Our study shows, for the first time, the association between HTLV-1 and dysthyroidism in a large sample, suggesting that thyroid function exploration should be systematically implemented in this population as this may have an impact on therapeutic management.

Effects of hypo- and hyperthyroid states on herpes simplex virus infectivity in the rat.

OBJECTIVE: Available data from in vitro studies show that thyroid hormones (THs) regulate herpes simplex virus (HSV) gene expression and may modulate latency/reactivation of the virus. Whether infectivity of the virus is also affected by THs is not known. Using animal models (in vivo study) and Vero cell culture (in vitro study), we examined the effects of alterations in THs level on HSV-1 infectivity. METHODS: Rats were rendered hypo- and hyperthyroid by daily addition of methimazole and l-thyroxine into their drinking water, respectively. Euthyroid animals served as control. All animals were given a single dose of HSV-1 (10(7)TCID50, ip) and sacrificed 3 d later. The spleen of the animals was then removed and viral particles were recovered from the tissue extract through aseptic procedures. Serial dilution of the extracts was prepared and added to Vero cell culture. For the in vitro study, the cultures were pretreated with l-thyroxine and the viral particles were then added. Virus titration was determined by Reed-Muench quantal assay. RESULTS: The viral load of spleen in hyperthyroid rats was significantly lower (1000-fold) than that of the euthyroid rats. Similarly, in vitro presence of supraphysiologic levels of l-thyroxine in the culture media of Vero cells decreased virus infectivity. Interestingly, hypothyroid animals showed a significant increase (10-fold) in spleen viral load as compared to that of their euthyroid counterparts. CONCLUSIONS: These data clearly show that the HSV-1 infectivity is affected by THs, and suggest that THs or their analogs may have a potential application in prevention and/or treatment of viral infections.

Abnormal thyroid function in older men with or at risk for HIV infection.

OBJECTIVES: The aim of the study was to evaluate the prevalence of and factors associated with abnormal thyroid function in older men with or at risk for HIV infection. METHODS: A cross-sectional analysis of 636 men > or =49 years old was carried out using data obtained from interviews, from measurements of body mass index (BMI), HIV-1 serology and viral load, CD4 cell count, hepatitis C virus (HCV) assays, thyroid-stimulating hormone (TSH) and free thyroid hormone levels. RESULTS: Participants were 54% black, 57% overweight/obese, 57% HIV seropositive, and 72% HCV seropositive; 38% reported recent cocaine or heroin use. Decreased TSH was found in 56 men (8.8%) and raised TSH in 23 men (3.6%). Only three men had abnormal free thyroxine levels. CONCLUSIONS: Abnormal TSH levels were noted in 12.4% of older men with or at risk for HIV infection, but nearly all reflected subclinical hyperthyroidism or subclinical hypothyroidism.

[Two cases of acute hepatitis E in patients with hyperthyroidism].

Acute hepatitis E occur commonly as outbreaks in endemic areas, but can occur sporadically in other part of the world. Acute hepatitis E has been reported rarely in Korea. A case of concurrent acute hepatitis E virus (HEV) infection and hyperthyroidism was reported in an inactive hepatitis B surface antigen carrier. We experienced two cases of concomitant acute HEV infection in patients with hyperthyroidism. The first case had acute HEV infection with subclinical hyperthyroidism while taking propylthiouracil. The second case suffered from acute HEV infection in a patient with Graves' disease intractable to propylthiouracil. Herein, we suggest the possible association between HEV infection and hyperthyroidism.

An informative case of Graves' disease with implications for schizophrenia.

The aetiology of schizophrenia and the other psychoses is not yet established. The Knight model, based on genetic and other evidence, proposes that schizophrenia is an autoimmune disease, caused by the development of forbidden clones of B lymphocytes that secrete autoantibodies that accidentally stimulate cell surface receptors on certain neurons, affecting the limbic system of the brain. An unusual defect in a Maori man with Graves' disease rendered him unresponsive to the usually effective antithyroid drugs, prompting his being treated with prednisone, a non-specific immunosuppressant agent. This was highly successful, reducing the blood level of the causative thyroid-stimulating autoantibodies with reduction of thyroid hormone levels and thyroid gland size. Unfortunately, high dosage prednisone can be used for only a month, because of steroid toxicity. A research pathway to effective therapy of receptor-mediated autoimmune diseases, which probably include the psychoses, is now apparent. It involves finding the autoantibodies, then cloning of their antigenic targets, as has been done for Graves' disease. This will provide knowledge of the peptide sequences necessary for constructing therapeutic agents for selectively destroying the pathogenic forbidden clones. Meanwhile, usage of short-term therapy with prednisone could be helpful in the management of schizophrenia and should be explored.

Enterovirus infection--a possible trigger for Graves' disease?

Viruses are potential environmental factors in autoimmune disease. Some evidence suggests a relationship between enteroviral infection (especially Coxsackie B virus) and autoimmunity. We investigated 21 individuals with recent onset of Graves' hyperthyroidism in regard of (subclinical) enterovirus infection. Thyrotoxic symptoms had started about two months before blood sample collection. The patients were from Upper Austria and mainly female (17/21). Their mean free thyroxin levels in blood were twice the maximum normal value and the majority achieved a euthyroid state 1 1/2 years later, after antithyroid medication. We employed a nested PCR reaction with primers of the enterovirus genome on blood samples. All were negative for RNA of the enterovirus group. Coxsackie and related viruses were not identified as a trigger factor in autoimmune thyrotoxic disease.

HTLV-I associated uveitis and hyperthyroidism.

The records of 76 consecutive patients with etiology-undefined uveitis examined during the 3-year period between 1990 and 1992 were reviewed and 6 patients were found who had concomitant hyperthyroidism. These 6 patients had presented with uveitis symptoms and signs when hyperthyroidism was relieved with thiamazole therapy. The uveal disease was characterized by acute, granulomatous or nongranulomatous anterior uveal involvement and granular or membranous vitreous opacities with or without retinal vascular change. These manifestations resolved in a few weeks in response to topical and/or systemic corticosteroids. Three patients had recurrence of uveitis after remission for months to years. All of the patients had serum antibodies to HTLV-I. The uveal disease resembled HTLV-I associated uveitis that may develop in patients with HTLV-I associated myelopathy or HTLV-I carriers; 2 cases had chronic myelopathy or arthropathy that was considered associated with the retrovirus. The present observations suggest that the association between uveitis and hyperthyroidism is not accidental but shares a common underlying etiologic factor, HTLV-I, although the pathomechanism remains to be defined.