Occurrence of five distinct red cell alloantibodies in a renal transplant recipient: Diagnostic and therapeutic implications of minor histocompatibility antigens (Kidd and Duffy) for renal allograft outcome

An update to Kidd blood group system

Since publication of the original Immunohematology review of the Kidd blood group system in 2015 (Hamilton JR. Kidd blood group system: a review. Immunohematology 2015;31:29-34), knowledge has mushroomed pertaining to gene structure, alleles causing variant and null phenotypes, clinical significance in renal transplant and hemolytic disease of the fetus and newborn, and physiologic functions of urea transporters in non-renal tissues. This review will detail much of this new information.

The Role of the Duffy Blood Group Antigens in Renal Transplantation and Rejection. A Mini Review

Finding a compatible donor for kidney transplant candidates requires overcoming immunological barriers such as human leukocyte antigens (HLA) compatibility and ABO compatibility. Emerging data suggest a role for red blood cell antigens (RCA) in renal transplant outcomes. The incidence of RCA alloimmunization is high in chronically transfused individuals, such as end stage renal disease patients, but whether antibodies to RCA can mediate renal graft rejection remains debatable. The Duffy blood group antigens (Fy) has been shown to be expressed in the kidney, among other tissues. There are some data to suggest that donor-recipient Fy mismatches may increase the risk for chronic allograft damage and that anti-Fy antibodies may be involved in renal graft rejection, however, while it is routine to screen renal transplant candidates for ABO antigens, detailed RCA phenotyping of the donor kidney is not routinely tested. In this paper, we review the current data on the role of Fy in renal transplantation and discuss the potential mechanisms of its biological function.

Phenotyping of clinically significant blood group antigens among the South Indian donor population

INTRODUCTION

Data on the prevalence of clinically significant antigens (Rh, Kell, Kidd, Duffy, MNSs, Lewis, P and Lutheran) among the Indian donor population is sparse.

OBJECTIVE

This prospective study was aimed at determining the prevalence of 21 clinically significant antigens for the first time in the South Indian donor population.

METHOD

A total of 672 regular O group blood donors were enrolled for Rh (C,c, E, e) and Kell (K) antigens typing. Of these, 188 donors were typed for other clinically significant antigens (k, Kpa, Kpb, Jka, Jkb, Fya, Fyb, M, N, S, s, P1, Lea, Leb, Lua and Lub).

RESULTS

Antigen frequencies were expressed in percentages. In our study, R1R1 and rr were the most common phenotypes among D+ and D- donors, respectively. Among the Rh antigens, the e antigen was expressed by 97.5% and 100% of D+ and D- donors, respectively. The K antigen was found in only 0.15% of donors. In the Duffy and Kidd blood group system, Fy (a+b+) and Jk (a+b+) were the most frequent phenotypes, respectively. In the MNSs blood group system, M+N+ and S-s+ were the most common phenotypes reported. The Le (a-b+) was found to be the phenotype with the highest prevalence in the Lewis blood group system. The Lu (a-b+) was the only phenotype found in the Lutheran blood group system.

CONCLUSION

Knowledge regarding the prevalence of antigens in a given population is essential in developing cost-effective in-house panels and a rare donor registry comprising donors typed negative for a high-frequency antigen or a combination of common multiple antigens.

The potential role of antibodies against minor blood group antigens in renal transplantation

Blood group antigens are red blood cell (RBC) surface markers comprising specific carbohydrate moieties attached to the glycolipids and glycoproteins within the membrane. In addition to the major ABO blood group antigens, at least 35 minor blood group antigens have been defined to date. These antigens have immunogenic potential and may cause a transfusion reaction. There is evidence for renal expression of antigens from the Kidd, MNS, Duffy and Lewis groups and therefore the potential for antibodies directed against these antigens to cross-react in a transplanted kidney. In individuals lacking a specific RBC antigen, antibodies may develop after de novo exposure to that antigen, in addition to the potential presence of pre-existing innate antibodies. Relatively little attention has been paid to non-ABO system antibodies, with most reports in the literature focusing on transfusion reactions rather than on any putative role in allograft rejection. Here, we review each of these antigens in the context of renal transplantation and what limited evidence there is on how such immunological risk may be assessed and managed.