Comparative evaluation of 14 immunoassays for detection of antibodies to the human T-lymphotropic virus types I and II using panels of sera from Sweden and West Africa.
BACKGROUND
A new generation of assays for the detection of human T-lymphotropic virus types I and II (HTLV-I/II) antibodies has been released. These assays incorporate HTLV-I- and HTLV-II-specific antigens, and some are based on new assay principles. Comparative evaluation data that include these new as well as previous assays are limited.


METHODS
Fourteen HTLV antibody assays were evaluated by using well-characterized panels of sera from Guinea-Bissau, West Africa, and Sweden. The sera included 127 HTLV-I-positive and 62 HTLV-II-positive specimens, as well as 919 consecutive negative samples.


RESULTS
The sensitivity for HTLV-I was 100 percent for all assays, except one, which repeatedly missed one sample. The sensitivity for HTLV-II varied between 86 percent and 100 percent. In general, new-generation assays incorporating HTLV-II-specific antigens, and some of which are based on new assay principles, had a higher sensitivity for HTLV-II than previous assays, which mainly are based on HTLV-I antigens. The specificity was generally higher for new assays than for the previous versions. Testing of Swedish blood donor sera gave higher specificities (94-100%) than did that of African specimens (90-99.7%). Most assays had low delta values (DVs), although there was a tendency toward increased DVs for the new generation of assays. Only two of the new generation of assays came close to a combination of high sensitivity for both HTLV-I and HTLV-II, high specificity, positive and negative predictive values, and high DVs.


CONCLUSIONS
The sensitivity for HTLV-I was generally high and appears to have improved for HTLV-II with the introduction of a new generation of assays incorporating HTLV-II-specific antigens. However, some assays still give false-negative results on HTLV-II-positive specimens. The specificities and the DVs were generally higher for the new assays than for the previous versions.
Andersson
S
S
Swedish Institute for Infectious Disease Control, Solna. soren.andersson@orebroll.se
Thorstensson
R
R
Ramirez
K G
KG
Krook
A
A
von Sydow
M
M
Dias
F
F
Biberfeld
G
G
D000354:Africa, Western; D015480:Deltaretrovirus Antibodies / Q000097:blood*; D005069:Evaluation Studies as Topic; D005188:False Negative Reactions; D015368:Human T-lymphotropic virus 1 / Q000276:immunology*; D015367:Human T-lymphotropic virus 2 / Q000276:immunology*; D006801:Humans; D008403:Mass Screening / Q000592:standards*; D012680:Sensitivity and Specificity; D013548:Sweden
D015480:Deltaretrovirus Antibodies