Which group of antibodies is commonly found as cold agglutinins?

Cold agglutinins are antibodies that react at lower temperatures, typically around 4°C, causing agglutination of red blood cells. The group of antibodies that is commonly known to exhibit cold agglutination properties includes the M and N blood group antibodies. Anti-M and anti-N can form complexes at colder temperatures, which is characteristic of cold agglutinins.

The other groups mentioned do not typically function as cold agglutinins. For instance, anti-K, anti-k, and anti-Jsb are warm-reactive antibodies and are not associated with the cold temperature agglutination phenomenon. Similarly, anti-D, anti-e, and anti-C are primarily implicated in antibody-mediated hemolytic reactions at body temperature rather than at cold temperatures. Anti-Fya and anti-Fyb also fall into the category of warm-reactive antibodies and do not commonly display cold agglutination characteristics. Hence, the presence and functionality of anti-M and anti-N make the correct selection relevant in the context of cold agglutinins.