Expression levels of CD47, CD35, CD55, and CD59 on red blood cells and signal-regulatory protein-α,β on monocytes from patients with warm autoimmune hemolytic anemia

• Published in: Transfusion (Philadelphia, Pa.) Vol. 49; no. 1; pp. 154 - 160
• Main Authors: Barros, Melca M.O., Yamamoto, Mihoko, Figueiredo, Maria S., Cançado, Rodolfo, Kimura, Elisa Y.S., Langhi Jr, Dante M., Chiattone, Carlos S., Bordin, Jose O.
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.01.2009; Wiley
• Subjects: Adult; Aged; Anemia, Hemolytic, Autoimmune - genetics; Anemia, Hemolytic, Autoimmune - metabolism; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Antigens, Differentiation - biosynthesis; Antigens, Differentiation - genetics; Biological and medical sciences; Blood. Blood and plasma substitutes. Blood products. Blood cells. Blood typing. Plasmapheresis. Apheresis; CD47 Antigen - biosynthesis; CD47 Antigen - genetics; CD55 Antigens - biosynthesis; CD55 Antigens - genetics; CD59 Antigens - biosynthesis; CD59 Antigens - genetics; Disease Models, Animal; Drug toxicity and drugs side effects treatment; Erythrocytes - metabolism; Female; Gene Expression Regulation - drug effects; Humans; Macrophages - metabolism; Male; Medical sciences; Mice; Mice, Knockout; Middle Aged; Monocytes - metabolism; Phagocytosis - genetics; Pharmacology. Drug treatments; Receptors, Complement 3b - biosynthesis; Receptors, Complement 3b - genetics; Receptors, Immunologic - biosynthesis; Receptors, Immunologic - genetics; Toxicity: blood; Transfusions. Complications. Transfusion reactions. Cell and gene therapy; Autoimmunity; Human; Immunopathology; Blood cell; Transfusion; Monocyte; Autoimmune hemolytic anemia; Red blood cell; Hemopathy
• ISSN: 0041-1132; 1537-2995; 1537-2995
• DOI: 10.1111/j.1537-2995.2008.01936.x

BACKGROUND: Animal models have shown that CD47‐deficient mice develop severe autoimmune hemolytic anemia (AIHA) because the binding of red blood cell (RBC) CD47 to signal‐regulatory protein (SIRP‐α) on macrophages contributes to the inhibition of phagocytosis. In contrast, complement‐inhibitory proteins such as CD35, CD55, and CD59 may protect RBCs against the lysis by complement. STUDY DESIGN AND METHODS: With the use of flow cytometric analyses, the expression of CD47, CD35, CD55, and CD59 on RBCs and of SIRP‐α,β on peripheral monocytes of 36 patients with warm AIHA (wAIHA; 23 with active wAIHA, 13 with wAIHA in remission) and 20 healthy subjects was evaluated. RESULTS: The mean fluorescence intensities (MFIs) of the expression of CD47, CD35, CD55, and SIRP‐α,β of active wAIHA patients, wAIHA in remission, and healthy subjects were not statistically different. Patients with active wAIHA showed significantly lower CD59 expression on RBCs than healthy individuals (MFI, 512.5 ± 59.6 vs. 553.7 ± 36.6; p = 0.009), while the CD59 expression in patients with wAIHA in remission was not significantly different from that of healthy controls (MFI, 538.4 ± 48.3 vs. 553.7 ± 36.6; p > 0.05). The expression of CD59 on RBCs of 3 patients who died from the wAIHA was lower than that seen on RBCs of healthy controls (MFI, 433.6 ± 69.6 vs. 553.74 ± 36.6; p = 0.0001). CONCLUSIONS: Our data show that the expression of CD47 on RBCs and SIRP‐α,β on monocytes of patients with wAIHA is not different from that seen in healthy individuals. In addition, we detected that patients with active wAIHA present low expression of CD59 and normal expression of CD35 and CD55 on their RBCs. Complement‐regulatory proteins may play an important role in protecting RBC destruction through the activation of complement.