on sera from 39,898 blood donors at ight blood centers in ographicll dict areas of the United States. Ten donors (0.025 percent) showed cvidelcc of HLV-I seropositivity by ezme immunoassays; this was firmed by protin immunuoblot and rioimmunoprecipitation. Seoevalce rates rantd from 0 to 0.10 percent at the locations sampled, with HLV-I antbodies found predominantly in donors from the southeasten and southwestern Unitd Stateb. Matched casc-control interviews and laboratory studics werc peroirmed on five seropositive women and two seropositive mcn who participated in an id -linked collection of sera from a subst of 33,893 donors at six ofthe eight blood centers. Four ofthe women and both men are black; one woman is Caca Four Ofthe sv oot inividuals admitted to prior intravenous drug abuse or sexual contact with an intravenous drug user. Sexual contact with native inhatn ofan HTLV-I endemic area was the only idene risk factor for one male. The distribltion of HTLV-I antibdies in this U.S. blood donor sample corroborates the previous reported pde i of this agent and sug that additional donor screning measures, includisg the tetng of donated bkood for HLV-I markr, may be ne to prevent the spead of HTfV-I to transfsion recipets.U.S. IV drug abusers and the unknown prevalence ofinfecton in the general population, there is increasing concem that asymiptomatic HTLV-I carriers may be present at low levels in the U.S. blood donor pool. Although all volunteer blood donors are highly screened by general health history information, specific exdusion criteria for AIDS risk factors, and laboratory tests for HIV-1 antibodies, hepatitis B surface antgen, antibodies to the hepatitis B core antigen, alanine aminotransferase (ALT), and syphilis serology, die efficacy of these measures to exdude HTLV-I carriers is unknown.

AHLE has a fulminant course requiring accurate and rapid diagnosis. Successful therapy requires aggressive management of intracranial pressure and immunosuppression. Two other reports of AHLE document successful management with TPE. Each of these patients survived with minimal neurologic impairments. Given the likely immune-mediated nature of this disease, combined treatment of steroids, surgery, and TPE may lead to shorter hospital stays and improved neurologic outcomes. Clinical studies are needed to further study the effect of TPE on neurologic outcome in AHLE.

To determine whether apparently healthy persons who have had repeatedly reactive enzyme immunoassays and an indeterminate Western blot assay for antibody to the human immunodeficiency virus type 1 (HIV-1) are infected with HIV-1 or HIV-2, we studied 99 such volunteer blood donors in a low-risk area of the country. The subjects were interviewed about HIV risk factors. Coded blood specimens were tested again for HIV-1 antibody (by two different enzyme immunoassays, a Western blot assay and a radioimmunoprecipitation assay) and for HIV-2 antibody by enzyme immunoassay, for HIV-1 by the serum antigen test, for HIV-1 by culture, for human T-cell leukemia virus Type I or II antibody by enzyme immunoassay, and for sequences of HIV DNA by the polymerase chain reaction. Of the 99 blood donors, 98 reported no risk factors for HIV-1 infection; 1 donor had used intravenous drugs. After a median of 14 months (range, 1 to 30) from the time of the initial test, 65 subjects (66 percent) were still repeatedly reactive for HIV-1 antibody on at least one immunoassay. In 91 subjects (92 percent) the Western blot results were still indeterminate, whereas in 8 they were negative. No donor met the criteria for a positive Western blot assay for HIV-1, and none had evidence of HIV-1 or HIV-2 infection on culture or by any other test. We conclude that persons at low risk for HIV infection who have persistent indeterminate HIV-1 Western blots are rarely if ever infected with HIV-1 or HIV-2.

Therapeutic plasma exchange (TPE) without plasma replacement results in coagulation factor removal. Warfarin decreases the activity of vitamin K dependent coagulation factors. The combined effect of TPE and warfarin on the coagulation system has not been studied. A prospective, observational study was conducted in patients undergoing TPE while on warfarin. One plasma volume TPEs were performed on the COBE Spectra Apheresis System (Terumo BCT, Lakewood, CO) with 5% albumin. International normalized ratio (INR), fibrinogen, and factor II activity were obtained pre and post procedure. Eight patients underwent 121 TPEs that met study criteria with pre and post data. The average pre values were INR 2.09 ± 0.58, fibrinogen 263 ± 76 mg/dl, and factor II 29 ± 16% and the average post values were INR 4.12 ± 1.44, fibrinogen 105 ± 31 mg/dl, and factor II 13 ± 7%. The pre-INR was ≥2.00 for 55% of TPEs. The pre value (Y0 ) predicts the post value (Y) by the following equations Y = -0.54 + 2.21Y0 , Y =12.10 + 0.35Y0, and Y =1.83 + 0.39Y0 for INR, fibrinogen, and factor II respectively. In conclusion, pre procedure laboratory values can predict the post laboratory values for patients on warfarin receiving single plasma volume TPE with albumin replacement. The post-INR is approximately twice the pre-INR. At normal and mildly elevated pre-INR, the effect of TPE on the INR is less marked. A single plasma volume TPE decreases the plasma level by ∼65% for fibrinogen and 60% for factor II.