Blood-stained letter received by HIV/AIDS reference laboratory in 1993--a historical case report.

We describe an interesting historical case of a blood-stained letter received in 1993 by Slovenian HIV/AIDS Reference Laboratory. According to the statement of the sender, the letter was spotted with HIV-infected blood. The polymerase chain reaction (PCR) amplification with two gag and env primer sets excluded the presence of HIV proviral DNA in the spot punches obtained from the dried blood spots. Although the presence of HV DNA was confirmed in 5 positive control blood spots using the same sets of primers, we still doubted in the accuracy of the HIV negative result. Fortunately, we obtained a serum sample of the author of the letter four months later from a psychiatric institution where he was hospitalized for paranoid schizophrenia. Since no anti HIV-1/2 antibodies were detected in his serum sample, our initial HIV negative findings based on PCR testing of blood spots were confirmed.