Q. A 53-year-old woman comes to the ER because of two episodes of severe pain in her fingers. She reports that "my fingers become white then turn to blue then red and they are very painful." The patient also mentions that she has had dyspnea and a cough with fever for 2 weeks. Initially the cough was "dry" (non-productive) but now she is noticing some phlegm (sputum) production (productive). On dermatological examination, you notice a papular rash across her trunk. On lung auscultation, she has decreased breath sounds and crackles. Chest X-ray reveals a reticulonodular pattern. Laboratory studies reveal: * Decreased hemoglobin concentration and decreased haptoglobin levels * A negative coombs test * Normal creatinine and BUN levels * Peripheral blood smear shows agglutination of RBCs. What is the pathophysiology of the disease that has led to anemia in this patient?