Clinical and diagnostic laboratory immunology, 1995
Blood is filtered for selective removal of leukocytes (WBC) to reduce the immunological and virol... more Blood is filtered for selective removal of leukocytes (WBC) to reduce the immunological and virological risks of transfusion. Exceedingly low numbers of residual WBC in leukodepleted blood cannot be enumerated by conventional hematologic methods. Therefore, we investigated the application of a DNA enzyme immunoassay (DEIA) for detecting a region of the HLA-DQ alpha gene following amplification by PCR. After hybridization with a specific probe coated onto the wells of a microtiter plate, the PCR-amplified DNA was detected by adding monoclonal antibodies to double-stranded DNA, enzyme tracer, and chromogen substrate for colorimetric measurement. The sensitivities of DEIA and radioisotopic liquid hybridization were similar in five sets of experiments performed with a known number of human WBC. The optical density and the number of spiked human WBC in the range of 1.0 to 0.05 cells per microliter showed good correlation in five calibration experiments performed with human WBC suspended ...
To evaluate the risk of transmitting blood-borne GB virus C/hepatitis G virus (GBV-C/HGV) and to ... more To evaluate the risk of transmitting blood-borne GB virus C/hepatitis G virus (GBV-C/HGV) and to define the natural course of infection, we performed a prospective study in a cohort of multitransfused β-thalassemics during a 6-year follow-up period. We analyzed serum samples of 150 patients collected at 3-year intervals from 1990 to 1996. GBV-C/HGV RNA was determined by reverse transcriptase-polymerase chain reaction and antibodies to E2-protein by an enzyme immunoassay. At baseline, 14.5% of patients had viremia and 18.5% anti-E2. None of the patients with anti-E2 in 1990 subsequently became viremic. Of the 100 GBV-C/HGV RNA−, anti-E2− patients, 10 acquired infection during follow-up, as indicated by positivity of GBV-C/HGV RNA (n = 2), anti-E2 (n = 7), or both markers (n = 1) in 1996. The incidence was 1.7 per 100 person-years (95% confidence interval [CI], 0.8 to 3). Since approximately 19,000 blood units were transfused to these patients during follow-up, the risk of infection w...
Sexual transmission of hepatitis C virus (HCV) can occur, albeit inefficiently, and this represen... more Sexual transmission of hepatitis C virus (HCV) can occur, albeit inefficiently, and this represents a possible cause of community-acquired infections. This study describes a case of asymptomatic HCV infection acquired by a repeat blood donor from her sexual partner. A female repeat blood donor showed anti-HCV seroconversion and a slight elevation in alanine aminotransferase. She had a normal physical examination and no clinical symptoms. She admitted a sexual partnership with a man with chronic HCV infection. Genotyping showed subtype 3a infection in both. Nucleotide sequence analysis of the hypervariable region of the viral envelope was performed on five clones obtained from the donor and the partner. Five blood donors with subtype 3a infection were analyzed as controls. The mean homology among clones was 99.3 percent (95% CI, 98.9-99.7) in the donor and 96.8 percent (95% CI, 94.4-99.2) in the partner, which suggests a more recent infection in the woman. The mean homology between donor and partner was 93.4 percent (95% CI, 93.1-93.8), which is different from that between donor and controls (76.2%; 95% CI, 73.3-79.1; difference between means, 17.2%; 95% CI, 16.0-18.4). This suggests that the infection was transmitted to the donor from her sexual partner. Sexual intercourse is the most probable route of transmission, because parenteral risk factors were absent. Heterosexual transmission of HCV can occur in the absence of a long-lasting contact, and the infection can be asymptomatic. It remains to be determined whether the sexual partners of HCV-infected subjects should be deferred from blood donation.
The clinical significance of single band reactivity (indeterminate pattern) at anti-hepatitis C v... more The clinical significance of single band reactivity (indeterminate pattern) at anti-hepatitis C virus (HCV) second-generation recombinant immunoblot assay (RIBA-2) was investigated in symptomless subjects with normal liver function tests to obtain data for their counseling and clinical management. Serum and hepatic HCV RNA were determined by the nested polymerase chain reaction, and liver histology was evaluated in 40 symptomless blood donors with stable indeterminate RIBA-2 pattern, including 38 reactive to c22-3. All but one had normal alanine aminotransferase (ALT) levels. Two new immunoblot tests, RIBA-3 and INNO-LIA HCV Ab III (LIA-III), which incorporate additional HCV antigens, were also done to assess whether they could identify the viremic subjects. Ten cases (25%, confidence interval 12 to 38) were HCV RNA positive. Three of the HCV RNA-positive and none of the HCV RNA-negative subjects had chronic hepatitis. RIBA-2 strong intensity of reaction (score > 2+) was observed in all the HCV RNA-positive and in 12 HCV RNA-negative subjects. RIBA-3 and LIA-III gave positive results in 9 of 10 and 10 of 10 HCV RNA-positive, but also in 8 of 30 and 24 of 30 HCV RNA-negative subjects. A c-22-3 reactivity score of 4+ by RIBA-3 and E2/NS1 reactivity by LIA-III were both strongly associated with HCV RNA (P < .001). Based on relatively high prevalence of chronic hepatitis in our series (30%), apparently healthy subjects with stable indeterminate RIBA-2 pattern and HCV RNA positivity should be considered for liver biopsy independently of ALT profile.(ABSTRACT TRUNCATED AT 250 WORDS)
Clinical and diagnostic laboratory immunology, 1995
Blood is filtered for selective removal of leukocytes (WBC) to reduce the immunological and virol... more Blood is filtered for selective removal of leukocytes (WBC) to reduce the immunological and virological risks of transfusion. Exceedingly low numbers of residual WBC in leukodepleted blood cannot be enumerated by conventional hematologic methods. Therefore, we investigated the application of a DNA enzyme immunoassay (DEIA) for detecting a region of the HLA-DQ alpha gene following amplification by PCR. After hybridization with a specific probe coated onto the wells of a microtiter plate, the PCR-amplified DNA was detected by adding monoclonal antibodies to double-stranded DNA, enzyme tracer, and chromogen substrate for colorimetric measurement. The sensitivities of DEIA and radioisotopic liquid hybridization were similar in five sets of experiments performed with a known number of human WBC. The optical density and the number of spiked human WBC in the range of 1.0 to 0.05 cells per microliter showed good correlation in five calibration experiments performed with human WBC suspended ...
To evaluate the risk of transmitting blood-borne GB virus C/hepatitis G virus (GBV-C/HGV) and to ... more To evaluate the risk of transmitting blood-borne GB virus C/hepatitis G virus (GBV-C/HGV) and to define the natural course of infection, we performed a prospective study in a cohort of multitransfused β-thalassemics during a 6-year follow-up period. We analyzed serum samples of 150 patients collected at 3-year intervals from 1990 to 1996. GBV-C/HGV RNA was determined by reverse transcriptase-polymerase chain reaction and antibodies to E2-protein by an enzyme immunoassay. At baseline, 14.5% of patients had viremia and 18.5% anti-E2. None of the patients with anti-E2 in 1990 subsequently became viremic. Of the 100 GBV-C/HGV RNA−, anti-E2− patients, 10 acquired infection during follow-up, as indicated by positivity of GBV-C/HGV RNA (n = 2), anti-E2 (n = 7), or both markers (n = 1) in 1996. The incidence was 1.7 per 100 person-years (95% confidence interval [CI], 0.8 to 3). Since approximately 19,000 blood units were transfused to these patients during follow-up, the risk of infection w...
Sexual transmission of hepatitis C virus (HCV) can occur, albeit inefficiently, and this represen... more Sexual transmission of hepatitis C virus (HCV) can occur, albeit inefficiently, and this represents a possible cause of community-acquired infections. This study describes a case of asymptomatic HCV infection acquired by a repeat blood donor from her sexual partner. A female repeat blood donor showed anti-HCV seroconversion and a slight elevation in alanine aminotransferase. She had a normal physical examination and no clinical symptoms. She admitted a sexual partnership with a man with chronic HCV infection. Genotyping showed subtype 3a infection in both. Nucleotide sequence analysis of the hypervariable region of the viral envelope was performed on five clones obtained from the donor and the partner. Five blood donors with subtype 3a infection were analyzed as controls. The mean homology among clones was 99.3 percent (95% CI, 98.9-99.7) in the donor and 96.8 percent (95% CI, 94.4-99.2) in the partner, which suggests a more recent infection in the woman. The mean homology between donor and partner was 93.4 percent (95% CI, 93.1-93.8), which is different from that between donor and controls (76.2%; 95% CI, 73.3-79.1; difference between means, 17.2%; 95% CI, 16.0-18.4). This suggests that the infection was transmitted to the donor from her sexual partner. Sexual intercourse is the most probable route of transmission, because parenteral risk factors were absent. Heterosexual transmission of HCV can occur in the absence of a long-lasting contact, and the infection can be asymptomatic. It remains to be determined whether the sexual partners of HCV-infected subjects should be deferred from blood donation.
The clinical significance of single band reactivity (indeterminate pattern) at anti-hepatitis C v... more The clinical significance of single band reactivity (indeterminate pattern) at anti-hepatitis C virus (HCV) second-generation recombinant immunoblot assay (RIBA-2) was investigated in symptomless subjects with normal liver function tests to obtain data for their counseling and clinical management. Serum and hepatic HCV RNA were determined by the nested polymerase chain reaction, and liver histology was evaluated in 40 symptomless blood donors with stable indeterminate RIBA-2 pattern, including 38 reactive to c22-3. All but one had normal alanine aminotransferase (ALT) levels. Two new immunoblot tests, RIBA-3 and INNO-LIA HCV Ab III (LIA-III), which incorporate additional HCV antigens, were also done to assess whether they could identify the viremic subjects. Ten cases (25%, confidence interval 12 to 38) were HCV RNA positive. Three of the HCV RNA-positive and none of the HCV RNA-negative subjects had chronic hepatitis. RIBA-2 strong intensity of reaction (score > 2+) was observed in all the HCV RNA-positive and in 12 HCV RNA-negative subjects. RIBA-3 and LIA-III gave positive results in 9 of 10 and 10 of 10 HCV RNA-positive, but also in 8 of 30 and 24 of 30 HCV RNA-negative subjects. A c-22-3 reactivity score of 4+ by RIBA-3 and E2/NS1 reactivity by LIA-III were both strongly associated with HCV RNA (P < .001). Based on relatively high prevalence of chronic hepatitis in our series (30%), apparently healthy subjects with stable indeterminate RIBA-2 pattern and HCV RNA positivity should be considered for liver biopsy independently of ALT profile.(ABSTRACT TRUNCATED AT 250 WORDS)
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