# Lewis-A Antibody in Clinical Practice: A Case Report

## TL;DR

A rare case of a clinically significant Lewis-a antibody causing transfusion challenges in a 58-year-old patient is reported.

## Contribution

This case highlights the rare clinical significance of anti-Lewis-a antibodies and their potential to cause hemolytic reactions.

## Key findings

- A naturally occurring anti-Le-a antibody was detected during routine blood grouping in a 58-year-old patient.
- Compatible blood units were found after crossmatching due to the low prevalence of Lewis antigens.
- Antigen-negative crossmatch compatible units are recommended to prevent hemolytic episodes.

## Abstract

Anti-Lewis antibodies are often not clinically significant since they do not react at 37°C. These antibodies have, however, occasionally been linked to hemolytic transfusion reactions (HTR). We report a case of naturally occurring anti-Lewis-a (Le-a) in a 58-year-old patient found during routine blood grouping. As Lewis antigen is a low-prevalence antigen, compatible units were found after crossmatching two units of packed red cells. Lewis blood group antigen antibodies frequently react at lower temperatures and remain clinically insignificant, but in rare cases, they may react at a higher temperature of 37°C and cause a hemolytic episode or impair the lifespan of incompatible red blood cells in the recipient. Hence, antigen-negative crossmatch compatible units should be used for transfusion. In an emergency, the donor's register, with its comprehensive phenotypic profile, can be quite helpful in supplying blood for transfusions.