Helio Moraes-Souza

Morbimortalidade em doença falciforme

A alta morbimortalidade referida na doenca falciforme (DF) levou-nos a estudar o perfil epidemiologico e respectivas intercorrencias clinicas dos pacientes atendidos no Hemocentro Regional (HR) e Hospital de Clinicas da Universidade (HC-U), de 1998 a 2007. Estudo retrospectivo de 151 pacientes, avaliados quanto a: idade, genero, cor da pele, procedencia, diagnostico, causa de atendimento no HR, causa e tempo de internacao no HC-U e a causa e a idade em caso de obito. Foi realizada analise estatistica descritiva simples. A media de idade foi de 17,7 anos, 52,4% eram do genero feminino, 58,2% procediam da cidade de Uberaba e em 92,2% dos prontuarios nao foram encontrados relatos sobre a cor da pele. A anemia falciforme representou 82,5% dos casos. Dos 910 atendimentos no HR e 589 internacoes no HC-U, a crise dolorosa afebril foi a causa mais frequente em ambas as instituicoes (61,9% e 25,3%, respectivamente). A idade media dos 11 obitos foi de 33,5 anos, sendo apenas um em menor de 10 anos e a falencia de multiplos orgaos a causa mais frequente. O perfil epidemiologico mostra predominio de criancas e adultos jovens, sexo feminino e genotipo SS. As taxas de internacao no HC-U, de atendimento no HR e a baixa media de idade ao obito confirmam a alta morbidade e mortalidade da DF. Contudo, o grande numero de criancas sem intercorrencias e/ou internacoes reflete a eficacia das medidas preventivas propiciadas pelo diagnostico precoce implantado nos ultimos 10 anos.

O controle da transmissão transfusional

The high prevalence of chagasic blood donors in blood centers in Brazil (6.9%) and in Latin America (6.5%) in the 60s and 70s, together with the combat to the vector since the 70s have made transfusion Chagas disease the main mechanism of the disease transmission in the 80s. However, the highly favorable results achieved to eliminate the vector and the serologic screening of blood donors, reduced the prevalence of serum positivity to 0.2% and 1.3%, respectively and the rate of annual transmission through blood transfusion from 20.000 to 13 in four decades in Brazil. Nevertheless, despite outstanding advancements in endemic countries, Chagas disease reached, via migration, non-endemic countries in North America and Europe besides Japan and Australia, placing their blood recipients at risk and turning Chagas disease into a worldwide health problem. Transfusion safety through serologic selection raised another big issue i.e. high proportion of inconclusive reactions as well as two great challenges: the meaning of such exams and what guidelines to provide the donor. However, the strategies adopted by non-endemic countries and the advancements achieved by endemics so far forecast the highly wished vector and transfusion control of Chagas disease.

The application of latent class analysis for diagnostic test validation of chronic Trypanosoma cruzi infection in blood donors.

The main strategy to prevent transfusion-associated Chagas disease is the identification of T. cruzi-infected blood donors by serological screening tests, however there is no perfect serological gold standard. We evaluated an enzyme immunoassay (EIA), an indirect hemaglutination (IHA), and an indirect immunofluorescence (IIF) test for detecting T. cruzi antibodies in Brazilian blood donors. The results were submitted to latent class analysis, and a radioimmunopreciptation (RIPA) test was performed on repeatedly positive samples. Among 1951 donors, 11 (0.56%) were positive by EIA, 6 (0.31%) by IHA and 16 (0.82%) by IIF. Six samples were positive with all tests, while 4 reacted with EIA and IIF. The RIPA was positive in 6 (75.0%), 7 (66.6%), and 4 (54.0%) samples reacting by the EIA, IHA and IIF tests, respectively. The latent class model detected a high sensitivity rate (100%) for the EIA and IIF, and a specificity rate of 99.95% and 99.69% for the EIA and IIF tests, respectively. The probability of being case according to the model was 99.92% when both EIA and IIF were positive, and 100% for the association of EIA, IIF, and IHA.

Alloimmunization screening after transfusion of red blood cells in a prospective study

Background Several irregular red blood cell alloantibodies, produced by alloimmunization of antigens in transfusions or pregnancies, have clinical importance because they cause hemolysis in the fetus and newborn and in transfused patients. Objective a prospective analysis of patients treated by the surgical and clinical emergency services of Hospital de Clínicas of the Universidade Federal do Triângulo Mineiro (HC/UFTM), Brazil was performed to correlate alloimmunization to clinical and epidemiological data. Methods Blood samples of 143 patients with initial negative antibody screening were collected at intervals for up to 15 months after the transfusion of packed red blood cells. Samples were submitted to irregular antibody testing and, when positive, to the identification and serial titration of alloantibodies. The Fisher Exact test and Odds Ratio were employed to compare proportions. Results Fifteen (10.49%) patients produced antibodies within six months of transfusion. However, for 60% of these individuals, the titers decreased and disappeared by 15 months after transfusion. Anti-K antibodies and alloantibodies against antigens of the Rh system were the most common; the highest titer was 1:32 (anti-K). There was an evident correlation with the number of transfusions. Conclusions Given the high incidence of clinically important red blood cell alloantibodies in patients transfused in surgical and clinical emergency services, we suggest that phenotyping and pre-transfusion compatibilization for C, c, E, e (Rh system) and K (Kell system) antigens should be extended to all patients with programmed surgeries or acute clinical events that do not need emergency transfusions.

Socioepidemiological screening of serologically ineligible blood donors due to Chagas disease for the definition of inconclusive cases

Epidemiological screening combined with serological tests has become an important tool at blood banks for the characterization of donors with or without Trypanosoma cruzi infection. Thus, the objective of the present study was to describe the sociodemographic and epidemiological characteristics of blood donors with non-negative serology for T. cruzito determine possible risk factors associated with serological ineligibility. Sociodemographic and epidemiological data were collected by analysis of patient histories and interviews. The data were analyzed descriptively using absolute and relative frequencies and odds ratio (OR) evaluation. The frequency of serological ineligibility was 0.28%, with a predominance of inconclusive reactions (52%) and seropositivity among first-time donors (OR = 607), donors older than 30 years (OR = 3.7), females (OR = 1.9), donors from risk areas (OR = 4) and subjects living in rural areas (OR = 1.7). The risk of seropositivity was higher among donors who had contact with the triatomine vector (OR = 11.7) and those with a family history of Chagas disease (OR = 4.8). The results demonstrate the value of detailed clinical-epidemiological screening as an auxiliary tool for serological definition that, together with more specific and more sensitive laboratory methods, will guarantee a higher efficacy in the selection of donors at blood centres.

Epidemiological profile of hepatitis C in blood donors at the Uberaba Regional Blood Center

The aim of the present study was to outline the serological profile of hepatitis C among blood donors seen at the Uberaba Regional Blood Center, Hemominas Foundation, over the last 14 years. The frequency of hepatitis C was compared between first-time and repeat donors and the epidemiological characteristics of those with positive and indeterminate ELISA anti-HCV (third and fourth generation) were analyzed based on the donor histories kept in the archives of the Uberaba Regional Blood Center. The serological ineligibility rate was 0.3%, with higher prevalence in the group of first-time donors. We did not find any significant differences regarding age, skin color, marital status or place of residence between eligible and ineligible donors; however, the frequency of positive serology was higher among men. The lower (0.3%) rate of ineligibility due to hepatitis C that was observed at the Uberaba Regional Blood Center, in relation to most Brazilian blood centers, is probably due to the large number of repeat donors (83.3%). This reinforces the importance of achieving donor commitment for increasing transfusion safety.

Identification of platelet refractoriness in oncohematologic patients

OBJECTIVES: To identify the occurrence and the causes of platelet refractoriness in oncohematologic patients. INTRODUCTION: Platelet refractoriness (unsatisfactory post-transfusion platelet increment) is a severe problem that impairs the treatment of oncohematologic patients and is not routinely investigated in most Brazilian services. METHODS: Forty-four episodes of platelet concentrate transfusion were evaluated in 16 patients according to the following parameters: corrected count increment, clinical conditions and detection of anti-platelet antibodies by the platelet immunofluorescence test (PIFT) and panel reactive antibodies against human leukocyte antigen class I (PRA-HLA). RESULTS: Of the 16 patients evaluated (median age: 53 years), nine (56%) were women, seven of them with a history of pregnancy. An unsatisfactory increment was observed in 43% of the transfusion events, being more frequent in transfusions of random platelet concentrates (54%). Platelet refractoriness was confirmed in three patients (19%), who presented immunologic and non-immunologic causes. Alloantibodies were identified in eight patients (50%) by the PIFT and in three (19%) by the PRA-HLA. Among alloimmunized patients, nine (64%) had a history of transfusion, and three as a result of pregnancy (43%). Of the former, two were refractory (29%). No significant differences were observed, probably as a result of the small sample size. CONCLUSION: The high rate of unsatisfactory platelet increment, refractoriness and alloimmunization observed support the need to set up protocols for the investigation of this complication in all chronically transfused patients, a fundamental requirement for the guarantee of adequate management.

Decline in the prevalence of HTLV-1/2 among blood donors at the Regional Blood Center of the City of Uberaba, State of Minas Gerais, from 1995 to 2008

INTRODUCTION A retrospective study was conducted in order to assess the prevalence and factors associated with seropositivity for HTLV-1/2 between 1995 and 2008 in Uberaba Regional Blood Center, and to describe the seropositive blood donors in relation to gender, age, marital status, skin color and origin. METHODS Descriptive statistical analysis, chi-square tests and odds ratios were produced to compare proportions, along with scatter charts with linear correlation coefficients. RESULTS Among the donors tested, the prevalence of seropositivity for HTLV was found to be 0.02%, with indeterminate results in 0.09%. There was a significant reduction in seropositivity for HTLV between 2002 and 2008, compared with the period from 1995 to 2001. Among the seropositive individuals, females were significantly predominant. CONCLUSIONS The gradual decrease in seropositivity over this period was attributed to the permanent exclusion of seropositive repeat donors and improvement in the clinical screening methods and serological tests over the years, with a positive impact on transfusion safety.INTRODUCAO: Estudo retrospectivo com o objetivo de avaliar a prevalencia e fatores associados a soropositividade para o HTLV-1/2, no periodo de 1995 a 2008, no Hemocentro Regional de Uberaba e descrever os doadores soropositivos quanto ao genero, idade, estado civil, cor de pele e procedencia. METODOS: Foram realizados analise estatistica descritiva, testes qui-quadrado e odds ratio para comparacao de proporcoes e grafico de dispersao com coeficiente de correlacao linear. RESULTADOS: Dentre x doadores testados, foi encontrada a prevalencia de sorologia positiva para o HTLV de 0,02% e indeterminada de 0,09%. Houve uma reducao significativa da sorologia positiva para HTLV, no periodo de 2002 a 2008, em comparacao ao periodo de 1995 a 2001. Dentre os soropositivos, observou predominio significante no genero feminino. CONCLUSOES: Imputamos a queda gradativa de soropositividade no periodo a exclusao permanente dos doadores de repeticao soropositivos e ao aprimoramento dos metodos de triagem clinica e dos testes sorologicos ao longo dos anos com reflexos positivos na seguranca transfusional.

Prevalence of Chagas disease in blood donors at the Uberaba Regional Blood Center, Brazil, from 1995 to 2009

INTRODUCTION A retrospective study was conducted to assess the occurrence of blood donations that were ineligible due to Chagas disease infection from 1995 to 2009 at the Uberaba Regional Blood Center (HRU), Brazil, verify the tendency of this ineligibility, and describe the epidemiologic profile of the donors. METHODS Retrospective studies of serological ineligibility due to Chagas disease, statistical analysis by means of the chi-square test and odds ratio, study of the tendencies using a dispersion graph and the linear correlation coefficient (r) were performed. RESULTS In the period under study, a 0.2% serum prevalence of ineligibility due to Chagas disease was found, with a significant drop in ineligible donations from 2001 to 2009. Among the serum positive-donors, there was a significant predominance among those aged 30 years or above and non-single individuals. CONCLUSIONS The results show a rate of occurrence that is lower than that described in literature, as well as a progressive drop during the 15 years under assessment. Such results are a consequence of systematic combat of the vector since the 70s and the progressive and consistent increase of returning donors, resulting in a drop of the contamination risk factor by means of blood transfusion and in the improvement of the quality of hemotherapy practices in the HRU.

Etiology of anemia of blood donor candidates deferred by hematologic screening

Objective: Iron deficiency is the most common cause of anemia and one of the main factors in the clinical deferral of blood donors. This fact prompted the current study that aimed to determine the prevalence and etiology of anemia in blood donor candidates and to evaluate the hematological screening technique used for the exclusion of these donors. Methods: This was a prospective study that compared two groups (Anemic and Non-anemic). Initially screening for anemia was performed by manually measuring hemoglobin (Bioclin® Kit); the results were subsequently compared with an automated screening method (Coulter T-890). The etiology was investigated by hemoglobin electrophoresis in alkaline and acid pH, Hb A2 dosage and measurement of the ferritin concentration by immunoagglutination. Differences and associations of interest were analyzed using the Yates and McNemars Chi-square tests and the Fisher, Mann-Whitney, Wilcoxon and Kruskal-Wallis tests. Results: The deferral rate due to anemia was 4.2%; iron deficiency was identified in 37.5% and beta thalassemia in 9.3% of the excluded candidates. There was a significant discrepancy between the two techniques used to measure hemoglobin with 38.1% of initially deferred donors presenting normal hemoglobin levels by the automated method. Conclusion: The results show a high rate of blood donors being deferred for anemia and confirm that iron deficiency is the most prevalent cause. The discrepancies found by comparing screening methods suggest that hemoglobin and hematocrit levels should be confirmed before deferring a donor due to anemia; this may increase supplies in blood banks.