Assessment of neutrophil apoptosis ex vivo in hepatosplenic patients with neutropenia pre and post splenectomy

The pathophysiology of neutropenia seen in patients with schistosomiasis or hepatitis C infection that complicates the course of liver disease is poorly understood. We evaluated the neutrophil apoptosis before and after splenectomy to clarify the role of apoptosis and splenomegaly in the occurrence of neutropenia. Neutrophils were isolated from 23 hepato-splenic patients with neutropenia, 8 hepatosplenic patients with normal neutrophil counts, 7 patients who were post splenectomy, and a further ten normal control subjects. These were cultured for 24 h and the time course of neutrophil apoptosis was assessed by determination of Annexin V and propidium iodide binding by flow cytometry. Fas and Bcl2 expression were determined on fresh neutrophils using flow cytometry. Levels of tumor necrosis factor alpha, interleukin 3, and gamma interferon were evaluated using an immunosorbent assay. Neutrophil apoptosis was minimal in the fresh neutrophils, however, cultured neutrophils exhibited significantly greater apoptosis in neutropenic patients when compared to non-neutropenic patients (P=0.01 at 4 h and P<0.05 at 24 h) and control group (P<0.01 at 4 h and 24 h). After splenectomy, the percentage of neutrophil apoptosis declined to the normal control levels (P>0.05). Fas and Bcl2 expression on neutrophil were significantly higher in the neutropenic group as compared to normal controls (P<0.05, P=0.01 respectively). Serum TNF alpha, IL-3, and IFN gamma levels were not significantly different in all studied groups.

IN CONCLUSION

Neutrophils from neutropenic hepatosplenic patients exhibit markedly accelerated apoptosis, which is normalized after splenectomy. Thus increased neutrophil apoptosis may in part be responsible for the occurrence of neutropenia.