Increased serum levels of CXCL8 chemokine in acute toxoplasmic retinochoroiditis

Cytokine profiles in patients with toxoplasmic lymphadenitis in the setting of pregnancy

INTRODUCTION

Majority of Toxoplasma gondii infections are benign and asymptomatic; however, some patients experience toxoplasmic lymphadenitis (TL). Factors associated as to whether infection will be symptomatic or not are unknown.

METHODS

Dye test titers of patients with acute toxoplasmosis (pregnant and not pregnant) with TL (TL+) were compared with those in patients with asymptomatic acute infection (TL-). Additionally, mean levels of 62 serum cytokines were compared between TL+ and TL- pregnant women and between TL+ pregnant and non-pregnant women.

RESULTS

During acute infection, mean dye test titer was higher in TL+ than in TL- patients (p=0.021). In addition, out of 62 cytokines, CXCL9andCXCL10 levels were higher (p<0.05) and resistin mean levels were lower (p<0.05) in pregnant women with TL+ compared to TL-. Among patients with TL+, levels of VCAM1andCCL2 were lower (p<0.05) in pregnant women than in non-pregnant women.

CONCLUSION

Here we report differences in dye test titers in patients with acute infection. Cytokine responses vary according to the presence of TL+ and to the pregnancy status. Factors underlying these differences are presently unknown and require further studies to define individual and combined roles of cytokines in TL+.

In vitro infection of human nervous cells by two strains of Toxoplasma gondii: a kinetic analysis of immune mediators and parasite multiplication

The severity of toxoplasmic infection depends mainly on the immune status of the host, but also on the Toxoplasma gondii strains, which differ by their virulence profile. The relationship between the human host and T. gondii has not yet been elucidated because few studies have been conducted on human models. The immune mechanisms involved in the persistence of T. gondii in the brains of immunocompetent subjects and during the reactivation of latent infections are still unclear. In this study, we analyzed the kinetics of immune mediators in human nervous cells in vitro, infected with two strains of T. gondii. Human neuroblast cell line (SH SY5Y), microglial (CMH5) and endothelial cells (Hbmec) were infected separately by RH (type I) or PRU (type II) strains for 8 h, 14 h, 24 h and 48 h (ratio 1 cell: 2 tachyzoites). Pro-inflammatory protein expression was different between the two strains and among different human nervous cells. The cytokines IL-6, IL-8 and the chemokines MCP-1 and GROα, and SERPIN E1 were significantly increased in CMH5 and SH SY5Y at 24 h pi. At this point of infection, the parasite burden declined in microglial cells and neurons, but remained high in endothelial cells. This differential effect on the early parasite multiplication may be correlated with a higher production of immune mediators by neurons and microglial cells compared to endothelial cells. Regarding strain differences, PRU strain, but not RH strain, stimulates all cells to produce pro-inflammatory growth factors, G-CSF and GM-CSF. These proteins could increase the inflammatory effect of this type II strain. These results suggest that the different protein expression profiles depend on the parasitic strain and on the human nervous cell type, and that this could be at the origin of diverse brain lesions caused by T. gondii.

Cytokine profiling reveals decreased serum levels of CCL2 in active ocular toxoplasmosis

BACKGROUND

Toxoplasma gondii infection is an important cause of ocular disease. Although parasite-mediated host cell lysis is probably the principal cause of tissue destruction in immunodeficiency states, hypersensitivity and inflammatory responses may underlie severe disease in otherwise immunocompetent individuals. The purpose of the current investigation was to study the cytokine profiles in serum from patients with ocular toxoplasmosis and to compare them with those obtained from healthy control subjects.

METHODS

Using a multiplex assay, we determined the serum concentration of granulocyte colony-stimulating factor (GCSF), interferon γ (IFNγ), interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10, chemokine (C-C motif) ligand 2 (CCL2) and tumour necrosis factor α (TNFα) in patients with inactive ocular toxoplasmosis (n=48), active ocular toxoplasmosis (n=21), and an age-matched and sex-matched healthy control group (n=25). In a subgroup of 17 patients with active disease, a second serum sample was obtained when the disease was inactive. Cytokine profiles were correlated with disease activity, severity and visual outcome.

RESULTS

Levels of CCL2 were significantly reduced in patients with active ocular toxoplasmosis compared to the control group (564 ± 42 pg/mL vs 455 ± 35 pg/mL, p<0.05). Moreover, CCL2 levels were significantly lower during active ocular toxoplasmosis compared to inactive disease (569 ± 32 pg/mL vs 433 ± 32 pg/mL, p<0.01). GCSF and TNFα were elevated in patients with toxoplasmosis with poor visual outcome. No significant correlations were found with specific cytokine profiles and disease severity.

CONCLUSIONS

Decreased serum levels of CCL2 may be associated with active ocular toxoplasmosis and could therefore serve as a marker of disease activity.

Increased serum levels of soluble tumor necrosis factor receptor-2 (sTNFR2) in patients with active toxoplasmic retinochoroiditis

This study aimed to investigate the serum levels of the cytokine TNF-α and its soluble receptors (sTNFR1 and sTNFR2) in patients with toxoplasmosis retinochoroiditis (TR) and controls. 37 patients with TR and 30 subjects with positive serology for toxoplasmosis but without history and signs of uveitis were included in this study. Serum concentrations of TNF-α, sTNFR1, and sTNFR2 were determined by ELISA. Serum concentrations of TNF-α and sTNFR1 were similar in controls (mean ± SD median values; 56.57±141.96 and 504.37±163.87, respectively) and TR patients (mean ± SD values, 121.62±217.56 and 511.15±189.30, respectively). Serum concentrations of sTNFR2 were higher in the uveitis group when compared to the control group (respectively, mean ± SD values, 1734.84±379.32 and 1442.75±309.47; p=0.002). There was no association between the serum levels of the molecules and the time of first symptoms, severity of vitreous haze, size or localization of active lesions, levels of visual acuity, and presence of vasculitis. These results suggest that TR is associated with changes in the circulating levels of inflammatory biomarkers, but they are not correlated with local/ocular signs.