Association between HL-A and red cell antigens. II. Absorption and titration analyses

Quantitative evaluation of elution methods for red cell antibodies

Two recent techniques using xylene and chloroform for antibody elution from red blood cells (RBC) were compared with the most widely used ether and heat elution by means of a quantitative 125I-antiglobulin test. Free serum alloantibodies and cell-bound alloantibodies from in vivo sensitization of delayed hemolytic transfusion reactions and of hemolytic disease of the newborn as well as autoantibodies in autoimmune hemolytic disease were studied. With alloantibodies, xylene proved more efficient than chloroform (p less than 0.025), while both methods were superior to heat or ether elution (p less than 0.005). Autoantibody elution was equally effective with xylene and chloroform (p less than 0.1) but again better than heat or ether elution (p less than 0.02). However, no single method produced the strongest eluate with all antibodies studied. We conclude that xylene and/or chloroform elution are valuable implementations in RBC serology, but, in selected instances, the classical elution methods will retain their importance.

Cross-reactions in the HLA system revealed by red blood cells expressing HLA determinants, with particular reference to cross-reaction between HLA-A2 and B17

Sera with cytotoxic and haemagglutinating activity towards HLA-A2/28 were also shown to react with red blood cells (RBC) expressing the HLA-B17 antigen determinant. Absorption procedures with white blood cells (WBC) indicated that this was due to an HLA-A2/B17 cross-reaction. Absorption experiments with some other sera which previously had shown cytotoxic and haemagglutinating activity towards different HLA specificities, revealed broad cross-reaction related to HLA-B locus antigens.

HLA-B7 on human red blood cells. Improved detection by a radioactive anti-IgG test

By means of a sensitive radioimmune anti-IgG test (RIAT) HLA-B7 was demonstrated on RBC of all B7 positive individuals (N = 52). Most antigens of the B7 cross-reacting group (B8, 13, w22, 27, 40; N = 36) were also detected. Eluates from B7 positive RBC exhibited clear B7 specificity against RBC as well as lymphocytes.

Changes in red cell Bg antigens in haematological disease

The red cell Bg antigens of patients with haematological diseases have been found to be more reactive than those of normal donors. Others HLA-related antigens that are of low incidence in normal donors are found in much higher incidence in these patients. A series of 40 CLL patients has been tested for both known and additional HLA-related antigens by hemagglutination and adsorption and the relationship between the antigens of the red cells and lymphocytes evaluated.

HLA antigens on red blood cells. Two donors with extraordinarily strong reactivity

We have shown exceptionally strong HLA reactivity of the red blood cells (RBC) of two healthy blood donors, concerning several HLA antigens. HLA antigens not usually detectable on RBC are also expressed on the RBC of these donors. The RBC show a broad spectrum of reactivity with sera containing HLA antibodies. Absorption/elution experiments with these RBC and HLA antisera proved successful. Absorption studies with leucocytes showed that HLA-A2 and A28 behaved as separate specificities also on RBC, even though antisera always seem to contain heamagglutinins that react with both specificities. We found no evidence that HLA is associated with beta2-microglobulin on the RBC membrane.

Association between HLA and red cell antigens. VII. Survival studies of incompatible red blood cells in a patient with HLA-associated haemagglutinins

Serum from a multitransfused patient with bladder papilloma was examined. The serum contained anti-Kell as well as polyspecific, cytotoxic HLA antibodies and HLA-associated haemagglutinins. The HLA haemagglutinins were demonstrated by the Auto Analyzer method and reacted predominantly with red blood cells (RBC) from HLA-A28-positive individuals, and were distinctly weaker with all other test cells. Survival studies with 51Cr-RBC from an HLA-A28-positive, Kell-negative donor with strong A28 RBC reactivity were performed. A small component of the RBC showed clearly reduced survival time, while the main component showed nearly normal survival.

Association between HLA and red cell antigens. V. A further study of the nature and behaviour of the HLA antigens on red blood cells and their corresponding haemagglutinins

The variation in the reactivity of red blood cells (RBC) with HLA haemagglutinins was studied, and the influence of some variable factors evaluated. A comparison of the HLA reactivity of RBC with automated and manual methods, showed the superiority of the Auto-Analyzer technique. The similarity in the nature and behaviour of HLA RBC antigens and the related Chido and Rg antigens is discussed. Inhibition/adsorption experiments were performed, and the results did not support the theory that HLA antigens on RBC originate from serum-HLA-active substance. The strength of the HLA reactivity of RBC from a donor was shown to vary from time to time without evidence of clinical disease.

Association between HLA and red cell antigens. VI. Family studies

The reactivity of the HLA antigens A28, B7 and B8 on red blood cells (RBC) has been studied, and the inheritance of the strength of reactivity examined in 13 families where the HLA haplotypes could be determined. Examination of individuals possessing more than one of the three antigens showed that the antigens seemed to be expressed independently of each other on RBC. The family studies showed that the HLA reactivity of RBC does not invariably follow the HLA haplotype determining the particular antigen. It was also shown that heterozygosity/homozygosity did not seem to have much influence on the strength of reactivity. Our conclusion is that several factors are likely to be responsible for the great variation in HLA reactivity of RBC.

Association between HLA and red cell antigens. IV. Further studies of haemagglutinins in cytotoxic HLA antisera

Cytotoxic HLA antisera of various specificities were examined on the AutoAnalyzer against red blood cells (RBC) from a great number of HLA-typed donors. HLA-associated haemagglutinins of different specificities were demonstrated. In cytotoxic anti-HLA-A9 and anti-HLA-A10, as well as in anti-HLA-B12, anti-HLA-Bw15 and anti-HLA-B17 sera, haemagglutinins of apparently corresponding specificities were found. This indicates that several HAL antigens may be present on RBC, but they are demonstrable only on RBC from a limited number of donors who possess the corresponding antigens on their white cells. Some antigens, like HLA-A28 and HLA-B7, are relatively strong RBC antigens, whereas others, like HLA-B12 or HLA-Bw15 seem to be much weaker. In cytotoxic anti-HLA-A1 and anti-HLA-B13 sera, no corresponding haemagglutinins were demonstrated. However, haemagglutinins of anti-HLA-B7 specificity were shown to be present in two cytotoxic anti HLA-A1 and three anti-HLA-B13 sera. No cytotoxic anti-HLA-B7 was found in these sera. Cross-reacting antibodies also seem to be frequent amoung HLA associated haemagglutinins.

Eluate analysis of anti-Bg a associated renal allograft rejection

Renal allograft rejection, following development of a positive indirect antiglobulin reaction, occurred in a multiply transfused recipient. Panel techniques confirmed both anti-Bga and anti-Kell antibodies. Recognition of the concordant antigenic specificity of the Bga and HL-A7 antigens led to an investigation of the potential role of this antibody in the rejection phenomenon. In the absence of serological cytotoxicity, a modified elution technique was used to directly obtain immunoglobulin from the rejected allograft. The eluate obtained displayed specificity for the Bga red blood cell antigen. The described technique affords an additional approach to the documentation of immunologically mediated graft rejection and obviates the limitations imposed by the absence of serological cytotoxicity. Emphasis is placed on the need for recognition of the relationship between red blood cell and HL-A antigens.