Herramientas diagnostico-terapéuticas en síndromes mielodisplásicos en Uruguay / Diagnostic and therapeutic tools in myelodysplastic syndromes in Uruguay / Instrumentos diagnóstico-terapêuticos nas síndromes mielodisplásicas no Uruguai

Los Síndromes Mielodisplásicos (SMD) son un grupo heterogéneo de enfermedades mieloides. Esta heterogeneidad en la presentación clínica complejiza el diagnóstico requiriendo diversos estudios complementarios. El tratamiento debe ser individualizado y adaptado al riesgo, desde terapias de soporte hasta intervenciones de alto costo. Para conocer la accesibilidad a las herramientas diagnóstico y terapéuticas se realizó una encuesta online dirigida a los hematólogos que asisten pacientes con SMD en Uruguay en 2016 y 2019. Las encuestas fueron respondidas por 32.5% y 26.6% de los miembros de la Sociedad de Hematología del Uruguay. Más del 90% tienen acceso a estudios histológicos, citogenéticos, FISH y citometría de flujo. La posibilidad de realizar paneles de secuenciación masiva se encuentra restringida a menos de 10% derivando la muestra al exterior, siendo mayor en 2019 en comparación a 2016. Los sistemas de estratificación de riesgo más utilizados son el sistema internacional de puntuación de riesgo (IPSS) y su versión revisada (IPSS-R). La disponibilidad de tratamientos de soporte (transfusiones, eritropoyetina y G-CSF), de azacitidina y del trasplante alogénico de precursores hematopoyéticos es amplia. Existió un aumento en indicación de azacitidina en 2019 con respecto a 2016. Sin embargo, el acceso a decitabina, lenalidomida y fármacos quelantes de hierro es escaso y no se cuenta con ensayos clínicos donde incluir pacientes que fallan o no responden a los tratamientos convencionales. La presente encuesta, realizada en dos períodos, describe la realidad y su evolución en nuestro país en cuanto a accesibilidad a herramientas diagnósticas y terapéuticas extrapolables a otras patologías oncohematológicas. Los datos recabados permitirán plantear estrategias tendientes a mejorar el abordaje diagnóstico-terapéutico de los pacientes con SMD en Uruguay.

Myelodysplastic Syndromes (MDS) constitutes an heterogenous group of hematological malignancies. Reaching an accurate diagnosis, represents in an important number of cases, a major challenge that requires different diagnostic tools. In order to acknowledge the scope of access to those tools in our country, we performed a survey addressed to Uruguayan hematologists who care for MDS patients in their clinical practice. The survey was carried out in 2016 and 2019 among Uruguayan Hematology Society members. Response rate was 32.5% and 26.6% respectively. Access to bone marrow biopsy, cytogenetics, FISH and flow cytometry was accessible to more than 90% of physicians. Less than 10% of respondents were able to request next generation sequencing (NGS) studies and in that case, they have to send them abroad. IPSS and R-IPSS were the most frequently used risk scores. Support treatment such as growth factors and transfusions are widely accessible. Azacytidine and allogenic transplant are available as well. However, access to decitabine, lenalidomide and iron chelating drugs is scarce and there are no clinical trials to include patients who fail or do not respond to conventional treatments. This survey, carried out in two periods, describes the reality and its evolution in our country in terms of accessibility to diagnostic and therapeutic tools that can be extrapolated to other oncohematological pathologies. We were able to get to know our country reality regarding diagnostic and therapeutic tools for MDS patients. This, would represent an important input in order to design health strategies aiming to improve clinical care for our patients.

As Síndromes Mielodisplásicas (SMD) são um grupo heterogêneo de doenças mielóides. Essa heterogeneidade na apresentação clínica torna o diagnóstico mais complexo, exigindo vários estudos complementares. O tratamento deve ser individualizado e adaptado ao risco, desde terapias de suporte até intervenções de alto custo. Para conhecer a acessibilidade de ferramentas diagnósticas e terapêuticas, foi realizada uma pesquisa online dirigida aos hematologistas que atendem pacientes com SMD no Uruguai em 2016 e 2019. As pesquisas foram respondidas por 32,5% e 26,6% dos membros da Sociedad de Hematologia do Uruguai. Mais de 90% têm acesso a estudos histológicos, citogenéticos, FISH e citometria de fluxo. A possibilidade de realização de painéis de sequenciamento massivo está restrita a menos de 10% provenientes da amostra no exterior, sendo maior em 2019 em relação a 2016. Os sistemas de estratificação de risco mais utilizados são o sistema internacional de pontuação de risco (IPSS) e sua versão revisada (IPSS -R). Tratamentos de suporte (transfusões, eritropoietina e G-CSF), azacitidina e transplante alogênico de células-tronco hematopoiéticas estão amplamente disponíveis. Houve aumento da indicação de azacitidina em 2019 em relação a 2016. No entanto, o acesso a decitabina, lenalidomida e quelantes de ferro é escasso e não há ensaios clínicos para incluir pacientes que falham ou não respondem aos tratamentos convencionais. Este inquérito, realizado em dois períodos, descreve a realidade e a sua evolução no nosso país em termos de acessibilidade a instrumentos diagnósticos e terapêuticos que podem ser extrapolados para outras patologias onco-hematológicas. Os dados coletados permitirão propor estratégias destinadas a melhorar a abordagem diagnóstico-terapêutica de pacientes com SMD no Uruguai.

Active Surveillance of Asymptomatic, Presymptomatic, and Oligosymptomatic SARS-CoV-2-Infected Individuals in Communities Inhabiting Closed or Semi-closed Institutions.

Background: The high COVID-19 dissemination rate demands active surveillance to identify asymptomatic, presymptomatic, and oligosymptomatic (APO) SARS-CoV-2-infected individuals. This is of special importance in communities inhabiting closed or semi-closed institutions such as residential care homes, prisons, neuropsychiatric hospitals, etc., where risk people are in close contact. Thus, a pooling approach-where samples are mixed and tested as single pools-is an attractive strategy to rapidly detect APO-infected in these epidemiological scenarios. Materials and Methods: This study was done at different pandemic periods between May 28 and August 31 2020 in 153 closed or semi-closed institutions in the Province of Buenos Aires (Argentina). We setup pooling strategy in two stages: first a pool-testing followed by selective individual-testing according to pool results. Samples included in negative pools were presumed as negative, while samples from positive pools were re-tested individually for positives identification. Results: Sensitivity in 5-sample or 10-sample pools was adequate since only 2 Ct values were increased with regard to single tests on average. Concordance between 5-sample or 10-sample pools and individual-testing was 100% in the Ct ≤ 36. We tested 4,936 APO clinical samples in 822 pools, requiring 86-50% fewer tests in low-to-moderate prevalence settings compared to individual testing. Conclusions: By this strategy we detected three COVID-19 outbreaks at early stages in these institutions, helping to their containment and increasing the likelihood of saving lives in such places where risk groups are concentrated.

[Preferences and limitations of hematologists to address the complexity of myelodysplastic syndromes]. / Preferencias y limitaciones de los hematólogos para afrontar la complejidad de los síndromes mielodisplásicos.

Argentina is a country characterized by a heterogeneous distribution of its population, its economic resources and, consequently, access to health services, which could affect the diagnosis and treatment of patients with myelodysplastic syndromes. Based on the increasing complexity to arrive at the diagnosis, estimate the risk and indicate an adequate treatment, we have conducted a survey of twenty-three questions to evaluate patterns of clinical practice. The questionnaire was distributed among 850 hematologists registered at the XXII Argentine Congress of Hematology, and 195 (22.9%) were answered; 40.0% report that < 75% of their patients access the karyotype, bone marrow histology and flow cytometry. This access decreases significantly due to low health coverage (OR 6.3), in the adult population (OR 3.8), when the cytogenetic study is derived (OR 3.2) and outside the metropolitan area of Buenos Aires (OR 2.4). The respondents avoid oncological terminologies (77.0%) when introducing the diagnosis and use the international prediction system or its review (74.2%) to stage risk. However, they prioritize age when selecting treatment and pediatricians preferentially recommend the transplantation of hematopoietic precursors. Most of the haematologists have prescribed the recommended treatments, whose suspensions were related to lack of response (62.7%), with reduced participation in clinical trials (8.9%). Therefore, they report heterogeneity in the access to complementary diagnostic tools with differences at the time of indicating a treatment, depending on the age of their patients without apparent limitations in their prescription.

La Argentina es un país caracterizado por una distribución heterogénea de su población, de sus recursos económicos y, consiguientemente, del acceso a los servicios de salud, lo cual podría afectar el diagnóstico y tratamiento de los pacientes con síndromes mielodisplásicos. Basados en la complejidad creciente para arribar al diagnóstico, estimar el riesgo e indicar un tratamiento adecuado, hemos conducido una encuesta de veintitrés preguntas para evaluar patrones de práctica clínica. El cuestionario se distribuyó entre los 850 hematólogos argentinos inscriptos al XXII Congreso Argentino de Hematología y 195 (22.9%) fueron contestados. El 40.0% refieren que < 75% de sus pacientes acceden al cariotipo, histología de la médula ósea y citometría de flujo. Este acceso disminuye significativamente por una baja cobertura sanitaria (OR 6.3), en población adulta (OR 3.8), al derivar el estudio citogenético (OR 3.2) y fuera del área metropolitana de Buenos Aires (OR 2.4). Los encuestados evitan terminologías oncológicas (77.0%) al introducir el diagnóstico y utilizan el sistema internacional de predicción o su revisión (74.2%) para estadificar riesgo. Sin embargo, éstos priorizan la edad al seleccionar tratamiento y los pediatras indican preferentemente el trasplante de precursores hematopoyéticos. La mayoría de los hematólogos ha prescripto los tratamientos recomendados, cuyas suspensiones se relacionaron con falta de respuesta (62.7%), con participación reducida en ensayos clínicos (8.9%). Por ende, refieren heterogeneidad en el acceso a las herramientas diagnósticas complementarias con diferencias al momento de indicar un tratamiento, dependiendo de la edad de sus pacientes, sin limitaciones aparentes en su prescripción.

Preferencias y limitaciones de los hematólogos para afrontar la complejidad de los síndromes mielodisplásicos / Preferences and limitations of hematologists to address the complexity of myelodysplastic syndromes

La Argentina es un país caracterizado por una distribución heterogénea de su población, de sus recursos económicos y, consiguientemente, del acceso a los servicios de salud, lo cual podría afectar el diagnóstico y tratamiento de los pacientes con síndromes mielodisplásicos. Basados en la complejidad creciente para arribar al diagnóstico, estimar el riesgo e indicar un tratamiento adecuado, hemos conducido una encuesta de veintitrés preguntas para evaluar patrones de práctica clínica. El cuestionario se distribuyó entre los 850 hematólogos argentinos inscriptos al XXII Congreso Argentino de Hematología y 195 (22.9%) fueron contestados. El 40.0% refieren que < 75% de sus pacientes acceden al cariotipo, histología de la médula ósea y citometría de flujo. Este acceso disminuye significativamente por una baja cobertura sanitaria (OR 6.3), en población adulta (OR 3.8), al derivar el estudio citogenético (OR 3.2) y fuera del área metropolitana de Buenos Aires (OR 2.4). Los encuestados evitan terminologías oncológicas (77.0%) al introducir el diagnóstico y utilizan el sistema internacional de predicción o su revisión (74.2%) para estadificar riesgo. Sin embargo, éstos priorizan la edad al seleccionar tratamiento y los pediatras indican preferentemente el trasplante de precursores hematopoyéticos. La mayoría de los hematólogos ha prescripto los tratamientos recomendados, cuyas suspensiones se relacionaron con falta de respuesta (62.7%), con participación reducida en ensayos clínicos (8.9%). Por ende, refieren heterogeneidad en el acceso a las herramientas diagnósticas complementarias con diferencias al momento de indicar un tratamiento, dependiendo de la edad de sus pacientes, sin limitaciones aparentes en su prescripción.

Argentina is a country characterized by a heterogeneous distribution of its population, its economic resources and, consequently, access to health services, which could affect the diagnosis and treatment of patients with myelodysplastic syndromes. Based on the increasing complexity to arrive at the diagnosis, estimate the risk and indicate an adequate treatment, we have conducted a survey of twenty-three questions to evaluate patterns of clinical practice. The questionnaire was distributed among 850 hematologists registered at the XXII Argentine Congress of Hematology, and 195 (22.9%) were answered; 40.0% report that < 75% of their patients access the karyotype, bone marrow histology and flow cytometry. This access decreases significantly due to low health coverage (OR 6.3), in the adult population (OR 3.8), when the cytogenetic study is derived (OR 3.2) and outside the metropolitan area of Buenos Aires (OR 2.4). The respondents avoid oncological terminologies (77.0%) when introducing the diagnosis and use the international prediction system or its review (74.2%) to stage risk. However, they prioritize age when selecting treatment and pediatricians preferentially recommend the transplantation of hematopoietic precursors. Most of the haematologists have prescribed the recommended treatments, whose suspensions were related to lack of response (62.7%), with reduced participation in clinical trials (8.9%). Therefore, they report heterogeneity in the access to complementary diagnostic tools with differences at the time of indicating a treatment, depending on the age of their patients without apparent limitations in their prescription.

Flow cytometry "Ogata score" for the diagnosis of myelodysplastic syndromes in a real-life setting. A Latin American experience.

INTRODUCTION: Flow cytometry (FC) is a helpful tool for the diagnosis of myelodysplastic syndrome (MDS). Different FC score systems have been developed. The "Ogata score" is a simple diagnostic score that has been validated having a sensitivity of 69% and a specificity of 92% in low-risk MDS. We aimed to study the feasibility and the utility of the "Ogata score" for the diagnosis of MDS among Latin America (LA) Laboratories. METHODS: This is a case and control study conducted in LA institutions members of Grupo Latinoamericano de Mielodisplasia (GLAM). A total of 146 MDS patients and 57 control patients were included. "Ogata score" was calculated. RESULTS: The sensitivity of "Ogata score" was 75.6% (95% CI, 66.8-81.3), specificity was 91.2% (95% CI, 79.7-96.7), PPV was 95.6% (95% CI, 88.5-98.3), and NPV was 65.4% (95% CI, 49.1-71.9). In low/intermediate-1 IPSS patients group, the sensitivity was 70.1% (95% CI, 60.2-78.2), specificity was 91.2% (CI-95%, 79.7-96.7), PPV was 94.2% (95% CI, 86.4-97.8), and NPV was 62.1% (95% CI, 53.0-78.7). In the group of patients "without MDS specific markers" (patients without ring sideroblasts, blast excess, or chromosomal abnormalities), the sensitivity was 66.7% (CI-95%, 55.8-76.0), specificity was 91.2% (95% CI, 79.7-96.7), PPV was 92.3% (95% CI, 82.2-97.1), and NPV was 63.5% (95% CI, 51.9-73.5). CONCLUSIONS: The diagnostic power found in this study was similar to the reported by Della-Porta et al. Also in LA, the analysis was made in modern equipment with acquisition of at least 100 000 events which permits a good reproducibility of the results.

Two novel unstable hemoglobin variants due to in-frame deletions of key amino acids in the ß-globin chain.

Hemoglobinopathies are the most common autosomal recessive disorders and are mostly inherited in a recessive manner. However, certain mutations can affect the globin chain stability, leading to dominant forms of thalassemia. The aim of this work was the molecular and structural characterization of two heterozygous in-frame deletions, leading to ß-globin variants in pediatric patients in Argentina. The HBB gene of the probands and their parents was sequenced, and other markers of globin chain imbalance were analyzed. Several structural analyses were performed, and the effect of the mutations on the globin chain stability was analyzed. In Hb JC-Paz, HBB:c.29_37delCTGCCGTTA (p.Ala10_Thr12del), detected in an Argentinean boy, one α-helix turn is expected to be lost. In Hb Tavapy, HBB:c.182_187delTGAAGG (p.Val60_Lys61del), the deleted residues are close to distal histidine (His63) in the heme pocket. Both mutations are predicted to have a destabilizing effect. The development of computational structural models and bioinformatics algorithms is expected to become a useful tool to understand the impact of the mutations leading to dominant thalassemia.

Esferocitosis hereditaria: experiencia clínica y diagnóstica en Argentina / Hereditary spherocytosis: clinical and diagnostic experience in Argentina / Esferocitose hereditária: experiência clínica e diagnóstica na Argentina

Los objetivos del presente estudio fueron: a) Analizar las características demográficas y clínicas de nuestra población al diagnóstico; b) Evaluar si las pruebas más recientes presentan ventajas sobre las tradicionales; c) Confirmar la frecuencia de las distintas deficiencias de proteínas de membrana; d) Establecer la relación entre severidad y resultado de las pruebas o tipo de deficiencia. Se analizaron 359 individuos estudiados desde 2007, cuando se incorporaron criohemólisis hipertónica (CH), citometría de flujo con eosina-5'- maleimida (5'EMA-CF), FOE por citometría de flujo (FOE-CF) y electroforesis de proteínas de membrana (SDS-PAGE) al estudio de laboratorio clásico, fragilidad osmótica eritrocitaria (FOE) y autohemólisis (AH). Criterios diagnósticos para Esferocitosis Hereditaria (ESH): esferocitos en frotis y dos pruebas positivas. Se identificaron 174 pacientes con ESH y 22 portadores sanos. El 74,9% eran menores de 12 años. La transmisión fue dominante en el 83,1% de los casos. Tuvieron manifestaciones neonatales 89,1%. Las pruebas con mayor sensibilidad fueron CH (92,0%), FOE diferida (91,1%) y 5'EMA-CF (88,5%). En los 125 pacientes en quienes se realizaron CH, 5'EMA-CF y FOE-CF se observó que todos tenían al menos una prueba positiva; 122 (97,6%) tuvieron dos o tres positivas. Las deficiencias más frecuentes fueron ankirina y espectrina. No hubo diferencia en el resultado de las pruebas entre los subgrupos de severidad. Se concluye que las deficiencias más frecuentes en Argentina son ankirina y espectrina, coincidiendo con otras poblaciones latinoamericanas. El uso simultáneo de CH, 5'EMA-CF y FOE-CF permite diagnosticar más del 97% de los casos. La incidencia de manifestaciones neonatales es elevada.

The aims of this study were (a) to assess demographic and clinical aspects of our population at diagnosis; (b) to evaluate diagnostic accuracy of hypertonic cryohemolysis (HC), eosin-5'-maleimide flow cytometry (EMA-FC) and flow cytometric osmotic fragility (OF-FC) in relation to standard screening tests osmotic fragility (OF) and autohemolysis (AH); (c) to confirm the previously reported prevalence of membrane proteins defects; and (d) to assess the relationship between severity of anemia and results of confirmatory tests. Since 2007, the following tests were available in our laboratory: OF, AH, HC, EMA-FC, OF-FC and SDS-PAGE of membrane proteins. Diagnostic criteria for hereditary spherocytosis were spherocytes in blood smear plus ≥2 positive tests. Data from 359 individuals were analyzed: 174 HS patients and 22 silent carriers were detected; 74.9% of patients were less than 12 years old; 83.1% of them showed a dominant inheritance pattern; antecedent of neonatal jaundice/anemia was registered in 89.1%. Tests with higher sensitivity were: HC (92.0%), incubated OF (91.1%), and EMA-FC (88.5%). HC, EMA-FC and OF-FC were simultaneously performed on 125 patients: each of them had at least 1 positive test; 122 (97.6%) had 2 or 3 positive tests. Ankyrin and spectrin were the most frequently found protein deficiencies. Comparison of test results in relation to severity of anemia showed no difference between groups. It can be concluded that compared toother Latin American countries, ankyrin and spectrin were the most frequent protein deficiencies. Simultaneous performing of HC, EMA-FC and OF-FC enabled diagnosing HS in more than 97% of patients. A high incidence of neonatal jaundice/anemia was observed.

Os objetivos do presente estudo foram: a) analisar as características demográficas e clínicas de nossa população ao diagnóstico; b) Avaliar se as provas mais recentes apresentam vantagens sobre as tradicionais; c) Confirmar a frequência das diversas deficiências de proteínas de membrana; d) Establecer a relação entre severidade e resultado das provas ou tipo de deficiência. Foram analisados 359 indivíduos estudados desde 2007, quando se incorporaram crio-hemólise hipertônica (CH), citometria de fluxo com eosina-5'-maleimida (5'EMA-CF), FOE por citometria de fluxo (FOE-CF) e eletroforese de proteínas de membrana (SDS-PAGE) ao estudo de laboratório clássico - fragilidade osmótica eritrocitária (FOE) e auto-hemólise (AH). Critérios diagnósticos para ESH: esferócitos em esfregaço e duas provas positivas. Foram identificados 174 pacientes com ESH e 22 portadores sadios. 74,9% eram menores de 12 anos. A transmissão foi dominante em 83,1%. Tiveram manifestações neonatais 89,1%. As provas com maior sensibilidade foram CH (92,0%), FOE diferida (91,1%) e 5'EMA-CF (88,5%). Nos 125 pacientes aos quais lhes realizaram CH, 5'EMA-CF e FOE-CF se observou que todos tinham no mínimo uma prova positiva; 122 (97,6%) tiveram duas ou três positivas. As deficiências mais frequentes foram anquirina e espectrina. Não houve diferença no resultado das provas entre os subgrupos de severidade. Conclui-se que as deficiências mais frequentes na Argentina são anquirina e espectrina, as quais coincidem com outras populações latinoamericanas. O uso simultâneo de CH, 5'EMA-CF e FOE-CF permite diagnosticar mais de 97% dos casos. A incidência de manifestações neonatais é elevada.

Influence of Acute Myeloid Leukemia Progression on the Prognosis of 831 Patients With Myelodysplastic Syndromes From the Argentine Database.

BACKGROUND: A large group of patients with myelodysplastic syndromes (MDS) will die of causes intrinsic to bone marrow failure. One third of patients will develop acute myeloid leukemia (AML), which is associated with an extremely poor outcome and a short survival. Our objectives were to analyze the prognostic variables and scoring systems in the attempt to determine the influence of progression on the overall survival of MDS patients. PATIENTS AND METHODS: We performed a retrospective analysis of 831 MDS patients, including those from the Argentine Registry. RESULTS: Of the 831 MDS patients, 158 (19.0%) experienced transformation, with a median overall survival of 17.9 months from diagnosis and 3.5 months after progression. The survival of patients with adverse karyotypes or greater risk, according to the International Prognostic Scoring System-revised (IPSS-R) or World Health Organization-based Prognostic Scoring System (WPSS) was not affected when stratified by patients with and without evolution to AML (P > .05). In contrast, the survival of lower risk patients was significantly reduced for those patients with progression to AML (P < .001) and those younger (P = .024) than those who died of non-AML-related causes. The intermediate-risk patients were heterogeneously distributed; however, an upgrade from a lower IPSS-R to a higher WPSS-hemoglobin risk category was associated with a worse outcome, not affected by progression (P = .420), with a median event-free survival of 16 months. CONCLUSION: The use of the IPSS-R and WPSS systems simultaneously might help in identifying those patients who require more aggressive treatment. Nevertheless, more efforts are needed to improve the identification of those lower risk patients whose survival is significantly reduced by progression to AML.

Red blood cell aquaporin-1 expression is decreased in hereditary spherocytosis.

Aquaporin-1 (AQP1) is the membrane water channel responsible for changes in erythrocyte volume in response to the tonicity of the medium. As the aberrant distribution of proteins in hereditary spherocytosis (HS) generates deficiencies of proteins other than those codified by the mutated gene, we postulated that AQP1 expression might be impaired in spherocytes. AQP1 expression was evaluated through flow cytometry in 5 normal controls, 1 autoimmune hemolytic anemia, 10 HS (2 mild, 3 moderate, 2 severe, and 3 splenectomized), and 3 silent carriers. The effect of AQP1 inhibitors was evaluated through water flow-based tests: osmotic fragility and hypertonic cryohemolysis. Serum osmolality was measured in 20 normal controls and 13 HS. The effect of erythropoietin (Epo) on AQP1 expression was determined in cultures of erythroleukemia UT-7 cells, dependent on Epo to survive. Independent of erythrocyte size, HS patients showed a lower content of AQP1 in erythrocyte membranes which correlated with the severity of the disease. Accordingly, red blood cells from HS subjects were less sensitive to cryohemolysis than normal erythrocytes after inhibition of the AQP1 water channel. A lower serum osmolality in HS with respect to normal controls suggests alterations during reticulocyte remodeling. The decreased AQP1 expression could contribute to explain variable degrees of anemia in hereditary spherocytosis. The finding of AQP1 expression induced by Epo in a model of erythroid cells may be interpreted as a mechanism to restore the balance of red cell water fluxes.

[Hereditary spherocytosis. Review. Part II. Symptomatology, outcome, complications, and treatment]. / Esferocitosis hereditaria. Revisión. Parte II. Manifestaciones clínicas, evolución, complicaciones y tratamiento.

Hereditary spherocytosis must always be suspected in children with anemia, hyperbilirubinemia, splenomegaly or cholelithiasis, in the asymptomatic individual with an affected relative, and in the neonate with hyperbilirubinemia with no blood group incompatibility; its early detection is key to avoid kernicterus. Follow-up of these patients is based on periodical control and supply of information on the adequate management of hemolytic or aplastic crisis, and early detection of cholelithiasis. The decision to perform splenectomy is usually associated with quality of life rather than life-threatening risk, and it should result from a consensus between patient, parents and physicians. The postsplenectomy follow-up is based on control of compliance with the prophylactic antibiotic therapy and the early diagnosis of infectious disorders.

[Hereditary spherocytosis: Review. Part I. History, demographics, pathogenesis, and diagnosis]. / Esferocitosis hereditaria: Revisión. Parte I. Historia, demografía, etiopatogenia y diagnóstico.

Hereditary spherocytosis is the most frequent hereditary anemia excluding beta thalassemia in Argentina. Historical, demographic, genetic and pathogenic aspects of the disease are reviewed, and confirmatory laboratory tests are described. Special characteristics on the outcome of the disease in our population and prevalent protein deficiencies in our country are described. Emphasis is given on new available laboratory tests, which allow an earlier diagnosis using volume of blood samples significantly smaller than required for conventional tests.

Esferocitosis hereditaria: Revisión. Parte I. Historia, demografía, etiopatogenia y diagnóstico / Hereditary spherocytosis. Review. Part I. History, demographics, pathogenesis, and diagnosis

La esferocitosis hereditaria es la anemia hereditaria más frecuente en nuestro país luego de la talasemia menor. En este artículo, se revisan aspectos históricos, demográficos, genéticos y etiopatogénicos de la enfermedad, y se describen las pruebas de laboratorio para su diagnóstico. Se remarca el comportamiento de la enfermedad en nuestra población y se detallan las deficiencias proteicas predominantes en nuestro país. Se enfatiza sobre las nuevas técnicas de laboratorio actualmente disponibles, con alta sensibilidad y especificidad, que permiten realizar un diagnóstico más temprano con volúmenes de muestra mucho menores que los necesarios para las pruebas convencionales.

Hereditary spherocytosis is the most frequent hereditary anemia excluding beta thalassemia in Argentina. Historical, demographic, genetic and pathogenic aspects of the disease are reviewed, and confirmatory laboratory tests are described. Special characteristics on the outcome of the disease in our population and prevalent protein deficiencies in our country are described. Emphasis is given on new available laboratory tests, which allow an earlier diagnosis using volume of blood samples significantly smaller than required for conventional tests.

Esferocitosis hereditaria: Revisión. Parte I. Historia, demografía, etiopatogenia y diagnóstico. / [Hereditary spherocytosis: Review. Part I. History, demographics, pathogenesis, and diagnosis].

Hereditary spherocytosis is the most frequent hereditary anemia excluding beta thalassemia in Argentina. Historical, demographic, genetic and pathogenic aspects of the disease are reviewed, and confirmatory laboratory tests are described. Special characteristics on the outcome of the disease in our population and prevalent protein deficiencies in our country are described. Emphasis is given on new available laboratory tests, which allow an earlier diagnosis using volume of blood samples significantly smaller than required for conventional tests.

Use of capillary blood to diagnose hereditary spherocytosis.

We studied 31 children with hemolytic anemia, or with positive family history for hereditary spherocytosis (HS), to assess the reliability of capillary blood samples for the diagnosis. HS was diagnosed in 20 patients. Cryohemolysis (CH) was positive in 94% and eosin-5'-maleimide flow cytometry in 90% of them, whereas flow cytometric osmotic fragility was positive in 94%. Capillary blood sampling showed to be useful for the diagnosis. Simultaneous use of these three tests allows confirming diagnosis in 100% of patients. The use of very small blood volumes (300 µl) allows an earlier diagnosis in neonates and small infants.

Oxidative stress due to aluminum exposure induces eryptosis which is prevented by erythropoietin.

The widespread use of aluminum (Al) provides easy exposure of humans to the metal and its accumulation remains a potential problem. In vivo and in vitro assays have associated Al overload with anemia. To better understand the mechanisms by which Al affects human erythrocytes, morphological and biochemical changes were analyzed after long-term treatment using an in vitro model. The appearance of erythrocytes with abnormal shapes suggested metal interaction with cell surface, supported by the fact that high amounts of Al attached to cell membrane. Long-term incubation of human erythrocytes with Al induced signs of premature erythrocyte death (eryptosis), such as phosphatidylserine externalization, increased intracellular calcium, and band 3 degradation. Signs of oxidative stress, such as significant increase in reactive oxygen species in parallel with decrease in the amount of reduced glutathione, were also observed. These oxidative effects were completely prevented by the antioxidant N-acetylcysteine. Interestingly, erythrocytes were also protected from the prooxidative action of Al by the presence of erythropoietin (EPO). In conclusion, results provide evidence that chronic Al exposure may lead to biochemical and morphological alterations similar to those shown in eryptosis induced by oxidant compounds in human erythrocytes. The antieryptotic effect of EPO may contribute to enhance the knowledge of its physiological role on erythroid cells. Irrespective of the antioxidant mechanism, this property of EPO, shown in this model of Al exposure, let us suggest potential benefits by EPO treatment of patients with anemia associated to altered redox environment.

A prospective study to assess the predictive value for hereditary spherocytosis using five laboratory tests (cryohemolysis test, eosin-5'-maleimide flow cytometry, osmotic fragility test, autohemolysis test, and SDS-PAGE) on 50 hereditary spherocytosis families in Argentina.

This prospective study was carried out to assess the usefulness of five laboratory tests in the diagnosis of hereditary spherocytosis (HS), based on the correlation of erythrocyte membrane protein defects with clinical and laboratory features, and also to determine the membrane protein deficiencies detected in Argentina. Of 116 patients and their family members tested, 62 of them were diagnosed to have HS. The specificity of cryohemolysis (CH) test was 95.2%, and its cut-off value to distinguish HS from normal was 2.8%. For flow cytometry, cut-off points of 17% for mean channel fluorescence (MCF) decrease and 14% coefficient of variation (CV) increase showed 95.9% and 92.2% specificity, respectively. Both tests showed the highest percentages of positive results for diagnosis. Either CH or flow cytometry was positive in 93.5% of patients. In eight patients, flow cytometry was positive only through CV increase. Protein defects were detected in 72.3% of patients; ankyrin and spectrin were the most frequently found deficiencies. The CV of the fluorescence showed significantly higher increases in moderate and severe anemia than in mild anemia (p = 0.003). Severity of anemia showed no other correlation with tests results, type of deficient protein, inheritance pattern, or neonatal jaundice. CH and flow cytometry are easy methods with the highest diagnostic accuracy. Simultaneous reading of mean channel fluorescence (MCF) decrease and CV increase improve diagnostic usefulness of flow cytometry. This test seems to be a reliable predictor of severity. The type of detected protein deficiency has no predictive value for outcome. Predominant ankyrin and spectrin deficiencies agree with reports from other Latin American countries.