Evaluation of some cytokine responses in ascitic fluid; their relation to circulating immune complexes

ABSTRACT

There is no clear consensus about the pattern of cytokine production and regulation that causes patients with chronic schistosomiasis to develop severe hepatosplenic disease, which is characterized by peri-portal fibrosis and portal hypertension. Circulating immune complexes [CICs], play an important role in the pathogenesis of many clinical syndromes during the course of hepatic schistosomiasis. Therefore, the aim of this study was to estimate interleukin-6 [IL-6] and tumor necrosis factor- alpha [TNF-alpha] levels in serum and ascitic fluid [AF] of schistosomal patients and to evaluate these cytokines response in relation to circulating immune complexes. The study enrolled 40 patients with hepatic schistosomiasis forming two groups; 20 patients with ascites [group I] and the other 20 patients without ascites [group II]. Apart from complete history taking, clinical examination, and routine laboratory work, blood and ascitic fluid [AF] samples were collected from the patients after hospital admission. Estimation of IL-6 and TNF- alpha in serum and AF according to the manufacturer instructions. Moreover, serum circulating immune complexes [CICs] were assayed as well. The mean serum level of IL-6 was 156.9 +/- 150.82 pg/ml in schistosomal ascitic patients and 121.63 +/- 68.47 pg/ml in non-ascitic cases. The mean serum concentration of TNF- alpha was 88.5 +/- 70.59 pg/ml in group I and 66 +/- 46.76 pg/ml in group II patients. IL-6 concentration in the ascitic fluid of schistosomal patients had a mean of 284.4 +/- 280.08 pg/ml while ascitic fluid TNF- alpha had a mean of 113.25 +/- 58.97 pg/ml. Schistosomal patients with ascites were shown to have significantly higher levels of IL-6 and TNF- alpha in their ascitic fluid than in serum. A significant positive correlation was detected between the serum and AF concentrations of IL-6 [r-=0.559*], and TNF- alpha [r-=0.556*], P<0.05 in each case. Ascitic patients had a significantly higher mean CIC [21.33 +/- 5.4 micro g Eq/ml] than the non-ascitic cases [15.51 +/- 5.27 micro g Eq/ml]. There was a significant positive correlation between serum level of IL-6 and CICs in schistosomal patients with ascites [r-=0.446*, P<0.05], and another significant positive correlation was demonstrated between ascitic fluid TNF- alpha and CICs in the same patients [r-=0.448*, P<0.05]. The study concluded that schistosomal patients with ascites had significantly higher levels of IL-6 and TNF- alpha in their ascitic fluid than in serum, while there was no significant differences between their serum levels in the ascitic and non-ascitic groups. Moreover, a significant positive correlation was detected between CICs and serum IL-6 in patients with ascites