A New Low‐Frequency Red Cell Antigen, ‘SARAH’

Abstract

There are more than 100 low-frequency antigens (LFAs) which have been given International Society of Blood Transfusion (ISBT) numbers as members of systems, collections or the 700 series. In addition, there are a number of well-known (to reference laboratories) unpublished LFAs. The presence of an LFA was suspected when 2 sera were found to react with a single example of K homozygous cells. Anti-K reacting with K homozygotes was eliminated on testing with other KK cells. Testing of the reactive cell with antibodies to known LFAs and the reactive sera with cells known to carry LFAs failed to identify the specificity. A study on the family of the cell donor showed inheritance of the antigen in two generations. Further testing, which included immunoblotting and RFLPs, was carried out in Australia, the UK, Canada and the USA. By March 1993 all published LFAs had been excluded, and an application was made to the ISBT to have the antigen, SARAH, assigned a 700 series number. In April the number 700.052 was provisionally designated for this new antigen.

SARA: a “new” low‐frequencyMNSantigen (MNS47) provides further evidence of the extreme diversity of theMNSblood group system

“…At first sight, these findings are in contrast with the original publication, which suggested that SARA was not an MNS blood group antigen as the SARA antigen is resistant to ficin and papain treatment while many MNS antigens, including M, N, Vw, Hut, Mur, M g , Vr, Hop, Bun, Mut, and Os a , are sensitive to treatment by these enzymes . However, this can be explained as on the glycophorin A molecule, Gly78 is a ficin proteolytic site and Arg80 is a papain proteolytic site.…”

“…The Wilcox serum is known to react with 20 low‐frequency Diego and glycophorin A antigens, including Dantu, Mt a , and Ri a . The original investigation into the SARA proband and family was undertaken using Wilcox serum . Based on the work performed by the original authors and consistent with our demonstration that SARA is a glycophorin A antigen, SARA should be added to the list of known specificities of this reagent.…”

“…* a Individuals who were participants in this current study; b individuals who were deceased before commencement of this study and whose serologic profiles were obtained from the original SARA study, noting that Individual I‐1 was deceased before discovery of the SARA antigen…”

“…The low‐frequency SARAH (SARA) red blood cell (RBC) antigen was discovered in 1990 when, during an antibody identification, a unique reaction between patient serum and a reagent RBC was observed. A subsequent investigation determined that the reagent RBC donor carried a novel, low‐frequency antigen, designated SARA . SARA was assigned to the 700 series (700.052) for antigens distinct from all other described antigens, without evidence of association with any of the defined blood group systems, with an incidence of less than 1% in populations tested and demonstrable inheritance over at least two generations…”

International society of blood transfusion working party on red cell immunogenetics and terminology: report of the Seoul and London meetings

“…System 2: MNS Two antigens have been added to the MNS system. Exome sequence analysis of samples from SARA+ and SARA-family members [1] identified a single nucleotide change c.240G>T in exon 3 of GYPA, which changes p.Arg80Ser. Sequence analysis of unrelated SARA+ samples confirmed the causative polymorphism [2].…”