Ana del Pozo

WHO comparative evaluation of serologic assays for Chagas disease

BACKGROUND: Evaluation of commercially available test kits for Chagas disease for use in blood bank screening is difficult due to a lack of large and well‐characterized specimen panels. This study presents a collaborative effort of Latin American blood centers and the World Health Organization (WHO) to establish such a panel.

Estimation of sensitivity and specificity of several Trypanosoma cruzi antibody assays in blood donors in Argentina.

BACKGROUND: The absence of a gold standard test for Trypanosoma cruzi antibodies represents a problem not only for the evaluation of screening tests, but also for appropriate blood donor counseling. The aim of this study was to estimate the sensitivity and specificity of multiple blood donor screening tests for T. cruzi antibodies in Argentina.

Transfusion‐transmitted infectious diseases in Argentina, 1995 through 1997

BACKGROUND: Assessment of the safety of the blood supply, the quality of screening procedures, and the risk of transfusion transmission of infectious diseases in any country can be estimated by reviewing the records of blood donations and screening procedures and the prevalence of serologic markers of infectious diseases.

Neuroprotective effects of human umbilical cord mesenchymal stromal cells in an immunocompetent animal model of Parkinson's disease

Microglial activation in the substantia nigra (SN) is a ubiquitous feature in PD which could mediate toxic effects. Human mesenchymal stromal cells (hMSCs) possess immunomodulatory properties. We evaluated whether the transplantation of hMSCs obtained from umbilical cord had a neuroprotective effect in a not-immunosuppressed rat Parkinsons disease (PD) model. Rats receiving hMSCs in the SN displayed significant preservation in the number of dopaminergic neurons in the SN at 21 days after lesion and an improved performance in behavioral tests compared to control rats. However, no differences in any inflammatory parameter tested were found. These results suggest that grafted hMSCs exert neuroprotection but not neuromodulatory effects on degenerating dopaminergic neurons.

Antibodies to hepatitis C and other viral markersin multi-transfused patients from Argentina

BACKGROUND The knowledge of transfusion-transmitted viral infections in Argentina is scarce. A regional study organized by the Pan American Health Organization let us asses the current status. OBJECTIVES To estimate the prevalence of HCV, HBV and HIV infection in a population of multi-transfused Argentinean patients. STUDY DESIGN Multi-center, cross sectional study of 504 patients from national referral institutions in Buenos Aires, who had received more than ten units of blood products in more than two occasions. Demographic and clinical data were collected using a standardized questionnaire. Blood samples were analyzed for a-HCV, a-HIV, HBsAg and a-HBcore. RESULTS Patients belonged to five diagnostic categories: onco-hematology (309; 61.3%); hemophilia (96; 19%); acute blood loss (54; 10.7% ); hemoglobinopathies (35; 6.9%); and hemodialysis (5; 1% ); five patients (1%) had two of the previous conditions. Overall prevalence rates of viral markers were: a-HCV 9.3% (CI(95%): 6.7-12.0); a-HBcore 4.8% (CI(95): 2.8-6.7); a-HIV 1.2% (CI(95%): 0.14-2.2) and HBsAg 0.20%(CI(95%): 0.2-0.59). The highest prevalence rates were found among patients living with hemophilia (PLH). There was a significant statistical association (p < 10(-5), OR =78.8 [29.7-209.7]) between a-HCV infection and having been transfused before 1993, when screening blood donors for a-HCV became mandatory in our country. The subpopulation of patients exposed to transfusion before 1993 was conformed mostly by PLH (70.9%) and hemoglobinopathies (18.6%). In this subpopulation, we found a significant association (p < 10(Dot;), OR -40 [5.68-281.66]) between years of exposure to transfusion and a-HCV among the patients under the median age (21.95 years old); however, there was no association for those above the median age (p=0.111). CONCLUSION a-HCV was found to be the most prevalent infection in the multi-transfused patient population under study. Most infected individuals were PLH, transfused before 1993. This study will provide support for further research aimed at improving blood safety in Argentina.

Bimodal distribution of Trypanosoma cruzi antibody levels in blood donors from a highly endemic area of Argentina: what is the significance of low‐reactive samples?

Low‐level seroreactive donor samples that are inconsistently detected by different Trypanosoma cruzi immunoassays are common, but the population distribution has not been reported in an endemic region. The objective was to understand the distribution of low‐level reactive samples using highly sensitive immunoassays and the relationship with epidemiologic evidence of exposure to T. cruzi.

HTLV-I proviral load in Argentinean subjects with indeterminate western blot patterns

Methodology A total of 87 indeterminate WB samples (HTLV blot 2.4 assayGenelabs Diagnostics-) were studied over a 10 year period referred from the Blood Bank at Garrahan Hospital (n=83) and from the Virology Unit at Muniz Hospital (n=4). HTLV-I and –II tax and pol proviral sequences were amplified by in-house nested PCR assays. HTLV-I pVL was estimated by a quantitative real-time PCR assay targeting the HTLV-I pol gene and the albumin gene as normalizer. The limit of detection of the assay was 2.6 log10 copies of HTLV-I/106 PBMCs (0.04% copies/100 PBMCs).

Re: “WHO evaluation of the serologic assays for Chagas disease”

to the rheology and to the adverse effects in patients as observed by Koch and coworkers. The results of the current rheologic studies and the survival studies can be considered complementary to each other, rather than contradictory. It suggests that not the altered rheology, nor membrane receptor expression (both would apply more or less to the whole population), but release products, such as iron or cytokines, contribute to the clinically adverse effects. These release products may even exist in part in the transfusion bag. If this can be proven it may result in effective measures, such as cell wash or antioxidant strategies. The implications of these observations also reach to the use of autotransfusion of suctioned blood during (heart) operation procedures, as discussed by Adamson. Even when the overall quality of these suctioned RBCs is good, it may contain a fraction of damaged or removalprone RBCs, which has clinical adverse effects in patients after transfusion. Since the quantity of suctioned blood during cardiopulmonary bypass procedures is substantial, a combined effect of older banked blood and suctioned blood is conceivable.