S u m m a r y A new ELISA kit was developed, based on highly purified whole-virus antigen derived from the Swiss maedi-visna virus strain OLV. The sensitivity, specificity and accuracy of this assay were compared with that of an established ELISA based on recombinant GAG (groupspecific antigens)-GST (glutathione S-transferase) fusion protein expressed in E. coli (GAG-GST ELISA). The whole-virus ELISA exhibits at least comparable specificity (99.3 Yo) but higher sensitivity (98.6 versus 86.3 Yo) and agreement with the 'true' status beyond chance in the detection of antiviral antibodies in serum from goats. Antibodies in milk samples are detected with higher specificity (98.9 versus 97.8 Yo) but lower sensitivity (91.4 versus 98.2 YO) than in GAG-GST ELISA. The specificity of the new ELISA in the detection of antibodies in serum might be superior, since a set of 40 samples falsely rated positive in GAG-GST ELISA in routine diagnostic work was negative in the new ELISA. In both assays, milk samples can be tested instead of serum, although with slightly reduced sensitivity in the new ELISA. The major advantage of the new test kit is the low number of equivocal samples needing confirmation in a supplementary test. Results obtained with sheep sera indicate that the new ELISA kit is also suitable for the detection of antibodies to maedi-visna virus. Recombinant GAG-GST fusion proteinRecombinant GAG-GST fusion protein derived from Dutch maedi-visna virus strain ZZV 1050 was produced in E . coli transformed with pGEX-2T/GAG(850) and purified as described by ZANONI et al. (1991b).ELISA and immunoblotting ELISA microtitre trays were coated monophasically with appropriate dilutions of highly purified virus in phosphate-buffered saline (PBS: 0.14 M NaC1, 2.6 mM KCI, 6.6 mM Na2HP04.12 H20, 1.5 mM KH2P0,1 p H 7.0), incubated overnight at 4 "C, blocked with 1 % chicken ovalbumin in PBS, washed, dried and stored at 4 "C after sealing with plastic foil. Coated microtitre trays and reagents were purchased as a kit from the manufacturer and ELISA was

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In Lithuania at least two hantaviruses, DOBV and PUUV, circulate and cause human infections. Additional investigations are needed to study the seroprevalence more precisely and to search for clinical cases of hantavirus infections.

We examined the value of performing alloabsorptions to detect clinically significant alloantibodies in patients with warm autoantibodies who must receive crossmatch-incompatible blood. One hundred and twenty-five (125) patients were evaluated using alloabsorption with red cells (RBCs) from three donors: R1R1, R2R2, and rr, whose phenotypes other than Rh were selected to exclude 98 percent of clinically significant alloantibodies. This technic was selected rather than autoabsorption due to insufficient quantities of patient cells available and to the possible presence of transfused cells in some instances. Patients were divided into three risk categories: I--no prior pregnancy or transfusion; II--history of pregnancy and/or one to five transfusions; and III--greater than five transfusions. No significant alloantibodies were found in 32 category I patients. Of 74 category II patients, 13 (17.5%) had significant alloantibodies detectable after absorption. Six of 19 (31.5%) category III patients had alloantibodies. The majority showed Rh specificity: anti-E (13), -C (6), -c (2), -D (1). Anti-K was found in five samples. Forty-two (42%) percent of the alloantibodies were undetectable prior to the alloabsorptions. We conclude that category II and particularly category III patients are at significant risk of allosensitization and should be evaluated by an absorption procedure prior to the transfusion of crossmatch-incompatible red cells.

Blood tests in cases of disputed paternity can be extremely useful even when the mother's blood sample is not available. The mean probability of exclusion (A) of red cell surface antigen, Gm, Hp, and HLA systems was determined in this situation for North American whites and blacks by creating pairs of a man and an unrelated child. In whites, the most valuable of the systems investigated to indicate nonpaternity for false fathers were HLA, Rh, Fy, and MNSs, in that order. HLA, MNSs, and Gm were the most valuable systems in blacks. With all of the genetic systems used in this study, the combined probability of exclusion (CPE) of men falsely accused of paternity, in cases where the mother is absent, is approximately 95 percent for whites and 92 percent for blacks. Since only indirect exclusions are possible without the mother, the common test panel of HLA and red cell antigens may not always allow an adequate study. Extended testing is recommended to include additional genetic systems in order to achieve an average combined probability of exclusion of at least 95 percent.