Warm autoimmune hemolytic anemia following recurrent mycoplasma pneumonia infections in a child with Down syndrome.

Mycoplasma pneumonia (MP) is mainly associated with cold agglutinin syndrome, whereas both cold IgM and warm IgG autoantibodies have been identified in only two cases in the literature. The authors present an 8-year-old boy with Down syndrome, who suffered from recurrent episodes of MP infection, followed by episodes of hemolytic anemia with normal titer of cold agglutinins. The first 6 episodes were sequenced by nonimmune hemolytic anemia, whereas the latter 7 episodes were followed by episodes of warm autoimmune hemolytic anemia. This is believed to be the first described case of hemolytic anemia with warm IgG autoantibodies, following MP infection.