Immunoconfirmation of central nervous system tuberculosis by blotting: A study of 300 cases.

Tuberculous meningitis (TBM) is a serious form of disease of the central nervous system. Early and accurate diagnosis of the disease and effective treatment are key important factors to contain the disease. The disease presents as chronic meningitis where other partners such as fungal meningitis, neurosyphilis, cysticercal meningitis, carcinomatous meningitis and partially treated pyogenic meningitis share a similar clinical picture making the diagnosis complicated. Culturing of the pathogen Mycobacterium tuberculosis (MTB) from the cerebrospinal fluid (CSF) sample has shown a poor response. The main immunological method for the immunodiagnosis of TBM is the detection of an antibody response in the CSF. In the present study, total MTB sonicated extract antigen was used for ELISA and Western blot. ELISA shows overall immune response of the test sample, whereas Western blotting reveals the specific reactivity to a particular molecular weight antigen. This would also reveal the immunodominant antigen. A total of 300 CSF samples were analyzed by both ELISA and Western blotting. Of the 240 clinically suspected TBM cases, 111 samples were positive by ELISA and 81 samples by Western blot. A total of 76 CSF samples were positive by both ELISA and Western blot. None of the control samples showed positivity either by ELISA or by Western blot. TBM patients revealed major antibody reactivity to 30-40 kD region, followed by 14 kD region. ELISA is sensitive with mild non-specific binding, but Western blot is specific in detecting the immune response. The findings will be useful in definitive immunodiagnosis of TBM.

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.

Rapid diagnosis of tuberculosis in aspirate, effusions, and cerebrospinal fluid by immunocytochemical detection of Mycobacterium tuberculosis complex specific antigen MPT64.

The aim of the study was to evaluate the diagnostic potential of immunocytochemical staining for the detection of Mycobacterium tuberculosis complex-specific antigen MPT64, in tuberculous lymph node aspirates, cerebrospinal fluid, and effusions from pleura and abdomen. One hundred ninety patients with a diagnosis of tuberculosis (cases) and 80 patients with nontuberculous lesions (controls) were enrolled and differentiated on the basis of clinical features, histology, cytology, clinical biochemistry, Ziehl-Neelsen staining, Lowenstein-Jensen culture, and response to antituberculous therapy. Cervical lymph nodes fine-needle aspirate (n = 150), cerebrospinal fluid (n = 27), pleural fluid (n = 41), and peritoneal fluid (n = 52) were collected and stained with anti-MPT64 and anti-BCG antibodies using immunocytochemistry. Nested-PCR for IS6110 was done for comparison and to calculate the diagnostic indices of the ICC staining. ICC staining with anti-MPT64 was positive in 128/190 (67.4%) tuberculous smears and in 4/80 (5%) control smears thus giving sensitivity of 67.4% and the specificity of 95%, while anti-BCG was positive in 112 (58.9%) tuberculous smears and in 16/80 (20%) control smears with sensitivity of 58.9% and specificity of 80%. When diagnostic validation of ICC was done using PCR as the gold standard, the overall sensitivity, specificity, positive- and negative-predictive values for ICC staining in smears with anti-MPT64 was 96, 96, 95, and 97%, respectively, while the corresponding values for anti-BCG were 87, 88, 86, and 88%. ICC staining using anti-MPT64 represents a robust and simple method for establishing an early etiological diagnosis of M. tuberculosis complex infection in extrapulmonary tuberculosis.

Post-streptococcal opsoclonus-myoclonus syndrome associated with anti-neuroleukin antibodies.

BACKGROUND: Adult opsoclonus-myoclonus (OM), a disorder of eye movements accompanied by myoclonus affecting the trunk, limbs, or head, is commonly associated with an underlying malignancy or precipitated by viral infection. METHODS: We present the first two reports of post-streptococcal OM associated with antibodies against a 56 kDa protein. Two young girls presented with opsoclonus and myoclonus following a febrile illness and pharyngitis. Protein purification techniques were employed. Amino acid sequences of human neuroleukin (NLK) and streptococcal proteins were compared using the protein-protein BLAST application. RESULTS: The antigen was identified as NLK (glucose-6-phosphate isomerase, GPI). GPI is present on the cell surface of streptococcus making the protein a candidate target for molecular mimicry. CONCLUSIONS: We have identified NLK as an antigenic target in two patients with post-streptococcal OM. The pathogenicity of the antibodies is uncertain. The potential role of anti-neuroleukin antibodies in the pathogenesis of OM is discussed. We propose that OM may represent a further syndrome in the growing spectrum of post-streptococcal neurological disorders. The role of streptococcus in OM and the frequency with which anti-NLK responses occur in both post-infectious and paraneoplastic OM should be investigated further.

Clinicopathological abnormalities and treatment response in 24 dogs seroreactive to Bartonella vinsonii (berkhoffii) antigens.

Bartonella vinsonii (B. vinsonii) subspecies berkhoffii is a recently recognized cause of endocarditis, myocarditis, and granulomatous disease in dogs. In an effort to elucidate other potential disease manifestations, the case records of 24 dogs that were seroreactive to B. vinsonii (berkhoffii) antigens were studied retrospectively. Diagnoses included immune-mediated hemolytic anemia, neutrophilic or granulomatous meningoencephalitis, neutrophilic polyarthritis, cutaneous vasculitis, and uveitis. Repeated B. vinsonii (berkhoffii) antibody titers became negative after treatment. This study indicates that a diverse spectrum of disease manifestations and clinicopathological abnormalities can be detected in dogs that are seroreactive to B. vinsonii (berkhoffii) antigens.

Immunodiagnosis of tuberculous meningitis: rapid detection of mycobacterial antigens in cerebrospinal fluid by reverse passive hemagglutination assay and their characterization by Western blotting.

Tuberculous meningitis (TBM) is one of the commonest chronic infections of the central nervous system (CNS). Diagnosis of TBM has been a problem as it causes various clinical manifestations which can be confused with those of other chronic infections of the CNS such as neurocysticercosis (NCC), neurobrucellosis and cryptococcal meningitis, that are prevalent in many underdeveloped and developing countries. Differential diagnosis of TBM can be made by detecting circulating mycobacterial antigens in CSF by immunoassays. In this study, a reverse passive hemagglutination (RPHA) has been developed using rabbit antimycobacterial IgG for detection of circulating mycobacterial antigens in CSFs from chronic infections of the CNS in order to develop a rapid, simple, sensitive and cost-effective method. Circulating mycobacterial antigens were characterized by immunoblot assay. The sensitivity limit of RPHA was 400 ng ml(-1). RPHA was specific as antimycobacterial IgG did not show any reaction with porcine Cysticercus cellulosae which was used as a control antigen. RPHA could detect mycobacterial antigens in CSF at a sensitivity level of 94.11% with a specificity of 99.0%. Immunoblot analysis of RPHA positive CSFs revealed predominantly 30-32 kDa and 71 kDa antigens whilst 6, 86, 120, 96 and 110 kDa showed varied degree of reactivity. Antigens of masses 30-32 and 71 kDa were absent in culture filtrate of Mycobacterium tuberculosis H37Rv grown in Proskeur-Beck liquid medium. RPHA is a rapid, simple and sensitive immunological method with a long shelf life of 6-8 weeks if stabilized coated erythrocytes are stored at +4 degrees C. RPHA could be used as an additional immunodiagnostic tool in both differential diagnosis and prognosis of TBM. Immunoblot results indicate that 30-32 kDa and 71 kDa antigens are cell wall derived.

Immunodiagnosis of tuberculous meningitis: detection of antibody reactivity to antigens of Mycobacterium tuberculosis and Cysticercus cellulosae in cerebrospinal fluid tuberculous meningitis patients by ELISA.

Enzyme-linked immunosorbent assay (ELISA) was standardized and evaluated for detection of antibody response in cerebrospinal fluid (CSF) to antigens of Mycobacterium tuberculosis and Cysticercus cellulosae. Sonicated extracts of heat killed M. tuberculosis H37Rv and C. cellulosae were prepared and used in ELISA to detect respective antibody response in CSFs for a definitive diagnosis as to tuberculous meningitis (TBM)/neurocysticercosis (NCC). ELISA was performed in a total of 201 CSF samples, which include Group I: chronic infections of the central nervous system (CNS) with possible diagnosis of TBM, tuberculoma, or NCC (n = 70), and Group II: control group of patients with infectious neurological (n = 19), non-infectious neurological (n = 82), and non-infectious non-neurological conditions, i.e., spinal anaesthesia CSFs (n = 30). Specificity in this study was 99.9% and no true cross-reactivity between antimycobacterial antibodies and C. cellulosae antigens and vice-versa was observed. However, in 17.14% of CSFs (12/70), both antimycobacterial and anticysticercal antibodies were detected, 50% of these cases were diagnosed as TBM. But none of the proven NCC cases showed presence of antimycobacterial antibodies. Results of this study would indicate that it would be beneficial if both antibody and antigen responses are detected in CSFs to infectious aetiologies such as M. tuberculosis, C. cellulosae, and C. neoformans in order to enhance the diagnostic accuracy and proper management, as these diseases are highly endemic in underdeveloped and developing countries.

Significance of laboratory findings for the diagnosis of neurosyphilis.

Our objective is to assess the specificity and sensitivity, and thus elaborate the relevance, of different laboratory findings for the diagnosis of neurosyphilis. One hundred and fourteen HIV-negative pairs of serum and cerebrospinal fluid (CSF) samples were examined by the Venereal Disease Research Laboratory (VDRL) test, a fluorescent treponemal antibody-absorption (FTA-ABS) test, microhaemagglutination assay with Treponema pallidum antigen (MHA-TP) test (serum) and Treponema pallidum haemagglutination assay (TPHA) test (CSF); further, albumin, total protein, and total IgG were determined and, in the CSF, cell count was performed. The donors were 60 patients with active neurosyphilis and 54 healthy persons with a former history of syphilis and with persisting positive results in the T. pallidum haemagglutination tests (serum: MHA-TP, CSF: TPHA), who supplied specimens for control. Albumin quotient, IgG index, TPHA index, modified TPHA index, Intrathecally produced T. pallidum Antigen (ITpA) index, its 2 modifications and, in 12 samples, the adenovirus group antibody (AVGA)/TPHA index were ascertained. The specificity and sensitivity of the TPHA index were 100% and 98.3%, of the modified TPHA index 50.0% and 96.7%, of the ITpA index 42.6% and 90.0%, of the modified ITpA indices 51.8% and 68.3% (first modification) and 53.7% and 63.3% (second modification). The AVGA/TPHA index yielded a specificity of 91.7% (11/12). The CSF VDRL test was positive in 55/60 (91.7%) of samples from patients with neurosyphilis and in none of the controls (0/54). A CSF-TPHA titre greater than 1:320 was observed in 59/60 (98.3%) of the neurosyphilis specimens and in none of the controls (0/54). A TPHA index above an outcome of 70, a positive CSF-TPHA test at a titre greater than 1:320 and, with lower sensitivity, the criteria of the Centers for Disease Control (CDC) guidelines yield the most reliable results for laboratory support to a diagnosis of neurosyphilis. The modified TPHA index, the ITpA index, and its 2 modifications produce results of minor sensitivity and poor specificity. Observations on the AVGA/THPA index are too limited yet for judgement. The diagnostic significance of a CSF-TPHA titre above 320 needs further confirmation on a greater number of observations made by different laboratories.

Diagnosis of tuberculous meningitis by detection of antigen and antibodies in CSF and sera.

OBJECTIVE: To evaluate diagnostic potential of three immunological tests, namely, detection of H37Rv antigen of M. Tuberculosis in CSF, detection of antibodies (IgG) against H37Rv in CSF and detection of antibodies (IgG) against H37Rv in serum for diagnosis of tuberculous meningitis in children. SUBJECTS: 50 children diagnosed as patients of tuberculous meningitis were included as cases and 48 children with CNS diseases of nontubercular etiology [pyogenic meningitis (n = 31), encephalitis (n = 10), seizure disorder of unknown etiology (n = 5), brain tumor (n = 2)] served as controls. METHODS: H37Rv antigen of M. tuberculosis was detected in CSF by Dot ELISA, and antibodies (IgG) against H37Rv in CSF and serum were detected by Plate ELISA. RESULTS: Detection of H37Rv antigen in CSF was the most sensitive (90%) and specific (95.83%) with positive and negative predictive values of 95.74% and 90.19%, respectively, followed by detection of antibodies in CSF (sensitivity-74%, specificity-89.58%, positive predictive value-88.10%, negative predictive value-76.78%). Detection of antibodies in serum had low sensitivity (50%), specificity (91.67%), positive predictive value (86.21%) and negative predictive value (63.76%). CONCLUSIONS: Detection of antigen in CSF is a rapid, sensitive and specific test for diagnosis of tuberculous meningitis in children. Detection of antibody in CSF may be useful in some cases but needs further evaluation. Detection of antibody in serum does not appear to be useful for diagnosis of tuberculous meningitis.

Visual loss in immunocompetent patients with Cryptococcus neoformans var. gattii meningitis.

In Papua New Guinea cryptococcal meningitis occurs predominantly in immunocompetent patients in whom Cryptococcus neoformans var, gattii is implicated in 95% of cases. Ocular complications are common. We have reviewed ophthalmic findings in 82 immunocompetent patients and have attempted to identify those features of the disease that predict an unfavourable visual outcome. Visual loss occurred in 52.6% of survivors and was associated with optic atrophy following optic disc swelling in 60.9%. Progression of disc swelling to optic atrophy was predicted by the presence of an abducens palsy (P = 0.049) and cerebrospinal fluid (CSF) cryptococcal antigen titres > 1:1024 (P = 0.036). Raised intracranial pressure (defined as opening CSF pressure > or = 300 mm on admission) was not associated with visual loss. Vision deteriorated in 17.3% of patients despite anticryptococcal therapy and in 3.7% it followed curative therapy. The high rate of visual loss in immunocompetent patients with C. neoformans var. gattii infection contrasts with others' experience of immunosuppressed patients with C. neoformans var. neoformans infection, in whom visual loss was rare. This difference may reflect immune mediated optic nerve dysfunction in C. neoformans var. gattii meningitis caused by either compression due to arachnoid adhesions or oedema and inflammatory cell-mediated damage.

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...

[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

[Cryptococcal meningitis in AIDS: successful long-term prophylaxis with fluconazole]. / Kryptokokkenmeningitis bei AIDS: erfolgreiche Langzeitprophylaxe durch Fluconazol.

A 30-year-old, HIV-positive, man who had been repeatedly treated with amphotericin B for oral thrush, developed headaches, fever up to 38.5 degrees C, dizzy spells with falling tendency, as well as disorder of speech and word finding. Cerebrospinal fluid (CSF) contained 5700/3 cells, of which 90% were encapsulated yeast-fungus. Cryptococcal antigen titres were elevated both in serum (1:256) and CSF (1:1024), providing the diagnosis of cryptococcal meningitis. Intravenous treatment was started with amphotericin B, 0.3 mg/kg daily and flucytosine, 150 mg/kg daily. The clinical, microbiological and serological findings regressed after 4 weeks. After 8 weeks the creatinine concentration rose to 2.5 mg/dl. Because amphotericin B nephrotoxicity was suspected, further intravenous administration was stopped after a cumulative dosage of 2 g. He was placed on a prophylactic dosage of fluconazole, 100 mg by mouth twice daily. The cryptococcal antigen titre had fallen to normal within one year. The prophylactic regimen has been continued now for three years without recurrence or other fungal infection.

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.

Rapid diagnosis of bacterial meningitis by an enzyme immunoassay of cerebrospinal fluid.

A total of 250 cerebrospinal fluid (CSF) specimens were analyzed using a rapid enzyme immunoassay (Pharmacia Meningitis EIA-Test) (EIA) for the detection of antigens of Haemophilus influenzae type b, Neisseria meningitidis (serogroups A,B,C) and Streptococcus pneumoniae (25 selected types). The test is performed in less than 1 h and read by the naked eye. EIA and coagglutination (CoA) were compared with a constructed reference that comprised samples which were either positive by culture and/or on direct microscopy (DM), or in which there were positive results with both EIA and CoA for the bacteria covered by the assays. Using this reference for CSF samples assayed in a period between two meningococcal meningitis epidemics, the sensitivity was 0.86 for EIA and 0.69 for CoA, the specificity 0.95 (EIA) and 0.97 (CoA), the predictive value for a positive result 0.81 (EIA) and 0.87 (CoA) and, the predictive value for a negative result 0.96 (EIA) and 0.93 (CoA). Antibiotics had been given to 54% of the patients before admission. All of the 56 samples that were positive in any of the tests taken during an epidemic of group A meningococcal disease were detected by EIA; CoA was negative in 45% and culture/DM was negative in 32%. Sequential dilutions of two CSF samples from which H. influenzae type b had been isolated, showed the EIA to be 16-32 times more sensitive than CoA. With both technical feasibility and good sensitivity and specificity, the EIA seems to be useful and reliable for the rapid diagnosis of bacterial meningitis, especially in situations where pretreatment with antibiotics are likely.