Date: Fri, 14 Jun 1996 02:29:51 -0400 From: "Flynn Mclean" Subject: CDC National AIDS Hotline Training Bulletin #174 ................................................................. CENTERS FOR DISEASE CONTROL AND PREVENTION HIV/AIDS PREVENTION CDC NATIONAL AIDS HOTLINE TRAINING BULLETIN ................................................................. March 21, 1996 #174 These are answers from the Centers for Disease Control and Prevention (CDC) to questions concerning the persistent lack of detectable HIV-1 antibody in a person with HIV infection--Utah, 1995, as reported in the March 8, 1996, MMWR. 1. What is this MMWR report about? This is a report of an HIV-infected plasma donor in whom HIV antibody tests were persistently negative. 2. How is this possible? Researchers do not know the exact reason why this person tested antibody negative. An unusual strain of HIV was ruled out. Testing showed that the man was infected with subtype B, which is the most common strain of HIV found in the United States. The most likely reason is that this patient had an unusual response to infection with HIV. Again, this would be very rare. CDC is aware of a few reports where HIV-infected people have persistently tested negative on antibody testing. In this reported case, however, HIV was eventually detected on antigen and polymerase chain reaction tests. 3. What else could cause this? Other possible reasons for an occurrence like this could be laboratory errors or the presence of other immunodeficiencies. But these were ruled out in this case. 4. What happened to the donations from this individual? In this case, the plasma that he sold was pooled or added to other plasma donations. These pooled plasma "lots" were then treated by the usual inactivation methods, using heat or chemicals. These inactivation methods, which have been in place since 1984, inactivate any HIV or other viruses that may be present. Thus, there is no danger from the donations from this individual. 5. If this man had donated blood instead of plasma, would the blood supply have been safe? Probably not. It is important to know that plasma is donated as often as once a week while blood can only be donated once every 6-8 weeks, which would exceed any window period. The window period is the time from HIV infection until lab tests detect HIV antibody or antigen. However, this case was very unusual and should not be confused with donations within the HIV window period. To maintain an even safer blood supply, the Food and Drug Administration (FDA) recommended in August 1995 that all donated blood also be tested for HIV-1 p24 antigen, which appears before antibody development. The March 1, 1996, MMWR(RR2), "U.S. Public Health Service guidelines for testing and counseling blood and plasma donors for HIV type 1 antigen," provides guidance for interpreting HIV-1 p24 antigen test results and counseling and follow-up of blood donors. 6. Wouldn't this case warrant routine antigen testing among all people who have been exposed to HIV? CDC does not recommend the p24 antigen test for routine use in HIV counseling and testing sites. Guidelines for counseling and testing individual patients already take into account the window period and recommend follow-up antibody testing. Antigen testing detects HIV infection only a few days before antibody testing does. And the time in which the antigen can be found is very short--once antibodies are detectable, antigen is often not detectable. Antibody testing at the recommended intervals is the best way for health care providers to routinely diagnose HIV in individual patients. 7. What does CDC recommend for cases like this? People who have illnesses associated with HIV infection but do not test positive for HIV antibodies should ask their physician to discuss additional laboratory testing with their state health department laboratory. Antigen testing, PCR, or other laboratory methods may be helpful in these rare instances. Disclaimer: CDC Hotline Training Bulletins The information in the "CDC Hotline Training Bulletins" is provided by CDC and NIH for use by the CDC National AIDS Hotline in responding to general questions from the public about HIV and AIDS. The bulletins are not intended to be comprehensive discussions of the subject areas. Treatment and drug therapy options change as new research and clinical experiences broaden scientific knowledge. Therefore, persons seeking information on drug therapy should refer to the product information sheet included in all drug packages for the most current and accurate information about a particular drug, especially if the drug is new or infrequently used. HIV-infected individuals should consult their personal physician for specific concerns about their health. For persons desiring more information on a specific topic, public, medical, and university libraries can provide excellent references. The AIDS Clinical Trials Information Service (800-874-2572) can provide information about ongoing HIV/AIDS clinical trials; the HIV/AIDS Treatment Information Service (800-448-0440) can assist with information about the latest treatments for persons with HIV infection or AIDS.