Document 1881
 DOCN  M94A1881
 TI    Ultrasensitive detection of HIV and other retroviruses in plasma by a
       novel test for reverse transcriptase (RT).
 DT    9412
 AU    Schupbach J; Pyra H; Boni J; Swiss National Center for Retroviruses,
       Swiss Federal Office of; Public Health, Zurich.
 SO    Int Conf AIDS. 1994 Aug 7-12;10(1):43 (abstract no. 147B). Unique
       Identifier : AIDSLINE ICA10/94370694
 AB    OBJECTIVE: The retrovirus safety of blood products is of vital interest.
       The ultimate goal is a test that detects all infectious retroviruses at
       the highest sensitivity and specificity. The fact that infectivity of a
       retrovirus particle depends on the presence of an enzymatically active
       RT offers a rational to achieve this goal. METHODS: Human plasma samples
       were tested blinded and in duplicate for particle-associated RT with the
       new Product-Enhanced Reverse Transcriptase (PERT) assay (Pyra et al,
       PNAS 1994;91:1544-8). This universal screening test for retroviruses
       detects as little as 10(-9) unit of recombinant MuLV RT, which
       corresponds to approx. 2 x 10(2) molecules or an estimated 3 to 11
       virions. RESULTS: In direct comparison using serial dilutions of
       HIV-1-positive materials the PERT assay was as sensitive as RNA-PCR. All
       of 30 plasma samples from HIV-1 infected patients (10 each stage II,
       III, IV) were positive. HIV-2 and HTLV-1 were also detected in plasma.
       Results of PERT assay and RNA PCR were quantitatively correlated. Of 160
       unselected Zurich blood donors 159 were negative. The positive donor had
       presented for 3 y with a slightly elevated liver enzyme (ALT), but had
       always been negative by all other blood bank tests including hepatitis
       virus serology. Another donor of a different series with a
       borderline-positive HIV screening test and antibodies to HIV-1 p24, but
       no full seroconversion, for 3 y was also highly positive. Both donors
       were negative for HIV or HTLV by DNA and RNA PCR, but PERT activity
       indicated 10(4)-10(5) particles/ml plasma. 0 of 222 plasma from cancers,
       autoimmune or allergic diseases was positive, but 6 of 25 with
       indeterminate HIV or HTLV Western blots results were. DISCUSSION AND
       CONCLUSIONS: The PERT assay is highly specific, as sensitive as RNA PCR,
       and detects all infectious retroviruses. The finding of 0.6% positives
       points to a prevalence of 0.016-3.4% (95% CI) of particle-associated RT
       in unselected Zurich blood donors. The 24% positives in indeterminate
       Western blots suggest true retrovirus infection in some of such
       indeterminates. Identification of these agents is urgently needed.
 DE    Blood Donors  Comparative Study  Human  HIV
       Infections/DIAGNOSIS/MICROBIOLOGY  HIV-1/*ENZYMOLOGY/GENETICS/*ISOLATION
       & PURIF  HIV-2/ENZYMOLOGY/ISOLATION & PURIF  HTLV-I/ENZYMOLOGY/ISOLATION
       & PURIF  Polymerase Chain Reaction/STATISTICS & NUMER DATA
       Retroviridae/*ENZYMOLOGY/*ISOLATION & PURIF  Retroviridae
       Infections/DIAGNOSIS/MICROBIOLOGY  Reverse Transcriptase/*BLOOD
       Sensitivity and Specificity  Switzerland  Viremia/MICROBIOLOGY
       Virology/*METHODS/STATISTICS & NUMER DATA  MEETING ABSTRACT

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