A 42-year-old man has had multiple episodes of painful red nodules on his skin from dermal venous thrombosis, as well as abdominal pain from mesenteric vein thrombosis over the past year. He notes passing darker urine. Laboratory studies show Hgb| 9.4 g/dL, Hct 29.2%, MCV 100 fL, platelet count 215,000/microliter, and WBC count of 8800/microliter. His RBCs show increased sensitivity to complement lysis. Flow cytometry is most likely to show reduction in which of the following markers on his RBCS? 1. CD 68 2. CD19 3, cd 4 4. CD55 5. CD33

A 42-year-old man has had multiple episodes of painful red nodules on his skin from dermal venous thrombosis, as well as abdominal pain from mesenteric vein thrombosis over the past year. He notes passing darker urine. Laboratory studies show Hgb| 9.4 g/dL, Hct 29.2%, MCV 100 fL, platelet count 215,000/microliter, and WBC count of 8800/microliter. His RBCs show increased sensitivity to complement lysis. Flow cytometry is most likely to show reduction in which of the following markers on his RBCS? 1. CD 68 2. CD19 3, cd 4 4. CD55 5. CD33