Clinical features and splenic pathologic changes in patients with autoimmune hemolytic anemia and congenital hemolytic anemia.

We characterized the pathologic changes in 50 spleens from patients with autoimmune hemolytic anemia and in 13 spleens from patients with congenital hemolytic anemia. The major pathologic findings in autoimmune hemolytic anemia were mild to pronounced cord congestion and variable white pulp area, erythrophagocytosis in conjunction with an increased polymorphonuclear neutrophil reaction, and increased deposition of hemosiderin and extramedullary hematopoiesis. In contrast, both the severity and the frequency of polymorphonuclear neutrophil reactions, deposition of hemosiderin, and extramedullary hematopoiesis were less in patients with congenital hemolytic anemia, and prominent cord congestion associated with an empty or collapsed sinus was noted in patients with hereditary spherocytosis. The activity of erythrophagocytosis in the sinus was more distinct in patients with congenital hemolytic anemia, especially those with nonspherocytic congenital hemolytic anemia, than in patients with autoimmune hemolytic anemia. These findings are consistent with the existence of different mechanisms of trapping and destruction of erythrocytes in autoimmune hemolytic anemia and congenital hemolytic anemia.