What is a common characteristic of anti-I antibodies?

Anti-I antibodies are primarily characterized by being of the IgM isotype, rather than IgG. They are cold-reactive antibodies that typically demonstrate stronger reactivity at lower temperatures, especially around room temperature (22°C) or colder, which is why they can often cause hemolytic activity at these cool temperatures. It's also notable that anti-I antibodies are not usually involved in warm autoimmune hemolytic anemia, which is predominantly associated with IgG antibodies that react at body temperature.

The common feature of anti-I antibodies lies in their tendency to react with cord red blood cells, exhibiting stronger reactivity at low temperatures, wherein they can exhibit hemolytic activity. Hence, the accurate characteristic concerning anti-I antibodies should reflect their nature of being IgM antibodies that react strongly at cold temperatures and with cord blood.