RESUMEN
BACKGROUND: Clearance of hepatitis B virus (HBV) infection requires a good host immune response. Cytokines like tumor necrosis factor-alpha (TNF- alpha) may play a role in such immune response. Genetic changes in TNF-a gene promoter region are known to influence TNF- alpha expression. We therefore studied the role of one such mutation in chronic HBV infection. METHODS: Presence of -308 G/A polymorphism in the promoter region of TNF- alpha gene was looked for in 100 patients with chronic HBV infection, 91 subjects with spontaneously recovered HBV infection and 89 healthy controls, using a PCR-RFLP method. RESULTS: Variant alleles (A/A or A/G) were found in 22 of 100 (22%) patients with chronic HBV infection, 21 of 91 (23%) subjects with spontaneous HBV clearance and 14 of 89 (15.7%) control subjects (p=ns for inter-group comparisons). CONCLUSION: TNF- alpha promoter polymorphism -308A is common in Iranian population, but has no association with development of chronic HBV infection.
Asunto(s)
Alelos , Distribución de Chi-Cuadrado , Frecuencia de los Genes , Hepatitis B Crónica/genética , Humanos , Irán , Polimorfismo Genético , Regiones Promotoras Genéticas/genética , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
Screening the blood donors for serological markers reduced the incidence of transfusion transmitted infections especially post-transfusion hepatitis C. However, there remains residual risk due to pre-seroconversion period. HCV RNA [PCR] of blood donations reduced theresidual risk of transfusion-transmitted HCV infection. In this study, blood donations werescreened for HCV RNA by RT-PCR method.An extra plasma sample was collected from 1026 blood donors. 1000 out of 1026 sampleswere negative for HBsAg, anti-HCV [EIA, third generation], anti-HIV and RPR. Every 5samples were pooled. The sensitivity of HCV-RNA detection by RT-PCR method was 380geq/ml according to Proficiency VQC panel. 1000 donations in 200 pools were tested.False reactivity of samples considered positive accounts for 5.5% of cases, and 5.5% were invalid due to non-specilic bands. 6% of the pools were false-positive. A false positive result was defined as positive on initial testing but negative on repeat single testing. However, all ofthe samples were negative for HCV RNA by RT-PCR method.No sample was found to be serologically negative and HCV RNA positive. However, further studies are recommended for further clarification
RESUMEN
The occurrence of colonization factor antigens I and II (CFA/I and II) and type 1 somatic pili was investigated in 197 enterotoxigenic Esch. coli (ETEC) isolated from 197 patients of diarrhoea (aged under 3 yr) during February 1985 to March 1986 in Tehran, Iran. Among ETEC strains, 154 strains were heat-stable enterotoxin (ST) producers, 27 strains were heat-labile enterotoxin (LT) producers, and 16 strains produced both toxins. Sixty five (33%) strains showed mannose-resistant haemagglutination (MRHA) of human and/or bovine erythrocytes; of these, 51 (86%) strains were positive for CFA/I and II. Seventy one (36%) strains also exhibited type 1 somatic pili. CFA/I was found in 4 (15%) LT producing, 24 (16%) ST producing, and 2 (13%) LT/ST producing strains. In contrast, CFA/II was only found in ST producing strains (17 strains) and those producing both toxins (4 strains). Patients having CFAs-positive ETEC strains had a significantly (P less than 0.001) higher number of stool evacuation per day and a longer duration of diarrhoea than those having CFAs-negative strains. Fifty nine patients had mixed infections of ETEC strains and other enteropathogens. CFA/I or II (CFAs)-positive and CFAs-negative ETEC strains were found in 17 and 42 patients with mixed infections respectively. The mean number of stool evacuations per day was much higher in patients with ETEC and rotavirus than those with only ETEC infection (P less than 0.001). However, severity of the disease was not affected by the presence or absence of CFA/I or II in ETEC strains found in these patients.