Correlation between specific IgM levels and percentage IgG-class antibody avidity to Toxoplasma gondii

Toxoplasmosis is an usually asymptomatic worldwide disseminated infection. In its congenital presentation it may lead to abortion or fetal malformations. Antenatal evaluation is considered of paramount importance to identify seronegative women and allow for prophylaxis. Recent improvements in sensitivity of IgM tests has made IgM detection an extremely protracted acute phase marker, and IgG avidity evaluation test became necessary. Observation has shown that a correlation can be established between IgM levels and avidity percentages, suggesting that frequently the avidity test may not be necessary. In this study we analyzed Toxoplasma gondii IgM levels of 202 samples and their IgG avidity percentages, in order to define specific levels whose IgM quantification could by itself define serodiagnosis and therefore make the avidity evaluation unnecessary. We showed that for IgM levels bellow 2.0 and above 6.0 serodiagnosis of toxoplasmosis could be established without need of IgG avidity test. IgM levels between these two parameters are associated with varying avidity indexes highlighting the importance of its evaluation as a means to confirm toxoplasmosis. Following this demonstration it was possible to avoid the avidity test for 75% of the cases, to reduce the turnaround time and to reduce costs.

SERUM LEVELS OF COPPER AND IRON IN DENGUE FEVER

SUMMARY The role of trace elements in dengue virulence is not yet known. The present study assessed the serum levels of two micronutrients, copper and iron, in cases of dengue fever. The study involved 96 patients of whom 48 had either severe or non-severe forms of dengue (with and without warning signs), and the remaining 48 were patients with other febrile illnesses (OFI), used as controls. Serum levels of copper and iron were evaluated at admission and by the time of defervescence using commercially available kits. At admission, no difference in the level of serum copper was observed between cases and controls. In the group of dengue cases, the copper level was found to be significantly decreased in severe and non-severe cases with warning signs, compared to non-severe cases without warning signs. In contrast, by the time of defervescence the copper level was found to be increased in all dengue cases compared to OFI controls, but no difference was observed among dengue cases. Unlike OFI controls, dengue cases showed an increasing pattern of copper levels from admission until defervescence. On the other hand, no such significant differences were observed in the serum level of iron in the clinical groups, except for a decreased iron level found in severe cases, compared to non-severe dengue without warning signs. The results show that copper is associated with dengue severity and this finding emphasizes the need to investigate the involvement of trace elements in disease severity so as to improve the prognosis of dengue.

Pattern of acquisition of rotavirus antibody in children followed up from birth to the age of three years

Nine hundred and forty-eight serum samples from 83 children living in Belem, Brazil, collected'within their first three years of life, were testedfor the presence of group- specific rotavirus-antibody by an enzyme-linked immunosorbent assay (ELISA) blocking-test. Passively transferred maternal antibody lasted about two and half months; subsequentely, low levels of rotavirus antibody started to appear at seven months, reaching a peak at eleven months of age. From one year onwards positivity gradually increased, reaching highest values at 34 months of life. Individual responses were examined in sera from 61 children who were followed up since birth to three years of age: 38 (62,3%) ofthem developed a long-term immunity following first infection; eleven (18.0%) children developed a short-term immunity after first infection by rotavirus; seven (11.5%) had no antibody response within their first three years of life; and 5 (8.2%) showed positive antibody response from birth to three years old.

Cytokine serum levels in patients infected by human immunodeficiency virus with and without Trypanosoma cruzi coinfection

This study assessed the number of CD4 T lymphocytes, the parasitemia and serum levels of interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), interleukin-1 (IL-1), IL-4 and IL-10 of patients infected by human immunodeficiency virus (HIV) and human immunodeficiency virus/Chagas' disease coinfection. CD4 T lymphocytes were low in the two groups of patients, although significantly lower in patients without Chagas' disease. Serum levels of IFN-gamma, IL-4 and TNF-alpha were significantly higher in patients with HIV/Chagas' disease. IL-4/IFN-gamma ratios were higher in patients with HIV/Chagas' disease, which showed a clear balance in favor of Th2-like cytokines in this group of patients. This Th2 balance was higher in patients with detectable parasitemia. We conclude that, although immunosuppression was observed, with CD4 T lymphocytes bellow 200/µm³, these patients did not display reactivation of T. cruzi infection and that a balance favorable to Th2 was associated with the presence of parasitemia.

Serum levels of interleukin-6, tumor necrosis factor-alpha and interferon-gama in infants with and without dengue

This study compared the serum levels of IL-6, TNF-alpha and IFN-gamma, in children under 1 year of age with and without dengue. Sera were collected from a total of 41 children living in the Department of Antioquia, Colombia (27 patients with dengue and 14 controls). The results showed higher cytokine levels in children with dengue than without dengue, with statistically significant differences for IL-6 and IFN-gamma. No statistically significant differences were found between clinical forms, although IL-6 and IFN-gamma levels were higher in dengue fever cases than in dengue hemorrhagic fever cases. On the other hand, TNF-alpha levels were higher in dengue hemorrhagic fever than in dengue fever. The levels of IL-6 and TNF-alpha were higher in secondary infection than in primary infection, although IFN-gamma levels were higher in primary infection. These results suggest that IL-6, TNF-alpha and IFN-gamma are involved in dengue infection independently of the clinical form.

Serum proteins and fractions, HDL-cholesterol and total IgG and IgE levels in cases of acute and chronic paracoccidioidomycosis

This study evaluated serum protein fractions, HDL-cholesterol, total immunoglobulin G and total immunoglobulin E levels in patients with acute and chronic paracoccidioidomycosis, by means of electrophoresis, enzymatic reaction and immunoenzymatic assay. The results demonstrated elevated levels of total immunoglobulin G, total immunoglobulin E, alpha-2 and gamma-globulins, which were more evident in acute than in chronic PCM, but no increase in HDL-cholesterol levels. There was a correlation between the levels of total immunoglobulin E and gamma-globulins and the alpha-2 and beta-globulin fractions in the acute form and between beta and gamma-globulins in both the acute and the chronic form. In conclusion, changes in total immunoglobulin G and immunoglobulin E levels and in the electrophoretic profile may be important markers for the prognosis and therapeutic follow-up of PCM cases, especially because protein electrophoresis is a simple laboratory test that can be applied when specific PCM serological tests are not available. In addition, levels of the gamma-globulin fraction greater than 2.0g/dl may suggest that the patient is developing a more severe form of PCM.

Digoxin serum levels in patients with Chagas' cardiomyopathy and heart failure

INTRODUCTION: The purpose of this study was to determine digoxin serum concentrations in patients with Chagas' cardiomyopathy with chronic heart failure, because little is known concerning this laboratory test in patients with this condition. METHODS: This study focuses on 29 (29%) out of 101 patients with chronic heart failure secondary to Chagas' cardiomyopathy receiving digoxin therapy. Digoxin was measured by the immune-enzymatic method. RESULTS: New York Heart Association Functional Class III/IV was noted in 13 (45%) patients. The mean potassium serum level was 4.3± 0.5mEq/L, mean creatinine serum levels 1.4± 0.3dg/100ml, and left ventricular ejection fraction 34.7± 13.8%. The median digoxin serum level was 1.27 (0.55; 1.79)ng/ml. Sixteen (55%) patients had digoxin serum levels higher than 1.0ng/ml. Abnormal digoxin serum levels were verified in 13 (45%) patients. Digoxin serum levels correlated moderately with creatinine serum levels (r = 0.39; p< 0.03) and negatively with sodium serum levels (r= -0.38; p= 0.03). CONCLUSIONS: Digoxin serum concentration should be measured in patients with Chagas' cardiomyopathy with chronic heart failure receiving digoxin therapy due to the potential for digoxin toxicity.

Preoperative serum levels of ca 72-4, cea, ca 19-9, and Alpha-fetoprotein in patients with gastric cancer

INTRODUCTION: The clinical importance of preoperative serum levels of CA 72-4, carcinoembryonic antigen (CEA), CA 19-9, and alpha-fetoprotein (AFP) was prospectively evaluated in 44 patients with gastric cancer. METHOD: The serum tumor marker levels were determined by commercial radioimmunoassay kits. Positivity for CA 72-4 (>4 U/mL), CEA (>5 ng/mL), CA 19-9 (>37 U/mL), and AFP (>10 ng/mL) were correlated according to the stage, histology, and lymph node metastasis. RESULTS AND DISCUSSION: CA 72-4 showed a higher positivity rate for gastric cancer (47.7%) than CEA (25%), CA 19-9 (25%), and AFP (0%). The combination of CA 72-4 with CEA and CA 19-9 increased the sensitivity to 61.4%. The positivity rates of CA 72-4 in patients at stages I and II (initial disease) and in patients at stages III and IV (advanced disease) were 9% and 60.6%, respectively (P < 0.005). No correlation was found between CEA and CA 19-9 levels and the stage of gastric cancer. There was a tendency of positivity for CA 72-4 to suggest lymph node involvement, but it was not significant (P = 0.075). Serum levels of tumor markers did not show a correlation with the histological types of gastric cancer. CONCLUSION: Preoperative serum levels of CA 72-4 provided a predictive value in indicating advanced gastric cancer.

Serum uric acid levels in Chagas' disease

Uricemia was studied in a sample of 192 individuals from a highly endemic site for Chagas' disease (Bambuí, State of Minas Gerais, Brazil). The sample had serologically negative individuals (controls) and the positive ones were classified on the basis of the presence of electrocardiographic alterations (63), altered esophageal emptying (16), or without any sign on sympton of the disease (76). Only the individuals with the digestive form of chronic Chagas' disease showed hyperuricemia, when compared with the appropriate controls. Family data suggest that hyperuricemia is an effect of the digestive pathology, rather than a cause, since the non-infected sibs of the megaesophagous patients did not show elevated levesl of serum uric acid. Possible mechanisms responsible for these findings are postulated.

Evaluation of antibody responses in american visceral leishmaniasis by ELISA and immunoblot

American visceral leishmaniasis (AVL) is an important disease among children of northeast Brazil. In order to characterize antibody responses during AVL, sera of hospitalized patients were analyzed by ELISA and Western blot using a Leishmania chagasi antigen preparation. The ELISA was positive (asorbance [greater than or equals to] 0.196) at a serum dilution of 1:1024 in all patients at presentation, and fell to ward control levels over the following year. Only one of 72 control subjects tested positive, and that donor had a sibling with AVL. Immunoblots of the patients' sera recognized multiple bands, the most frequent of which were at approximately 116 kDa, 70 kDa, and 26 kDa. Less frenquently observed were bands at approximately 93 kDa, 74 kDa, 62 kDa, 46 kDa and 32 kDa. The ELISA responses and patterns of banding were distinctive for AVL, and could be used to differentiate patients with AVL from those with Chagas' disease of cutaneous leishmaniasis. Sera from six AVL patients followed for up to six weeks after treatment identified no new bands. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of surface iodinated parasite proteins showed one major band and four minor bands, whereas SDS-PAGE of biotinylated prarasite proteins revealed a banding pattern similar to those of patient sera. AVL appears to produce characteristic immunoblot patterns which can be used along with a sensitive screening ELISA to diagnose AVL.

Circulating soluble CR1 (CD35). Serum levels in diseases and evidence for its release by human leukocytes.

C receptor type 1 (CR1, CD35) is present in a soluble form in plasma (sCR1). Soluble CR1 was measured with a specific ELISA assay in normal individuals and in patients with different diseases. The mean serum concentration of sCR1 in 31 normal donors was 31.4 +/- 7.8 ng/ml, and was identical in plasma. An increase in sCR1 was observed in 36 patients with end-stage renal failure on dialysis (54.8 +/- 11.7 ng/ml, p &lt; 0.0001), and in 22 patients with liver cirrhosis (158.3 +/- 49.9 ng/ml, p &lt; 0.0001). The mean sCR1 levels dropped from 181 +/- 62.7 to 52.1 +/- 24.0 ng/ml (p &lt; 0.001) in nine patients who underwent liver transplantation, and was 33.5 +/- 7.3 in 10 patients with functioning renal grafts, indicating that the increase in sCR1 was reversible. Soluble CR1 was elevated in some hematologic malignancies (&gt; 47 ng/ml), which included B cell lymphoma (12/19 patients), Hodgkin's lymphoma (4/4), and chronic myeloproliferative syndromes (4/5). By contrast, no increase was observed in acute myeloid or lymphoblastic leukemia (10) or myeloma (5). In two patients with chronic myeloproliferative syndromes, sCR1 decreased rapidly after chemotherapy. The mean concentration of sCR1 was not significantly modified in 181 HIV-infected patients at various stages of the disease (34.8 +/- 14.4 ng/ml), and in 13 patients with active SLE (38.3 +/- 19.6 ng/ml), although in both groups the number of CR1 was diminished on E. There was a weak but significant correlation between sCR1 and CR1 per E in HIV infection and SLE (r = 0.39, p &lt; 0.0001, and r = 0.60, p &lt; 0.03 respectively). In vitro, monocytes, lymphocytes, and neutrophils were found to release sCR1 into culture supernatants. In vivo, sCR1 was detected in the serum of SCID mice populated with human peripheral blood leukocytes. The sCR1 levels correlated with those of human IgG (r = 0.97, p &lt; 0.0001), suggesting synthesis of sCR1 by the transferred lymphocytes. The mechanisms underlining the increased levels of sCR1 and its biologic consequences remain to be defined.

Detection of the common acute lymphoblastic leukemia antigen in the serum of leukemia patients.

The common acute lymphoblastic leukemia antigen (CALLA) has been detected in biological fluids using a radioimmunoassay based on the inhibition of binding of 125I-labeled monoclonal anti-CALLA antibody to glutaraldehyde-fixed NALM-1 cells. With this assay, we showed first that CALLA was released in culture fluids from NALM-1 and Daudi cell lines but was absent from culture fluids from CALLA negative cell lines. Then, we found that the sera of 34 out of 42 patients (81%) with untreated common acute lymphoblastic leukemia (c-ALL) contained higher CALLA levels than any of the 42 serum samples from healthy controls. The specificity of these results was further demonstrated by testing in parallel the sera from 48 patients with CALLA negative leukemias, including 26 acute myeloid leukemia (AML), 12 T-cell acute lymphoblastic leukemia (T-ALL), and 10 acute undifferentiated leukemia (AUL). All of these sera gave negative results, except for one patient with AUL, who had a significantly elevated circulating CALLA level, and one patient with AML, who had a borderline CALLA level, 3 SD over the mean of the normal sera. Preliminary results suggest that circulating CALLA is associated with membrane fragments or vesicles, since the total CALLA antigenic activity was recovered in the pellet of the serum samples centrifuged at 100,000 g. In addition, the CALLA-positive pellets contained an enzyme considered as a membrane marker, 5'-nucleotidase. Evaluation of the clinical importance of repeated serum CALLA determinations for the monitoring of c-ALL patients deserves further investigation.

Circulating Antigens Levels in Different Clinical Forms of the Schistosoma mansoni Infection

With the aim to evaluate the circulating cathodic antigen (CCA) levels in relation to the different clinical phases of Schistosoma sp. infection a sandwich ELISA using monoclonal antibody 5H11 was performed. The sera of three groups of 25 Brazilian patients with acute, intestinal and hepatosplenic forms of S. mansoni infection were tested and compared to a non-infected control group. Patients and control groups were matched for age and sex and the number of eggs per gram of feces was equally distributed among the three patient groups. Sensitivity of 100%, 72%, 52% of the assay was observed for the intestinal, hepatosplenic and acute toxemic groups respectively. The specificity was 100%. Intestinal and hepatosplenic groups presented CCA levels significantly higher in comparison to those observed for acute patients (F-ratio = 2,524; p = 0.000 and F-ratio = 6,314; p = 0.015 respectively). There was no significant difference of CCA serum levels between hepatosplenic and intestinal groups (F-ratio = 1,026; p = 0.316).

Serum and CSF levels of neuron-specific enolase (NSE) in cardiac surgery with cardiopulmonary bypass: a marker of brain injury?

We investigated whether neuron-specific enolase (NSE) in serum or cerebrospinal fluid (CSF) reflects subtle or manifest brain injury in children undergoing cardiac surgery using cardiopulmonary bypass (CPB). NSE was measured in serum (s-NSE) before, and up to, 102 h after surgery in 27 children undergoing cardiac surgery with CPB. In 11 children, CSF-NSE was also measured 48 or 66 h post-surgery. As erythrocytes contain NSE, hemoglobin concentration in the samples was determined spectrophotometrically at 550 nm (cut-off limit: absorbance 0.4 = 560 mg/l) in 14 children and in a further 13 children by spectroscopic multicomponent analysis (cut-off limit 5 micromol/l = 80 mg/l). One hundred and one of 214 post-operative serum samples (47%) had to be discarded because of hemolysis (18% spectrophotometrically at 550 nm and 88% with spectroscopic multicomponent analysis). On the first and second post-operative day, the median s-NSE values were significantly higher when compared with samples taken after 54 h or longer (P = 0.008 and P = 0.002). All CSF-NSE levels were within the normal range and below the s-NSE measured in the same patient. Although in our study elevated s-NSE seems to indicate brain injury in CPB-surgery, the low concentration of NSE in the post-operative CSF of 11 children puts the neuronal origin of s-NSE in question. NSE from other non-neuronal tissues probably contributes to the elevated s-NSE. Additionally, normal post-operative CSF-NSE values in two children with post-operative neurological sequelae might question the predictive value of CSF-NSE with regard to brain injury.