Detection of high titres of Toxoplasma gondii antibodies in sera of patients with leprosy in Pakistan

BCG activation of trained immunity is associated with induction of cross reactive COVID-19 antibodies in a BCG vaccinated population

BACKGROUND

Pakistan is endemic to a diverse set of parasitic, mycobacterial and viral diseases. The recognition of BCG Trained Immunity (TI) led us to postulate that the continued presence of BCG-TI may play a protective role, previously reported for both infectious and noninfectious conditions. Most of the previous studies have addressed the issue of BCG-TI in the paediatric populations. This study addressed the key issue of maintenance of BCG-TI in a wider age range (adolescent and adults) to identify the strength and quality of the immune responses.

OBJECTIVE

To assess the BCG-induced recall responses in healthy individuals by cytokines secreted from the TI network and its potential role in providing cross-protection against COVID-19 and other viral infections.

STUDY DESIGN

In this cross-sectional study, healthy young adults and adolescents (n = 20) were recruited from 16-40 years of age, with no prior history of TB treatment, autoimmune, or chronic inflammatory condition.

METHODS

BCG-induced cytokine responses were assessed using prototypic markers for cells of the TI network [macrophages [M1 (TNFα, IFNγ), M2 (IL10)], NK (IL2), Gamma delta (γδ) T (IL17, IL4)] and SARS CoV2 IgG antibodies against RBD using short-term (12 hrs.) cultures assay.

RESULTS

Significant differences were observed in the magnitude of recall responses to BCG with macrophage cytokines showing the highest mean levels of TNFα (9148 pg/ml) followed by IL10 (488 pg/ml) and IFNγ (355 pg/ml). The ratio of unstimulated vs.BCG-stimulated cytokines was 132 fold higher for TNFα, 40 fold fo r IL10, and 27 fold for IFNγ. Furthermore, SARS-CoV-2 antibodies were also detected in unstimulated plasma which showed cross reactivity with BCG.

CONCLUSION

The presence of cross reactive antibodies to SARS-CoV-2 and the relative ratio of pro- and anti-inflammatory cytokines secreted by activated TI cellular network may play a pivotal role in protection in the early stages of infection as observed during the COVID-19 pandemic in the younger age groups resulting in lower morbidity and mortality.

Molecular identification of Toxoplasma gondii in domesticated and broiler chickens (Gallus domesticus) that possibly augment the pool of human toxoplasmosis

Toxoplasma gondii (T. gondii) is a protozoan parasite that infects all warm-blooded animals including domesticated birds and humans. Birds normally get infected by ground feeding and human beings contract the disease by consumption of undercooked chicken meat. This study aimed to analyze seroprevalence and DNA of T. gondii in chickens (domesticated and broiler) and to assess possible transfer to humans by review of available literature from Pakistan. Blood from and tissues from domesticated and broilers chickens were analyzed for Toxo-IgM/IgG and Toxoplasma DNA through ELISA and PCR respectively. Furthermore, research articles published during 1990-2019 on the prevalence of T. gondii in humans from Pakistan, were analyzed to assess the possible infection burden in the area in connection to transmission from chickens. The overall prevalence of IgM and IgG for T. gondii was 17.83% and 8.8% respectively in the study areas. Significant seroprevalence was found in domesticated chickens than broilers. In domesticated chickens, the prevalence was high in age ≥ 2 years. Toxoplasma DNA was detected in tissues with an overall prevalence of 10.84%. Higher prevalence was observed in liver (10.50%) than heart (9.5%) and muscles (7.11%). Only 4.78% broiler and 2.38% domesticated chickens were positive for both IgM and DNA, 1.2% domesticated and 1.30% broilers were positive for IgG and DNA, while 2.98% domesticated and 2.17% broilers were positive for IgM, IgG, and DNA. Available literature showed that 25.8% of human beings were infected with T. gondii in Pakistan. The prevalence was 20.64% in male and 26.82%in the female. The rate of infections increases with age and high (37.36%) was found in humans of age range 40 to 60 years. A high prevalence of T. gondii is found in both domesticated and broiler chickens in the study area. Moreover, the literature survey indicates that a high seroprevalence of T. gondii is present in human beings of Pakistan. It is concluded that the high prevalence of T. gondii in humans may be associated with the parasite transmission through infected chicken's meat in Pakistan.

Serological evidence of Toxoplasma gondii infection as potential risk for the development of lepromatous leprosy in an endemic area for both neglected tropical diseases in Brazil

Background

Mycobacterium leprae and Toxoplasma gondii infections are both neglected tropical diseases highly prevalent in Brazil. Infection with certain parasite species can significantly alter susceptibility to other important pathogens, and/or influence the development of pathology. Here we investigated the possible influence of M. leprae/T. gondii co-parasitism on the manifestation of leprosy and its clinical forms.

Methods

Participants (n = 291) were recruited in Campos dos Goytacazes city, Rio de Janeiro state, southeast Brazil, from August 2015 to December 2019 and clinically diagnosed for leprosy. Participants were selected based on the presence (patients) or absence (healthy controls) of the leprosy disease. Contacts of patients were also recruited for this study. Serum samples from patients (n = 199) with leprosy, contacts (n = 40) and healthy controls (n = 52) were investigated for levels of IgM and IgG anti-phenolic glycolipid-1 (PGL-1) by ELISA. Additionally, IgG antibody against soluble Toxoplasma antigen (STAg) was measured in sera samples from leprosy patients, contacts and healthy controls for Toxoplasma gondii serology by ELISA. Anti-PGL-1 IgG and IgM levels were compared using one-way ANOVA Kruskal-Wallis or Mann-Whitney, while Spearman test was used to correlate levels of IgG anti-STAg and IgM/IgG anti-PGL-1 from seropositive and seronegative individuals for T. gondii infection. The risk of T. gondii infection for leprosy disease was assessed using Fisher’s test.

Results

Levels of IgM anti-PGL-1 antibodies were significantly higher in multibacillary (MB) patients compared to paucibacillary (PB) patients (P = 0.0068). Higher IgM and IgG levels anti-PGL-1 were detected in patients with the lepromatous forms. The serologic prevalence for T. gondii infection was 74.9%. We detected increased anti-STAg antibody levels in leprosy patients (79.4%), reaching 88.8% within those with lepromatous form of this disease. The leprosy risk increase in T. gondii seropositive individuals was two-fold (odds ratio [OR] = 2.055; 95% confidence intervals [95% CI]: 1.18–3.51) higher than those seronegative, and considering the lepromatous leprosy risk this increase was even dramatic (OR = 4.33; 95% CI: 1.76–9.69) in T. gondii seropositive individuals. Moreover the leprosy risk in T. gondii seropositive individuals was weakly correlated to the levels of IgG anti-STAg and IgM/IgG anti-PGL-1.

Conclusions

Altogether, our results suggest that T. gondii infection may exert immunomodulatory properties that influence to the susceptibility of leprosy, mainly on its more severe clinical form. A better understanding of parasite immunomodulation can ultimately contribute to the development of medical applications.