Human T-cell lymphocytotrophic virus prevalence in German blood donors and "at-risk" groups

Clinical and Public Health Implications of Human T-Lymphotropic Virus Type 1 Infection

Human T-lymphotropic virus type 1 (HTLV-1) is estimated to affect 5 to 10 million people globally and can cause severe and potentially fatal disease, including adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The burden of HTLV-1 infection appears to be geographically concentrated, with high prevalence in discrete regions and populations. While most high-income countries have introduced HTLV-1 screening of blood donations, few other public health measures have been implemented to prevent infection or its consequences. Recent advocacy from concerned researchers, clinicians, and community members has emphasized the potential for improved prevention and management of HTLV-1 infection. Despite all that has been learned in the 4 decades following the discovery of HTLV-1, gaps in knowledge across clinical and public health aspects persist, impeding optimal control and prevention, as well as the development of policies and guidelines. Awareness of HTLV-1 among health care providers, communities, and affected individuals remains limited, even in countries of endemicity. This review provides a comprehensive overview on HTLV-1 epidemiology and on clinical and public health and highlights key areas for further research and collaboration to advance the health of people with and at risk of HTLV-1 infection.

No significant HTLV seroprevalence in German people who inject drugs

Background

Although human T-lymphotropic virus (HTLV) is transmitted via the same routes as human immunodeficiency virus (HIV), its worldwide seroprevalence differs drastically because HTLV is transmitted mainly via infected cells rather than free virus. The sharing of needles and other equipment places people who inject drugs (PWID) at particularly high-risk for such blood-borne diseases.

Methods

To validate the methodology used to process and analyze the dried blood spots (DBS) utilized in the study, dried serum spots (DSS) with dilutions of sera from known HTLV infected individuals were analyzed by ELISA and Western blot. DBS collected between 2011 and 2015 from 2,077 PWID in eight German cities recruited by respondent-driven sampling were tested for HTLV-specific antibodies.

Results

The validation demonstrated that the use of DSS allowed identification of samples with even low titers of HTLV-specific antibodies, although a confirmatory Western blot with an additional venous blood sample would often be required. Despite numerous HIV and HCV positive individuals being identified within the study population, none tested positive for HTLV.

Conclusion

While the HIV and HCV prevalences in German PWID are comparable to those in other European countries, the very low prevalence of HTLV reflects the situation in the general population.

Tissue donation and virus safety: more nucleic acid amplification testing is needed

In tissue and organ transplantation, it is of great importance to avoid the transmission of blood-borne viruses to the recipient. While serologic testing for anti-human immunodeficiency virus (HIV)-1 and -2, anti-hepatitis C virus (HCV), hepatitis B surface antigen (HBsAg), anti-hepatitis B core antigen (HBc), and Treponema pallidum infection is mandatory, there is until now in most countries no explicit demand for nucleic acid amplification testing (NAT) to detect HIV, hepatitis B virus (HBV), and HCV infection. After a review of reports in the literature on viral transmission events, tissue-specific issues, and manufacturing and inactivation procedures, we evaluated the significance of HIV, HCV, and HBV detection using NAT  in  donors of various types of tissues and compared our results with the experiences of blood banking organizations. There is a significant risk of HIV, HCV, and HBV transmission by musculoskeletal tissues because of their high blood content and the high donor-recipient ratio. If no effective virus inactivation procedure for musculoskeletal tissue is applied, donors should be screened using NAT  for  HIV, HCV, and HBV. Serologically screened cardiovascular tissue carries a very low risk of HIV, HCV, or HBV transmission. Nevertheless, because effective virus inactivation is impossible (retention of tissue morphology) and the donor-recipient ratio may be as high as 1:10, we concluded that NAT  should be performed for HIV, HCV, and HBV as an additional safety measure. Although cornea allografts carry the lowest risk of transmitting HIV, HCV, and HBV  owing to corneal physiology, morphology, and the epidemiology of corneal diseases, NAT  for  HCV should still be performed. If the NAT  screening of a donor for HIV, HCV, and HBV is negative, quarantine storage of the donor tissue seems dispensable. In view of numerous synergistic effects with transfusion medicine, it would be advantageous for tissue banks to cooperate with blood bank laboratories in performing virological tests.