Expressions and roles of periostin in otolaryngological diseases

Periostin is a 90-kDa member of the fasciclin-containing family; it functions as part of matricellular proteins, and its production by airway epithelial cells is induced by IL-4 and IL-13. Periostin is secreted by fibroblasts and upregulated in the airway epithelia of patients with bronchial asthma; it is considered to contribute to remodeling under this pathological condition. However, despite many studies in diverse research areas, our overall understanding of this intriguing molecule is still inadequate. Here, we integrate the available evidence on periostin expression and its roles in otolaryngological diseases, including allergic rhinitis, chronic rhinosinusitis with nasal polyps, aspirin-induced asthma, organized hematoma, eosinophilic otitis media, and IgG4-related disease. Periostin might be involved as an important structural mediator in pathological processes such as insult and injury, Th2-driven inflammation, extracellular matrix restructuring, fibrosclerosis, tumor angiogenesis, and tissue remodeling.

Molecular genotyping of anisakis larvae in Middle Eastern Japan and endoscopic evidence for preferential penetration of normal over atrophic mucosa

BACKGROUND

Anisakiasis is a parasitic disease caused primarily by Anisakis spp. larvae in Asia and in Western countries. The aim of this study was to investigate the genotype of Anisakis larvae endoscopically removed from Middle Eastern Japanese patients and to determine whether mucosal atrophy affects the risk of penetration in gastric anisakiasis.

METHODS

In this study, 57 larvae collected from 44 patients with anisakiasis (42 gastric and 2 colonic anisakiasis) were analyzed retrospectively. Genotyping was confirmed by restriction fragment length polymorphism (RFLP) analysis of ITS regions and by sequencing the mitochondrial small subunit (SSU) region. In the cases of gastric anisakiasis, correlation analyses were conducted between the frequency of larval penetration in normal/atrophic area and the manifestation of clinical symptoms.

RESULTS

Nearly all larvae were A. simplex seusu stricto (s.s.) (99%), and one larva displayed a hybrid genotype. The A. simplex larvae penetrated normal mucosa more frequently than atrophic area (p = 0.005). Finally, patients with normal mucosa infection were more likely to exhibit clinical symptoms than those with atrophic mucosa infection (odds ratio, 6.96; 95% confidence interval, 1.52-31.8).

CONCLUSIONS

In Japan, A. simplex s.s. is the main etiological agent of human anisakiasis and tends to penetrate normal gastric mucosa. Careful endoscopic examination of normal gastric mucosa, particularly in the greater curvature of the stomach will improve the detection of Anisakis larvae.

OK-432 treatment of ranula extending to the parapharyngeal space

CONCLUSIONS

Our results confirmed that OK-432 therapy is simple, easy, safe, and effective and can be used as a substitute for surgery in the treatment of ranula extending to the parapharyngeal space.

OBJECTIVE

The aim of this study was to evaluate the outcome and complications of the OK-432 treatment of patients with ranula extending to the parapharyngeal space.

METHODS

This was a case series with planned data collection at Yamagata University and Fukase clinic. We tried this therapy in six patients with ranula extending to the parapharyngeal space, between January 2001 and February 2012. We injected OK-432 solution into the lesion with an 18 or 27 gauge needle depending on the patient's condition (location and size of ranula and complications). This treatment was performed on an outpatient basis without hospitalization.

RESULTS

Disappearance or marked reduction of the lesion were observed in all patients who had this therapy, and local scarring and deformity of the injection sites did not occur in any patients. As side effects, local pain at the injection site and fever (37-39°C) were observed in 40% of the patients who had this therapy, but such problems resolved within a few days.

Roles of TGF-beta and periostin in fibrosclerosis in patients with IgG4-related diseases

CONCLUSION

These results suggest that transforming growth factor (TGF)-beta and periostin could be useful as novel biomarkers and therapeutic targets in IgG4-related disease.

OBJECTIVES

IgG4-related disease is an uncommon fibrosclerosing and inflammatory mass-forming disease that can be systemic or can affect single organs. To clarify the roles of TGF-beta, periostin, and interleukin (IL)-13 in the pathogenesis of IgG4-related disease, we studied a total of 36 serum and 11 tissue samples from patients with IgG4-related disease.

METHODS

This was a retrospective clinical study. The patient group consisted of six females and seven males (average age 60 years, range 38-74 years). Serum IgG4 levels, the tissue density of IgG4-positive plasmacytes, and the expression of TGF-beta and periostin in the affected tissues were examined immunohistochemically.

RESULTS

Serum IgG4 levels were elevated in all patients (mean 776.6, range 185-2820 mg/dl), and IgG4-positive plasmacytes were observed in the affected salivary glands. Seven patients with prominent infiltration of the involved glands with IgG4-positive plasmacytes had fatal systemic complications, including pancreatitis, after swelling of the salivary glands. Overexpression of TGF-beta and periostin was observed in affected tissues obtained from these patients.

Hookworm-related cutaneous larva migrans in patients living in an endemic community in Brazil: immunological patterns before and after ivermectin treatmen

Hookworm-related cutaneous larva migrans (Hr-CLM) is caused by animal hookworm larvae migrating in the human epidermis where they elicit an inflammatory response. This study describes the immunological profile in Hr-CLM patients. In 77 Hr-CLM patients from Manaus, Brazil, peripheral eosinophils were counted, and serum concentrations of total immunoglobulin E (IgE) and selected cytokines were determined by ELISA before and after treatment with ivermectin. Controls included patients' household members (endemic controls), non-endemic Brazilian and Japanese individuals. Eosinophil counts and total IgE in Hr-CLM patients were higher than in controls and correlated with disease severity. Concentrations of interleukin (IL)-4, IL-5, IL-6, and IL-10 were higher in Hr-CLM patients than in endemic controls (p < 0.001) while no differences were detected for interferon (IFN)-γ, tumor necrosis factor (TNF)-α, IL-1β, IL-2, or transforming growth factor (TGF)-β. Following ivermectin treatment, numbers of eosinophils and concentrations of IL-4, IL-5, and IL-10 decreased whereas IgE, IFN-γ, and TGF-β concentrations increased. The IL-5/IFN-γ ratio declined from 5.9 (interquartile range [IQR] 0.8-31.6) before to 0.1 (IQR 0.05-0.2; p = 0.001) after treatment. Thus, although an impact of other infections on the immune parameters determined cannot be excluded, Hr-CLM in endemic areas is associated with eosinophilia and elevated cytokine levels, particularly of IL-5 and IL-10, which decrease following ivermectin treatment.

The skin is an important bulwark of acquired immunity against intestinal helminths

IL-4–producing basophils promote the trapping of N. brasiliensis in the skin during secondary infection, a process critical for limiting the spread of infection to the lungs.

Once animals have experienced a helminthic infection, they often show stronger protective immunity against subsequent infections. Although helminthic infections are well known to elicit Th2-type immune responses, it remains ill-defined where and how acquired protection is executed. Here we show that skin-invading larvae of the intestinal helminth Nippostrongylus brasiliensis are surrounded by skin-infiltrating cells and are prevented from migrating out of infected skin during the second but not the first infection. B cell– or IgE receptor FcεRI–deficient mice showed impaired larval trapping in the skin. Selective ablation of basophils, but not mast cells, abolished the larval trapping, leading to increased worm burden in the lung and hence severe lung injury. Skin-infiltrating basophils produced IL-4 that in turn promoted the generation of M2-type macrophages, leading to the larval trapping in the skin through arginase-1 production. Basophils had no apparent contribution to worm expulsion from the intestine. This study thus reveals a novel mode of acquired antihelminth immunity, in which IgE-armed basophils mediate skin trapping of larvae, thereby limiting lung injury caused by larval migration.

The first genetically confirmed case of Dioctophyme renale (Nematoda: Dioctophymatida) in a patient with a subcutaneous nodule

We describe a nematode larva in a subcutaneous nodule excised from a 44-year-old Chinese male who had been living in Japan for 15 years. Morphological features suggested that the worm was a dioctophimatid nematode. PCR amplification and sequencing of small subunit ribosomal DNA and mitochondrial cytochrome subunit c oxidase genes allowed us to identify the larva as the giant kidney worm, Dioctophyme renale (Goeze, 1972). This is the first molecularly confirmed human case of a dermal D. renale infection.

First report of Angiostrongylus cantonensis (Nematoda: Angiostrongylidae) infections in invasive rodents from five islands of the Ogasawara Archipelago, Japan

BACKGROUND

Angiostrongylus cantonensis (Chen, 1935) is a parasite of murid rodents and causative agent of human neuro-angiostrongyliasis. In 2011, the Ogasawara Islands in the western North Pacific were assigned a World Natural Heritage site status. The occurrence of A. cantonensis is well documented in the Chichijima, Hahajima, and Anijima Islands. However, the occurrence of A. cantonensis in the other islands of the Ogasawara Islands has not been reported.

METHODOLOGY/PRINCIPAL FINDINGS

Between March 2010 and July 2011, 57 Rattus norvegicus and 79 R. rattus were collected from 9 islands (the Hahajima group: Anejima, Imoutojima, Meijima, Mukohjima, and Hirajima; Chichijima group: Minamijima; Mukojima group: Nakoudojima and Yomejima; and Iwojima group: Iwojima). Adult nematodes were found in the pulmonary artery of 46 R. norvegicus collected in the 5 islands of the Hahajima group (Anejima, Meijima, Imoutojima, Hrajima, and Mukohjima Islands). These nematodes were identified by molecular analysis as A. cantonensis. Comparison of the mitochondrial DNA sequences confirmed that all the samples from the Ogasawara Islands shared only a single lineage of A. cantonensis, which has been previously detected in the Okinawa, Hawaii, and Brazil.

CONCLUSIONS/SIGNIFICANCE

We describe new endemic foci of rat angiostrongyliasis in the Hahajima group (Anejima, Meijima, Imoutojima, Hirajima, and Mukohjima Islands) of the Ogasawara Islands. These findings indicate that the endemic foci of A. cantonensis are widely distributed in the Ogasawara Islands. Although human cases have not yet been reported in the Ogasawara Islands, the widespread detection of A. cantonensis could be of importance from the perspective of public health.

Aortic aneurysm rupture as a rare complication of granulomatosis with polyangiitis: a case report

Introduction

Granulomatosis with polyangiitis is characterized by systemic inflammation of medium and small blood vessels. Aortic involvement in granulomatosis with polyangiitis is extremely rare. As far as we know this is the first reported case of successful treatment in a patient with granulomatosis with polyangiitis complicated with aortic aneurysm rupture.

Case presentation

We describe a case of granulomatosis with polyangiitis in a 38-year-old Japanese man who developed an aortic aneurysm rupture 22 years after disease onset. The patient was operated on and a J-graft was inserted. He recovered uneventfully.

Conclusion

Recommendations in regard to, and consideration of, aortic involvement should be kept in mind in the long-term careful follow up of granulomatosis with polyangiitis.

The antibody responses to adult-worm antigens ofSchistosoma haematobium, among infected and resistant individuals from an endemic community in southern Ghana

Antibody responses to antigens from adult Schistosoma haematobium were investigated in an endemic community in Ghana, using microplate-ELISA. The results of a survey of egg output in urine and of a questionnaire-based investigation of water-contact activities were used to select 'endemic normal' (EN) and patently infected (PI) individuals as subjects. The plasma levels of antibodies reacting with the adult-worm antigens were determined and compared and the correlations between these levels and the age, water-contact index and egg output of each subject were evaluated. Compared with the EN subjects, the PI generally had higher levels of anti-worm IgG and IgE but lower levels of anti-worm IgA. When the data for the EN and PI groups were combined, the levels of anti-worm IgG and IgE were found to be positively correlated with egg output and with each other. Whichever the antibody class considered, levels of anti-worm antibodies were never negatively correlated with egg output. These results indicate that anti-worm IgE and IgG could be used as markers to reflect current infection intensity, and that anti-worm antibodies may not act as protective antibodies in the natural course of urinary schistosomiasis.

Severity assessment of Japanese cedar pollinosis using the practical guideline for the management of allergic rhinitis in Japan and the allergic rhinitis and its impact on asthma guideline

BACKGROUND

This study intended to assess the severity of Japanese cedar pollinosis using the Practical Guideline for the Management of Allergic Rhinitis in Japan (PG-MARJ) and the Allergic Rhinitis and its Impact on Asthma (ARIA) Guideline.

METHODS

An Internet questionnaire survey of patients with pollinosis was conducted in mid-May 2011 and responses were obtained from 3382 individuals who had potential symptoms of Japanese cedar pollinosis from February to early May 2011 and who had experienced such symptoms for at least two pollen seasons.

RESULTS

According to PG-MARJ, 23.5% of the respondents had severest rhinitis, 29.4% severe rhinitis, 31.3% moderate rhinitis, 13.8% mild rhinitis and 2.0% asymptomatic rhinitis. According to ARIA, 67.2% of them had moderate/severe persistent rhinitis, 23.8% moderate/severe intermittent rhinitis, 4.4% mild persistent rhinitis and 4.6% mild intermittent rhinitis.

CONCLUSIONS

Moderate to severe rhinitis was diagnosed in more than 80% of the respondents according to PG-MARJ, while moderate/severe rhinitis was diagnosed in more than 90% of the respondents according to ARIA. Most of the respondents suffered relatively severe pollinosis. More than 80% of the respondents had all the three major symptoms (i.e., sneezing, rhinorrhea and nasal blockage). Disagreement in the severity assessment between the two guidelines was noted in approximately 20% of the respondents.

Expression of pendrin and periostin in allergic rhinitis and chronic rhinosinusitis

BACKGROUND

Pendrin and periostin are newly identified mediators of the inflammatory process. The expression of these proteins in human sinonasal tissue and their roles in allergic rhinitis and chronic rhinosinusitis remain to be elucidated. This study investigated the expression of pendrin and periostin in sinonasal tissue of patients with allergic rhinitis, chronic rhinosinusitis, and aspirin-induced asthma. Prospective control study conducted at Yamagata University, Japan.

METHODS

Surgical samples were investigated by means of real-time reverse transcription-polymerase chain reaction to evaluate the expression of pendrin and periostin mRNA. The presence and location of pendrin and periostin were determined by immunohistochemistry and Western blotting.

RESULTS

Pendrin and periostin production was significantly higher in patients with nasal disorders than in controls. Further significant increases in periostin expression were noted in patients with chronic rhinosinusitis with nasal polyps and in those with aspirin-induced asthma. Immunohistochemistry revealed positive staining for pendrin in epithelial cells and submucosal glands and for periostin in the basement membrane in all three disorders, and additionally for periostin in nasal polyp tissue in chronic rhinosinusitis and aspirin-induced asthma.

CONCLUSIONS

Production of pendrin and periostin is upregulated in allergic rhinitis, chronic rhinosinusitis with nasal polyps, and aspirin-induced asthma. These findings suggest that pendrin can induce mucus production and that periostin can induce tissue fibrosis and remodeling in the nasal mucosa. Therefore, these mediators may be therapeutic target candidates for allergic rhinitis, chronic rhinosinusitis with nasal polyps, and aspirin-induced asthma.

CD36-related protein in Schistosoma japonicum: candidate mediator of selective cholesteryl ester uptake from high-density lipoprotein for egg maturation

Familial cholesteryl ester transfer protein (CETP) deficiency is more common in some East Asian populations than elsewhere, suggesting the possibility of a selective advantage of this genetic defect against regional infectious diseases. Historically, infection with the Asian blood fluke Schistosoma japonicum has been endemic in these regions, including Japan. We previously reported that eggs of S. japonicum require cholesteryl ester uptake from normal high-density lipoprotein (HDL) but not from CETP-deficient HDL for their maturation to miracidia, a critical step of the hepatic pathogenesis of schistosomiasis. Herein we show that cholesteryl ester uptake is selective from HDL, and identified CD36-related protein (CD36RP) as a candidate to mediate the reaction. CD36RP was cloned from the adult and the egg developmental stages of S. japonicum, with 1880 bp encoding 506 amino acid residues exhibiting the CD36 domains and two transmembrane regions. Using antibodies against recombinant peptides representing the potential extracellular domains of CD36RP, Western blotting detected a protein with a molecular mass of 82 kDa in the particulate fraction of the adult parasite cells, which was reduced to 62 kDa after N-glycanase treatment. The extracellular domain peptide bound human HDL, as established by immunoblots following nondenaturing gel electrophoresis. Antibodies against the extracellular domain suppressed HDL cholesteryl ester uptake and maturation of the eggs in vitro. CD36RP is a candidate receptor on eggs of S. japonicum that facilitates uptake of HDL cholesteryl ester necessary for egg embryonation and maturation.

Autophagy-related Atg8 localizes to the apicoplast of the human malaria parasite Plasmodium falciparum

Autophagy is a membrane-mediated degradation process, which is governed by sequential functions of Atg proteins. Although Atg proteins are highly conserved in eukaryotes, protozoa possess only a partial set of Atg proteins. Nonetheless, almost all protozoa have the complete factors belonging to the Atg8 conjugation system, namely, Atg3, Atg4, Atg7, and Atg8. Here, we report the biochemical properties and subcellular localization of the Atg8 protein of the human malaria parasite Plasmodium falciparum (PfAtg8). PfAtg8 is expressed during intra-erythrocytic development and associates with membranes likely as a lipid-conjugated form. Fluorescence microscopy and immunoelectron microscopy show that PfAtg8 localizes to the apicoplast, a four membrane-bound non-photosynthetic plastid. Autophagosome-like structures are not observed in the erythrocytic stages. These data suggest that, although Plasmodium parasites have lost most Atg proteins during evolution, they use the Atg8 conjugation system for the unique organelle, the apicoplast.

Treatment of Ranula by OK-432: Pearls and Pitfalls

Objective: Intralesional injection therapy with OK-432 was developed as a therapy for operatively difficult lymphangioma (cystic hygroma) and is currently becoming a first choice treatment of this disease. The aim of this article was to evaluate the outcome and complications of the treatment of patients with ranula by OK-432 therapy.

Method: We tried this therapy in 55 patients with ranula between January 2001 and February 2012. We injected OK-432 solution into the lesion with a 27-gauge needle to prevent the leak of the agent out of the cyst. We performed this treatment on an outpatient basis without hospitalization.

Results: Disappearance and marked reduction of the lesion were observed in all patients who had this therapy, and local scarring and deformity did not occur in any patients. As side effects, local pain at the injection site and fever (37 to 39°C) were observed in few cases of the patients who had this therapy, but such problems resolved within a few days. Dermoid cyst might be kept in mind to make differential diagnosis for ranula.

Conclusion: These results may allow us to speculate that intralesional injection therapy with OK-432 is simple, easy, safe, and effective, and it can be used as a substitute for surgery in the treatment of ranula.

IgG4-Related Sialadenitis: Pearls and Pitfalls in Management

Objective: A new concept of IgG4-related sialadenitis characterized by high serum IgG4 levels and tissue infiltration of IgG4-expressing plasmacytes has recently been proposed. To determine appropriate serum levels of IgG4 for monitoring disease activity, a total of 36 serum samples and 8 tissue samples from patients with IgG4-related sialadenitis were studied.

Method: The patient group consisted of 6 men and 4 women with an average age of 60 years (range, 47 to 74 years). Serum levels of IgG4 and the density of IgG4-positive plasmacytes in affected tissues were studied.

Results: All patients had elevated serum IgG4 levels (>135 mg/dL), and IgG4-positive plasmacytes (IgG4+ plasma cells/IgG+ plasma cells >50%) were observed in the involved salivary glands. Six patients with IgG4-related sclerosing sialadenitis with high IgG4/IgG ratios and prominent infiltration of IgG4-positive plasmacytes in the involved salivary glands had systemic complications, including pancreatitis, retroperitoneal fibrosis, and/or inflammatory pseudotumor of the lung after swelling of the salivary glands. All 6 of these patients were successfully treated with systemic corticosteroids.

Conclusion: In the 6 patients with systemic complications, treatment with systemic corticosteroids reduced the salivary gland enlargement and lowered serum IgG4 concentrations. These results suggest that IgG4 levels and IgG4/IgG ratios may be used as additional indicators of disease activity and as biomarkers for potential life-threatening complications.

Roles of IL-17, Th1, and Tc1 cells in patients with IgG4-related sclerosing sialadenitis

OBJECTIVES/HYPOTHESIS

Immunoglobulin G4 (IgG4)-related sclerosing sialadenitis is a recently recognized disease entity characterized by high serum IgG4 concentration and IgG4-producing plasma cell expansion in affected organs, which show fibrotic or sclerotic changes. However, little is known about the roles of CD4+ and CD8+ T cells or interleukin (IL)-17 in this disease. The purpose of this study was to evaluate the characteristics of CD4+ and CD8+ T cells and IL-17 in patients with IgG4-related sclerosing sialadenitis.

STUDY DESIGN

A retrospective clinical study at the Yamagata University School of Medicine.

METHODS

The patient group consisted of six males and four females with an average age of 57.9 years (range, 38 to 73 years). Subsets of T helper (Th)1, Th2, T cytotoxic type (Tc)1, and Tc2 cells from patients with IgG4-related sclerosing sialadenitis were examined by using intracellular cytokine flow cytometry. Expression of IL-17 in the patients' lesions was also investigated immunohistochemically.

RESULTS

Six patients with IgG4-related sclerosing sialadenitis with high ratios of IgG4/IgG and prominent infiltration of IgG4-positive plasmacytes in the involved salivary glands had systemic complications, including pancreatitis, retroperitoneal fibrosis, and/or inflammatory pseudotumor of the lung after the initial swelling of the salivary glands. Populations of Th1 and Tc1 cells were significantly greater in IgG4-related sclerosing sialadenitis than in the controls (P < .05), but Th2 and Tc2 cell populations were not significantly increased. Expression of IL-17 was observed in the lesions of affected patients.

CONCLUSIONS

Increases in Th1 and Tc1 cell populations and IL-17 expression might be involved in the mechanism of pathogenesis of IgG4-related sclerosing sialadenitis.

The role of periostin in eosinophilic otitis media

CONCLUSION

We investigated the localization of periostin in middle ear specimens from patients with eosinophilic otitis media (EOM) and from a newly constructed animal model for EOM. Periostin-positive immunostaining was observed in the middle ear sections obtained from the EOM patients. Immunoreactivity for periostin was also seen in the animal model. These results suggest that periostin plays an important role in subepithelial fibrosis in the middle ear in EOM.

OBJECTIVE

The purpose of the present study was to investigate the role of periostin in the middle ear of EOM patients and an animal model.

METHODS

Histological and immunohistochemical analyses for periostin were carried out in the middle ear specimens of six EOM patients with/without asthma. An animal model of EOM was constructed by intraperitoneal and topical sensitization with ovalbumin (OVA). Histological and immunocytochemical analyses for periostin were also performed in this model.

RESULTS

Immunoreactivities for periostin were observed in the basement membrane and extracellular matrix of the middle ear sections obtained from all EOM patients with/without asthma. In the animal model, eosinophil infiltration and middle ear mucosa thickness were observed. Moreover, periostin-positive immunostaining was shown in the extracellular matrix of the middle ear mucosa on the side topically boosted by OVA.

Clinical and pathological characteristics of IgG4-related sclerosing sialadenitis

OBJECTIVES/HYPOTHESIS

A new concept of IgG4-related sclerosing sialadenitis characterized by high serum IgG4 levels and tissue infiltration of IgG4-expressing plasmacytes has recently been proposed. To determine appropriate serum levels of IgG4 for monitoring disease activity, a total of 36 serum samples and eight tissue samples from patients with IgG4-related sclerosing sialadenitis were studied.

STUDY DESIGN

A retrospective clinical study at Yamagata University School of Medicine.

METHODS

The patient group consisted of six males and four females with an average age of 60 years (range, 47-74 years). Serum levels of IgG4 and the density of IgG4-positive plasmacytes in affected tissues were studied.

RESULTS

All patients had elevated serum IgG4 levels (>135 mg/dL), and IgG4-positive plasmacytes (IgG4+ plasma cells/IgG+ plasma cells >50%) were observed in the involved salivary glands. Six patients with IgG4-related sclerosing sialadenitis with high IgG4/IgG ratios and prominent infiltration of IgG4-positive plasmacytes in the involved salivary glands had systemic complications, including pancreatitis, retroperitoneal fibrosis, and/or inflammatory pseudotumor of the lung after swelling of the salivary glands. All six of these patients were successfully treated with systemic corticosteroids.

CONCLUSIONS

In the six patients with systemic complications, treatment with systemic corticosteroids reduced the salivary gland enlargement and lowered serum IgG4 concentrations. These results suggest that IgG4 plays an important role in the pathogenesis of IgG4-related sclerosing sialadenitis, and that IgG4 levels and IgG4/IgG ratios may be used as additional indicators of disease activity and as biomarkers for potential life-threatening complications.

Loop-mediated isothermal amplification (LAMP): early detection of Toxoplasma gondii infection in mice

Background

Toxoplasmosis is a widespread zoonotic parasitic disease that occurs in both animals and humans. Traditional molecular assays are often difficult to perform, especially for the early diagnosis of Toxoplasma gondii infections. Here, we established a novel loop-mediated isothermal amplification targeting the 529 bp repeat element (529 bp-LAMP) to detect T. gondii DNA in blood samples of experimental mice infected with tachyzoites of the RH strain.

Findings

The assay was performed with Bst DNA polymerase at 65°C for 1 h. The detection limit of the 529 bp-LAMP assay was as low as 0.6 fg of T. gondii DNA. The sensitivity of this assay was 100 and 1000 fold higher than that of the LAMP targeting B1 gene (B1-LAMP) and nested PCR targeting 529 bp repeat element (529 bp-nested PCR), respectively. The specificity of the 529 bp-LAMP assay was determined using the DNA samples of Trypanosoma evansi, Plasmodium falciparum, Paragonimus westermani, Schistosoma japonicum, Fasciola hepatica and Angiostrongylus cantonensis. No cross-reactivity with the DNA of any parasites was found. The assay was able to detect T. gondii DNA in all mouse blood samples at one day post infection (dpi).

Conclusions

We report the following findings: (i) The detection limit of the 529 bp-LAMP assay is 0.6 fg of T. gondii DNA; (ii) The assay does not involve any cross-reactivity with the DNA of other parasites; (iii) This is the first report on the application of the LAMP assay for early diagnosis of toxoplasmosis in blood samples from experimentally infected mice. Due to its simplicity, sensitivity and cost-effectiveness for common use, we suggest that this assay should be used as an early diagnostic tool for health control of toxoplasmosis.