ABSTRACT
Human-T lymphotrophic virus Type 1 may be transmitted by cellular blood products. A low but definite risk exists that recipients of HTLV-1 infected products may develop severe even fatal disease. After one year of screening for HTLV-1 antibodies in 12,851 units of blood collected from a multinational volunteer donor population of which 42.6% were Saudi nationals, we found two units of blood which reacted repeatedly positive in the screen test. In both cases, the Western Blot confirmatory test was indeterminate in that not all bands required for a positive reaction were present. Both donors were expatriates from North America either living in an endemic area or with Caribbean ancestors. Although more than 5,000 Saudi national donors were tested and found negative for HTLV-1 antibodies, a statistical estimate of the maximal risk of finding a positive donor in this donor population subgroup is in the order of 0.055%. Based on these results it is recommended that blood banks in this region screen for HTLV-1.
ABSTRACT
Based on the screening of 10,646 units of blood by a recombinant hepatitis C antibody enzyme-linked immunosorbent assay (ELISA), the prevalence of hepatitis C (HCV) antibody-reactive donors was established in a Saudi Arabian donor population. The overall prevalence of HCV antibody was found to be 1.01%. By nationality, the antibody frequency was 1.00% (Saudi males), 2.30% (other Middle Easterners), 0.71% (Far East nationals), and 0.39% (Europeans/North Americans). The ELISA HCV antibody reactive units were further tested by a recombinant immunoblot assay (RIBA) in which 47.2% of the initially reactive samples were found to contain specific antibodies to two recombinant antigens. HCV antibody seroprevalence defined by reactiveness in both tests was 0.48% for the entire population, 0.33% (Saudis), 1.42% (Middle Easterners), 0.27% (Far East nationals and Europeans/North Americans). The surrogate markers alanine aminotransferase (ALT) and hepatitis B core (HBc) antibody identified 7.7 to 40% and 20 to 56.4%, respectively, of donors of different nationalities testing repeatedly reactive in the HCV ELISA. Likewise, ALT and HBc antibody identified 20 to 57.1% and 0 to 66.75%, respectively, of HCV ELISA and RIBA reactive donor samples, depending on nationality. It was concluded that the present anti-HCV testing, althought useful in screening blood for HCV carriers, must be supplemented by surrogate tests until additional specific tests are available.
