Very low prevalence of hepatitis C virus infection in rural communities of northeastern Brazil with a high prevalence of schistosomiasis mansoni

The association of hepatitis C virus infection and the hepatosplenic form of schistosomiasis mansoni has been claimed to result in the concomitant evolution of the two pathologies, with a poor prognosis due to aggravated liver disease. Recently, however, some authors have begun to reject the hypothesis of a higher susceptibility of hepatosplenic schistosomal patients to HCV. The aim of the present transverse study carried out between July and August 1990 was to determine the possible association between SM and HCV markers in residents of Catolândia, Bahia State. Anti-HCV markers were assayed by ELISA-II and RIBA-II in serum samples obtained from 1,228 residents (85.8%). The anti-HCV antibody (ELISA-II) was positive in six (0.5%) individuals, eight (0.6%) cases were inconclusive and 1,214 (98.9%) were negative. However, only in one ELISA-positive serum sample (0.08%) were antibodies confirmed by RIBA-II, while two other samples assayed by RIBA-II were indeterminate. These three patients presented the hepatointestinal form of SM during the follow-up period (1976 to 1996). In conclusion, no association was observed between HCV and SM in the endemic area studied, especially among patients with the hepatosplenic form of the disease.

Nitric oxide levels are not changed in saliva of patients infected with hepatitis C virus

The aim of this investigation was to determine nitric oxide metabolite levels in saliva samples from hepatitis C virus-positive patients in an attempt to test the hypothesis if increased levels of nitric oxide metabolites correlates with the presence of HCV-RNA in saliva. Saliva of 39 HCV-positive patients and 13 HCV-negative patients, without clinical or laboratorial evidence of liver disease were tested for nitric oxide metabolites. HCV-RNA was detected in serum and saliva by a RT-PCR method and nitric oxide level was determined by evaluation of its stable degradation products, nitrate and nitrite. No differences were found between the concentration of nitrite in saliva from HCV patients and controls, in despite of the presence or not of HCV RNA in saliva. Patients with HCV and cirrhosis had higher concentrations of nitrite but not significantly different from the control group or the groups of anti-HCV patients without cirrhosis. Increased levels of nitrite were not detected in anti-HCV positive patients, an indirect indication that chronic sialoadenitis are infrequent in these patients or occurs with low intensity not sufficient to increase nitric oxide metabolite levels in saliva.

Cytokine serum levels in patients infected by human immunodeficiency virus with and without Trypanosoma cruzi coinfection

This study assessed the number of CD4 T lymphocytes, the parasitemia and serum levels of interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), interleukin-1 (IL-1), IL-4 and IL-10 of patients infected by human immunodeficiency virus (HIV) and human immunodeficiency virus/Chagas' disease coinfection. CD4 T lymphocytes were low in the two groups of patients, although significantly lower in patients without Chagas' disease. Serum levels of IFN-gamma, IL-4 and TNF-alpha were significantly higher in patients with HIV/Chagas' disease. IL-4/IFN-gamma ratios were higher in patients with HIV/Chagas' disease, which showed a clear balance in favor of Th2-like cytokines in this group of patients. This Th2 balance was higher in patients with detectable parasitemia. We conclude that, although immunosuppression was observed, with CD4 T lymphocytes bellow 200/µm³, these patients did not display reactivation of T. cruzi infection and that a balance favorable to Th2 was associated with the presence of parasitemia.