HP and Alzheimer disease: Two haptoglobin (Hpt) chains (β chain ~ 45 kDa - Fig. 2 fraction 2, arrow d and α1 chain ~ 8.9 kDa - Fig. 2 fraction 2 reverse phase fraction, arrow e) were significantly higher in AD pools (2.0-fold, p < 0.01 and 2.4-fold, p < 0.02 respectively, Table 2).