Expansion of the Kell blood group system: two new high-prevalence antigens and two novel K0 (Kellnull ) phenotypes.

BACKGROUND: The number of KEL alleles associated with new antigens or loss of expression of high-prevalence antigens continues to increase. We investigated KEL in five samples: two with K0 (null) phenotypes and three with normal Kell expression and antibodies to high-prevalence antigens. STUDY DESIGN AND METHODS: Red blood cell (RBC) typing and antibody identification were by standard methods. Genomic DNA was isolated from white blood cells and DNA array testing and sequencing of KEL exons was performed by standard methods. RESULTS: Proband 1, an Asian woman with Kp(b+) RBCs, presented with alloanti-Kp(b) . Four years later, the antibody was reactive with all RBCs except K0 . She was homozygous for KEL c.877C>T change (p.Arg293Trp), and the high-prevalence antigen absent from her RBCs was named KHUL. Probands 2 and 3, both Japanese and homozygous for KEL c.875G>A (p.Arg292Gln), presented with an antibody reactive with all except K0 RBCs. The antibody, named KYOR, recognizes an antigen antithetical to KYO (KEL31). Proband 4, a pregnant Middle Eastern woman, presented with alloanti-Kp(b) , but her RBCs did not express Kell antigens. She was homozygous for KEL c.230G>T (p.Cys77Phe). Proband 5, a multiply transfused Caucasian female with an antibody reactive with all RBCs except K0 and lacking Kell antigens, was a compound heterozygote carrying a silenced allele c.574C>T (p.Arg192Stop) in trans to c.1664G>A (p.Gly555Glu). CONCLUSION: We describe two new high-prevalence Kell antigens, KHUL (ISBT 006037; KEL37) and KYOR (ISBT 006038; KEL38), and two novel alleles encoding K0 phenotypes. We caution that antibodies produced by individuals with K0 RBCs or lacking high-prevalence antigens can present as anti-Kp(b) .

A novel RHCE*ce 48C, 733G allele with Nucleotide 941C in Exon 7 encodes an altered red blood cell e antigen.

BACKGROUND: Several RHCE*ce alleles have in common a 733C>G (Leu245Val) change. Some encode an altered expression of e on red blood cells (RBCs) and individuals with such RBCs can make e-like alloantibodies. The identification of an apparent anti-hr(B) in the serum of an E-e+ African American patient prompted us to analyze her DNA, which revealed a novel RHCE*ce allele. We also screened blood samples from African Americans to determine the frequency of the novel allele. STUDY DESIGN AND METHODS: Hemagglutination tests and molecular analyses were performed by standard procedures. RESULTS: Analysis of the proband's DNA revealed RHCE*ce 48C/C, 733G/G, 941T/C, and 1006G/T. Of 272 samples from African Americans, 257 were RHCE*941T/T (wild type), and 15 (6%) were RHCE*941T/C. Of these 15, 14 were RHCE*ce/ce, 10 with 733C/G and four with 733G/G, and one was RHCE*ce/cE, 733C/G. Cloning experiments confirmed the Nucleotide 941 change and showed that 48C, 733G, 941C, and 1006T were carried on the same allele. RBCs from the 15 samples carrying the RHCE*941C variant typed V/VS+ and hrB+W. CONCLUSION: This study identifies a novel allele, RHCE*ce 48C, 733G, 941C, 1006T which is predicted to encode 16Cys, 245Val, 314Ala, and 336CyS and was shown to encode c, V/VS, and an altered expression of e and hrB antigens. The clinical significance of the antibody found in the proband is not established because E+e- RBC components were transfused to the patient. The novel RHCE*ce 48C, 733G, 941C, 1006T allele was present in 5.5% of samples from African Americans and thus, in this small cohort, it had a frequency of 0.028.

RHCE*ceCF encodes partial c and partial e but not CELO, an antigen antithetical to Crawford.

BACKGROUND: RH43 (Crawford) is encoded by RHCE*ce with nucleotide changes 48G>C, 697C>G, and 733C>G (RHCE*ceCF). We investigated the Rh antigen expression and antibody specificities in four patients with this allele. STUDY DESIGN AND METHODS: Hemagglutination tests, DNA extraction, polymerase chain reaction (PCR)-restriction fragment length polymorphism, allele-specific PCR, reticulocyte RNA isolation, reverse transcription-PCR cDNA analyses, cloning, and sequencing were performed by standard procedures. RESULTS: Red blood cells (RBCs) from two patients typed D+C-E-c+e+/-, hrS-/+W, hrB- and their serum was reactive (3+) with all RBC samples of common Rh phenotype tested, but nonreactive with Rhnull or D-- RBCs (apparent alloanti-Rh17). At the RHCE locus, Patient 1 was homozygous for RHCE*ceCF, and Patient 2 inherited RHCE*ceCF in trans to a silenced RHCE*cE. Cross-testing of serum and RBCs from these two samples showed mutual compatibility, indicating that both antibodies define the same novel high-prevalence antigen on Rhce. Two additional patients, one whose serum contained alloanti-c but the RBCs typed C+c+ and one whose serum contained anti-e but the RBCs typed E+e+, also had RHCE*ceCF. RHCE*Ce was present in trans in the former and RHCE*cE in the latter patient. CONCLUSION: We report that amino acid changes on RhceCF (Trp16Cys, Gln233Glu, and Leu245Val) alter the protein to the extent that c and e antigens are partial, and a high-prevalence antigen, we have named CELO (provisional ISBT Number 004058; RH58) is not expressed. CELO is antithetical to RH43 (Crawford).

Neutrophil apoptosis in preeclampsia, do steroids confound the relationship?

AIM: To investigate the influence of maternal corticosteroid administration on neutrophil apoptosis in early onset preeclampsia. METHODS: We investigated five groups: early onset preeclampsia (EOPET, <34 weeks, n = 10); late-onset preeclampsia (LOPET, > or =34 weeks, n = 7); normotensive intrauterine growth restriction (nIUGR, n = 11); normal pregnancy (NPC, n = 22); and non-pregnancy (n = 10). We examined, by flow cytometry, spontaneous neutrophil apoptosis after 18 h culture (hypodiploid DNA, Annexin V binding, propidium iodide [PI] permeability). RESULTS: For the 10 women with EOPET exposed to betamethasone in the previous 48 h, we found that neutrophil apoptosis was not inappropriately inhibited, in contrast to our previous findings in women not thus exposed. Neither LOPET nor nIUGR differed from normal pregnancy. CONCLUSION: Betamethasone alters the rate of spontaneous neutrophil apoptosis in EOPET. The anti-inflammatory influence of betamethasone may explain some of the differences between our previous and present findings with respect to neutrophil apoptosis in EOPET. Corticosteroids ameliorate the course of antenatal and postnatal preeclampsia. These results may reflect the mechanisms that underlie the transient improvements seen with antenatal dexamethasone use.