Dennis Piszkiewicz

INACTIVATION OF HTLV-III/LAV DURING PLASMA FRACTIONATION

The authors present the results of studies on the stability of human T-lymphotropic virus type III (HTLV-III) infectivity to ethanol. In the 1st experiment the residual infectivity of HTLV-III seeded into RPMI-1640 medium or plasma and exposed to ethanol for 10 minutes was measured. In 1 single-donor plasma sample at -23 degrees C infectivity was reduced 10(2)-fold whereas in 3 samples at -5 degrees C infectivity was reduced by 10(2.7) and 10(0.7) in 2 and not reduced in the 3rd sample. In contrast infectivity in medium at 23 degrees C was reduced 10(3)-fold. These results suggest that HTLV-III is more stable to 20% ethanol in plasma than in medium. Some characteristic of the plasma possibly lipid content or protein composition can stabilize the virus to ethanol. Lower temperatures may also stabilize the virus. The 2nd experiment was designed to simulate the precipitation of fractions I+II+III by 20% ethanol at pH 6.9 and -5 degrees C as in a common manufacturing procedure. Samples seeded with HTLV-III were drawn periodically after addition of ethanol to a final concentration of 20% then immediately diluted 1:10 in RPMI-1640 medium and frozen to stop the inactivation. Virus in the control plasma (no ethanol) lost very little infectivity over a 2-hour period while infectivity fell more than 10(3.5) in 5 minutes in an identical sample containing 20% ethanol. Compared with a pH 7 control infectivity was reduced 10(3)-fold in 10 minutes at pH 5.7. These findings indicate that steps in large scale plasma fractionation especially ethanol at -5 degrees C and low pH reduce the risk of infected plasma products.

Immunoglobulin a concentrations in commercial immune globulins

Commercial immune globulins contain varying concentrations of IgA as a minor constituent. For patients who are both IgA deficient and IgA hypersensitive, the administration of most immune globulins is contraindicated due to potentially lethal anaphylactic reactions. We have measured the IgA levels in a broad range of commercial immune globulin preparations by means of a competitive-binding solid-phase radioimmunoassay. Of the products tested, all immune globulins intended for intramuscular administration and most immune globulins for intravenous use had IgA levels of over 150 µg/ml. Only two of the intravenous products had IgA concentrations in the range of 10 µg/ml or less.

Inactivation and removal of human immunodeficiency virus in monoclonal purified antihemophilic factor (human) (hemofil®m)

Cold supernatant which was prepared from factor VIII:C containing cryoprecipitate was seeded with HIV-1, then treated with a mixture of tri (n-butyl) phosphate (TNBP) and triton X-100. A greater than 10(11)-fold reduction of HIV-1 infectivity was observed. In a separate experiment, cold supernatant which had been seeded with HIV-1 was chromatographed on an immunoaffinity column, resulting in a 10(4)-fold reduction of infectivity. None of the 17 patients treated with the purified product and followed for at least three months has shown serologic evidence of HIV-1 or other viral infections.

Inactivation of HIV in antithrombin-III concentrate by pasteurization

osmotic lysis. We obtained results by this method that are the reverse of the (direct) urea lysis test, i.e., no lysis of Jk3 but lysis of Jk-3 red cells. These results are not consistent with the conclusion of Edwards-Moulds and Kasschau.3 in that impairment of urea transport in Jk:-3 red cells is clearly implicated. This latter method also has been adapted to a microplate method that we call the reversed urea lysis test (Table 1). This test has an advantage over the direct test in that the results do not change with extended incubation in the urea solution. Over a 2-year period we have tested a totalof 52.908 blood donor samples by both urea lysis methods without finding a Jk-3 blood. However, six different, known Jk-3 samples were tested blind during this period and gave the expected results. DOUGLAS C. J. MCDOUGALL, FIMLS, MSc MARTIN MCGREGOR. FIMLS Nor th-h t Thames Regwwl Transfuswn Centre Crescent Drive B r e n t w d Errex, CM15 8DR England

Effect of screening for antibody to the human immunodeficiency virus and alanine aminotransferase on antibody content of intravenous immune globulin

when papain pretreated red cells were used. Bartholomew et al.’ tested dextran 40 (Rheomacrodex, Pharmacia AB) at dextran concentrations of 2.5 to 12.1 mg per ml and reported no problems using enzyme-treated red cells. This finding suggests that the molecular weight of the dextran determines its effect on enzyme-treated red cells, although some earlier reports di~agree.~ When evaluating the effect of dextrans on compatibility testing, several points need consideration. Are “enzymeonly” antibodies clinically significant? Routine tests with enzyme-treated red cells are seldom performed in US blood banks. Further, antibody screening tests using enzymetreated red cells may soon be replaced by methods using new potentiators such as polybrene or polyethylene glycol (PEG). These new low-ionic-strength methods use untreated red cells and are thus unlikely to be affected by dextrans. Indeed, no problems were encountered with the PEG technique in preliminary experiments using blood samples containing 18 mg per ml of dextran. GUY GODWIN, BSC, FIMLS Blood Bank Westminster Hospital Dean Ryle Street London, UK