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Biomedical subjects

B R Wylie

Publications and source records attributed to B R Wylie.

At least 19 recordsLinked to original sources
PubMed1996

Effect of blood donation on the establishment of normal ranges of lymphocyte subsets.

BACKGROUND: Absolute counts of CD4+ T-lymphocytes are used in the management of patients with human immunodeficiency virus infection. Low absolute counts of CD3+CD4+ cells have also been observed in healthy people--a phenomenon called idiopathic CD4 lymphocytopenia. It is common practice for normal ranges for lymphocyte subsets to be derived from samples taken from blood donors. STUDY DESIGN AND METHODS: A sample of EDTA blood was taken through the donation line tubing, after donation from 565 blood donors in Sydney, Australia, who were selected from a range of age groups. An additional 12 donors provided a predonation sample as well as a postdonation sample. Hematologic assays were performed on two analyzers. Samples were stained for CD3, CD4, CD8, CD19, and CD56 and analyzed on a flow cytometer. RESULTS: Three donors were found to have absolute CD3+CD4+ counts < 300 cells per microL. The percentage of CD3+CD4+ cells was found to increase with age. Both the percentage and the absolute count of CD3+CD8+ cells decreased with age, which resulted in an increased CD4:CD8 ratio with age. Men had consistently higher absolute counts of CD3-CD56+ cells than women. The 12 additional donors all had greater percentages of CD3+CD4+ cells and lower absolute counts for CD3+, CD3+CD4+, CD3+CD8+, CD19+ and CD3-CD56+ cells after donation than they had before donation (p < 0.001). CONCLUSION: It is not satisfactory to base normal ranges for lymphocyte subsets on donor blood, from which the blood sample has been obtained after donation.

Adolescent↗
PubMed1995

Post-transfusion hepatitis revisited.

OBJECTIVE: To evaluate the risk of post-transfusion and postoperative non-A non-B hepatitis in Australia immediately before the introduction of screening for hepatitis C. DESIGN: Retrospective testing of blood samples from a prospective study of cardiac surgery patients. Samples were taken from transfusion recipients and non-transfused controls at regular intervals for 12 months after surgery during 1987-1989. For all donor, recipient and control samples, alanine aminotransferase (ALT) levels were measured and tests for antibody to hepatitis B (anti-HBc, anti-HBs) and, when available, to hepatitis C (anti-HCV) were performed. SETTING: Cardiac surgery units. PARTICIPANTS: Participants were included if they lived in the metropolitan area, and had not had a transfusion in the past year. MAIN OUTCOME MEASURES: Post-transfusion hepatitis (two consecutive samples showing raised ALT levels, > 90 IU/L with no other known cause); hepatitis C infection and carriage (antibody to hepatitis C). RESULTS: Post-transfusion hepatitis occurred in 1.1% of 736 recipients of blood not screened for hepatitis C (i.e., two cases per 1000 unscreened units given). No hepatitis occurred in 514 controls. Seven of the eight patients with post-transfusion hepatitis seroconverted to hepatitis C virus infection. Seven of the 26 anti-HCV-positive donations transmitted hepatitis C, six of these were positive by recombinant immunoblot assay (RIBA) (one by second generation testing only) and one was RIBA indeterminate. Nineteen were RIBA non-reactive; one transmitted hepatitis but the recipient did not develop anti-HCV, although hepatitis C RNA was detected in the donation. Serum ALT was raised in four of the six infective donations. CONCLUSIONS: Hepatitis C virus infection accounted for almost all cases of non-A non-B post-transfusion hepatitis. First generation anti-HCV tests detected about 85% of infective donations. Surrogate testing of donations by ALT or anti-HBc offers no additional advantage.

Alanine Transaminase↗
PubMed1993

Transfusion transmitted infection: viral and exotic diseases.

Viral and other exotic diseases may be transmitted by blood transfusion. These infections include human immunodeficiency virus (HIV), hepatitis viruses (A, B, C, D and E), syphilis, malaria, retrovirus HTLV-1, and cytomegalovirus. Other more exotic diseases which may be transmitted by transfusion of blood or blood components include Chagas' disease (Trypanosomiasis cruzi), Lyme disease (Borrelia burgdorferi), and Jakob-Creutzfeldt disease. Screening procedures currently used in Australian blood banks minimise transfusion-transmitted infection. The risk of acquiring any infection in this manner may be less than 0.1%.

Humans↗
PubMed1992

Prevalence of hepatitis C virus antibodies in Sydney blood donors.

OBJECTIVE: To determine the prevalence of hepatitis C virus (HCV) antibodies in the Sydney blood donor population. DESIGN: All blood donations collected from Red Cross blood donors in Sydney from February 1990 until April 1991 were tested for HCV antibodies. For those samples found reactive in an anti-HCV screening test, a confirmatory test was carried out for the presence of HCV antibodies and the alanine aminotransferase level was measured. RESULTS: The prevalence of repeated reactivity to the screening test was 0.45% among blood donations overall, and 1.02% in donors giving blood for the first time in the study period. The confirmatory test result was positive for 30.8% of donations found to be repeatedly reactive in the screening test. There was little change over the study period in the HCV antibody prevalence of donors giving blood for the first time, but there was a clear decrease in the prevalence among all donations. Prevalence in males was nearly twice the prevalence in females--a difference which was consistent across age groups. The highest prevalence in both sexes was in the age group 30-34 years. Among samples for which the screening test results was positive, there was a strong correlation between the reactivity recorded for the screening test and both the proportion found positive by the confirmatory test and the proportion with an elevated alanine aminotransferase level. CONCLUSION: The small proportion of blood donations found to be repeatedly reactive by anti-HCV screening and the relatively good correlation with the confirmatory test and liver function assay indicate that a policy of discarding these donations will decrease the risk of transfusion-transmitted HCV infection without materially affecting the supply of blood.

Adult↗
PubMed1992

Risk factors for hepatitis C virus infection in blood donors: a case-control study.

OBJECTIVE: To investigate risk factors for hepatitis C virus (HCV) infection in Sydney blood donors. DESIGN: Blood donors confirmed to be positive for HCV antibodies were compared with blood donors with a positive result of a screening assay, but whose HCV antibody status had not been confirmed. A questionnaire on sexual, parenteral and other potential risk factors was administered to both groups. SETTING: Blood Transfusion Service in Sydney. PARTICIPANTS: The study enrolled 220 donors who had confirmed HCV infection, and 210 donors who did not. RESULTS: The relative risk associated with injecting drug use was 63 (95% confidence interval, 19-260) when comparison was made with all other donors. Among donors who did not report injecting drug use, a significant, independent increase in risk was found in association with having had a tattoo. Among donors who did not give a history of parenteral exposure, there was a significantly greater risk in people with more than one life-time sexual partner than in those with at most one partner. CONCLUSION: A history of injecting drug use was elicited as the most important risk factor in Sydney blood donors with antibodies to hepatitis C. Having had a tattoo, and an increased number of lifetime sexual partners were also independently associated with HCV infection.

Adult↗
PubMed1992

Clinical assessment and incidence of hepatitis C RNA in 50 consecutive RIBA-positive volunteer blood donors.

OBJECTIVES: (i) To assess evidence of liver disease in 50 consecutive volunteer blood donors who were anti-hepatitis C virus (anti-HCV) antibody positive and who were referred to one hepatologist; (ii) to assay for viral RNA in serum in these patients. SETTING: Royal Prince Alfred Hospital, a teaching hospital of the University of Sydney. PATIENTS: Fifty people who were detected by the NSW Red Cross Blood Transfusion Service to be anti-HCV antibody positive and to have a positive result on recombinant immunoblot assay (RIBA) were assessed by one hepatologist for symptoms, signs and biochemical evidence of hepatic dysfunction. These patients were consecutive referrals from this source. Sixteen of these patients also consented to liver biopsy assessment. All patients had serum assayed for viral RNA by polymerase chain reaction with a combination of 3' and 5' primers. RESULTS: The 50 blood donors consisted of 28 men and 22 women, with a mean age of 34.5 years. Forty-six patients were asymptomatic. Only six had a past history of hepatitis while 14 had minor signs of chronic liver disease. In 28, injecting drug use was thought the most likely source of exposure to HCV. The minimal mean time since exposure to HCV in these patients was 8.8 +/- 5.2 years. Eight patients had received a blood transfusion at a mean time of 15.0 +/- 9.8 years from the time of consultation. The mean maximum level of alanine aminotransferase (ALT) in all 50 patients was 102.8 U/L. Five patients had persistently normal ALT levels; another 22 had at least one normal ALT level. Liver biopsies indicated chronic persistent hepatitis in 11 patients, mild chronic active hepatitis in three patients and more severe chronic active hepatitis in one. One patient had cirrhosis on biopsy. Forty-two patients had viral RNA detected in serum. CONCLUSION: Chronic infection with HCV in blood donors was invariably asymptomatic; 78% of patients had no signs of chronic liver disease and 68% had a maximum hepatic transaminase level of less than 100 U/L. Although severe liver disease was seen in two of 16 biopsies, the majority of these patients have mild liver disease despite a mean of about 10 years since exposure to the virus. Eighty-four per cent of patients had evidence of viral RNA in serum.

Adult↗