The effect of cyclosporine on haematological parameters in patients with paroxysmal nocturnal haemoglobinuria.

Four patients with paroxysmal nocturnal haemoglobinuria (PNH) were treated with cyclosporine. The treatment with cyclosporine was based on the hypothesis that immune-mediated bone-marrow damage is the common pathogenetic mechanism of aplasia and PNH, with lack of GPI-linked ligands for an immune attack (i.e. LFA-3, CD58) rendering PNH cells a growth advantage over other bone marrow cells. In the first patient, presenting with a mixed AA/PNH syndrome, a gradual recovery from aplasia was seen after prolonged treatment with cyclosporine. In a second patient, with a mixed AA/PNH syndrome, no haematological improvement was noted during cyclosporine administration, but this patient became transfusion-independent with increasing neutrophil and platelet counts after a course of ATG in combination with androgen therapy. Both these patients showed an increment in the proportion of neutrophils with normal expression of GPI-linked proteins concurrently with the improvement of haematological characteristics. In the two other patients, presenting with typical PNH, cyclosporine treatment did not result in any change in haematological characteristics, nor in PNH parameters. No significant change in haemolytic parameters was seen in any of the patients. It is concluded that immunosuppressive therapy may be of benefit in patients with a mixed AA/PNH syndrome. This effect became apparent after prolonged treatment with cyclosporine in one patient, and after a subsequent course of ATG with concomitant androgen therapy in another.