**Author details**

166 Toxoplasmosis – Recent Advances

recurrence of ocular toxoplasmosis [54].

**6. Conclusion** 

considering that this cytokine is a very important to parasite control replication, the patients presenting the AA genotype for the IFN- +874 T/A polymorphism likely have a similar profile of specific cellular immune response with that observed for the group that presented lesions of types B and BC, as shown in Figure 3, and multiple type scar lesions, as shown in Figure 4. Namely, they would tend to produce moderate to low levels of IFN- and IL-13 and low levels of CXCL 10, which most likely causes an immune response that is not sufficient to efficiently prevent/control parasite proliferation; as a consequence, retinal/retinochoroidal tissues damage occurs. It is important to note that to determine the frequency of the genotype AA among individuals grouped by the type of scar lesions, in association with phenotypic parameters of the immune response, like cytokines and chemokines, would be of value to improve our understanding of the possible pathological

mechanisms that occur in the different types of scar lesions in ocular toxoplasmosis.

Other reports in the literature have described genetic association studies of cytokines with toxoplasmic ocular diseases in Brazil. However, they describe small casuistic related to patients from ophthalmologic reference centers and do not find significant associations [52- 54], although one suggests the association of polymorphism at IL-1 alfa gene and the

We have presented data related to a decade of research on a hyperendemic area to *T. gondii* infection, considering aspects linked to the clinical presentation of ocular disease in a population exposed to high risk of waterborne toxoplasmosis, the profile of *in vitro* specific immune response in the function of the disease's clinical presentation, and genetic

It is important to consider the conclusions and advances that can be derived based on the study of PBMC from patients who exhibit different clinical presentations of ocular toxoplasmosis, stimulated *in vitro* with parasite antigens. One can argue that the study of the specific responses of PBMC *in vitro* does not reflect the eye's immune-privileged environment, for instance. However, the study of PBMC represents is a non-invasive approach that is adequate for population-based studies such that in the genomic medicine era, it will improve our understanding of relevant gene response, i.e., their activation and regulation in inflammatory process within the eye. The associations between phenotype and genotype data from cohorts accelerate our understanding of the molecular mechanisms involved in the disease's pathology. Our data on P2X7 genotyping genes together with the PBMC immune profile illustrate this aspect. Namely, our initial hypothesis on an exacerbation of the inflammatory response with high levels of pro-inflammatory cytokines, especially IFN secretion, concomitant with relatively low levels of anti-inflammatory cytokines like IL-13 secretion in response to parasite antigens, which was identified by *in vitro* PBMC stimulation experiments and could contribute to the development of ocular disease, is reinforced by the findings on *P2RX7* genotypingat the SNP rs1718119. This data showed that the ancestral allele is highly protective for the development of ocular disease. The SNP rs1718119 has been

association studies with candidate genes in ocular toxoplasmosis.

Lílian M.G. Bahia-Oliveira\* , Alba L.P. Rangel, Marcela S.B. Boechat, Bianca M. Mangiavacchi\*\*, Livia M. Martins\*\*, Francielle B. Ferraz\*\*, Maycon B. Almeida and Flavia P. Vieira *Laboratório de Biologia do Reconhecer (LBR) Centro de Biociências e Biotecnologia (CBB) Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, RJ, Brazil* 

<sup>\*</sup> Corresponding Author

<sup>\*\*</sup> Equal Contribution

Elisa M. Waked Peixoto and Ricardo G. Peixe *Laboratório de Biologia do Reconhecer (LBR) Centro de Biociências e Biotecnologia (CBB) Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF),Campos dos Goytacazes, RJ, Brazil Faculdade de Medicina de Campos, Campos dos Goytacazes, RJ, Brazil* 

Immunological and Immunogenetic Parameters on the Diversity of Ocular Toxoplasmosis: Evidence to Support Morphological Criteria to Classify Retinal/Retinochoroidal Scar Lesions in Epidemiologic Surveys 169

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