T‐lymphocytes escape membrane defect in paroxysmal nocturnal haemoglobinuria

Publisher Website
Google Scholar
Abstract
Erythrocytes, granulocytes and platelets from patients with paroxysmal nocturnal hemoglobinuria (PNH) are abnormally sensitive to lysis by complement. T-lymphocytes were studied from PNH patients for abnormal complement lysis sensitivity. T-lymphocytes free of other contaminating blood cells were prepared by sedimentation, nylon wool filtration and density gradient centrifugation. The lymphocytes were then labeled with 51Cr and lysis induced by antithymocyte globulin and rabbit complement. PNH lymphocytes were no more susceptible to complement-mediated lysis than lymphocytes from normal individuals. The unusual sensitivity of PNH erythrocytes could still be demonstrated when rabbit serum was a source of complement so the lack of any difference in the sensitivity of normal and PNH lymphocytes was probably not attributable to the inability of rabbit serum to elicit the membrane defect. PNH erythrocytes and granulocytes also acquire more membrane-bound C3 when human complement is activated. Increased membrane C3 binding on PNH lymphocytes was searched for using anti-I antibody and human serum as a complement source. C3 binding was measured using 125I-labeled monoclonal mouse anti-human C3. While increased membrane C3 binding on PNH granulocytes was verified during complement activation, similar differences between PNH and normal T-lymphocytes were not shown. Thus PNH T-lymphocytes do not share the membrane abnormalities of PNH erythrocytes and granulocytes.