Comparación de adenosina deaminasa y detección de anticuerpos anti-antígeno A60 para el diagnóstico de meningitis tuberculosa / A comparative study for adenosine deaminase and anti-antigen A-60 antibodies detection for the diagnosis of tuberculous meningitis

Background: Diagnosis of tuberculous meningitis (TBM) is hampered by the lack of rapid and accurate diagnostic tools. We evaluated the immunological response to Mycobacterium tuberculosis anti-A60 antibodies in cerebrospinal fluid (CSF) in comparison to adenosine deaminase (ADA) determination, for the diagnosis of TBM. Methods: A total of 63 CSF samples were analyzed by indirect ELISA for the detection of anti- A60 IgG, IgM and IgA. These include samples from 17 patients with confirmed TBM and 46 control patients with other infections. Results: The mean individual anti-A60 IgM, IgG and IgA CSF antibody titers were significantly higher in TBM in comparison with control groups (p < 0.01). The best discriminatory CSF antibody for confirming TBM diagnosis was IgM, with an area under the receiver operating characteristic curve of 0.928 (95%CI 0.834-0.978), compared to 0.863 (95% CI: 0.752-0.936) for ADA testing (p = NS). The sensitivity of anti- A60 IgM CSF antibody titers (cutoff > 0.06 U/ml) was 94.1% compared to 88.2% for ADA (cutoff > 6.2 U/ml), p = NS. Both anti A60 IgM and ADA showed the same moderate specificity (80.4%). Two cases of TBM were correctly identified by anti-A60 IgM but missed by ADA. Conclusion: The ELISA test for anti-antigen A60 antibodies (IgM) is a rapid and sensitive tool for the rapid diagnosis of TBM that can be a complement to ALDA determination. The specificity of both tests is still a limitation in TBM diagnosis.

Antecedentes: El diagnóstico de meningitis tuberculosa (MTBC) se ve limitado por la ausencia de técnicas diagnósticas rápidas y precisas en líquido cefalorraquídeo (LCR). En este estudio evaluamos la respuesta inmunoló-gica de anticuerpos anti-antígeno A60 de Mycobacterium tuberculosis en LCR en comparación a la determinación de adenosina deaminasa (ADA). Métodos: Un total de 63 muestras de LCR fueron estudiadas mediante ELISA indirecto para detección de IgG, IgM e IgA anti-A60. Estas muestras incluyeron 17 casos de MTBC confirmada y 46 controles con otras infecciones. Resultados: Los títulos de IgG, IgM e IgA anti A-60 resultaron significativamente superiores en casos de MTBC versus controles (p > 0,01). El anticuerpo con mej or poder discriminatorio resultó IgM, con un área bajo la curva ROC de 0,928 (95%IC 0,8340,978), comparado a 0,863 (95% IC: 0,752-0,936) para ADA (p = NS). La sensibilidad de IgM anti-A60 (nivel de corte > 0,06 U/ml) fue de 94,1% versus 88,2% para ADA (nivel de corte > 6,2 U/ml), p = NS. Ambos IgM anti-A60 y ADA presentaron la misma especificidad baja-moderada (80,4%). Dos casos de MMTBC fueron correctamente identificados por IgM anti-A60 pero no por ALDA. Conclusión: La detección de anticuerpos anti-A60 (IgM) puede ser de ayuda en el diagnostico de MTBC en forma complementaria a la determinación de ALDA. La baja especificidad de ambos tests constituye su principal limitante.

[A comparative study for adenosine deaminase and anti-antigen A-60 antibodies detection for the diagnosis of tuberculous meningitis]. / Comparación de adenosina deaminasa y detección de anticuerpos anti-antígeno A60 para el diagnóstico de meningitis tuberculosa.

BACKGROUND: Diagnosis of tuberculous meningitis (TBM) is hampered by the lack of rapid and accurate diagnostic tools. We evaluated the immunological response to Mycobacterium tuberculosis anti-A60 antibodies in cerebrospinal fluid (CSF) in comparison to adenosine deaminase (ADA) determination, for the diagnosis of TBM. METHODS: A total of 63 CSF samples were analyzed by indirect ELISA for the detection of anti- A60 IgG, IgM and IgA. These include samples from 17 patients with confirmed TBM and 46 control patients with other infections. RESULTS: The mean individual anti-A60 IgM, IgG and IgA CSF antibody titers were significantly higher in TBM in comparison with control groups (p < 0.01). The best discriminatory CSF antibody for confirming TBM diagnosis was IgM, with an area under the receiver operating characteristic curve of 0.928 (95%CI 0.834-0.978), compared to 0.863 (95% CI: 0.752-0.936) for ADA testing (p = NS). The sensitivity of anti- A60 IgM CSF antibody titers (cutoff > 0.06 U/ml) was 94.1% compared to 88.2% for ADA (cutoff > 6.2 U/ml), p = NS. Both anti A60 IgM and ADA showed the same moderate specificity (80.4%). Two cases of TBM were correctly identified by anti-A60 IgM but missed by ADA. CONCLUSION: The ELISA test for anti-antigen A60 antibodies (IgM) is a rapid and sensitive tool for the rapid diagnosis of TBM that can be a complement to ALDA determination. The specificity of both tests is still a limitation in TBM diagnosis.

Immunodiagnosis of pneumococcal meningitis using Dot-enzyme-linked immunosorbent assay.

A diagnosis of bacterial meningitis requires isolation of the pathogen from cerebrospinal fluid (CSF). However, cultures of CSF are usually insensitive, thus, in the majority of patients, the etiology is rarely determined. A total of 90 CSF samples from pediatric patients with clinical diagnosis of bacterial meningitis were evaluated by Dot-ELISA. This method was standardized in order to detect pneumococcal polysaccharide antigen in CSF samples previously treated with 0.1 M EDTA and dotted on nitrocellulose membrane strips. Pneumococcal omniserum diluted 1:200 was employed for pneumococcal antigen detection. Dot-ELISA showed relative indices of 100 and 90 per cent for sensitivity and specificity, respectively. This method is cheaper than counter immunoelectrophoresis for pneumococcal antigen detection.

Detection of antibodies to Brucella cytoplasmic proteins in the cerebrospinal fluid of patients with neurobrucellosis.

The diagnosis of human neurobrucellosis usually relies on the detection of antibodies to Brucella lipopolysaccharide (LPS) in cerebrospinal fluid (CSF) by agglutination tests or enzyme-linked immunosorbent assay (ELISA). Here we describe the detection of immunoglobulin G (IgG) to cytoplasmic proteins (CP) of Brucella spp. by ELISA and Western blotting in seven CSF samples from five patients with neurobrucellosis. While IgG to CP (titers of 200 to 12, 800) and IgG to LPS (800 to 6,400) were found in the CSF of these patients, these antibodies were not detected in CSF samples from two patients who had systemic brucellosis without neurological involvement. The latter, however, had serum IgG and IgM to both LPS and CP. No reactivity to these antigens was found in CSF samples from 14 and 20 patients suffering from nonbrucellar meningitis and noninfectious diseases, respectively. These findings suggest that, in addition to its usefulness in the serological diagnosis of human systemic brucellosis, the ELISA with CP antigen can be used for the specific diagnosis of human neurobrucellosis.

[Detection of Neisseria meningitidis group B antigens by MB-Dot-Elisa test in patients with meningitis]. / Detección de antígenos de Neisseria meningitidis del grupo B con la prueba MB-Dot-ELISA en pacientes con meningitis.

Infection with Neisseria meningitidis group B has been difficult to detect, partly because this bacterial group's polysaccharide is a weak immunogen. This article describes work carried out to test a new procedure (MB-Dot-ELISA) employing a high-titered horse antiserum for detection of N. meningitidis group B antigens. The study assayed cerebrospinal fluid samples from 585 subjects, 574 with suspected meningitis cases and 11 with neurologic disorders. The results of the assay indicated a sensitivity of 0.991 and a specificity of 0.826. These results were superior to those obtained with latex agglutination and in substantial agreement with the results of counterimmunoelectrophoresis and bacteriologic methods. Overall, the MB-Dot-ELISA was found to be sensitive, inexpensive, and suitable for public health laboratory investigations.

Diagnosis of bacterial meningitis and septicemia by serum counterimmunoelectrophoresis.

We compare the results obtained by counterimmunoelectrophoresis in samples of serum and cerebrospinal fluid with microbiologic methods for 3,298 patients suspected of bacterial meningitis and/or septicemia at Instituto Adolfo Lutz, São Paulo, in a retrospective study of the period from July 1998 to July 1994. Of the 415 patients (12.6% of the total cases studied) who were positive by the serum test, only 249 (7.6% of the total cases studied) were also positive when cerebrospinal fluid was assayed. Thus, 40% of the positives (5.6% of the total) were identifiable by analysis of serum but not of cerebrospinal fluid. Neisseria meningitidis accounted for 77.7% (129) and Haemophilus influenzae for 22.3% (37) of the positive results obtained only when serum was examined. These data show that although sensitivity and specificity of serum counterimmunoelectrophoresis are relatively low compared to cerebrospinal fluid counterimmunoelectrophoresis, the serum test is necessary to complement cerebrospinal fluid counterimmunoelectrophoresis data.

Diagnosis of bacterial meningitis and septicemia by serum counterimmunoelectrophoresis

We compare the results obtained by counterimmunoelectrophoresis in samples of serum and cerebrospinal fluid with microbiologic methods for 3,298 patients suspected of bacterial meningitis and/or septicemia at Instituto Adolfo Lutz, Säo Paulo, in a retrospective study of the period from July 1988 to July 1994. Of the 415 patients (12.6 percent of the total cases studied) who were positive by the serum test, only 249 (7.6 percent of the total cases studied) were also positive when cerebrospinal fluid was assayed. Thus, 40 percent of the positives (5.6 percent of the total) were identifiable by analysis of serum but not of cerebrospinal fluid. Neisseria meningitidis accounted for 77.7 percent (129) and Haemophilus influenzae for 22.3 percent (37) of the positive results obtained only when serum was examined. These...

Bacterial antigen detection in cerebrospinal fluid by the latex agglutination test.

Eighty purulent cerebrospinal fluid (CSF) samples from patients with clinical evidence of meningitis were studied using the Directigen latex agglutination (LA) kit to determine the presence of bacterial antigen in CSF. The results showed a better diagnostic performance of the LA test than bacterioscopy by Gram stain, culture and counterimmunoelectrophoresis (CIE), as far as Neisseria meningitidis groups B and C, and Haemophilus influenzae type b are concerned, and a better performance than bacterioscopy and culture considering Streptococcus pneumoniae. Comparison of the results with those of culture showed that the LA test had the highest sensitivity for the Neisseria meningitidis group C. Comparing the results with those of CIE, the highest levels of sensitivity were detected for N. meningitidis groups B and C. Regarding specificity, fair values were obtained for all organisms tested. The degree of K agreement when the LA test was compared with CIE exhibited better K indices of agreement for N. meningitidis groups B and C.

Blood stained cerebrospinal fluid responsible for false positive reactions of latex particle agglutination tests.

The accuracy of the latex particle agglutination test (LPAT) was assessed in blood stained cerebrospinal fluid (CSF) specimens from 166 paediatric patients, aged from three months to 13 years. A commercial LPAT kit was used to detect Haemophilus influenzae type b, Streptococcus pneumoniae, and Neisseria meningitidis A, B, and C soluble antigens. Culture of CSF specimens was used as the standard and all laboratory procedures were performed blind. The mean CSF erythrocyte count was 66,406 cells/mm3 in the cases and 11,560 cells/mm3 in the controls. The sensitivity and the specificity of LPAT were 83.8 and 94.0%, respectively, suggesting that LPAT is a useful diagnostic tool even in blood stained CSF specimens.

Clinical usefulness of cerebrospinal fluid bacterial antigen studies.

A retrospective chart review was performed to evaluate the effect that positive results of cerebrospinal fluid bacterial antigen tests had on the care of patients with presumed bacterial meningitis. Of 901 tests ordered, costing $26,000 per year, 29 showed positive results--and only four of these affected patient care. By using cerebrospinal fluid bacterial antigen testing only when another test does not identify an organism, or in an attempt to determine central nervous system infection late in therapy for presumed sepsis, one can greatly reduce costs with no detrimental effect on patients.

[Involvement of the nervous system in leptospirosis. III. Immunologic reactions in the blood and cerebrospinal fluid]. / Comprometimento do sistema nervoso na leptospirose. III. Reações imunológicas no sangue e líquido cefalorraqueano.

From January 1st up to September 30th 1990, 77 patients with leptospirosis were admitted at the Infectious and Parasitic Diseases Service of the Hospital das Clínicas of the Universidade Federal de Pernambuco. The majority (64) were male patients, and average age was 28 years old. Serovars icterohaemorrhagic and canicola were the most frequent. CSF examination was performed in 67 (87.0%) patients and it was abnormal in 64 (95.52%). Micro-agglutination test for leptospirosis with live antigens was performed in CSF, as well as immunological tests for syphilis, cysticercosis and schistosomiasis for differential diagnosis. Concerning the serovar identification, results of microagglutination test for leptospirosis in CSF were significant considering the similitude of responses when compared to those found for blood samples.

Comprometimento do sistema nervoso na leptospirose: III. Reaçöes imunológicas no sangue e líquido cefalorraqueano / Involvement of the nervous system in leptospirosis: III. Immunologic reactions in the blood and cerebrospinal fluid

Entre 1-janeiro e 30-setembro-1990 foram estudados 77 pacientes com diagnóstico de leptospirose: 64 (83,11 por cento) eram do sexo masculino e a média de idade, 28 anos. Os sorovars icterohemorrhagiae e canicola foram os mais frequentes. O exame do LCR, realizado em 67 (87,0 por cento) dos pacientes, foi anormal em 64 (95,52//). A reaçäo de microaglutinaçäo para leptospirose com antígenos vivos foi realizada no LCR, bem como reaçöes imunológicas para sífilis, cisticercose e esquistossomose para diagnóstico diferencial. Bastante signficativa foram os resultados da reaçäo de microaglutinaçäo para leptospirose no LCR, pela semelhança das respostas àquelas encontradas no sangue quanto à identificaçäo do sorovar

Deteccion de antigeno del polisacarido capsular de Cryptococcus neoformans en pacientes con SIDA y neurocriptococosis en Sao Paulo, Brasil / Detection of capsular polysaccharide antigen of Cryptococcus neoformans in patients with AIDS and neurocryptococcosis in Sao Paulo, Brazil

Antigeno del polisacarido capsular (AgPC) de Cryptococcus neoformans fue detectado por la tecnica de aglutinacion de latex (AL) en LCR y suero de pacientes con Sindrome de Inmunodeficiencia Adquirida (SIDA) y primer episodio de neurocriptococosis, usando como patron el examen micologico (examen directo y cultivo) de LCR. Se obtuvo una sensibilidad de 100 por ciento de AL para detectar AgPC de C. neoformans, el cual por su rapidez permite tratamiento especifico precoz. Titulos iniciales de AgPC de la levadura en esos pacientes pueden ser>1.000.000, pareciendo que cuando esos titulos estan presentes en suero, se relacionan con mortalidad durante el tratamiento. En los pacientes que sobrevivieron se observo que el examen micologico directo y AgPC de C. neoformans, en LCR y suero, permanecen positivos aun despues de tratamiento y mejoria clinica del paciente.

[Latex agglutination tests of the cerebrospinal fluid in bacterial meningitis: an analysis of 333 cases]. / Provas de aglutinação do látex no líquido cefalorraqueano em meningites bacterianas: análise de 333 casos.

The study is based on 333 cerebrospinal fluid (CSF) samples from patients with clinical diagnosis of acute bacterial meningites. The aim of the study is a critical evaluation on latex agglutination tests in CSF for H. influenzae type b, N. meningitidis A and C, and S. pneumoniae. These tests are compared with direct examination (Gram method), and culture results. It was shown that results of the latex test in the CSF are basic for rapid diagnosis of etiological agent in a bacterial meningitis. Data on 106 CSF samples confirmed the etiology through latex tests in 98.2% for H. influenzae type b, in 15.8% for N. meningitidis A or C, in 96.8% for S. pneumoniae. Emphasis is given for evidence of antibiotic therapy previous to CSF collection, which may be responsible for the great number of negative results registered in the present series.

The use of monoclonal antibodies in the diagnosis of partially treated Pseudomonas aeruginosa meningitis: patient report.

The objective of this study was to evaluate the efficacy of mouse anti-pseudomonas monoclonal antibodies to detect small numbers of pathogenic pseudomonas in the spinal fluid of a patient who had been treated with antibiotics for meningitis. Anti-605 monoclonal antibody against Pseudomonas aeruginosa PAC 605, a rough mutant, showed sensitivity similar to that of anti-Fisher 1 monoclonal antibody in detecting P. aeruginosa Fisher 1 antigens in boiled spinal fluid drawn from a patient with a P. aeruginosa perispinal abscess and partially treated meningitis.