Diagnosis of HIV infection from bloodstains by PCR. A further marker for identification

The forensic usefulness of the detection of HIV infection in bloodstains is linked to the increasing spread of HIV infection and the consequent rise in the number of forensic cases involving HIV-positive subjects. This study was designed to detect HIV infection in bloodstains of various ages obtained from HIV-positive patients treated with zidovudine (3'-azido-3'-deoxythymidine, AZT) using PCR methods. Of the 3 kinds of extraction and amplification methods checked, only a nested PCR method for the amplification of a sequence located in the HIV Reverse Transcriptase (RT) region was successful. This method, involving 2 amplification steps (1: fragment of 768 bp; 2: codons 41-67-70-215-219), encompasses the mutations commonly observed during AZT therapy and overcomes the limitations inherent in serological testing. The discriminatory power of the method can detect specific mutation patterns in the RT gene linked to drug resistance and compares the specific pattern of the blood-stain with fresh blood or other specimens from the subject in question.