The membrane abnormalities in paroxysmal nocturnal hemoglobinuria (PNH).

Paroxysmal nocturnal hemoglobinuria (PNH) cells are characterized by an abnormal membrane which interacts abnormally with normal serum complement. These abnormal reactions occur at two levels of the sequence: 1) All abnormal PNH cells fix more C3 than normal cells for a given activation of complement; 2) PNH III cells are more readily lysed by a given number of assembled terminal complexes. The nature of the lesion yielding these abnormal reactions is not known.