Anti‐Vel reactivity diminished by adsorption with rabbit RBC stroma

Abstract

Anti-Vel was completely or partially adsorbed by RESt. Caution should be used when interpreting cold agglutinins with this method. The manufacturer warns that uncommon alloantibodies may be adsorbed.

Immunoglobulin M red blood cell alloantibodies are frequently adsorbed by rabbit erythrocyte stroma

“…In the study by Pawlikowski, 8 for example, the reduction in reactivity also occurred in six of the nine sera tested in the AHG phase after RESt adsorption. Reduction in alloantibody reactivity during the AHG phase after adsorption had also been reported by others 4,7,11 . Such findings suggest that some IgG antibodies may be removed as well or, alternatively, could represent the reduction in the carryover IgM reactivity seen in the tube agglutination method or simply due to dilution.…”

“…Notably, in a report by Mechanic and coworkers 11 all eight stored sera with anti‐Vel tested showed some reduction in reactivity after adsorption. Because anti‐Vel antibodies are somewhat unusual in that they are generally a mixture of warm‐reactive IgM and IgG, the adsorption of anti‐Vel in these cases was felt by Storry and colleagues to be due to the fact that rabbit RBC stroma adsorbs IgM antibodies nonspecifically, regardless of RBC antigen specificity 13 .…”

“…There are concerns regarding such reagents' potential for adsorbing clinically significant alloantibodies and thus preventing their detection. The manufacturer's insert for the commercial RESt reagent states that RESt can partially or completely adsorb anti‐I, ‐IH, ‐H, ‐B, and ‐P and that “the possibility that a rare alloantibody will be adsorbed by this reagent cannot be unequivocally excluded.” 5 There are also reports in the literature of the adsorption of various alloantibodies, including Rh, Kell, MN, Duffy, and Kidd antibodies, 4,7‐10 as well as several examples of anti‐Vel 11,12 …”

Rabbit red blood cell stroma bind immunoglobulin M antibodies regardless of blood group specificity

“…These characteristics hint at the possible carbohydrate nature of the antigen, an observation that was perhaps reinforced by the unusually high incidence of the P 2 phenotype among Vel‐negative individuals in northern Sweden 3 . Following reports, both anecdotal and documented, 4,5 that anti‐Vel sera were adsorbed with rabbit RBC stroma, we performed a study to investigate this further. Four different anti‐Vel plasma samples that had been shown previously to contain both IgG‐ and IgM‐specific anti‐Vel (data not shown) were adsorbed with rabbit RBC stroma (RESt™, donated for this study by Immucor, Inc., Norcross, GA) according to the manufacturer’s instructions.…”

Characterization of a new human monoclonal antibody directed against the Vel antigen

“…As the Vel blood type is particularly rare (prevalence of 4/10 000 in the French population) , transfusion with compatible RBCs is quite challenging and usually requires the help from national or international rare bloods banks . Identification of Vel‐negative individuals relies on typing, but no reagents exist except polyclonal sera from immunized individuals . Unfortunately, specific anti‐Vel sera are poorly available, and other alternative techniques, such as absorption–elution, are not satisfying .…”