In the plasma and/or sera from donated volunteer from July to November in 1987 at Kagoshima Red Cross Blood Center, the prevalence of antibodies to adult T-cell leukemia associated antigen (anti-ATLA) was 11.1% (6, 740/60, 771 persons). Of these persons with anti-ATLA, 2, 842 out of 6, 740 persons (42.2%) showed low titer of seropositivity (24-26). Ninety-eight sera which showed low titer of anti-ATLA in CPD added plasma were randomly collected and examined in this study. Anti-ATLA in 93 out of 98 sera could be studied for anti-ATLA by the PA and the ELISA method and compared, each other. Of these 93 sera, 44 sera (47.3%) showed low titer (24-25) positive by the PA method, but negative by the ELISA method.
Ninety-eight sera could be studied for anti-ATLA (IgG and IgM antibody) by Western blotting (WB) method. IgG antibody was detected only in 1 serum, but IgM antibody was not seen in any sera.
Of 98 sera, which were available for this study, 44 sera showed low titer positive by the PA method in both CPD added plasma and serum. Of these 44 sera, anti-DNA antibody was positive only in 1 serum and antinuclear factor in 2 sera.
These results elicited the following:
1) In donated volunteers in Kagoshima district, an endemic area of human T-cell leukemia virus type I, the rate of positive sera with low titer (24-26) for anti-ATLA examined by the PA method was high (42.2%). 2) There are many sera showing false positive in the positive sera with low titer for anti-ATLA. 3) Factors which cause false positive reaction for anti-ATLA by the PA method might not be associated with autoantibodies in serum. Moreover, it was seen more frequently in plasma than in serum.
In conclusion, the PA method for anti-ATLA, which is now performed, is considered to contain some problems in the procedure. Therefore, it is necessary to clarify these problems in the PA method in order to make good use of blood transfusion, effectively.
