Large clones with PNH-type phenotype are not common in patients presenting with intra-abdominal thrombosis--a prospective study.

Intra-abdominal thrombosis is a complication of paroxysmal nocturnal hemoglobinuria (PNH). There is scarcity of data on cases presenting with thrombosis in whom PNH is the predisposing factor. We assessed the role of PNH defect in 81 patients with intra-abdominal thrombosis, 44 patients of Budd Chiari syndrome and 37 patients of extra hepatic venous obstruction. Flowcytometry with glycosylphosphatidyl inositol-anchored proteins (GPI-AP)-CD55, -CD59, and -CD16 was performed on all patients and controls to assess the prevalence of deficiencies and PNH-type phenotype clone size. Deficiencies of individual GPI-AP were seen in 17.3% cases versus 3.4% controls. This was due to CD55 deficiency on red blood cells and CD16 deficiency on the granulocytes. Deficiency of multiple GPI-APs was less frequent (3.7% cases). Data of this study indicate that the PNH defect as detected with CD55, CD59, and CD16 is not an important cause of intra-abdominal thrombosis in northwestern India.