ELISA for human nm23-H1 protein in plasma. (A) Demonstration of the quantitative nature of this system. The linearity of the quantitation of nm23-H1 protein, but not nm23-H2protein, was determined using recombinant nm23 fusion protein. (B) Detection of nm23-H1 protein in human plasma/serum diluted with PBS. (C) Plasma nm23-H1 levels and free hemoglobin levels in 149 aggressive lymphomas (▩), 21 healthy controls (•), and blood red cell extracts with various amounts of free hemoglobin (▵).