ReferencesMarks MR. Reid ME. Ellisor SS. Adsorption of unwanted cold autoagglutinins by formaldehyde treated rabbit red blood cells (abstract). Transfusion I980;20:629. Waligora SK. Edwards JM. Use of rabbit red cells for adsorption of cold autoagglutinins. Transfusion 1983:23:328. A D variant, DtI?To the Editor:We noticed that some D-negative red cells, though they were negative in a D" test after exposure to anti-D, could bind anti-D and yield it o n elution.We temporarily call these red cells D,I. As shown in Table I , most phenotypes with D,I had C. c, and e antigens, but no cells of an EEhomozygote have yet adsorbed anti-D. We used a commercial anti-D (Ortho Diagnostics. Raritan. NJ). a purified anti-D (kindly sent from Mr. Moulds. Gamma Biologicals. Houston. TX) and a monoclonal anti-D (kindly distributed by Prof. Ono. Nihon University) for absorption-elution studies. but the purified and monoclonal anti-D reagents were not available for use with all the Rhnegative cells tested. Eluates were made by the chloroformt richloroet hylene method. '

69:481-484). In this study, we revealed that monocyte CD36 cDNA from two type II deficient subjects was heterozygous for C478 and T478 form, while platelet CD36 cDNA of these subjects consisted of only T478 form. In a type I deficient subject, both platelet and monocyte CD36 cDNA showed only T478 form. Expression assay using C478 or T478 form of CD36 cDNA transfected cells revealed that there was an 81-kD precursor form of CD36, and that the maturation of the 81-kD precursor form to the 88-kD mature form of CD36 was markedly impaired by the substitution. The mutated precursor form of CD36 was subsequently degraded in the cytoplasm. These results indicate that the 478C-T substitution directly leads to CD36 deficiency via defects in posttranslational modification, and that this substitution is the major defects underlying CD36 deficiency. (J. Clin. Invest. 1995. 95:1040-1046

We developed an allele-specific polymerase chain reaction (ASPCR) method using originally designed primers to determine the genotype of the human platelet antigens (HPAs) 2, 3 and 4 in parallel. The results were compared with those obtained by PCR restriction fragment length polymorphism and the mixed passive hemagglutination test. Seventy-three individuals were tested and the ASPCR results were in good agreement with those determined by the other two methods. This method enables the genotyping of HPA-2, -3 and -4 in parallel without the use of platelets, platelet-specific alloantibodies or restriction enzymes.

A new method was studied for eliminating HLA class I antigens from the surface of platelets without damaging the cells. Platelets were exposed to an acid solution (pH 3.0) to eliminate the antigenicity of HLA class I antigens. The reduction in antigenicities of HLA class I common antigen and individual HLA class I antigens by acid treatment was marked. Patients' sera which contained multispecific HLA antibodies reacted with PBS-treated platelets, but not with acid-treated platelets. No changes were observed in the antigenicities of glycoprotein Ib or glycoprotein IIb/IIIa. The viability of acid-treated platelets was 83%. Ultrastructural investigations revealed no significant difference between the PBS-treated platelets and acid-treated platelets. The platelet function studies showed that the aggregation of acid-treated platelets induced by various agonists was only slightly reduced compared with PBS-treated platelets. We propose that acid-treated platelets are promising for clinical use in patients refractory to platelet transfusions and may be superior to chloroquine-treated platelets for analysis of the specificity of antiplatelet antibodies.

CD36 is a multifunctional integral-membrane glycoprotein that acts as a receptor for thrombospondin, collagen, long-chain fatty acids, and oxidized LDL. Platelet CD36 deficiency can be divided into two groups. In type I, neither platelets nor monocytes/macrophages express CD36; in type II, monocytes/macrophages express CD36 but platelets do not. Two known mutations cause CD36 deficiency, ie, a 478C-->T substitution in codon 90 (proline90-->serine) and a dinucleotide deletion at nucleotide 539 in codon 110. In this study we investigated a type I Japanese subject (A.T.) and identified a new mutation, a single nucleotide insertion at nucleotide 1159 in codon 317. This mutation leads to a frameshift and the appearance of a premature stop codon. CD36 gene analysis indicated that A.T. was a compound heterozygote for a dinucleotide deletion at nucleotide 539 and the single nucleotide insertion at nucleotide 1159. RNase protection studies suggested that the new mutation as well as the dinucleotide deletion led to a marked reduction in the level of CD36 mRNA in her macrophages. However, the new mutation could be detected in macrophage but not platelet CD36 mRNA. These data suggest that the allele having the single nucleotide insertion in this subject has an additional abnormality that results in the absence of the mutated CD36 mRNA in platelets.

Del (D-elute) in the Rh blood group system is a variant with very weak D antigen and no agglutination is found by the indirect antiglobulin test. This variant is characterized by the presence of anti-D eluate obtained after an adsorption-elution test using anti-D antibodies. We studied here the molecular genetic status of Del by using polymerase chain reaction with sequence-specific primers (PCR-SSP). We screened 306 serologically apparent D-negative Japanese donors comprising 102 Del types for exons 7, 4 and 10 of the RHD gene. No PCR product was found in all 204 non-Del samples from the D-seronegative donors. However, PCR products were found in all 102 Del samples and all 70 D-seropositive samples tested by the three PCR methods for exons 7, 4 and 10 analysis. Del was found with CCee, CcEe and Ccee, but not with CCEe, CcEE, ccEE, ccEe or ccee phenotype. The incidences of Del in the samples with the serological phenotypes CCee, CcEe and Ccee were 80.0% (4/5), 68.2% (45/66) and 61.6% (53/86), respectively. The results provide evidence that Del samples have exons 4, 7 and 10 of an RHD gene present in some form. This is consistent with the evidence that D antigen is present on the cells although only detected by antibody adsorption and elution. The PCR-SSP method in the present study is useful to confirm Del among serologically apparent D-negative samples.

SummaryWe performed family studies with type II CD36 deficiency. In the Mi.Y family, the proband (YII.1) and his brother (YII.2) displayed a type II deficient phenotype. In the mother(YI.2), binding of the anti CD36 monoclonal antibody, 0KM5, to both platelets and monocytes was reduced as compared to CD36 positive control cells. In the father (YI.1), while 0KM5 binding to his platelets was reduced, that of his monocytes was almost the same as normal control monocytes. Analysis of genomic DNA showed that YI.2, YII.1 and YII.2 were heterozygous for a proline90→serine mutation, and showed that both alleles of YI.1 did not have the mutation. Analysis of CD36 cDNA showed that the Pro90 form of CD36 cDNA could be detected in monocytes, but not in platelets from YII.1 and YII.2. These data indicated that YII.1 and YII.2 could be compound heterozygotes; an allele having a platelet-specific mRNA expression defect(s), which was responsible for the different CD36 expression between their platelets and monocytes, and the Ser90 allele. YI.1 was suggested to be a carrier of the platelet-specific silent allele. The platelet-specific silent allele was linked to a specific genotype of a polymorphic microsatellite sequence in the CD36 gene, supporting our hypothesis that mRNA expression defect(s) occurred at or near the CD36 gene. In a second type IICD36 deficient family, we also obtained results consistent with this hypothesis.

Fourteen Jk(a-b-) persons were detected by testing 638,460 Osaka blood donors with an automated 2 M urea technique. Two of these 14 Jk(a-b-) samples were quite different from the hitherto reported Jk(a-b-) phenotype, and a family study showed that the mode of the inheritance was dominant. The red cell membranes of these Jk(a-b-) samples were studied by polyacrylamide gel electrophoresis and unusual protein bands (apparent mw, 67,000 d) were detected.