Anti-Toxoplasma gondii antibodies in patients with beta-hemoglobinopathies: the first report in the Americas

Marina Neves Ferreira,Claudia Regina Bonini-Domingos,Luiz Carlos de Mattos,Clarice Lopes de Castro Lobo,Cinara Cássia Brandão de Mattos,Gisele Cristina Souza Carrocini,Octávio Ricci,Isabeth Fonseca Estevão,Aparecida Perpétuo Silveira-Carvalho

doi:10.1186/s13104-017-2535-7

Abstract

BackgroundIn Brazil, there have been no previous studies of Toxoplasma gondii infection in sickle cell anemia patients and carriers of severe forms of beta-thalassemia. This study evaluated T. gondii infection in patients with beta-hemoglobinopathies.MethodsA total of 158 samples, 77 (48.7%) men and 81 (51.3%) women, were evaluated. Three groups were formed: G1 (85 patients with sickle cell disease); G2 (11 patients with homozygous beta-thalassemia; G3 (62 patients with heterozygous beta-thalassemia). ELISA was employed to identify anti-T. gondii IgM and IgG antibodies, and molecular analysis was performed to determine beta-hemoglobin mutations. Fisher’s exact test was used to compare frequencies of anti-T. gondii IgM and IgG antibodies in respect to gender and age.ResultsAnti-T. gondii IgG antibodies were found in 43.5% of individuals in G1, 18.1% in G2 and 50% in G3. All samples from G1 and G2 were seronegative for anti-T. gondii IgM antibodies, but 3.2% from G3 were seropositive. Considering anti-T. gondii IgG antibodies, no statistical significant differences were found between these groups nor in seroprevalence between genders within each group. Despite this, comparisons of the mean ages between G1, G2 and G3 were statistically significant (G2 vs. G1: p value = 0.0001; G3 vs. G1: p-value <0.0001; G3 vs. G2: p-value = 0.0001).ConclusionA comparison by age of patients with sickle cell anemia showed a trend of lower risk of infection among younger individuals. Therefore, this study demonstrates that T. gondii infection occurs in patients with beta-thalassemia and sickle cell anemia in Brazil as seen by the presence of anti-T. gondii IgM and IgG antibodies.

Highlights

In Brazil, there have been no previous studies of Toxoplasma gondii infection in sickle cell anemia patients and carriers of severe forms of beta-thalassemia
Given the fact that no previous studies have investigated T. gondii infection in patients with beta-thalassemia and sickle cell anemia in Brazil, the aim of this study was to evaluate the presence of anti-T. gondii immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies in patients with beta-thalassemia major and intermedia and with sickle cell anemia diagnosed and treated in three referral centers
Molecular analysis of beta‐thalassemia mutations by allele‐specific polymerase chain reaction (PCR) Because high frequencies of some mutations of betathalassemia are found in the Brazilian population [23, 24], the following were investigated: CD39 (HBB: c.118C>T), IVSI-110 (HBB: c.93-21G>A), IVSI-6 (HBB: c.92 + 6T>C) and IVSI-1 (HBB: c.92 + 1G>A)

Summary

Introduction

In Brazil, there have been no previous studies of Toxoplasma gondii infection in sickle cell anemia patients and carriers of severe forms of beta-thalassemia. This study evaluated T. gondii infection in patients with beta-hemoglobinopathies. Sickle cell disease is a hereditary hemoglobinopathy characterized by the presence of hemoglobin (Hb) S, generated from a point mutation in the β-globin gene. Homozygosity for this point mutation leads to severe anemia with clinical manifestations such as hemolytic. In Brazil, this is the most common hereditary disease due to the influence of African descendants in the composition of the population and, in particular, to the high rate of miscegenation [3, 4]. The variability in the disease phenotypes ranges from clinically asymptomatic to severe anemia [5, 6].

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