Incidence of Aplastic Anemia in a Defined Subpopulation from Mexico City

Associations between the HLA-A/B/DRB1 polymorphisms and aplastic anemia: evidence from 17 case-control studies

OBJECTIVE

To estimate the associations between HLA-A/B/DRB1 polymorphisms and aplastic anemia (AA), we carried out the meta-analysis.

METHODS

In this meta-analysis, all publications in English and Chinese were considered up to 30 September 2015. The electronic databases we searched were Pubmed, Science Direct, Embase, Web of Science, CNKI, Wanfang Data and VIP. We conducted all statistical data analyses in the Stata11.0 software.

RESULTS

A total of 17 studies including 9164 subjects (containing 1372 cases and 7792 controls) were retrieved, which studied the relationship between HLA-A/B/DRB1 and AA. Odds ratios (ORs) with 95% confidence intervals (CIs) for the comparisons between cases and controls were calculated. The result revealed that HLA-A*02 and HLA-DRB1 (*0407, *15 and *1501) polymorphisms might increase the risk of AA. Otherwise, HLA-DRB1 (*0301, *04, *0406, *0802, *1301, *1302 and *14) were protective against AA. But, other sites of HLA-A/B/DRB1 in our study had no correlations with AA (all P_c > 0.05).

CONCLUSION

In conclusion, HLA-A/B/DRB1 polymorphisms may play an important role in AA, but higher quality and larger sample studies are needed to confirm.

Trend and treatment patterns of aplastic anemia in Korea, pure red cell aplasia and myelodysplastic syndrome in Korea: a nation-wide analysis

Aplastic anemia (AA) and pure red cell aplasia (PRCA) appear to be more prevalent in Asian countries including Korea. However, there are no exact data regarding its prevalence and frequency of allogeneic hematopoietic cell transplantation (HCT) in Korea. Here, we present demographic data relating to AA/PRCA/MDS in Korea. Data were prepared by retrieval from a computerized database maintained by the National Health Insurance Service and Korea National Statistical Office. HCT data were collected from all HCT centers in Korea. The crude incidence rate of AA decreased from 2002 to 2010 and from 35 to 28 per million persons. Females were more affected by AA. The peak ages of onset of AA were in the seventh decade or older. The frequency of HCT for AA increased from 2002 to 2012 and from 69 to 131 per year. The crude incidence rates of MDS increased from 2002 to 2010, with 8-20 per million persons, and the frequency of HCT also increased, from 30 in 2002 to 132 in 2011. Even allowing for the possibility of overestimation, the crude incidence of AA is significantly higher in Korea than in western countries.

Human embryonic stem cell therapy for aplastic anemia

Human embryonic stem cell (hESC) therapy is the potential therapeutic option for the treatment of patients with aplastic anemia (AA). The study showed a remarkable improvement in the AA patient subsequent to hESC administration. No adverse events occurred in the patient. hESC therapy is safe and effective for AA patients.

The ancestry of the HLA-DRB1*15 allele predisposes the Mexican mestizo to the development of aplastic anemia

Aplastic anemia (AA) is a hematological disorder characterized by pancytopenia in peripheral blood and hypoplasia in the bone marrow; the majority of cases have no known etiology, but it is thought that genetic and environmental factors can be involved in its pathogenesis. From the genetic viewpoint, it has been reported a significant increase frequency of the human leukocyte antigen HLA-DRB1(∗)15 in patients with AA as compared to ethnically matched healthy controls, this is true in different populations worldwide, which would suggests that this allele participates in the immune regulation of the disease.

OBJECTIVE

To determine gene frequencies of HLA-DRB1 alleles in Mexican mestizo patients with AA.

METHODS

We analyzed and compared the HLA-DRB1 alleles in 36 Mexican mestizo patients (female gender, n=13; male gender, n=23) with AA to those present in 201 umbilical cord blood (UCB) samples as a control group, this was done by means of the polymerase chain reaction-single specific primer (PCR-SSP) technique.

RESULTS

Analysis of gene frequencies of HLA-DRB1(∗) alleles exhibits a significant increase of HLA-DRB1(∗)15 allele in the group of patients with AA as compared to those present in the control group (15.27% vs. 2.23%, respectively; p=1×10(-5); odds ratio [OR]=9.3; 95% confidence interval [95% CI]=3.2-27.8).

CONCLUSIONS

Our results showed a positive association of the DRB1(∗)15 allele in Mexican patients with aplastic anemia, which coincides with that reported internationally. In addition, we think that this allele was introduced to the Mexican population structure inherited from European ancestry.

Incidence and risk factors of aplastic anemia in Latin American countries: the LATIN case-control study

Background Associations between aplastic anemia and numerous drugs, pesticides and chemicals have been reported. However, at least 50% of the etiology of aplastic anemia remains unexplained.

DESIGN AND METHODS

This was a case-control, multicenter, multinational study, designed to identify risk factors for agranulocytosis and aplastic anemia. The cases were patients with diagnosis of aplastic anemia confirmed through biopsy or bone marrow aspiration, selected through an active search of clinical laboratories, hematology clinics and medical records. The controls did not have either aplastic anemia or chronic diseases. A total of 224 patients with aplastic anemia were included in the study, each case was paired with four controls, according to sex, age group, and hospital where the case was first seen. Information was collected on demographic data, medical history, laboratory tests, medications, and other potential risk factors prior to diagnosis.

RESULTS

The incidence of aplastic anemia was 1.6 cases per million per year. Higher rates of benzene exposure (>/=30 exposures per year) were associated with a greater risk of aplastic anemia (odds ratio, OR: 4.2; 95% confidence interval, CI: 1.82-9.82). Individuals exposed to chloramphenicol in the previous year had an adjusted OR for aplastic anemia of 8.7 (CI: 0.87-87.93) and those exposed to azithromycin had an adjusted OR of 11.02 (CI 1.14-108.02). Conclusions The incidence of aplastic anemia in Latin America countries is low. Although the research study centers had a high coverage of health services, the underreporting of cases of aplastic anemia in selected regions can be discussed. Frequent exposure to benzene-based products increases the risk for aplastic anemia. Few associations with specific drugs were found, and it is likely that some of these were due to chance alone.

Subcutaneous alemtuzumab plus cyclosporine for the treatment of aplastic anemia

Aplastic anemia (AA) is most frequently due to autoimmune attack on its own stem cells. Alemtuzumab is a monoclonal antibody which recognizes the CD52 antigen on the surface of T and B cells. It has proved useful in autoimmune diseases, lymphoproliferative conditions, and graft versus host disease. Based on its immunosuppressive properties, we treated 14 AA patients with alemtuzumab. Median age was 23 years. Ten milligrams of alemtuzumab were injected subcutaneously each day for five consecutive days. Cyclosporine A was also administered orally at a dose of 2 mg/kg every 12 h for 3 months, and then gradually tapered. Response to alemtuzumab was followed for a median of 20 months. There were eight responses (57.1%), two complete and six partial. Whereas six (42.8%) patients were non-responders. Median complete blood count values on alemtuzumab responders were Hb 13.1 mg/dL, absolute neutrophil count 2.4 x 10(9)/L, and platelets 97.5 x 10(9)/L. A good response was produced in 57% of AA patients with the administration of alemtuzumab, who lacked a stem cell donor.

Pattern of haematological diseases diagnosed by bone marrow examination in Yemen: a developing country experience

There is lack of information about the relative prevalence of haematological disorders in Yemen and other Middle East countries. The aim of this study was to evaluate the pattern of haematological diseases diagnosed by bone marrow examination in Yemen considering the limited diagnostic facilities. At the referral haematology centre in Yemen, between November 1999 and November 2005, 785 patients >14 years old were evaluated by bone marrow examination. Relevant investigations were performed when needed. A total of 627 patients had haematological disorders other than lymphoma, and their data were analysed. There were 273 females and 354 males. A total of 159 patients had Acute myeloid leukaemia, 75 had acute lymphocytic leukaemia, 87 had chronic myeloid leukaemia, 36 chronic lymphocytic leukaemia, eight had multiple myeloma, 13 myelodysplastic syndromes, seven myelofibrosis, seven polycythaemia vera, three primary thrombocythaemia, two hairy cell leukaemia, two metastases, 36 aplastic anaemia, 29 immune thrombocytopenic purpura (ITP), nine autoimmune haemolytic anaemia, three pernicious anaemia, 65 iron deficiency anaemia, 57 megaloblastic anaemia and malaria, 18 mixed deficiencies, and 11 patients had visceral leishmaniasis. Sex- and age-related distribution of the various disorders was also presented. In conclusion, the leukaemias were the most frequently encountered diagnosis followed by iron deficiency anaemia, megaloblastic anaemia and malaria, aplastic anaemia and ITP respectively. The other haematological disorders were less common. These findings are comparable with that seen in other developing and developed countries.

Incidence of aplastic anemia and agranulocytosis in Latin America--the LATIN study

CONTEXT AND OBJECTIVE

Aplastic anemia and agranulocytosis are rare but life-threatening disorders, often caused by drugs and other environmental exposures. Reported incidence of these diseases seems to vary between different geographic regions, and few data on their incidence are available for Latin American countries. The aim of this work is to determine the incidence of agranulocytosis and aplastic anemia in Brazil.

DESIGN AND SETTING

Incidence study. Seven centers took part in the pilot phase, so as to represent all Brazilian regions.

METHODS

Each center conducted an active search for new cases in a defined region by means of regular contacts with all hematologists, main clinical laboratories and clinicians in hospitals of the region.

RESULTS

74 patients with aplastic anemia and 16 with agranulocytosis were identified. Patients with agranulocytosis had a median age of 31 years (interquartile range, IQR: 12.5-48.2); 32.2% were male and 81.2% were white. The median age of aplastic anemia patients was 21 years (IQR 15.0-35.2); 62.2% were male, 50.0% were white and 39.2% mulatto. The incidence of agranulocytosis was estimated to be 0.5 cases per million individuals per year, ranging from 0.0 to 1.1 cases per million per year between regions. The incidence of aplastic anemia was 2.7 cases per million per year, ranging from 1.1 to 7.1 cases per million per year between regions.

CONCLUSIONS

Aplastic anemia and agranulocytosis are rare diseases in Brazil. However, there is considerable variability in their incidences between different regions.

Long-term results of the immunosuppressive treatment of patients with severe acquired aplastic anemia: a single institution study

In México, only few patients can afford adequate treatment for aplastic anemia. In a single institution 61 individuals with severe aplastic anemia (SAA) were identified; of these, 33 were followed for at least 3 months, 26 could be treated with immunosuppression (IS), 20 with antithymocyte globulin and cyclosporin A (ATG + CyA) and 6 with CyA, whereas 7 individuals were given only anabolic androgens. In the patients treated with IS a complete remission was achieved in 12 and a partial remission in 6, the overall response rate being 69%. The 5,729-day overall survival (SV) was 54%; it was superior for the patients who received both ATG and CyA (58 vs. 50%). These data contrast with those of the patients who were given only androgens: 14% SV at 5,510 days. Within the group of patients who received IS, one developed acute myelogenous leukemia, another paroxysmal nocturnal hemoglobinuria and another a primary Sjögren's syndrome-associated low-grade, B cell, non-Hodgkin's lymphoma. Two individuals who received IS were allografted from HLA-identical siblings and survived 70 and 413 days after the allograft. On the other hand, we also found that, for several reasons, mainly economic ones, only 41% of individuals with SAA finally benefited from the best immunosuppressive therapeutic approach. IS was a good therapeutic choice for some patients with SAA, clearly better than androgen treatment.