Cynthia A. Heynen

Seroprevalence of GB virus C and persistence of RNA and antibody

Exposure to GB virus C (GBV‐C) was determined in several U.S. populations by both reverse‐transcription‐polymerase chain reaction (RT‐PCR) and by an enzyme linked immunosorbent assay (ELISA) for antibodies to mammalian cell‐expressed GBV‐C envelope protein, E2 (GBV‐C E2). Most individuals exposed to GBV‐C were either RNA positive/ELISA negative or ELISA positive/RNA negative. Exposure, therefore, was measured as the sum of GBV‐C RNA positive and GBV‐C E2 antibody positive specimens, and was higher in commercial plasmapheresis donors (40.5%) than in volunteer blood donors (5.5%). In intravenous drug users (IVDUs), GBV‐C exposure was 89.2%. Serial bleed specimens tested for GBV‐C RNA indicate that some patients remain viremic for at least 3 years and fail to produce detectable antibodies to GBV‐C E2. In other exposed individuals who tested negative for GBV‐C RNA, antibodies to E2 appear to be similarly long‐lived (greater than 3 years) with a fairly constant titer (ranging in reciprocal endpoint dilution from 336 to 21,504). Since the detection of GBV‐C RNA and GBV‐C E2 antibody are mutually exclusive in most exposed individuals, studies pertaining to incidence and prevalence of GBV‐C infection require both antibody and nucleic acid detection. J. Med. Virol. 53:167–173, 1997.

Hepatitis C infection in potential recipients with normal liver biochemistry does not preclude renal transplantation

The hepatitis C virus (HCV) may be an important cause of chronic liver disease in renal transplant recipients. We investigated retrospectively the incidence and outcome of HCV infection in long-term renal transplant recipients and patients on hemodialysis. Stored, pretransplant sera of transplant recipients with normal liver biochemistry at surgery were tested for hepatitis C by a second-generation enzyme immunoassay. Hemodialysis patients were tested by a first-generation enzyme-linked immunosorbent assay (ELISA) against c100-3. We studied 252 renal transplant recipients and 58 hemodialysis patients followed for 65±10 months and 26±6 months, respectively. Fifteen percent (38/252) of the transplant recipients were HCV positive as were 3/58 (5%) of the hemodialysis patients. Over liver disease occurred in 22/252 (8.7%) transplant recipients and none in the hemodialysis group. Thirty-six percent (8/22) of transplant recipients with overt liver disease were HCV positive. No HCV-positive patients died of liver failure. Of six biopsies in the HCV-positive transplant group, two had histological evidence of CAH. CAH was seen in six of eight biopsies in the HCV-negative transplants and two of these latter patients progressed to cirrhosis. No hemodialysis patients had clinical or histological evidence of chronic liver disease. Two HCV-negative transplant patients died of liver failure, while no deaths related to liver disease occurred in hemodialysis patients regardless of HCV status. We conclude that hepatitis C may cause chronic hepatitis in renal transplant patients. However, chronic liver disease in HCV-positive renal transplant recipients appears to be a clinically and histologically benign entity. HCV-positive potential renal allograft recipients with normal liver biochemistry should not be excluded from renal transplantation.

Frequency of cells positive for HIV-1 p24 antigen assessed by flow cytometry

ObjectiveMarkers of HIV disease progression such as soluble p24 antigen detection and CD4 lymphocyte depletion are most useful in the later stages of HIV disease and are relatively insensitive as therapeutic monitors. Flow cytometric detection of HIV-1 replication in CD4 lymphocytes was evaluated for use as a marker in predicting disease progression earlier in the course of HIV disease. DesignTo determine whether the number of HIV-1-infected CD4 cells, as measured by p24 antigen detection, can be correlated with disease progression, we used flow cytometry to detect intracellular HIV-1 p24 in CD4 lymphocytes from HIV-1-seropositive subjects at all stages of HIV disease. MethodsMononuclear cells from HIV-1-seropositive subjects and uninfected control subjects were permeabilized and stained with anti-HIV-1 p24 monoclonal antibodies. The cells were then stained with a fluorescein isothiocyanate-conjugated goat antimurine immunoglobulin G followed by a phycoerythrin-conjugated monoclonal anti-CD4 antibody. The percentage of p24-positive CD4 lymphocytes was compared with absolute CD4 counts, soluble p24 detection and Walter Reed classification. ResultsCD4 lymphocyte absolute counts and the percentage of CD4 lymphocytes declined as the Walter Reed classification indicated disease progression. The mean percentage of p24 antigen-positive CD4 lymphocytes increased with disease progression. Only 30% of Walter Reed stage 6 subjects were soluble p24 antigen-positive, whereas 68% were cellular p24 antigen-positive. ConclusionThe percentage of p24 antigen-positive CD4 lymphocytes increased as HIV disease progressed. Flow cytometric quantitation of p24 antigen-positive CD4 cells is a useful method of monitoring in vivo HIV replication and disease progression.

Seroprevalence of HTLV-I/II and HIV-1 Infection Among Male Intravenous Drug Abusers in Chicago

Summary:We surveyed for serologie evidence of either HIV-1 or HTLV-I/II infection in 387 male veterans who entered into an inpatient drug treatment center. Serum was obtained after receiving written informed consent. Serum specimens were tested by enzyme-linked immunosorbent assay for antibody to HIV-1 and for antibody to HTLV-I/II; sera that were repeatedly reactive were then tested by Western blot (HIV-1/HTLV-I/II) and radioimmunoprecipitation assay (HTLV-I/II). Sixty-five of 387 (16.79%) patients were tested and confirmed as positive for HTLV-I/II only antibodies and 30 of the 387 (7.75%) were positive for HIV-1 only antibodies. An additional nine patients (2.32%) were seropositive for antibodies to both viruses. A statistically significant difference in the CD4/CD8 lymphocyte ratio was associated with HIV-1 sero-positivity. HTLV-I/II seropositivity was strongly associated with black race, age, and duration of i.v. drug use, but not with sexual intercourse as determined by lifetime history of number of sexual partners, incidence of sexually transmitted diseases, type of drug used, or needle-sharing practices.