EVALUATION OF SURROGATE MARKERS FOR HUMAN IMMUNODEFICIENCY VIRUS INFECTION AMONG BLOOD DONORS AT THE BLOOD BANK OF “HOSPITAL UNIVERSITÁRIO REGIONAL NORTE DO PARANÁ”, LONDRINA, PR, BRAZIL

In industrialized countries, the use of sensitive human immunodeficiency virus (HIV) screening tests, donor deferral, and more conservative use of blood have resulted in a dramatic decrease in the transmission of HIV infection by blood transfusion. The risk of HIV transmission in the United States by blood screened negative for HIV antibody was recently estimated at one in 440,000-660,000 donations. However, in many developing countries where the prevalence of HIV infection among blood donors is orders of magnitude greater than in industrialized countries, an estimated 5 to 10% of HIV infections are due to blood transfusion10. More strategies and measures to improve the effectiveness of the routine screening of blood donors and the safety of the blood components have been evaluated. The rate of hepatitis B virus (HBV) infection in HIV infected patients is 10-30 times higher then in general population from United States19 . During the HBV infection, the HBV produces envelope protein or surface antigen (HBsAg) in vast excess during the period before seroconversion. For this reason, antigen tests with sufficient sensitivity were available for blood donation screening at a very early stage. With exposure to the neutralizing anti-HBs antibodies, the HBsAg disappears. The core particle of the hepatitis B virus (HBcAg) is an extremely potent antigen that elicits strong B- and T-cell responses in individuals exposed to the virus. The antibody to core antigen (anti-HBc) occurs early in acute infection, 4-10 weeks after appearance of surface antigen of hepatitis B virus (HBsAg), usually persists longer, or for lifetime, than other hepatitis B virus (HBV) markers, is associated with an elevated risk of transmission of non-A non-B hepatitis and has been used as a surrogate to screen blood donors14,20. Anti-HBc was introduced in routine donor screening in 1987 in an attempt to identify donors at risk of transmitting posttransfusion non-A non-B hepatitis13. Anti-HBc detects persons who have been previously infected with HBV and can therefore serve as surrogate test for other infectious agents. In addition to indicating previous exposure to HBV, the anti-HBc assays have been used as surrogate marker for the presence of other infectious agents. In some blood banks in regions of high prevalence of HIV infection, the anti-HBc was implemented as a surrogate test for HIV infection9 . Exclusion of anti-HBc positive donors reduces the incidence of post-transfusion hepatitis and possibly other vir