Testing Efficacy of Anti-D Sera by a Panel of Donor Red Cells with Weak Reacting D Antigen and with Partial D Antigens

Abstract

In 1987 the definition of an Rh-negative donor in the Netherlands was changed from C-, E- as well as D^u-negative to D-negative only. The use of 2 different strong anti-D sera without an antiglobulin phase (D^u test) was considered sufficient to reveal the clinically important D antigen. In applying this policy, we identified 32 donors in 13,500 consecutive blood donations whose indirect antiglobulin test (IAT) (D^u)-positive red cells gave negative reactions with at least 2 out of 11 anti-D sera and whose cells might therefore be typed as Rh(-D-)-negative in routine investigations. IgG anti-D used by a one-stage bromelain technique and anti-D with modified IgG appeared to be relatively insensitive in detecting D^u in this study. Polyclonal anti-D in an enhancement medium and monoclonal anti-D scored better, although differences exist between the products of various manufacturers. It is suggested that if IAT (D^u) testing is omitted, only anti-D sera with a high index of detectability of cells expressing weak D antigens should be accepted.

Quality Control of Anti-D Sera by a Panel of Donor Red Cells with Weak Reacting D Antigen and with Partial D Antigens by the Federation of Netherlands Red Cross Blood Banks

“…Results of the tests are given in table 1. The test results confirm previous findings [2] and il lustrate, that the reactivity with the various polyclonal anti-D sera of cells with weak reacting D antigens varies greatly. Particularly modified IgG anti-D failed to agglut inate a high percentage of these cells.…”

“…Recent investigations [2] revealed important differences among commercially available anti-D reagents with regard to the recognition of the D antigen when the antiglobulin phase was omitted. The Federation of Netherlands Red Cross Blood Banks started a quality control program on anti-D reagents using a panel of donor red cells.…”

“…The Federation of Netherlands Red Cross Blood Banks started a quality control program on anti-D reagents using a panel of donor red cells. The panel was selected among 17,000 donors of the Red Cross Blood Bank Zuid Limburg and is representative for a Dutch do nor population [2]. The panel consists of red cells from 37 donors (0.22% of the donor population) with weakly react ing D antigen (Du) and from 7 donors with partial D antigen category VI (0.04% of the donor population) [3,4] and is stored in liquid nitrogen.…”

Quantitation of D Sites on Selected 'Weak D' and 'Partial D' Red Cells

“…The weak D cells were obtained from a survey of 13,500 blood donations at the Red Cross Blood Bank in Maas tricht; samples from 32 donors were initially phenotyped as Rh-negative using agglutinating anti-D sera, but on further investigation were found to be weak D using an antiglobulin reagent [7], Ten of these weak D samples have been selected for use in a panel to establish the ability of anti-D sera to detect cells of this phenotype, and it is these cells which have been used to determine the number of D sites, using three different monoclonal anti-D anti bodies. In addition, 3 examples of weak D red cells which had been involved in immunisation of recipients were also examined, as it is of considerable interest to know how small a number of D sites on cells are able to stimulate anti-D production.…”