PROS1 and anemia (phenotype): The patients from Group 3 (viral infection without anemia) were characterized by a significant alteration in a subset of the proteome (Figure 3A), with significant depletion of several RBC membrane proteins (SLC4A1, ANK1, SPTA1, SPTB, stomatin (STOM), band 4.1 E4BP1, flotillin (FLOT2), glycolytic enzymes (fructose bisphosphate aldolase (ALD), glyceraldehyde-3-phosphate dehydrogenase (GAPDH)) and hemoglobin/heme metabolism enzymes (HBA, HBB, and biliverdin reductase B–BLVRB) (Figure 3B).