Co-trimoxazole-dependent autoagglutinin with anti-Sd^a specificity detected only by column agglutination technique

In vitro serological reactions due to antibodies in the presence of certain chemicals are rare occurrences. Although such antibodies are often considered harmless, their innocuous nature requires verification. We investigated a pan-agglutinating antibody that reacted in the presence of BLISS used in the gel card device.

The gel cards used for serological compatibility tests were of commercial sources (Ortho Diagnostics, USA and Tulip Diagnostics, India), soluble antigens used for antibody neutralization tests were locally obtained, and certain antibiotics and dialysis bags were procured from the local market. Serological workup was carried out by standard methods.

A 13-year-old female cancer patient with a pan-reacting autoantibody showed mixed-field agglutination in serological tests. It reacted only on a gel card system that uses BLISS-containing antibiotic co-trimoxazole. Autoantibody was identified as anti-Sd^a by hemagglutination inhibition test using guinea pig urine.

The autoantibody with anti-Sd^a specificity was detected on the gel card only in the presence of the antibiotic co-trimoxazole in BLISS.