Association between Toxoplasma gondii exposure and paediatrics haematological malignancies: a case-control study

The opposing effect of acute and chronic Toxoplasma gondii infection on tumor development

BACKGROUND

The interplay between Toxoplasma gondii infection and tumor development is intriguing and not yet fully understood. Some studies showed that T. gondii reversed tumor immune suppression, while some reported the opposite, stating that T. gondii infection promoted tumor growth.

METHODS

We created three mouse models to investigate the interplay between T. gondii and tumor. Model I aimed to study the effect of tumor growth on T. gondii infection by measuring cyst number and size. Models II and III were used to investigate the effect of different stages of T. gondii infection on tumor development via flow cytometry and bioluminescent imaging. Mouse strains (Kunming, BALB/c, and C57BL/6J) with varying susceptibilities to tumors were used in the study.

RESULTS

The size and number of brain cysts in the tumor-infected group were significantly higher, indicating that tumor presence promotes T. gondii growth in the brain. Acute T. gondii infection, before or after tumor cell introduction, decreased tumor growth manifested by reduced bioluminescent signal and tumor size and weight. In the tumor microenvironment, CD4+ and CD8+ T cell number, including their subpopulations (cytotoxic CD8+ T cells and Th1 cells) had a time-dependent increase in the group with acute T. gondii infection compared with the group without infection. However, in the peripheral blood, the increase of T cells, including cytotoxic CD8+ T cells and Th1 cells, persisted 25 days after Lewis lung carcinoma (LLC) cell injection in the group with acute T. gondii. Chronic T. gondii infection enhanced tumor growth as reflected by increase in tumor size and weight. The LLC group with chronic T. gondii infection exhibited decreased percentages of cytotoxic CD8+ T cells and Th1 cells 25 days post-LLC injection as compared with the LLC group without T. gondii infection. At week 4 post-LLC injection, chronic T. gondii infection increased tumor formation rate [odds ratio (OR) 1.71] in both KM and BALB/c mice.

CONCLUSIONS

Our research elucidates the dynamics between T. gondii infection and tumorigenesis. Tumor-induced immune suppression promoted T. gondii replication in the brain. Acute and chronic T. gondii infection had opposing effects on tumor development.

Toxoplasma gondii Infection in Immunocompromised Patients in Iran (2013-2022): A Systematic Review and Meta-Analysis

Background

Toxoplasma gondii infection (toxoplasmosis) has the potential to cause a serious disease in immunocompromised patients and can be fatal in this population. We conducted a systematic review and meta-analysis to assess comprehensively the pooled seroprevalence of toxoplasmosis among immunocompromised patients including HIV/AIDS patients, cancer patients, and transplant recipients in Iran.

Methods

PubMed, Web of Science, Scopus, Embase, and Google Scholar databases (international) and Scientific Information Database (SID), Magiran, IranMedex, and IranDoc databases (national) were systematically searched for all reports that possibly contained data for T. gondii prevalence in different immunocompromised populations in Iran between 2013 and 2022.

Results

Overall, IgG seroprevalence rate of toxoplasmosis in Iranian immunocompromised patients was 45.1% (95% confidence interval (CI), 37.4-52.9). IgG seroprevalence rate of toxoplasmosis in 12 studies that included 2279 cancer patients, 19 studies that included 2565 HIV/AIDS patients and in 3 studies that included 200 transplant recipients was 43.6% (95% CI, 30.2-57.0), 45.9% (95% CI, 34.8-57.1) and 45.8% (95% CI, 32.5-59.0), respectively. Moreover, IgM seroprevalence rate in the 26 studies was 2.6% (95% CI, 1.4-3.7).

Conclusion

Our findings represent a high seroprevalence rate of Toxoplasma IgG among immunocompromised patients. Health improvement and education toward prevention of toxoplasmosis is of great importance for these susceptible populations.

Blastic plasmacytoid dendritic cell neoplasm and cerebral toxoplasmosis: a case report

BACKGROUND

The present case contributes to the limited literature on central nervous system involvement of blastic plasmacytoid dendritic cell neoplasm (BPDCN).  CASE PRESENTATION : A 63-year-old male presented to the department of neurology with a three-day history of rapidly progressing headache, fatigue, and confusion. Physical examination revealed multiple bruise-like skin lesions. Initial laboratory workup raised suspicion of acute leukemia, and a brain computer tomography identified several hyperdense processes. A bone marrow biopsy gave the diagnosis BPDCN, a rare and aggressive hematologic malignancy derived from plasmacytoid dendritic cells with a poor prognosis. Lumbar puncture showed not only signs of BPDCN, but also cerebral toxoplasmosis, thus providing a differential diagnosis. Despite intensive systemic and intrathecal chemotherapy, the patient died 25 days later due to multi-organ failure.

DISCUSSION

The exact incidence of BPDCN is unknown and perhaps underestimated but may account for 0.5 - 1% of all hematological malignancies. The median age at onset is 60 to 70 years, and most patients are men. Cutaneous lesions are the most frequent clinical manifestation at diagnosis. Other symptoms present at time of diagnosis or during disease progression include lymphadenopathy, splenomegaly and cytopenia caused by bone marrow involvement. Although the majority of BPDCN patients have no symptoms or signs of central nervous system involvement, plasmacytoid dendritic cells have been detected in the cerebrospinal fluid in more than 50%.

CONCLUSIONS

This case highlights the importance of considering hematological malignancies as a differential diagnosis in patients developing acute neurological symptoms and raises suspicion of a possible association between toxoplasmosis and hematological malignancies.

Toxoplasma gondii Infection Among Institutionalized Children with Down syndrome in Sana'a city, Yemen: Implications of Low IgG Seroprevalence

Purpose

To assess the IgG seroprevalence of Toxoplasma gondii as an indicator of past exposure and immunity against infection among children with Down syndrome (DS) in Sana’a city, Yemen. This preliminary study is justified by the primary immunodeficiency of children with DS and the opportunistic nature of the parasite, considering the vague situation of anti-Toxoplasma IgG seroprevalence among children with DS because of neglecting its study on local and global scales.

Methods

This descriptive, facility-based, cross-sectional study was conducted among 107 children with DS hosted in six randomly selected rehabilitation centers for children with special needs in Sana’a city. Demographics of children and their mothers’ knowledge of toxoplasmosis were collected using a pre-designed, structured questionnaire. Anti-Toxoplasma IgG antibodies were measured in the sera of children using electrochemiluminescence assay.

Results

Of 107 children with DS, 3 (2.8%) were seropositive for anti-Toxoplasma IgG. Approximately two-thirds (71/106) of the mothers of children with DS were aware of toxoplasmosis. Of whom, 83.1% (59/71) were aware of its congenital complications.

Conclusion

The majority of children with DS in Sana’a city are seronegative for anti-Toxoplasma IgG, where the seropositivity rate is lower than 3.0%. Therefore, children with DS are non-immune and susceptible to the acquisition of primary infections during their life. Further analytical studies are recommended to determine whether the defective immune response of children with DS is associated with false seronegativity, to assess the role of their mothers’ knowledge in reducing their exposure to infection if they were confirmed truly seronegative and to identify the predictors of infection among them.

Serology for Toxoplasma in Immunocompromised Patients: Still Useful?

Toxoplasmosis represents one of the most common comorbidity factors in solid organ or hematopoietic stem cell transplant recipients as well as in other immunocompromised patients. In the past decades, availability and performance of molecular tools for the diagnosis or the exclusion of toxoplasmosis in these patients have greatly improved. However, if accurately used, serology remains a complementary and essential diagnostic tool for physicians and medical parasitologists for the prevention and management of toxoplasmosis in immunocompromised patients as well. It is required for determination of the immunological status of patients against Toxoplasma. It also helps diagnose and monitor complex cases of opportunistic Toxoplasma infection in immunocompromised patients. New perspectives are available to further enhance their yield and ease of use.

Increased Risk of Toxoplasma gondii Infection in Patients with Colorectal Cancer in Eastern China: Seroprevalence, Risk Factors, and a Case-Control Study

The aim of this study was to explore the epidemiology of Toxoplasma gondii infection in patients with colorectal cancer (CRC) in eastern China. Therefore, 287 primary CRC patients and 287 age-matched healthy control subjects were recruited to estimate the seroprevalence of T. gondii and identify the risk factors of infection. Enzyme-linked immunoassays were used to test for anti-T. gondii immunoglobulin G (IgG) and IgM antibodies. Forty-six (16%) samples were positive for anti-T. gondii IgG antibodies in patients with CRC, compared with 26 (9.1%) in the healthy controls, a significant difference (P = 0.007). By contrast, eight (2.8%) patients tested positive for T. gondii IgM antibodies, compared with three (1.1%) in the controls, a difference that was not significant (P = 0.13). Multivariable backward stepwise logistic regression analysis revealed that a rural residence (OR 2.83; 95% CI 1.15–7.01; P = 0.024) and treatment with chemotherapy (OR 2.16; 95% CI 1.02–4.57; P = 0.045) were risk factors for T. gondii infection in patients with CRC. Thus, T. gondii infection is serious in patients with CRC, and a rural residence and treatment with chemotherapy are independent risk factors for infection by this parasite. Therefore, medical professionals should be aware of this pathogen in patients with CRC, and the causes of T. gondii infection in these patients need to be explored further.

Association between Toxoplasma gondii exposure and hematological malignancies: A systematic review and meta-analysis

The possible association between Toxoplasma gondii infection and hematological malignancies has been suggested by several studies. The current systematic review and meta-analysis was directed to further understand this relationship. In the present study, five electronic databases were reviewed for T. gondii infection in patients with blood cancer. The random effects model and 95% confidence intervals (CI) were used to determine the overall odds ratio (OR). Heterogeneity was deliberate with Cochran's Q test and I² statistic. In total, 13 studies including 1504 patients with hematological neoplasia and 2622 subjects without any malignancies were included in this meta-analysis. Overall, 324 patients with blood cancer and 391 subjects without any malignancies were exposed to Toxoplasma infection. The pooled random effect favored a statistically significant increased risk of T. gondii infection in patients with hematological neoplasia compared with non-cancer individuals [OR = 2.43; 95% CI: 1.49-3.97; χ2 = 49.7, I² = 75.9%, P = 0.00]. Also, significant pooled ORs of positive association were observed for studies which measured anti- Toxoplasma antibodies (IgG) [OR = 2.66; 95% CI: 1.46-4.83; χ2 = 40.3; I² = 82.6%, P = 0.00]. T-value and P-value were obtained 0.20 and 0.85 by Harbords modified regression test. This meta-analysis demonstrates that toxoplasmosis may be associated with an elevated risk of hematological malignancies. Also, it has found that immunoglobulin class and types of blood cancer are the specific sources of heterogeneity. Additional studies should be performed to examine the impact of T. gondii infection in the onset or development of hematologic neoplasms in the future.

Acute toxoplasmosis and pox-viral dermatitis in a juvenile bald eagle (Haliaeetus leucocephalus) in New Brunswick, Canada

Although birds of prey are commonly subclinically infected by Toxoplasma gondii tissue cysts, clinical disease is relatively rare in these species. The present report describes a rare case of fatal toxoplasmosis in a juvenile bald eagle in New Brunswick. Necropsy investigation revealed severe emaciation and poxviral dermatitis which partially obscured the palpebral fissures. Microscopically there was severe lymphoplasmacytic inflammation and necrosis of the lung that was associated with abundant protozoal tachyzoites. Infection with T. gondii was confirmed in the lung via immunohistochemistry and DNA sequencing. Key clinical message: Wildlife rehabilitation centers should be aware of the potential occurrence of acute clinical toxoplasmosis in stressed malnourished raptors.

Seroprevalence of Toxoplasma gondii infection in cancer patients: A systematic review and meta-analysis

Toxoplasmosis, caused by Toxoplasma gondii, is a great public health concern in cancer patients, which can induce serious pathological effects. This systematic review and meta-analysis was performed to evaluate the worldwide seroprevalence rate of T. gondii infection among cancer patients. A search was conducted on five electronic databases that reported data on T. gondii seroprevalence in cancer patients. The searching process resulted in the inclusion of 57 studies. The results showed that T. gondii had the pooled prevalence of 30.8% in cancer patients using a random-effect model (95% CI: 26.3-35.6). Cancer patients had a higher overall prevalence of T. gondii infection, compared to those without cancer. Furthermore, the odds ratio of toxoplasmosis in cancer patients was 3.1 times, compared to that of controls (95% CI: 2.5-3.8, P < 0.0001). Toxoplasmosis had a higher prevalence in females (40%) than in males (33%). Furthermore, the age group of upper 40 years had the highest prevalence infection rate (30%). In addition, a significant association was also observed between toxoplasmosis infection and year (P < 0.001), type of cancer (P < 0.001), country (P < 0.001), gender (P < 0.001), age (P = 0.006) and diagnostic method (P < 0.001) in cancer patients. Considering the high prevalence of T. gondii infection in cancer patients and its serious outcomes, the researchers are suggested to carry out further studies to prevent and control toxoplasmosis among this population.