Quantitation of Antibody Binding to Erythrocytes in LISS

Abstract

The amount of antibody bound to cells in a low ionic strength solution (LISS) has been quantitated for several antibodies including anti-D, anti-c, anti-Kell, anti-Fya, and anti-Jka. With the exception of the Kell antibodies there was an enhancement of the rate of antibody uptake in LISS. For Rh antibodies the amount bound after a 5-min LISS incubation is comparable to that bound after 45 min in saline. For Kell antibodies a smaller amount was bound in LISS than in saline. The effect of the ratio of serum to cells was also studied, and with several antibodies there was an increase in the amount of antibody bound with a higher serum to cell ratio irrespective of suspending medium. For Kell antibodies this ratio appears to be of greater importance than the ionic strength for antibody detection. A modification to the LISS method to increase the serum to cell ratio is, therefore, presented.

An explanation and the clinical significance of the failure of microcolumn tests to detect weak ABO and other antibodies

“…The detection of weak anti-K does present certain difficulties: the antibody is better detected in NISS IAT tests (Molthan & Strohm, 1981;Merry et al, 1984). Early LISS IAT tube tests used one volume of 5% red cells suspended in LISS mixed with one volume of serum (serum to red cell concentration ratio 20 : 1) (Voak et al, 1980).…”

“…The use of two volumes of serum in the otherwise DiaMed standard IAT microcolumn test did increase the reactivity of anti-K with Kk red cells, probably by improving the serum to red cell ratio, albeit with a raised final ionic strength (Table 5). For the detection of anti-K, the serum to red cell concentration ratio does appear to be of a greater importance than the ionic strength of the suspension medium (Merry et al, 1984). However, the use of two volumes of serum is not being recommended as a modification to the DiaMed standard IAT microcolumn test; it has not been evaluated against a range of known antisera and 'inert' samples.…”

Two individuals with elliptocytic red cells apparently lack three minor erythrocyte membrane sialoglycoproteins

“…Serological methods were as described in Parsons et al (1982). Estimation of the number of binding sites of monoclonal antibodies was as described by Merry et al (1984).…”

Can pooled red cells be used for antibody screening of patients' specimens?

“…Microcolumn tests are able to separate unagglutinated from agglutinated red cells and, in theory, offer the ability to use pooled red cells subject to the loading capacity of the gel or glass bead column matrix. Neither of the investigators used red cells with a homozygous expression of the K antigen, antibodies to which can be difficult to detect in low-ionic-strength antiglobulin tests (Molthan & Strohm, 1981;Merry et al, 1984) and for which the serum to red cell concentration appears to be more important than the ionic strength of the suspension medium (Merry et al, 1984). Table 1 shows 10 anti-K antisera tested by microcolumn tests using a pool of two red cells samples: one with a homozygous expression of K, the other K negative.…”