Evaluation of reticuloendothelial function in autoimmune hemolytic anemia using an in vitro assay of monocyte-macrophage interaction with erythrocytes.
We have used an in vitro assay of monocyte-RBC interaction to study the correlation of in vitro monocyte activity with in vivo lysis in patients with autoimmune hemolytic anemia (AIHA). All of 16 patients with a positive direct antiglobulin test (DAT) (0.5 + to 4+) and clinical evidence of hemolysis showed elevated association (ARBC) and phagocytic (PRBC) indices. Of 6 patients studied with a positive DAT (0.5+ to 4+) without clinical evidence of hemolysis, none showed elevated PRBC while 2 showed slightly elevated ARBC. Thus, when using a PRBC index, our assay distinguished between hemolysing and non-hemolysing patients independent of the degree of red cell sensitization as determined by the DAT. In addition, we have studied 6 patients with a positive DAT following alpha-methyldopa therapy. Two of these patients were hemolysing, 4 were not. Again, our assay correlated with in vivo lysis. Finally, we have studied red cells from 11 patients with DAT-negative acquired hemolytic anemia. Seven of these patients showed elevated ARBC and PRBC indices, indicating a possible immune etiology involving extravascular lysis in some DAT-negative acquired hemolytic anemias.
D000744:Anemia, Hemolytic, Autoimmune / Q000097:blood* / Q000188:drug therapy; D002448:Cell Adhesion / Q000187:drug effects; D002450:Cell Communication / Q000187:drug effects; D003298:Coombs Test; D004912:Erythrocytes / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D008264:Macrophages / Q000502:physiology*; D008750:Methyldopa / Q000627:therapeutic use; D012157:Mononuclear Phagocyte System / Q000166:cytology* / Q000503:physiopathology; D010587:Phagocytosis / Q000187:drug effects; D011241:Prednisone / Q000627:therapeutic use
D008750:Methyldopa; D011241:Prednisone