This page was last modified on 18 May 2016, at 10:17.


HTLV-I and HTLV-II are closely related RNA retroviruses that are transmitted parenterally and sexually, and typically cause life-long chronic infection.

Individual at risk



Guidance at RECRUITMENT for adult volunteer donor and maternal donor (cord blood donation)


Notify and counsel donor

Guidance at CT/WORK-UP


Notify and counsel donor


Justification for guidance

HTLV-I is associated with a small risk of myelopathy and other inflammatory conditions, but more importantly causes immune suppression with consequent risk of cancer and opportunistic infections.

HTLV-II is less common and has no firmly established disease association, but it would be wise to assume that similar immune effects to HTLV-I could occur.

HTLV-I is efficiently transmitted via blood products, with lookback studies suggesting a transmission rate of 13-75%. With the virus’ predilection for CD4+ T-helper cells, this efficiency may be even greater for haematopoietic stem cell products.

Considering that HSCT recipients already face a high degree of immune suppression and concomitant cancer/infection risk, it would seem reasonable to maintain the current recommendation of permanent exclusion of donors with HTLV-I or HTLV-II.


Goncalves DU, Proietti FA, Ribas JGR, Araujo MG, Pinheiro SR, Guedes AC and Carneiro-Proietti BF. Epidemiology, treatment, and prevention of human T-cell leukemia virus type 1-associated diseases. Clin Microbiol Revs 2010; 23:577-589.

Manns A, Wilks R, Murphy EL, Haynes G, Figueroa P, Barnett M, Hanchard B and Blattner WA. A prospective study of transmission of HTLV-I and risk factors associated with seroconversion. Int J Cancer 1992; 51:886-891.

Boxus M and Willems L. Mechanisms of HTLV-I persistence and transformation. Br J Cancer 2009; 101:1497-1501.

Namen-Lopes MSS, Martins ML, Drummond PC, Lobato RR, Interdisciplinary HTLV Research Group (GIPH) and Carneiro-Proietti ABF. Lookback study of HTLV-1 and 2 seropositive donors and their recipients in Belo Horizonte, Brazil. Transfusion Med 2009; 19:180-188.


There may also be legal and/or regulatory issues with the collection, transport and administration of a HTLV-positive product.


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