The specificity of enzyme immunoassays for antibodies to human immunodeficiency virus: impact on record and donor management.
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Biomedical subjects
Publications and source records attributed to H V Lamberson.
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We have compared two IgM-specific cytomegalovirus (CMV) antibody assays, an immunofluorescence assay (IFA-M) and an enzyme-linked antigen immunoassay (ELA-M), with an assay for CMV total antibody (ELISA) and viral culture for the detection of active CMV infection in renal transplant recipients. Of 75 patients (49 ELISA negative pretransplant, 26 ELISA positive), CMV-specific IgM was detected in 35 (27 ELISA negative pretransplant, 8 ELISA positive) using the IFA-M assay and in 25 (16 ELISA negative pretransplant, 9 ELISA positive) using the ELA-M test. Of the 25 patients identified as positive by ELA-M, 21 had positive viral cultures post-transplant, two seronegative patients had evidence of infection indicated by post-transplant seroconversion, and two patients were seropositive pretransplant but remained viral culture negative throughout the follow-up period. ELA-M and CMV total antibody ELISA detected primary infection in renal transplant recipients equally well, but ELA-M was found to be superior to ELISA and IFA-M for detecting reinfection and reactivation infections.
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Five hundred blood donors were evaluated for cytomegalovirus (CMV) viruria, antibody to CMV early antigens (EA-ab), CMV seropositivity by two screening assays, and CMV-specific immunoglobulin M by two methods. Three donors were viruric, EA-ab positive, and seropositive; two viruric donors were immunoglobulin M positive.
Antibodies to the membrane antigens of human T-cell lymphotropic virus-I (anti-HTLV-MA) have been detected in patients with the acquired immune deficiency syndrome (AIDS) and in patients with hemophilia. The authors examined sera from 71 AIDS patients and 46 hemophiliac children for the presence of anti-HTLV-MA using an indirect membrane immunofluorescence assay with flow cytometry analysis. Thirty-seven of the 71 (52%) AIDS patients and 7 of the 46 (15%) hemophiliac patients had high titered anti-HTLV-MA, using a T-lymphoid cell line infected with the leukemia virus. None of the 78 control subjects had high titered antibody. All seven hemophiliac patients with elevated anti-HTLV-MA used Factor VIII concentrates, and all had inverted T-lymphocyte helper-suppressor (T4 [Leu-3]/T8 [Leu 2]) ratios. No correlations were found between inverted T4/T8 ratios and antibody to cytomegalovirus, Toxoplasma gondii, or hepatitis B. This work supports contentions that HTLV-like organisms cause AIDS and that these organisms are transmitted by blood products such as Factor VIII concentrate.
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The response of lymphocyte subpopulations to pokeweed mitogen (PWM) was studied in normal volunteers and patients with B-cell chronic lymphocytic leukemia (CLL). Since unfractionated peripheral blood mononuclear (PBM) cells from CLL patients consist of a markedly increased proportion of B-lymphocytes and a decreased proportion of T-lymphocytes, enriched fractions of CLL B-cells and CLL T-cells were cultured in 1:1 proportions in autologous and allogeneic combinations with normal B-cell and T-cell-enriched fractions. Cultures containing normal B-cells with either autologous or allogeneic normal T-cells responded well to PWM. CLL T-cells were capable of providing a helper function for both proliferation and differentiation of normal B-cells, which was not significantly different from that provided by allogeneic normal T-cells. CLL B-lymphocytes were unresponsive to PWM when cultured in the presence of either autologous CLL T-lymphocytes or allogeneic normal T-lymphocytes. The responsiveness of CLL B-cells was not restored by the addition of normal peripheral blood monocytes to the cultures. These experiments indicate that there is an intrinsic B-cell defect which prevents CLL B-lymphocytes from responding to PWM.
Previously the authors demonstrated that most patients with AIDS have serum antilymphocyte antibodies. Therefore, in an attempt to decrease these antibodies and at least transiently increase blood lymphocytes, they treated one AIDS patient with three courses of plasmapheresis. During or after each course, his T4 lymphocytes rose significantly but subsequently fell to baseline values within two weeks after therapy. The increase in T4 lymphocytes was associated with removal of patient plasma rather than infusion of heterologous plasma. These results suggest the need for more investigation into plasmapheresis as adjunct therapy for AIDS.
We have previously reported spuriously elevated values for serum thyrotropin (TSH) measured by immunoradiometric assay (IRMA). We tested those sera showing interference with the TSH assay in a ferritin IRMA which used 125I-rabbit antiferritin antibody and solid phase goat antiferritin antibody as reagents and spleen ferritin as standard. In this assay, we obtained falsely low ferritin values that were corrected by addition of 0.2% non-immune rabbit serum to the labelled antibody. Two other radioimmunoassays gave results with these sera that were not falsely lowered. The interference was shown to be due to human IgG reactive with rabbit serum, the specificity of the interfering antibody being similar in all affected sera. Human antibodies directed against immunoassay reagents may lead to spuriously increased or decreased immunoassay results depending on the specific reagents involved.
Mouse erythrocytes form spontaneous rosettes with a population of B lymphocytes from normal individuals and from patients with B cell chronic lymphocytic leukaemia (CLL). Since lymphocytes from patients with CLL respond poorly to pokeweed mitogen (PWM), we have compared mouse rosette positive (MR+), mouse rosette negative (MR-), and unfractionated B lymphocytes from normal individuals in their response to PWM. Mononuclear cells were fractionated into B, MR+ and MR- cell populations and then combined in 1:1 proportions with mitomycin-C treated T cells in culture media. Lymphocyte co-cultures were incubated for up to 10 days in the presence of PWM. Supernatant immunoglobulin (SIg) levels, percentage intracytoplasmic immunoglobulin (ICIg), and proliferative responses were determined. MR+ cells alone failed to produce significant levels of SIg (P less than 0.025) or percentages of ICIg positive cells This decreased synthesis of immunoglobulin by MR+ cells occurred in the presence of adequate T cells, macrophages and a satisfactory proliferative response.
Biases were compared for eight analytes determined using common chemistry instruments. Data for three levels of liquid control sera were obtained from over 350 laboratories participating in a quality control program. These data were contrasted with comparable results for lyophilized material and reported in a CAP proficiency survey. In general, biases appeared to be proportional to analyte level. For some analytes, biases with liquid material were less than with lyophilized material, but for most analytes, biases were greater with liquid than lyophilized material. However, when liquid material is used for monitoring interlaboratory precision, the consequences of analytic biases are minimized because of large pool sizes.
We previously reported spuriously high values for thyrotropin (TSH), presumably owing to an antibody in human serum that reacts with both reagent rabbit antibodies in an immunoradiometric assay (IRMA). We used this IRMA to measure TSH. Five of 20 sera from laboratory animal handlers showed spuriously high values. When we added 2 mL of nonimmune rabbit serum per liter to the labeled IRMA rabbit antibody reagent and reassayed the five affected specimens, the results were within the reference interval. Smaller additions partly corrected the TSH values, but nonimmune sera of eight other species had no effect. Substitution of goat solid-phase antibody decreased, but did not eliminate, the increases in TSH in three of the five affected sera. Chromatographic properties, results of rheumatoid factor testing, and measurement of human anti-rabbit immunoglobulin suggest that the interference is ascribable to an antibody of the IgG class that reacts with rabbit antibody. Evidently, antibody interference with IRMA procedures may be common in certain populations. It can be avoided by including nonimmune serum corresponding to the species used to produce reagent antibody.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
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Routine cervical cultures for chlamydia were obtained during the third trimester of pregnancy to identify infected mothers whose infants may also be infected. The effectiveness of maternal erythromycin therapy in preventing disease due to chlamydia among infants born to these women was also assessed. Clinical outcome of treated mothers and infants was compared to that of untreated subjects. Of 1082 women who were cultured, 85 (7.8%) were positive for chlamydia. Erythromycin therapy was prescribed for 38 of these women. Nasopharyngeal/conjunctival chlamydia cultures were obtained from 16 infants of culture-positive, treated mothers and 21 infants of culture-positive, untreated mothers. None of the infants born to culture-positive, treated mothers developed infection with chlamydia, while five of 21 infants of untreated mothers (p less than 0.04) were culture-positive and symptomatic (four with conjunctivitis, one with pneumonia). On follow-up of the infants born to chlamydia-positive mothers, there was no evidence that chlamydia-infected infants had more frequent episodes of upper respiratory infection and otitis media during the first six months of life. This study demonstrated that diagnosis and treatment of cervical chlamydia infection during the third trimester of pregnancy provides a practical approach to the prevention of infection in the newborn.