Chagas disease: Performance analysis of immunodiagnostic tests anti-Trypanosoma cruzi in blood donors with inconclusive screening results

Background

The screening ofTrypanosoma cruzi-infected blood donors using two serological techniques frequently leads to conflicting results. This fact prompted us to evaluate the diagnostic performance of four “in-house” immunodiagnostic tests and two commercially available enzyme-linked immunosorbent assays (ELISAs).

Material and Methods

One hundred and seventy-nine blood donors, whose screening for Chagas disease was doubtful, underwent three in-house ELISAs, one in-house immunoblotting test (TESA-blot), and two commercial ELISAs (bioMérieux and Wiener) in an attempt to define the presence or absence of infection. Simultaneously, 29 donors with previous positive results from three conventional serological tests and 30 donors with constant negative results were evaluated.

Results

The ELISA-Wiener showed the highest rate in sensitivity (98.92%) and the ELISA-bioMérieux, the highest specificity (99.45%), followed by the TESA-blot, which showed superior performance, with lower false-negative (2.18%) and false-positive (1.12%) rates. In series, the combination composed of the TESA-blot and ELISA-bioMérieux showed slightly superior performance, with trifunctional protein deficiency (TFP) = 0.01%.

Conclusion

Our study confirms the high sensitivity and specificity of commercial kits. To confirm the presence or absence of T. cruzi infection, the combination of TESA-blot and ELISA-bioMérieux may be suggested as the best alternative. Individually, the TESA-blot performed the closest to the gold standard; however, it is not commercially available.

Reappraisal of antibodies against Saccharomyces cerevisiae (ASCA) as persistent biomarkers in quiescent Crohn's disease

A clear correlation exists between microbiota and the dysregulation of the immune response in Inflammatory Bowel Diseases (IBD), which comprise Crohn's disease (CD) and ulcerative colitis (UC). These unbalanced reactions also involve humoral responses, with antibodies against Saccharomyces cerevisiae. Thus, here we aimed to quantify IgA and IgG specific to S. cerevisiae (ASCA) in quiescent CD and UC, to correlate the production of these antibodies with patient's inflammatory response and disease clinical presentation. Twenty-nine subjects (16 CD and 13 UC) and 45 healthy controls were enrolled in this study and had plasma samples tested for ASCA and cytokines (IL-2, IL-4, IL-6, IL-10, IFN-γ, TNF-α), besides clinical evaluation. IBD patients had increase IgA and IgG ASCA, especially those with colonic (L2) and fistulizing (B3) CD. Similarly, patients who dropped out the treatment had augmented ASCA, while IgG was reduced in those receiving sulfasalazine treatment. Furthermore, the quiescent CD patients had elevated IL-6 on plasma, especially in the absence of treatment, together with increased counter regulatory response of IL-10. There was a positive correlation between IgA and IgG on CD but not UC, as well as between IgA and TNF in total IBD patients. In addition, the levels of IgG x TNF, IgA x IL-10 and IgG x IL-10 were also correlated in CD, indicating that ASCA production may be influenced by the inflammatory response. Finally, we concluded that ASCA could be pointed as relevant biomarker of CD presentation and residual inflammation, even in clinical remission patients.

Evaluation of the cytotoxic response mediated by perforin and granzyme B in patients with non-Hodgkin lymphoma

This study quantified the perforin and granzyme B in patients with non-Hodgkin lymphoma (NHL) at the time of diagnosis. Protein quantification was performed by flow cytometry. NHL patients had a higher number of cytotoxic T lymphocytes (CTLs) expressing perforin as well as a greater number of activated CTLs than the control group. However, intracellular perforin levels in natural killer cells were lower in the NHL patients compared to the control group. Quantitative real time PCR showed that patients had more expression of perforin and granzyme B transcripts compared to the control group. In addition, patients who had expression of both genes below the median found for the NHL group had lower survival rates. Considering this, we believe that perforin and granzyme B are potential prognostic markers in NHL and thus it is fundamental to pay attention to their expressions in these patients.

COMPARATIVE ANALYSIS OF IMMUNOLOGICAL PROFILES IN WOMEN UNDERGOING CONVENTIONAL AND SINGLE-PORT LAPAROSCOPIC CHOLECYSTECTOMY

Background

Surgical trauma triggers an important postoperative stress response characterized by significantly elevated levels of cytokines, an event that can favor the emergence of immune disorders which lead to disturbances in the patient's body defense. The magnitude of postoperative stress is related to the degree of surgical trauma.

Aim

To evaluate the expression of pro-inflammatory (TNF-α, IFN-γ, IL-1β, and IL-17) and anti-inflammatory (IL-4) cytokines in patients submitted to conventional and single-port laparoscopic cholecystectomy before and 24 h after surgery.

Methods

Forty women with symptomatic cholelithiasis, ranging in age from 18 to 70 years, participated in the study. The patients were divided into two groups: 21 submitted to conventional laparoscopic cholecystectomy and 19 to single-port laparoscopic cholecystectomy.

Results

Evaluation of the immune response showed no significant difference in IFN-γ and IL-1β levels between the groups or time points analyzed. With respect to TNF-α and IL-4, serum levels below the detection limit (10 pg/ml) were observed in the two groups and at the time points analyzed. Significantly higher postoperative expression of IL-17A was detected in patients submitted to single-port laparoscopic cholecystectomy when compared to preoperative levels (p=0.0094).

Conclusions

Significant postoperative expression of IL-17 was observed in the group submitted to single-port laparoscopic cholecystectomy when compared to preoperative levels, indicating that surgical stress in this group was higher compared to the conventional laparoscopic cholecystectomy.

Evaluation of clinical and laboratory markers of cardiometabolic risk in overweight and obese children and adolescents

OBJECTIVE:

This study analyzed the frequency of cardiometabolic risk markers and metabolic syndrome occurrence in overweight and obese children and adolescents.

METHODS:

The participants included 161 overweight (n=65) and obese (n=96) individuals aged between 5 and 19 years. Clinical markers were assessed (body mass index, body fat percentage, waist circumference, acanthosis, systolic and diastolic blood pressures, laboratory parameters [glucose, insulin, cholesterol (total and fractions) and triglyceride levels and homeostasis model assessment of insulin resistance (HOMA-IR) index] and leptin and adiponectin levels). The frequency of changes, odds ratios and correlations among markers were determined. Metabolic syndrome was assessed according to International Diabetes Federation criteria.

RESULTS:

A high frequency of acanthosis (51.6%); increased waist circumference (45.4%), systolic blood pressure / diastolic blood pressure (8.1% / 9.3%), glucose (10%), insulin (36.9%) and HOMA-IR (44.3%) values; and reduced high-density lipoprotein levels (47.2%) were observed. Leptin levels were increased in 95% of obese and in 66% of overweight subjects. Adiponectin was decreased in 29.5% of obese and in 34% of overweight subjects. An odd ratio analysis revealed a greater probability of increased waist circumference (9.0), systolic blood pressure (4.1), triglyceride (2.3) and insulin (2.9) levels and HOMA-IR (3.0) in the obese group than in the overweight group. The clinical and laboratory parameters and leptin levels exhibited significant correlations, whereas adiponectin was negatively correlated with systolic blood pressure. The occurrence rate of metabolic syndrome was 13.6%.

CONCLUSIONS:

The high frequency of changes in clinical, laboratory and adipokine markers indicates the need for early interventions aimed at preventing cardiometabolic complications in adulthood.

IMMUNOLOGICAL EVALUATION OF PATIENTS WITH TYPE 2 DIABETES MELLITUS SUBMITTED TO METABOLIC SURGERY

BACKGROUND

Immunological and inflammatory mechanisms play a key role in the development and progression of type 2 diabetes mellitus.

AIM

To raise the hypothesis that alterations in immunological parameters occur after duodenojejunal bypass surgery combined with ileal interposition without gastrectomy, and influences the insulin metabolism of betacells.

METHODS

Seventeen patients with type 2 diabetes mellitus under clinical management were submitted to surgery and blood samples were collected before and six months after surgery for evaluation of the serum profile of proinflammatory (IFN-γ, TNF-α, IL-17A) and anti-inflammatory cytokines (IL-4, IL-10). In addition, anthropometric measures, glucose levels and insulin use were evaluated in each patient.

RESULTS

No changes in the expression pattern of proinflammatory cytokines were observed before and after surgery. In contrast, there was a significant decrease in IL-10 expression, which coincided with a reduction in the daily insulin dose, glycemic index, and BMI of the patients. Early presentation of food to the ileum may have induced the production of incretins such as GLP-1 and PYY which, together with glycemic control, contributed to weight loss, diabetes remission and the consequent good surgical prognosis of these patients. In addition, the control of metabolic syndrome was responsible for the reduction of IL-10 expression in these patients.

CONCLUSION

These findings suggest the presence of low-grade inflammation in these patients during the postoperative period, certainly as a result of adequate glycemic control and absence of obesity, contributing to a good outcome of surgery.

Evaluation of DPPD, a single recombinant Mycobacterium tuberculosis protein as an alternative antigen for the Mantoux test

Although the tuberculin test has aided in the diagnosis of tuberculosis for more than 85 years, its interpretation is difficult particularly because sensitization with non-tuberculous mycobacteria leads to false positive tests. Using the guinea pig model of tuberculosis, we have recently described a recombinant antigen (DPPD) that could circumvent this problem. The DPPD gene is unique to the M. tuberculosis complex organisms and is absent in the organisms representative of all other members of the Mycobacterium genus. Moreover, DPPD induced strong DTH in 100% of the guinea pigs infected with M. tuberculosis and in none of the guinea pigs immunized with nine different species of Mycobacterium. Here we present results of a clinical investigation using DPPD. Mantoux test using both PPD and DPPD was initially performed in 26 patients with confirmed pulmonary tuberculosis and in 25 healthy PPD negative individuals. The results indicated that both PPD and DPPD elicited DTH in 24 out of the 26 patients. No DTH was observed in any of the PPD negative individuals. In addition, a small clinical trial was performed in a population of 270 clinically healthy and randomly selected individuals. DPPD produced a bimodal histogram of skin reaction size and PPD produced a skewed histogram. Because the DPPD gene is not present in non-tuberculous bacilli, these results suggest that this molecule can be an additional tool for a more specific diagnosis of tuberculosis.