Search

The aetiology of paroxysmal nocturnal haemoglobinuria (PNH) is a somatic mutation in the X-linked phosphatidylinositol glycan class A gene (PIGA), resulting in global deficiency of glycosyl phosphatidylinositol–anchored proteins (GPI-APs). This study applied RNA-sequencing to examine functional effects of the PIGA mutation in human granulocytes. CXCR2 expression was increased in GPI-AP− compared to GPI-AP+ granulocytes. Macrophage migration inhibitory factor, a CXCR2 agonist, was significantly higher in plasma of PNH patients. Nuclear factor-κB phosphorylation was upregulated in GPI-AP− compared with GPI-AP+ granulocytes. Our data suggest novel mechanisms in PNH, not obviously predicted by decreased production of the GPI moiety.

The effectiveness of salvage therapy for aplastic anemia patients unresponsive to initial rabbit antithymocyte globulin (r-ATG) or cyclophosphamide is not known. We investigated the administration of standard horse ATG (h-ATG) plus cyclosporine (CsA) in patients who were refractory to initial r-ATG/CsA (n = 19) or cyclophosphamide/CsA (n = 6) (registered at clinicaltrials.gov as NCT00944749). The primary endpoint was hematologic response at 3 months and was defined as no longer meeting the criteria for severe aplastic anemia. Of the 19 patients who received r-ATG as initial therapy, 4 (21%) achieved a hematologic response by 3 months, and of the 6 patients who received cyclophosphamide, only 1 (17%) responded by 6 months. Among the responders there were no cases of relapse, and in nonresponders 2 patients evolved to monosomy 7. The overall survival for the cohort at 3 years was 68% (95% CI, 50-91%). These results suggest that only a minority can be successfully salvaged after receiving as first therapy either r-ATG or cyclophosphamide. Although h-ATG may be utilized in the salvage setting, the overall response rate probably will be lower than when h-ATG is used as initial treatment.