Lewis antigens on newborn red cells.

This study aimed to screen for Lewis antigens in Thai newborns. Although, these antigens are known to be weak or absent on the red cells of newborns, we encountered a case of a Le(a+) newborn baby when testing with monoclonal antibody and human anti-Le(a). Such a finding led us to conduct this study to explore further evidence of Lewis antigens in Thai newborn red cells. A total of 197 cord blood samples were tested with monoclonal anti-Le(a) and anti-Le(b). (Bioclone, Ortho Diagnostic Systems, USA). The tests were performed according to the manufacturer's recommendations. The results revealed that none of the cord red cells in this study group possessed Lewis antigens. This study showed that Lewis antigens were absent or were so extremely weak on the red cells of these newborn infants that they could not be demonstrated despite the use of potent monoclonal antibodies. However, further study should be done by using more cord blood samples, a more sensitive technique or even more potent antisera.

Evaluation of donor self exclusion program.

Donor self exclusion is a low technology procedure to avoid blood donations from the high-risk groups for HIV infection. This strategy has been widely used in western countries to reduce the risk of transfusion associated AIDS. At Ramathibodi Hospital, we conducted a study on donor self exclusion program during March-December 1991. It was found 2.60%-6.55% (mean = 4.59%) of a total of 4,286 units of blood that were from the donors who indicated that their blood may not be safe for transfusion while the rest of them declared that their blood was safe based on sexual behavior during the past 3 months and the history of intravenous drug use. Among 202 units of unsafe blood, there were 1 (0.49%) positive for HIV-Ag, 7 (3.46%) for anti-HIV, 5 (2.48%) for anti-HCV, 10 (4.95%) for HBsAg and 6 (2.97%) for VDRL while there was no HIV-Ag detected in 4,084 units of safe blood but 19 (0.46%) were positive for anti-HIV (p < 0.05), 65 (1.59%) for anti-HCV, 219 (5.36%) for HBsAg and 56 (1.37%) for VDRL. It was clearly demonstrated in this study that confidential self-exclusion or HIV-Ag testing would have eliminated this HIV-Ag reactive unit in the "window period" from transfusion, while the syphilis screening would not have had any value as a surrogate marker. However, self-exclusion programs are likely to prove too non-specific and need more time to educate the donors.(ABSTRACT TRUNCATED AT 250 WORDS)