Serodiagnosis and Immunotherapy in Infectious Disease最新文献

The IgG, IgM and IgA antibody responses against the immediate-early, early and late proteins of human cytomegalovirus (HCMV) strain AD169 in sera from HCMV-seropositive subjects and from patients with primary and secondary HCMV infections were studied by immunoblotting. Antibodies against 16 HCMV proteins with molecular masses of 150, 145, 140, 130, 100, 92, 85, 72, 65, 62, 55, 52, 45, 39, 32 and 28 kDa were identified. The antibodies significantly associated with HCMV infection were directed against the 92 and 72 kDa immediate-early gene products, the 130, 62 and 45 kDa early gene products and the 150, 65, 52, 39 and 32 kDa late gene products. Our results also showed that the detection of IgA antibodies against HCMV proteins was as sensitive but less specific than the detection of IgM for the diagnosis of HCMV infections.

This study presents details of four male patients with meningoencephalitis of chronic evolution, probably due to Histoplasma capsulatum. The diagnoses were mainly made by immunodiffusion test (ID), counterimmunoelectrophoresis test (CIF) and complement fixation test (CFT) with specific antigens. In case 1, the diagnosis of histoplasmosis was established through the isolation of H. capsulatum from a cutaneous biopsy and in the other three patients, through the results of serological tests. The neurological changes were those typical of chronic meningitis of basal predominance, with non-purulent cerebrospinal fluid (CSF) and signs of hydrocephaly in three patients. Two patients had other organ involvement which was clinically consistent with histoplasmosis (nose, oral mucosa, lungs, adrenal glands). The four patients were treated with amphotericin B and received fluconazole, itraconazole, cotrimoxazole (TMS) and ketoconazole, in most cases as secondary prophylaxis. Three of the patients presented episodes of valvular obstruction which complicated their clinical courses.

Serum specimens from 58 hospitalized patients with clinical suspicion of dengue fever were obtained in a prospective study. All 58 acute serum samples were tested by IgM capture enzyme-linked immunosorbent assay (ELISA) and commercial Dengue Blot serological assays, virus isolation in C6/36 mosquito cells, and polymerase chain reaction (PCR) by single-step and semi-nested approaches using NS3 gene primers. Of the 22 acute sera positive by any one of the five methods, 17 (77.3%) were positive by IgM capture ELISA, 12 (54.5%) by Dengue Blot, none (0%) by virus isolation, two (9.1%) by single-step PCR and three (13.6%) by the more sensitive semi-nested PCR approach. Dengue virus type 2 was detected by both PCR assays. Convalescent sera were also collected from 13 of the 58 patients and haemagglutination inhibition (HI) tests performed on paired serum samples. HI confirmed five positive sera, while the other eight sera were negative or inconclusive. In our study cohort, although PCR was more sensitive than virus isolation for detecting the presence of dengue virus in sera, serological techniques were able to identify more dengue infections than both PCR and virus isolation. These results may be attributed to the collection of serum samples after the period of viraemia which is appropriate for serological assays, in contrast to early or highly viraemic sera which are more suitable for PCR and virus isolation methods.

Medical laboratory scientists who had agreed to participate in an evaluation which required them to measure the level of anti-HBs in a panel of sera, were given a brief clinical scenario for seven of the results and asked to comment on the person's immune status. The interpretations of immune status were assessed against the matters considered by the authors to reflect the current state of knowledge about immunity to hepatitis B and recommendations from authorities. There were a number of common but not universal misconceptions in the interpretation of results and current guidelines, particularly regarding appropriate use of hepatitis B immune globulin (HBIG), equating the absence of anti-HBs in a previous seroconverter with no immunity or the need to institute a new course of vaccination, and inappropriate recommendations for further testing or retesting. Given that the cost of serology for anti-HBs now exceeds the cost of three doses of vaccine, more effective and rational testing of immune status to hepatitis B is required.

A dichromatic latex agglutination test was employed to measure antibodies to Toxoplasma gondii in 160 sera. Reactions were deemed negative, weak positive, positive or strong positive on the basis of rapidity of agglutination and/or colour change. This semiquantitative determination agreed well with antibody titres measured by immunofluorescence.

Sera or plasma from 52 blood donors, initially reactive by Ortho HCV EIA 2.0 were tested by other immunoassays (Abbott HCV EIA, UBI HCV EIA and Innotest HCV EIA). Positivity was confirmed by confirmatory assays (RIBA 2.0 or RIBA 3.0 and Inno-LIA or Inno-LIA III); hepatitis C virus (HCV) RNA was detected by reverse transcription nested polymerase chain reaction (RT-nested PCR). Forty-four (84.6%) were repeatedly positive by Ortho, 41 (78.8%) by Abbot, 37 (71.2%) by Innotest and 36 (69.2%) by UBI. When tested for RIBA 2.0, 35 (67.3%) were positive. Only 26 sera (50%) were positive for HCV RNA. None of the Innotest or UBI negative sera were positive for HCV RNA nor for confirmatory tests. UBI and Innotest seem more reliable for detection of antibodies against HCV, and combined application of anti-HCV immunoblot assay and HCV RNA detection by PCR is required for confirmation of HCV infection.

A sandwich antigen capture assay using a double monoclonal antibody system revealed the presence of lipoarabinomannan (LAM) antigen in about 25% of the serum samples in subjects with pulmonary tuberculosis and tuberculoid leprosy. Lepromatous leprosy sera showed about 40% antigen positivity. Anti-LAM antibodies could be detected in about 90% of subjects with pulmonary tuberculosis and lepromatous leprosy. However in tuberculoid leprosy sera anti-LAM antibodies were positive in only 22% of the patients. Antigen and antibody levels in pulmonary tuberculosis and lepromatous leprosy declined steadily during anti-mycobacterial therapy, whereas in the tuberculoid type leprosy a distinct increase in antibody positivity was noticed. The high percentage of anti-LAM antibodies in pulmonary tuberculosis subjects may be of diagnostic significance.