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Biomedical subjects

A C Hekker

Publications and source records attributed to A C Hekker.

At least 19 recordsLinked to original sources
PubMed1989

An enzyme immunoassay to detect specific antibodies to protein and lipopolysaccharide antigens of Chlamydia trachomatis.

We have developed an enzyme immunoassay to measure antibodies to the proteins and lipopolysaccharide (LPS) of Chlamydia trachomatis. Antibodies to proteins could be differentiated from antibodies to lipopolysaccharide (LPS) by treatment of the antigen with periodate or Triton X-100. Some important parameters of the oxidation by periodate were studied by comparing the response of several monoclonal antibodies. Four types of response could be observed: type I, a reduced response after mild or strong oxidation; type II, a normal response after mild oxidation, but reduced after strong oxidation; type III, not affected; type IV, an increased response after oxidation. Treatment with Triton X-100 had the same effect as mild oxidation and confirmed the response types I, III, and IV. Treatment of antigen with periodate reduced the IgG response measured in sera from patients with evidence of Chlamydia psittaci infection.

Antibodies, Bacterial↗
PubMed1987

Herpes-virus immunity and acute graft-versus-host disease.

The influence of pretransplant herpes-virus antibodies in 126 marrow-graft recipients and their HLA-identical (A, B, C, DR) sibling donors on the incidence of grades II-IV acute graft-versus-host disease (GVHD) was studied in relation to previously reported risk factors for GVHD. Logistic regression procedures were used to control for confounding factors. Increasing donor age (odds ratio 3.7 per decade; p = 0.02) and donor seronegativity for Epstein-Barr virus (EBV; odds ratio 10.1; p = 0.005) were associated with a high incidence of GVHD. Total rather than selective gastrointestinal decontamination (odds ratio 0.1; p = 0.004), donor seronegativity for herpes simplex virus (HSV; odds ratio 0.1; p = 0.003), and recipient EBV-seronegativity (odds ratio 0.05; p = 0.002) were associated with a low incidence of GVHD. Pretransplant EBV and HSV serology may thus contribute substantially to the estimation of the risk for GVHD.

Acute Disease↗
PubMed1987

Effects of herpes virus carrier status on peripheral T lymphocyte subsets.

We studied the effects of herpes virus carrier status on peripheral blood T lymphocyte subsets in 334 healthy individuals. IgG-class antibodies against cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV), and varicella-zoster virus (VZV) were used as markers for the carrier status of those viruses. CMV carrier status was associated with significant increases in the numbers of some T cell subsets, whereas the carrier status of EBV, HSV, and VZV had no significant effects. The 159 CMV-seropositive individuals had higher numbers of HNK1+ T cells than did the 175 CMV-seronegative individuals [mean (SD), 292 (196)/microL v 164 (89)/microL, respectively], including the CD4+HNK1+ T cells [38 (48)/microL v 9 (13)/microL, respectively] and the CD8+HNK1+ T cells [166 (146)/microL v 73 (54)/microL, respectively]. Morphological and cytochemical studies showed that the expression of HNK1 by the CD4+ and CD8+ T cells was associated with the occurrence of azurophilic cytoplasmatic granules and a loss of nonspecific esterase activity. The numbers of CD4+HNK1+ and CD8+HNK1+ T cells increased proportionally to the levels of the IgG-class CMV antibody titers. We suggest that the increased numbers of CD4+HNK1+ and CD8+HNK1+ granular T cells in CMV carriers reflect the persistent interaction between CMV and the immune system of its hosts.

Age Factors↗
PubMed1987

Marrow donor immunity to herpes simplex virus: association with acute graft-versus-host disease.

The interactions between humoral and cellular immunity to herpes simplex virus (HSV) in bone marrow donors, the occurrence of active HSV infections, and the development of grades II-IV acute graft-versus-host disease (GVHD) in their HLA-A,B,C,DR-identical sibling recipients were studied. The absence of IgG-class HSV antibodies in the marrow donors was associated with a low incidence of GVHD: 38 of 53 recipients (72%) of marrow from HSV-seropositive donors developed GVHD versus only two of 15 recipients (13%) with HSV-seronegative donors (p = 0.0004). The cellular immunity to HSV was studied in vitro by evaluating the degree of lymphocyte proliferative responses to that virus and was also significantly associated with GVHD: 30 of 43 recipients (70%) of marrow from donors with a positive test developed GVHD versus 10 of 25 recipients (40%) of marrow from donors with a negative test (p = 0.03). The previously reported risk for GVHD attributed to donor CMV antibodies increased the risk of GVHD due to donor HSV antibodies. Of 31 recipients of marrow from donors who were both HSV- and CMV-seropositive, 27 (85%) developed GVHD versus 11 of 22 recipients (50%) of marrow from HSV-seropositive but CMV-seronegative donors (p = 0.008).

Adolescent↗
PubMed1986

Evaluation of six enzyme immunoassays for antibody against human immunodeficiency virus.

Six commercial enzyme immunoassays (EIA) were evaluated in 6488 serum samples, with immunoblot analysis as the confirmatory test for antibodies against human immunodeficiency virus (HIV). The Abbott and Wellcome tests identified all 163 immunoblot-positive samples correctly, whereas the other tests did not detect 1-3 samples. In AIDS patients (predominantly with antibodies to gp41env) Organon's EIA was less sensitive (p less than 0.05) and Wellcome's more sensitive (p less than 0.05) than the immunoblot assay. In symptom-free anti-HIV-positive subjects (antibodies to almost all viral antigens and high titres of anti-p24gag) all the EIA were significantly (p less than 0.05) less sensitive than the immunoblot assay. The frequencies of false-positive reactions in a "tricky" panel of samples from patients with autoimmune and acute viral diseases and in a blood-donor panel were Abbott 9.5%, 0.42%: Organon 1.7%, 0%; Litton 1.0%, 0.4%; Behring 2.7%, 0.06%; Wellcome 0%, 0%; and Pasteur 0%, 0.02%. The results of a seventh EIA (Dupont) were excluded from the study at the company's request. All six EIA evaluated are suitable tests for anti-HIV screening in samples from patients and blood donors.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Acquired immunodeficiency syndrome in Rwanda.

To evaluate acquired immunodeficiency syndrome (AIDS) in central Africa a prospective study was done in Kigali, Rwanda, where Kaposi's sarcoma (KS) is endemic. During a 4 week period, 26 patients (17 males and 9 females) were diagnosed. 16 patients had opportunistic infections, associated with KS in only 2; 1 had multifocal KS alone; and 9 had clinical conditions consistent with prodromes of AIDS. All patients had severe T-cell defects characterised by cutaneous anergy, a striking decrease in the number of helper T cells, and a decreased OKT4:OKT8 ratio (mean 0.27). 21 of the 22 adult patients were living in urban centres and many of them were in the middle to upper income bracket. Most of the men were promiscuous heterosexuals and 43% of the females were prostitutes. No patient had a history of homosexuality, intravenous drug abuse, or transfusion in the previous 5 years. This study suggests that AIDS is present in central Africa as an entity probably unrelated to the well-known endemic African KS. An association of an urban environment, a relatively high income, and heterosexual promiscuity could be a risk factor for AIDS in Africa.

Acquired Immunodeficiency Syndrome↗
PubMed1979

Indirect immunofluorescence test for detection of IgM antibodies to cytomegalovirus.

A technique for the detection of IgM antibodies to cytomegalovirus (CMV) by immunofluorescence was developed. In order to prevent interference by rheumatoid factor in the sera, IgG was removed by prior immunoabsorption with antiserum to gamma Fc. Sera from 63 patients with a rise in titer of antibody to CMV, indicated by complement fixation, were IgM-positive, but yielded negative results on the Paul-Bunnell-Davidsohn test for infectious mononucleosis. Convalescent-phase serum samples from 20 patients with a seroconversion to herpes simplex virus and from 20 patients with a seroconversion to varicella-zoster virus also had no IgM antibodies to CMV. Sera from six of 10 patients with infectious mononucleosis and two of 100 normal blood donors were positive for IgM antibodies to CMV. In 38 of 63 patients, the diagnosis of CMV infection could be made several weeks earlier by the immunofluorescence test than by the complement-fixation test. IgM antibodies to CMV persisted for more than two months after onset of symptoms of the infection.

Antibodies, Viral↗
PubMed1976

Large-scale use of freeze-dried smallpox vaccine prepared in primary cultures of rabbit kidney cells.

A lyophilized smallpox vaccine made from infected monolayer cultures of primary rabbit kidney cells was used together with a calf lymph vaccine in a field trial in Lombok, Indonesia, in 1973. About 60 000 children below 15 years of age were vaccinated: some 50 000 with the tissue culture vaccine and about 10 000 with calf lymph vaccine. Similar results were obtained with both vaccines in primary vaccinees and in revaccinees as regards the take rate, pock reactions, and serious secondary reactions.

Adolescent↗