Small Animal Internal Medicine Resident Faculté de médecine vétérinaire, Université de Montréal Saint Hyacinthe, Quebec, Canada
Since the discovery of the feline Mik antigen, several studies have described blood incompatibilities unrelated to the AB system. Based on the presence of naturally occurring alloantibodies (NOAb), the purpose of this study was to begin mapping the corresponding feline erythrocyte antigens (FEA) behind these incompatibilities.
By groups of six, 274 transfusion-naïve cats were prospectively evaluated for the presence of alloantibodies using a gel column crossmatch test. When non-AB-related alloantibodies were detected in a cat, its plasma was used to assess the presence or absence of the corresponding antigen in cats included thereafter in the study (blood typing).
Plasma from 18 of 263 type-A cats (6.8%) caused 49 incompatible results out of 1257 crossmatches performed (3.9%). Presence of NOAb was statistically associated with an age of < 2 years (P = 0.04). Using 7 of the 18 alloantibodies, systematic blood typing was performed, and results compared. Based on agreement analysis, 3 NOAb appeared to correspond to the same antigen (k ³ 0.64); hence the identification of 5 different putative FEA (numbered in order of identification). FEA 1, 4 and 5 were most frequent with a prevalence of 84%, 65% and 96%, respectively. Only FEA 1 was significantly associated with NOAb (P = 0.005), which were observed in 8 of 43 FEA 1-negative cats (19%).
This study represents a first step of FEA’s identification outside the AB system. Because of its prevalence and association with NOAb, FEA 1 may correspond to the lost Mik antigen. Banked alloantibodies will facilitate future studies, notably regarding their clinical relevance.