|Interleukin-1, Tumor Necrosis Factor-Alpha
and Interferon Gamma in Hepatic Schistosomiasis: Relation to Erythropoiesis.
|Nabil A. El-Halawani1, Hoda A. El-Aggan2, Myriam
Abou Seif 3 and Sawsan M. Bakhubira1.
|Departments of Medicine (Hematology1 and Hepatobiliary2
Units) and Clinical Pathology3, Faculty of Medicine, Alexandria
Hepatic schistosomiasis is an immunoregulatory disease characterized
by elaboration of various cytokines and is frequently associated with anemia.
Therefore, the present study was designed to determine the inter-relationship
between serum interleukin-1 (IL-1), tumor necrosis factor- alpha (TNF-a)
and interferon gamma (IFN-g) and erythropoiesis in this disease. Thirty
eight patients with schistosomal hepatic fibrosis (SHF) and well- compensated
liver disease (23 were anemic and 15 were non-anemic), were included in
the study as well as 12 healthy subjects as a control group. Active schistosomiasis
was found in 26 patients. Serum levels of IL- 1b, TNF-a and IFN-g were
measured using immunoenzymatic assay. Bone marrow (BM) was examined for
cytological study and by Prussian blue stain to detect iron granules. Parameters
of serum iron status (serum iron, total iron binding capacity, transferrin
saturation and serum ferritin) were also measured. In patients with SHF,
serum levels of IL-1B, TNF-a and IFN-g were significantly elevated unrelated
to disease activity. Bone marrow examination in these patients showed erythroid
hyperplasia with late erythroid maturation arrest regardless of the presense
of anemia. Using Prussian blue stain, only patients with anemia had reduced
sideroblast percentage associated with hypoferremia and low transferrin
saturation. However, despite these changes, BM iron stores and serum ferritin
levels were normal (functional iron deficiency) in 10 (43.5%) patients
with anemia simulating the picture of "anemia of chronic disease"
and were below normal in the other anemic patients suggesting the coexistence
of true iron deficiency. Of the studied cytokines, only TNF-a serum levels
were significantly higher in anemic than in non-anemic patients. This cytokine
showed a direct relationship with the degree of late erythroid maturation
arrest and inverse correlations with serum iron levels, transferrin saturations,
sideroblast percentages and hemoglobin crationcentons in patients with
SHF. It is concluded that elevation of serum levels of IL-1b, TNF-a and
IFN-g occurs in hepatic schistosomiasis unrelated to disease activity.
Of these cytokines, TNF-a seems to play an important role in the suppression
of late erythropoiesis, disturbance in iron metabolism and development
of anemia in this disease. Therefore, the immune-mediated mechanism has
to be considered in the management of anemia in patients with hepatic schistosomiasis.