A 35-year-old woman presents to the clinic with fatigue, shortness of breath, and jaundice. Physical examination reveals pallor and mild splenomegaly. Laboratory studies show anemia with an elevated reticulocyte count, indirect hyperbilirubinemia, and positive serum lactate dehydrogenase (LDH). A Direct Coombs test is positive. Which of the following is the most likely diagnosis?
