The sensitivity, specificity and efficiency values of some serological tests used in the diagnosis of paracoccidioidomycosis

This work reports on the results of double immunodiffusion (ID), counterimmunoelectrophoresis (CIE), complement fixation (CF) and indirect immunofluorescence (IIF) techniques in the serodiagnosis of paracoccidioidomycosis. The study was undertaken on four groups of individuals: 46 patients with untreated paracoccidioidomycosis, 22 patients with other deep mycoses, 30 with other infectious diseases (tuberculosis and cutaneous leishmaniasis) and 47 blood donors as negative controls. Data were obtained using Paracoccidioides brasiliensis antigens, i.e.,a yeast culture filtrate for ID, CIE and CF, and a yeast cell suspension for IIF. The sensitivity, specificity and efficiency values were measured according to GALEN & GAMBINO8.The gel precipitation tests (ID and CIE) showed the greatest sensitivity (91.3 and 95.6%, respectively), maximum specificity (100%) and the highest efficiency values when compared to the CF and IIF tests.

Stool examination and rectal biopsy in the diagnosis and evaluation of therapy of schistosomiasis mansoni

From each of a group of 217 adult males selected through enzyme-immunoassay or skin-test (Group A), six stool samples were examined by both the Lutz/Hoffman, Pons & Janer (Lutz/HPJ) and Kato/Katz methods. In addition, one oogram of the rectal mucosa was performed. By these methods, schistosomiasis was detected in 44.7%, 47.5% and 40.1% of the individuals respectively. To evaluate the methods in the assessment of cure, the last 40 patients from group A, treated with a single oral dose of oxamniquine at 15 mg/kg were followed up for six months (Group B). The criteria for parasitological cure included three stool examinations by Kato/Katz and Lutz/HPJ methods, one, three and six months post-treatment and a rectal biopsy between the fourth and sixth months post-treatment. The examinations were negative in 87.5%, 90% and 95% of the patients, respectively. The efficacy of oxamniquine was 82.5% when the three methods were considered together and there was no statistically significant difference between the sensitivity of the individual methods.

The value of adenosine deaminase (ADA) determination in the diagnosis of tuberculous ascites

In order to evaluate the role of the determination of adenosine deaminase activity (ADA) in ascitic fluid for the diagnosis of tuberculosis, 44 patients were studied. Based on biochemical, cytological, histopathological and microbiological tests, the patients were divided into 5 groups: G1 - tuberculous ascites (n = 8); G2 - malignant ascites (n = 13); G3 - spontaneous bacterial peritonitis (n = 6); G4 - pancreatic ascites (n = 2); G5 - miscelaneous ascites (n = 15). ADA concentration were significantly higher in G1 (133.50 ± 24.74 U/l) compared to the other groups (G2 = 41.85 ± 52.07 U/l; G3 = 10.63 ± 5.87 U/l; G4 = 18.00 ± 7.07 U/l; G5 = 11.23 ± 7.66 U/l). At a cut-off value of >31 U/l, the sensitivity, specificity and positive and negative preditive values were 100%, 92%, 72% and 100%, respectively. ADA concentrations as high as in tuberculous ascites were only found in two malignant ascites caused by lymphoma. We conclude that ADA determination in ascitic fluid is a useful and reliable screening test for diagnosing tuberculous ascites. Values of ADA higher than 31 U/l indicate more invasive methods to confirm the diagnosis of tuberculosis.

Intestinal spirochetosis: first cases reported in Brazil and the use of immunohistochemistry as an aid in histopathological diagnosis

Colonization of the colon and rectum by intestinal spirochetes is detected for the first time in Brazil in 4 of 282 (1.41%) patients who had undergone sigmoidoscopy and/or colonoscopy with a histopathological diagnosis of chronic non specific-colitis. This frequency is probably understimated, since surgically obtained specimens were not considered in the present study. Histopathological diagnosis was performed using routine stains like hematoxylin-eosin which showed the typical, of 3-µm thick hematoxyphilic fringe on the brush border of the surface epithelium, and by silver stains like the Warthin-Starry stain. Immunohistochemical procedures using two, polyclonal, primary antibodies, one against Treponema pallidum and the other against Leptospira interrogans serovar copenhageni serogroup Icterohaemorrhagiae cross-reacted with spirochetal antigen/s producing a marked contrast of the fringe over the colonic epithelium, preserving the spiral-shaped morphology of the parasite. In one case with marked diarrhea, immunohistochemistry detected spirochetal antigen/s within a cell in an intestinal crypt, thus demonstrating that the infection can be more widely disseminated than suspected using routine stains. Immunohistochemical procedures, thus, greatly facilitate the histological diagnosis of intestinal spirochetosis and may contribute to a better understanding of the pathogenesis of the disease. Transmission and scanning electron microscopy performed in one case showed that the spirochete closely resembled the species designated as Brachyspira aalborgi.

Cross-Reactions between Toxocara canis and Ascaris suum in the diagnosis of visceral larva migrans by western blotting technique

Visceral larva migrans (VLM) is a clinical syndrome caused by infection of man by Toxocara spp, the common roundworm of dogs and cats. Tissue migration of larval stages causes illness specially in children. Because larvae are difficult to detect in tissues, diagnosis is mostly based on serology. After the introduction of the enzyme-linked immunosorbent assay (ELISA) using the larval excretory-secretory antigen of T. canis (TES), the diagnosis specificity was greatly improved although cross-reactivity with other helminths are still being reported. In Brazil, diagnosis is routinely made after absorption of serum samples with Ascaris suum antigens, a nematode antigenicaly related with Ascaris lumbricoides which is a common intestinal nematode of children. In order to identify T. canis antigens that cross react to A. suum antigens we analyzed TES antigen by SDS-PAGE and Western blotting techniques. When we used serum samples from patients suspected of VLM and positive result by ELISA as well as a reference serum sample numerous bands were seen (molecular weight of 210-200 kDa, 116-97 kDa, 55-50 kDa and 35-29 kDa). Among these there is at least one band with molecular weight around 55-66 kDa that seem to be responsible for the cross-reactivity between T. canis e A. suum once it disappears when previous absorption of serum samples with A. suum antigens is performed

A retrospective evaluation of a score system adopted by the Ministry of Health, Brazil in the diagnosis of pulmonary tuberculosis in childhood: a case control study

Based on a retrospective case-control study we evaluated the score system adopted by the Ministry of Health of Brazil (Ministério da Saúde - MS), to diagnose pulmonary tuberculosis (PTB) in childhood. This system is independent of bacteriological or histopathological data to define a very likely (> or = 40 points), possible (30-35 points) or unlikely (< or = 25 points) diagnosis of tuberculosis. Records of hospitalized non-infected HIV children at the Instituto de Puericultura e Pediatria Martagão Gesteira of Federal University of Rio de Janeiro (IPPMG-UFRJ), were reviewed. Patients were adjusted for age and divided in two different groups: 45 subjects in the case group (culture-positive) [mean of age = 10.64 mo; SD 9.66]; and 96 in the control group (culture-negative and clinic criteria that dismissed the disease) [mean of age = 11.79 mo.; SD 11.31]. Among the variables analyzed, the radiological status had the greater impact into the diagnosis (OR = 25.39), followed by exposure to adult with tuberculosis (OR = 10.67), tuberculin skin test >10mm (OR = 8.23). The best cut-off point to the diagnosis of PTB was 30 points, where the score system was more accurate, with sensitivity of 88.9% and specificity of 86.5%.

Cystoscopy in the diagnosis and follow-up of urinary schistosomiasis in Brazilian soldiers returning from Mozambique, Africa

The assessment of urinary schistosomiasis in individuals coming from endemic areas often requires diagnostic resources not used in areas of exposure in order to determine complications or to establish more precise criteria of cure. Cystoscopy and 24-hour urine examination were performed, after treatments with praziquantel 40 mg/kg body weight, single dose, on 25 Brazilian military men who were part of a United Nations peace mission to Mozambique in 1994. The median age of the individuals was 29 years and all presented a positive urine parasitological exam. The alterations detected by cystoscopy were hyperemia and granulomas in the vesical submucosa in 59.1% of the individuals and only granulomas in 40.9%. A vesical biopsy revealed granulomas in all patients and viable eggs in 77.3% even after a period during which the patients no longer excreted eggs in urine. Cystoscopy after treatment, followed by biopsy and histopathological evaluation, performed in areas where the evolution of the disease can be better monitored, was found to be a safe criterion of parasitological cure.

The usefulness of adenosine deaminase in the diagnosis of tuberculous pericarditis

The objective of this study was to evaluate the adenosine deaminase (ADA) activity usefulness in the diagnosis of tuberculous pericarditis (TP), comparing its value with pericardial effusions (PE) caused by other pericardial diseases. A retrospective case-control study was conducted with nine cases of TP and 39 other than TP diseases (12 neoplastic, 11 septic and 16 unknown origin). Every patient included in this study had PE samples submitted to ADA activity measures and microbiological analysis, and then had pericardial tissue samples submitted to microbiological and histopathological examination. Considering the value of 40 U/L as the cut-off for the diagnosis of TP, the specificity and sensitivity were respectively of 72% and 89%. The specificity of ADA activity for the TP was best applied in the differential diagnosis from PE of unknown origin. The present study demonstrates the clinical value of the measurement of ADA activity in PE in the diagnosis of TP.

Difficulties in the diagnosis of HTLV-2 infection in HIV/AIDS patients from Brazil: comparative performances of serologic and molecular assays, and detection of HTLV-2b subtype

The current diagnosis of human T-lymphotropic virus type-2 (HTLV-2) infection is based on the search of specific antibodies; nevertheless, several studies conducted in Brazil pointed deficiencies of the commercially available kits in detecting HTLV-2, mostly in HIV/AIDS patients. This study searched for the presence of HTLV-1 and -2 in 758 HIV/AIDS patients from Londrina, Paraná, Brazil. Serum samples were screened for HTLV-1/2 antibodies using two EIA kits (Vironostika and Murex), and confirmed by WB (HTLV Blot 2.4, Genelabs). The results obtained by EIA disclosed 49 (6.5%) reactive sera: 43 positive by both EIA kits, and six with discordant results. WB confirmed HTLV-1 infection in seven samples (0.9%) and HTLV-2 in 21 sera (2.8%). Negative and indeterminate results were detected in four (0.5%) and 16 (2.1%) sera, respectively. Blood from 47 out of 49 HTLV seroreactive patients were collected and analyzed for the presence of env, LTR and tax genomic segments of HTLVs by PCR. PCR confirmed six cases of HTLV-1 and 37 cases of HTLV-2 infection (14 out of 16 that were found to be WB indeterminate). Restriction analysis of the env PCR products of HTLV-2 disclosed 36 isolates of HTLV-2a/c subtype, and one of HTLV-2b subtype. These results emphasize the need of improving serologic tests for detecting truly HTLV-2 infected patients from Brazil, and confirm the presence of HTLV-2b subtype in the South of this country.

Immunoperoxidase technique using an anti-Leishmania (L.) chagasi hyperimmune serum in the diagnosis of culture-confirmed American tegumentary leishmaniasis

The present study reports the production of the rabbit anti-Leishmania (L.) chagasi hyperimmune serum, the standardization of the immunohistochemistry (IHC) technique and the evaluation of its employment in cutaneous leishmaniasis (CL) lesions diagnosed by Leishmania sp. culture isolation. Thirty fragments of active CL lesions were examined as well as 10 fragments of cutaneous mycosis lesions as control group. IHC proved more sensitive in detecting amastigotes than conventional hematoxylin-eosin (HE) stained slides: the former was positive in 24 (80%) biopsies whereas the latter, in 16 (53%) (p = 0.028). The reaction stained different fungus species causing cutaneous mycosis. Besides, positive reaction was noticed in mononuclear and endothelial cells. Nevertheless, this finding was present in the control group biopsies. It is concluded that IHC showed good sensitivity in detecting amastigotes.

Histopathology, serology and cultures in the diagnosis of cryptococcosis

Cryptococcosis is one of the most common opportunistic fungal infections in patients with acquired immunodeficiency syndrome (AIDS). We report 13 cases of cryptococcal infection based on histopathology, serology and cultures. Epidemiological analysis, histochemical techniques of hematoxilin and eosin (HE) and Grocot's silver (GMS), as well special histochemical techniques such as Mayer's mucicarmine (MM) and Fontana-Masson (FM), cryptococcal antigen test (CrAg) and isolation on fungal media: Sabouraud's (SAB), brain-heart infusion agar (BHI) and canavanine-glycine-bromothymol blue (CGB) agar were analyzed. Unsatisfactory staining results by MM stain associated to negative titers by CrAg test, which FM stain confirmed that capsule-deficient Cryptococcus infections were observed in four cases. Eight isolated cases were identified as follows: six cases were infection with Cryptococcus neoformans and two cases were Cryptococcus gattii.

Use of elisa employing homologous and heterologous antigens for the detection of IgG and subclasses (IgG1 and IgG2) in the diagnosis of Canine visceral leishmaniasis

Indirect immunofluorescence is the method recommended for the diagnosis of visceral leishmanisis in dogs, however, the accuracy of this technique is low and its use on a large scale is limited. Since ELISA does not present these limitations, this technique might be an option for the detection of IgG or specific IgG1 and IgG2 subclasses. Canine ehrlichiosis is an important differential diagnosis of American Visceral Leishmaniasis (AVL). The present study compared ELISA using Leishmania chagasi and Leishmania braziliensis antigen for the detection of anti-Leishmania IgG and subclasses in serum samples from 37 dogs naturally infected with L. chagasi (AVL) and in samples from four dogs co-infected with L. braziliensis and L. chagasi (CI). The occurrence of cross-reactivity was investigated in control serum samples of 17 healthy dogs (HC) and 35 infected with Ehrlichia canis (EC). The mean optical density obtained for the detection of IgG was significantly higher when L. chagasi antigen was used, and was also higher in subgroup VLs (symptomatic) compared to subgroup Vla (asymptomatic). The correlation between IgG and IgG1 was low. The present results suggest that IgG ELISA using homologous antigen yields the best results, permitting the diagnosis of asymptomatic L. chagasi infection and the discrimination between cases of AVL and ehrlichiosis in dogs.

USEFULNESS OF kDNA PCR IN THE DIAGNOSIS OF VISCERAL LEISHMANIASIS REACTIVATION IN CO-INFECTED PATIENTS

SUMMARYIt is important to develop new methods for diagnosing relapses in the co-infection of visceral leishmaniasis (VL) and HIV to enable earlier detection using less invasive methods. We report a case of a co-infected patient who had relapses after VL treatment, where the qualitative kDNA PCR showed a good performance. The kDNA PCR seems to be a useful tool for diagnosing VL and may be a good marker for predicting VL relapses after treatment of co-infected patients with clinical symptoms of the disease.

The Role of Sensory Modulation Deficits and Behavioral Symptoms in a Diagnosis for Early Childhood

To contribute to the validation of the sensory and behavioral criteria for Regulation Disorders of Sensory Processing (RDSP) (DC:0-3R, 2005), this study examined a sample of toddlers in a clinical setting to analyze: (1) the severity of sensory modulation deficits and the behavioral symptoms of RDSP; (2) the associations between sensory and behavioral symptoms; and (3) the specific role of sensory modulation deficits in an RDSP diagnosis. Based on clinical observations, 78 toddlers were classified into two groups: toddlers with RDSP (N = 18) and those with‘‘other diagnoses in Axis I/II of the DC:0-3R’’ (OD3R; N = 60). The parents completed the Infant Toddler Sensory Profile and the Achenbach Checklist. The results revealed that the RDSP group had more severe sensory modulation deficits and specific behavioral symptoms; stronger, although not significant, associations between most sensory and behavioral symptoms; and a significant sensory modulation deficit effect. These findings support the validity of RDSP.