The second example of Lu:-7 phenotype: serology and immunochemical studies

We describe the second example of red blood cells (RBCs) with the Lu:-7 phenotype in a 37-year-old Latino female (SA). Her RBCs were nonreactive with anti-Lu7 (Mrs. GA) but were reactive with all other antibodies to high-prevalence antigens tested, including those in the Lutheran blood group system. No Lu:-7 RBCs were available for testing. SA's serum was nonreactive by the indirect antiglobulin test against (1) recessive and dominant Lu(a-b-) RBCs and (2) trypsin-treated or a-chymotrypsin-treated RBCs of common phenotype. By immunoblotting, eluates containing anti-Lu7 from both Mrs. GA and SA reacted with apparently the same bands in RBC membranes of common phenotype as did human anti-Lub, reacted weakly with Lu(a-b-) RBCs of the dominant type, and were nonreactive with SA's RBC membranes. These findings raise the Lu7 antigen from its Lutheran-related (para-Lutheran) status to a bona fide member of the Lutheran blood group system.