First Vel-null alloimmunized blood donor identified in Uruguay.

A 52-year-old, first-time blood donor presented with panreactivity during routine antibody screening. Current serologic evaluation showed uniform 2+ reactivity by the gel-indirect antiglobulin test and the conventional tube low-ionic-strength saline-indirect antiglobulin test. The molecular analyses revealed a homozygous 17-base pair deletion spanning nucleotides 64-80 in exon 3 of SMIM1 (VEL*01N.01/VEL*01N.01), confirming the Vel-null phenotype. The antibody was identified as anti-Vel IgG3, reacting in tube testing, exclusively in the anti-human globulin phase. We present the first case of a Vel-null alloimmunized donor identified in Uruguay and describe the serologic, molecular, and functional characteristics of the associated antibody.