An alloantibody to a high-prevalence MNS antigen in a person with a GP.JL/Mk phenotype.

The low-prevalence MNS blood group antigenTSEN is located at the junction of glycophorin A (GPA) to glycophorin B (GPB) in several hybrid glycophorin molecules. Extremely rare people have RBCs with a double dose of the TSEN antigen and have made an antibody to a high-prevalence MNS antigen. We report the first patient who is heterozygous for GYP.JL and Mk. During prenatal tests,an alloantibody to a high-prevalence antigen was detected in the serum of a 21-year-old Hispanic woman. The antibody detected an antigen resistant to treatment by papain, trypsin, alpha-chymotrypsin, or DTT. The antibody was strongly reactive by the IAT with all RBCs tested except those having the MkMk, GP.Hil/GP.Hil, or GP.JL/GP.JL phenotypes. The patient's RBCs typed M+N-S+/-s-U+, En(a+/-), Hut-, Mi(a-), Mur-, Vw-, Wr(a-b-), and were TSEN+, MINY+. Reactivity with Glycine soja suggested that her RBCs had a decreased level of sialic acid. Immunoblotting showed the presence of monomer and dimer forms of a GP(A-B) hybrid and an absence of GPA and GPB. Sequencing of DNA and PCR-RFLP using the restriction enzyme RsaI confirmed the presence of a hybrid GYP(AB). The patient's antibody was determined to be anti-EnaFR. She is the first person reported with the GP.JL phenotype associated with a deletion of GYPA and GYPB in trans to GYP.JL.

Cefotetan-induced immune hemolytic anemia following prophylaxis for cesarean delivery.

Second- and third-generation cephalosporins, notably cefotetan, are increasingly implicated in severe, sometimes fatal immunemediated hemolytic anemia. We describe a 26-year-old woman who developed severe hemolytic anemia 2 weeks after receiving a single prophylactic dose of cefotetan during cesarean delivery. The patient's DAT was weakly reactive for IgG and her serum reacted with cefotetan-coated RBCs. The antibody had a titer of 4,096 by antiglobulin testing. The patient required treatment with two units of PRBCs and experienced gradual resolution of hemolysis. Our case emphasizes the need for increased awareness of delayed onset hemolytic anemia following prophylactic use of cefotetan.

A MAR-like antibody in a DCWe/DCWe person.

BACKGROUND: MAR (RH51), a high-incidence antigen in the Rh blood group system, is absent from RBCs with a double dose of CW or CX or a single dose each of CW and CX antigens, as well as from rare Rh phenotypes including D- - and Rh(null). The MAR antigen is associated with the presence of Ala36 and Gln41 on the RhCe protein. The original example of anti-MAR, described in 1994, was made by a DCWe/DCXe woman. It was possible that the antibody directed against a high-incidence antigen in the Rh system made by a DCXe/DCXe woman (CM) in 1983 was anti-MAR. CASE REPORT: A 52-year-old, multiply transfused, white woman (CJ) with pre-existing anti-c, -E, and -Jk(a) presented for preoperative work-up for her fifth open heart procedure. The strength of the reaction of her RBCs with anti-CW suggested a double dose of CW antigen. Her serum, which unexpectedly was strongly reactive with c-, E-, Jk(a-) RBCs by PEG indirect antiglobulin test, was incubated with E-c-, Jk(a-) RBCs, and an eluate was prepared. This eluate reacted 3+ with E-c-, Jk(a-) RBCs but did not react with Rh(null) (n = 5), - - (3), DCW- (2), Dc- (1), or DCWe/DCWe (1) RBCs. Two related DCXe/DCXe and two unrelated DCWe/DCXe RBC samples were weakly agglutinated. The patient's RBCs were negative with the original anti-MAR but reacted as strongly as the positive control RBCs with the antibody made by the DCXe/DCXe person. CONCLUSION: This is the first example of a MAR-like antibody made by a DCWe/DCWe woman. The specificity cannot be called anti-MAR, because some MAR-negative samples react, albeit weakly. The original anti-MAR, made by a DCWe/DCXe woman, did not react with DCWe/DCWe, DCWe/DCXe, or DCXe/DCXe RBCs. It is apparent that the specificity of "anti-MAR" differs slightly, depending on the CW/CX status of the antibody maker.

First example of hemolytic disease of the newborn caused by anti-Or and confirmation of the molecular basis of Or.

BACKGROUND AND OBJECTIVES: The rare MNS antigen Or (MNS31) is sensitive to ficin, papain and sialidase, but partially resistant to trypsin (0.05%); the effect of alpha-chymotrypsin is not known. A point mutation, 204C --> T in exon 3 of GYPA, is associated with the Or+ phenotype. We report here the first case of hemolytic disease of the newborn (HDN) caused by anti-Or, and expand the information on the nature of the Or determinant. MATERIALS AND METHODS: A woman, gravida 4, para 0, delivered a baby whose red blood cells (RBCs) were positive (2+) on the direct antiglobulin test (DAT). The mother's serum, an eluate made from the baby's RBCs and the RBCs of the baby's father were investigated. Exon 3 of GYPA, extracted from the father's genomic DNA, was amplified and sequenced. RESULTS: The mother's serum reacted at room temperature, 37 degrees C and on the indirect antiglobulin test with RBCs from the baby's father. The father's RBCs were M+N+S-s+Or+. The antibody in the mother's serum and in the baby's eluate was identified as anti-Or. The serum did not react with the father's RBCs treated with trypsin (180,000 U/ml), but did react with his alpha-chymotrypsin-treated RBCs. Amplification and sequencing of DNA from the father revealed a single point mutation, 204C --> T, in GYPA exon 3. At birth, the baby had clinical symptoms of HDN and was transfused with 36 ml of packed RBCs and received phototherapy for eight days. At week 11, the baby's M+N+S+s+Or+ RBCs were negative on the DAT. CONCLUSION: This is the first case of HDN caused by anti-Or. The observed point mutation, 204C --> T, confirms that of a previous report and predicts a change of Arg (Or-) to Trp (Or+) at amino acid 31.

New genotypes in Fy(a-b-) individuals: nonsense mutations (Trp to stop) in the coding sequence of either FY A or FY B.

Duffy blood group antigens are carried on a glycoprotein that is predicted to pass through the erythrocyte membrane seven times and is a promiscuous chemokine receptor. The Fy(a- b-) phenotype is present in two-thirds of African-American Blacks but is rare in Caucasians. In Blacks, the phenotype is due to a non-functional GATA-1 motif in the FY B, which silences the gene in erythrocytes but not in other tissues, and these patients do not generally make anti-Fyb or anti-Fy3. We describe here the molecular analysis of FY in three unrelated Caucasians who were studied because they had strong anti-Fy3 in their serum. Each was found to have a point mutation that was predicted to change a tryptophan to a premature stop codon in the coding sequence. In one patient (patient 1), the nonsense mutation was at nucleotide 287 of the major transcript in FY A; in another (patient 2), it was at nucleotide 407 in the major transcript of FY B; and in a third (patient 3), it was at nucleotide 408 of the major transcript of FY A.

Severe delayed hemolytic transfusion reaction secondary to anti-At(a).

BACKGROUND: Anti-At(a) is a rare red cell (RBC) alloantibody found in the black population. It has been described as causing one case of mild hemolytic disease of the newborn, but its ability to cause hemolytic transfusion reactions is uncertain. CASE REPORT: The patient was a 60-year-old black female with a history of three uneventful pregnancies but no transfusions. On admission, her direct and indirect antiglobulin tests were negative, total bilirubin was 0.5 mg per dL, and lactate dehydrogenase was 224 IU per L. She received nine units of compatible RBCs in the perioperative period of a hemicolectomy. Her hemoglobin rose appropriately and stabilized at 12.6 g per dL by the 6th postoperative day. By Day 10 after surgery her hemoglobin had dropped to 6.8 g per dL, and her total bilirubin and lactate dehydrogenase had risen to 1.4 mg per dL and 783 IU per L, respectively. The direct and indirect antiglobulin tests were now newly positive with strengths of 3+. A warm hemolytic autoantibody was suspected. She was transfused two units of incompatible RBCs for a rapidly falling hemoglobin and symptomatic anemia. On Day 11, the total bilirubin rose to 3.5 mg per dL, and the lactate dehydrogenase was 1154 IU per L with a hemoglobin of 7.6 g per dL. Corticosteroids were begun. Studies of serum and an acid eluate revealed anti-At(a), but no other RBC antibodies. The patient stabilized, and further transfusion was avoided. CONCLUSION: Although anti-At(a) was previously described as being of uncertain clinical significance, this patient demonstrated the ability of the antibody to cause a severe delayed hemolytic transfusion reaction.

Two examples of an inseparable antibody that reacts equally well with DW+ and Rh32+ red blood cells.

BACKGROUND AND OBJECTIVES: Anti-DW is a rare specificity that detects an antigen on DVa red blood cells (RBCs). Some anti-DW contain an inseparable component that cross-reacts weakly with RBCs expressing the low-incidence Rh antigen Rh32. RH32 is expressed by RBCs with either the R=Nor the DBT phenotype. CASE REPORT: We describe here an antibody found in the serum of 2 patients that reacts equally well with RBCs possessing either DVa, R=N, or DBT phenotypes. The reactivity for DW and Rh32 antigens could not be separated by adsorption onto and elution from DW+Rh32- or from DW-Rh32+ RBCs. CONCLUSIONS: We suggest that amino acids encoded by nucleotides at the junction of exon 4 of RHD to exon 5 of RHCE may induce a conformation that is recognized by these equally reactive inseparable antibodies. Until such time that the epitope recognized by these antibodies is defined, we recommend use of the descriptive name anti-DW/Rh32.

Disappearance of antibodies to Cromer blood group system antigens during mid pregnancy.

The Cromer blood group system consists of 7 high incidence and 3 low incidence antigens that are carried on the complement regulatory glycoprotein called decay-accelerating factor (DAF; CD55). Despite laboratory results that would predict clinical significance, antibodies with specificities in the Cromer blood group system have not been reported to cause hemolytic disease of the newborn. It is possible that strong expression of DAF on the apical surface of antigen-positive fetally derived placental trophoblasts may absorb maternal antibodies that are directed to antigens in the Cromer blood group system. We studied two cases where strongly reactive anti-Cra and anti-Dra became undetectable during second and third trimesters of pregnancies.

A second example of anti-Esa, an antibody to a high-incidence Cromer antigen.

A blood sample contained an antibody to a high-incidence antigen that reacted with all red blood cells (RBCs) tested by the indirect antiglobulin test (IAT). The antibody reacted with papain-, ficin-, and trypsin-treated RBCs, but not with a-chymotrypsin-treated RBCs. This pattern of reactivity suggested the possibility that the antibody was recognizing an antigen in the Cromer blood group system. Tests against RBCs deficient in decay-accelerating factor (which carries the Cromer antigens) were weakly positive. Tests with antibodies to high-incidence Cromer antigens and with RBCs lacking high-incidence Cromer antigens led to identification of the second example of anti-Esa in an Es(a-) person. The antibody was IgG1 and reacted by the IAT to a titer of 64. The monocyte monolayer assay indicated potential clinical significance of this antibody in relation to transfusion.

A novel variant of the human blood group K1 antigen.

A discrepancy in duplicate anti-K1 typing in a parentage case led to the discovery of an unusual K1 blood group antigen. Red blood cells from the propositus (JC) express a rare variant of the K1 antigen that is detectable by only 8 of 72 sera containing anti-K1. Absorption and elution studies using reactive anti-K1 confirmed the presence of a K1 antigen. Nonreactive anti-K1 was not absorbed by or eluted from JC's red blood cells. Red cells from 3 of the propositus's siblings also had the variant K1 antigen. The variant antigen exhibited qualitative as well as quantitative differences as compared to normal K1, and we have named it K1var.