An atypical case of chronic paracoccidioidomycosis in a dog caused by a fungus from the Paracoccidioides brasiliensis complex.

Paracoccidioidomycosis (PCM) is a systemic mycosis endemic in Latin American countries and one of the most important fungal diseases regarding incidence and mortality in humans. PCM has also been described in some animal species such as dogs. In this study we describe a new case of PCM disease in a dog that differed from previous records in the literature which includes a progressive evolution of fungal dermatitis causing a deforming lesion in the nose, like those found in human patients, and humoral response against gp70 instead of gp43, the major diagnostic antigen for human PCM. The clinical isolate through the ITS and partial gp43 gene phylogenetic analysis was grouped in the Paracoccidioides brasiliensis complex. This case describes several features which may contribute to improving diagnosis and understanding of canine paracoccidioidomycosis.

Histopathological survey of free-ranging neotropical bats with dermatitis.

Bats have a fundamental ecological role, and no wildlife disease has decimated more individuals than white-nose syndrome (WNS). This impactful mycosis has raised the importance of monitoring disease threats to bat populations. In this study, we aimed to investigate gross skin lesions in neotropical bats by histopathology to survey the occurrence of dermatitis that could resemble WNS cases in Brazil. Eleven species of free-ranging bats were sampled from the rabies surveillance program in 9 municipalities of Northern Paraná. Members of the Molossidae family were the most frequent ones among the 126 analyzed individuals, and 4 cases of dermatitis in 2 black mastiff bats (Molossus rufus), 1 great fruit-eating bat (Artibeus lituratus), and a big free-tailed bat (Nyctinomops macrotis) were detected. Gross lesions included alopecia, macules, discoloration, and hyperkeratosis. Among the bats with gross lesions, dermal thickening and mild inflammation were observed histologically. Two M. rufus bats had dermal fungal invasion; however, none resembled WNS.

Seroprevalences Against Paracoccidioides cetii: A Causative Agent for Paracoccidiomycosis Ceti (PCM-C) and Coccidioides posadasii; for Coccidioidomycosis (CCM) in Dall's Porpoise (Phocoenoides dalli) and Harbor Porpoise (Phocoena phocoena) Stranded at Hokkaido, Japan.

Paracoccidiodomycosis ceti (PCM-C) is a zoonotic mycosis characterized by chronic granulomatous cutaneous lesions in cetaceans. It is distributed worldwide and is caused by an unculturable fungus; Paracoccidioides cetii. On the other hand, coccidioidomycosis (CCM), caused by Coccidioides spp., is also a zoonotic and highly pathogenic fungal infection endemic in both American continents. Even though the Far East is not an endemic area of CCM, an autochthonous case has been reported in China. Although the seroprevalence against P. cetii in captive dolphins was 61.0%, there is no information on wild dolphins living in cold waters. The present study aimed to investigate the seroprevalence against P. cetii and C. posadasii in 15 Dall's porpoises (Phocoenoides dalli) and 11 harbor porpoises (Phocoena phocoena) stranded in Hokkaido, Japan. The seroprevalence against P. cetii in the above dolphins was 26.9% (7/26), which was recorded only in Dall's porpoises (7/15), and that against C. posadasii was 15.4% (4/26), three in Dall's porpoises and one in harbor porpoise. The present study demonstrated positive seroprevalence against P. cetii and C. posadasii in wild cetaceans living in the subarctic areas of the Far East as the first records, and would issue the warning those who live in the area were exposed to the causative agent of CCM from seawater.

In vitro Arthrographis kalrae biofilm formation: Scanning electron microscopy and cytotoxic analysis.

To our knowledge, this study represents the first demonstration of Arthrographis kalrae biofilm formation in vitro by scanning electron microscopy and the distinct cytotoxic activity between planktonic and biofilm extracts on RAW 264.7 cell line. Higher activity was observed with biofilm. It could impact host immune response, that require furthers study.

Distinct Pattern of Paracoccidioides lutzii, P. restrepiensis and P. americana Antigens Recognized by IgE in Human Paracoccidioidomycosis.

Paracoccidioidomycosis (PCM) is caused by the fungi Paracoccidioides spp. The main antigens recognized by IgE are known for P. brasiliensis species complex, but not for P. lutzii. Current research investigated the major P. lutzii (LDR2) antigens recognized by IgE, in comparison to P. restrepiensis and P. americana (former P. brasiliensis species complex), besides IgG recognition. Cell-free antigens (CFA) from P. lutzii (LDR2), P. restrepiensis (B339) and P. americana (LDR3) were analyzed by ELISA and immunoblotting (IB) by detecting specific IgG and IgE from sera from patients with PCM presumable by P. brasiliensis species complex (n = 24). Additionally, somatic antigen (SA) was analyzed by IB. P. lutzii (LDR2) antigens showed significantly lower reactivity than P. restrepiensis (B339) and P. americana (LDR3) in ELISA for both IgE and IgG (p < 0.05). The IgE-IB pattern was different between P. lutzii (LDR2) and the other species, regarding components with ~30 kDa and ~70 kDa in CFA and a ~200 kDa in SA. P. lutzii (LDR2) present at least three antigens recognized by IgE which mainly differ from P. restrepiensis (B339) and, to a lesser extent, from P. americana (LDR3). Current research evidenced for the first time the major P. lutzii (LDR2) antigens recognized by IgE.

IgG reactivity profile to Paracoccidioides spp. antigens in people with asymptomatic Paracoccidioidomycosis.

Introduction. Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides spp. As the disease is known to affect mostly men over 40 years old who previously worked handling soil, some cities of agricultural economy in endemic regions may have more cases of paracoccidioidal infection.Gap statement. The true frequency of PCM cannot be established in Brazil because it is not a disease of mandatory reporting. The detection of paracoccidioidal infection may assist in the planning of health services, in order to provide early detection of the disease and to prevent its worsening or even progression to death. In addition, little is described about sera reactivity with antigens from different species of Paracoccidiodes, especially P. lutzii.Aim. Current research was conducted in an inland municipality of southern Brazil, in order to assess infection rate within this endemic region of PCM disease.Methodology. ELISA was employed to evaluate 359 sera from random volunteers from Guarapuava, Paraná, Brazil, to detect IgG against cell-free antigens (CFA) from P. restrepiensis B339, P. americana LDR3 and P. lutzii LDR2. Confirmatory ELISA employed gp43 from B339. Reduction of cross-reactions was sought by treatment with sodium metaperiodate (SMP-CFA, SMP-gp43). Immunoblot was performed with 37 selected sera among those reactive in ELISA. Epidemiological profile was assessed by questionnaire.Results. ELISA reactivity was: CFA/SMP-CFA in general 37.3/17.8 %, B339 25.3/14.5 %, LDR3 24.5/1.4 %, LDR2 8.3/5.8 %; gp43/SMP-gp43 7.2/4.7 %. There were sera reactive with multiple CFAs. In immunoblot, five sera showed the same reaction profile with P. lutzii's antigens as PCM disease sera. Rural residence and soil-related professions were risk factors for paracoccidioidal infection.Conclusion. The low prevalence is in accordance with previous reports of lower PCM disease endemicity in Guarapuava than in other areas of Paraná. Although P. brasiliensis seems to be the prevalent strain of the region, 21 sera from people who only lived in Guarapuava reacted with P. lutzii LDR2. CFA-ELISA with whole antigens seems a good option for serological screening in epidemiological surveys.

Tryptophan Attenuates the Effects of OTA on Intestinal Morphology and Local IgA/IgY Production in Broiler Chicks.

Ochratoxin A (OTA) is a mycotoxin produced by species of Penicillium and Aspergillus that can contaminate products of plant origin that are used as animal feed. Through oral exposure, this mycotoxin primarily affects the chicken gastrointestinal system. The present study evaluated the intestinal toxic effects of OTA and the introduction of L-tryptophan to alleviate these effects in chickens. One-day-old chicks were exposed to a single OTA dose (1.4 mg/kg body weight-b.w.) and treated with or without four daily doses of L-tryptophan (100 mg/kg b.w.). Duodenal villus height/crypt depth, fecal immunoglobulin A/immunoglobulin Y (IgA/IgY) levels, and duodenal positive immunoglobulin A cells (IgA+) were evaluated by histology, ELISA, and immunohistochemistry, respectively, on the 14th day. There were significant changes in the duodenal villus height, crypt depth, and levels of fecal IgA/IgY and duodenal IgA+ cells (p < 0.05) in groups exposed to OTA. On the other hand, groups exposed to OTA and treated with L-tryptophan showed similar levels of villus height, IgA/IgY levels, and duodenal IgA+ cells to those of the control group (p > 0.05). In conclusion, exposure to a single dose of OTA orally induces changes in intestinal morphology, levels of IgA/IgY antibodies, and IgA+ cells. Thus, treatment with L-tryptophan may be a valid alternative means to reduce the harmful effects of OTA on the intestinal mucosa, which requires further study.

Seroprevalence of Antibodies Against Paracoccidioides Spp. in Captive Dolphins from Three Aquaria in Japan.

The skin disease paracoccidioidomycosis ceti occurs in several dolphin species globally. Infection by the unculturable fungi Paracoccidioides brasilensis or other Paracoccidioides spp. results in chronic cutaneous and granulomatous lesions. In this study we used immunohistochemistry to investigate the seroprevalence of antibodies to Paracoccidioides spp. in captive dolphins from three aquaria in Japan. We had previously reported that there were serological cross-reactions for Paracoccidioides spp. with related species in the order Onygenales. We hypothesized that the degree of serological cross-reactions for Paracoccidioides spp. might be lower in areas, such as Japan, where the fungal diseases coccidiodomycosis and paracoccidiodomycosis are not endemic. Sera from 41 apparently healthy dolphins, including 20 Atlantic bottlenose dolphins (BD: Tursiops truncatus), 6 Indo-Pacific bottlenose dolphins (IPBD: Tursiops aduncus), 2 F1 generation of a cross between BD and IPBD (F1), 3 Pacific white-sided dolphins (PWD: Lagenorhynchus obliquidens), 2 pantropical spotted dolphins (PSD: Stenella attenuata), 6 false killer whales (FKW: Pseudorca crassidens), and 2 rough-toothed dolphins (RTD: Steno bredanensis) were investigated. Sera from three dolphins with paracoccidioidomycosis ceti were used as a positive control. The yeast-form cells of Paracoccidioides spp. in the cutaneous tissue sample derived from the first Japanese paracoccidioidomycosis ceti case were used as the antigen for the immunohistochemistry. Of the 41 dolphins tested, 61.0% had antibodies against Paracoccidioides spp. This indicates that dolphins of several species in Japanese aquaria have likely been exposed to the pathogen Paracoccidioides spp.

Unraveling the susceptibility of paracoccidioidomycosis: Insights towards the pathogen-immune interplay and immunogenetics.

Paracoccidioidomycosis (PCM) is a life-threatening systemic mycosis caused by Paracoccidioides spp. This disease comprises three clinical forms: symptomatic acute and chronic forms (PCM disease) and PCM infection, a latent form without clinical symptoms. PCM disease differs markedly according to severity, clinical manifestations, and host immune response. Fungal virulence factors and adhesion molecules are determinants for entry, latency, immune escape and invasion, and dissemination in the host. Neutrophils and macrophages play a paramount role in first-line defense against the fungus through the recognition of antigens by pattern recognition receptors (PRRs), activating their microbicidal machinery. Furthermore, the clinical outcome of the PCM is strongly associated with the variability of cytokines and immunoglobulins produced by T and B cells. While the mechanisms that mediate susceptibility or resistance to infection are dictated by the immune system, some genetic factors may alter gene expression and its final products and, hence, modulate how the organism responds to infection and injury. This review outlines the main findings relative to this topic, addressing the complexity of the immune response triggered by Paracoccidioides spp. infection from preclinical investigations to studies in humans. Here, we focus on mechanisms of fungal pathogenesis, the patterns of innate and adaptive immunity, and the genetic and molecular basis related to immune response and susceptibility to the development of the PCM and its clinical forms. Immunogenetic features such as HLA system, cytokines/cytokines receptors genes and other immune-related genes, and miRNAs are likewise discussed. Finally, we point out the occurrence of PCM in patients with primary immunodeficiencies and call attention to the research gaps and challenges faced by the PCM field.

Parengyodontium album Isolated from Cutaneous Lesions of a Pacific White-Sided Dolphin (Lagenorhynchus obliquidens) During Treatment for Paracoccidioidomycosis Ceti.

The prominence of seafood in Japan motivates close monitoring of its seas and marine lives for potentially pathogenic fungi. During the treatments of the male Pacific white-sided dolphin (Lagenorhynchus obliquidens) for paracoccidioidomycosis ceti (PCM-C), 5 white and floccose colonies showing identical genotype and morphological characteristics were isolated from two skin biopsy samples of cutaneous granulomatous lesions in 2018. The isolates were identified as Parengyodontium album known as one of fungal species having abilities to produce industrially important proteases, and to become a causative agent for emerging mycosis based on morphological and molecular biological characteristics. These lesions consisted of non-malignant pearl-like structures of hyperplastic keratinocytes. Interestingly, although the isolates could grow at 35 °C, their DNA sequences were phylogenetically located in a cluster consisting of environmental and clinical isolates lacking the ability to grow at 35 °C, based on previous reports. The opportunistic infection we observed in the dolphin might be caused by immune disorder due to PCM-C. Notably, although P. album is recognized as non-harmful, and has significant industrial importance and antitumor activity, it has potential to cause not only superficial but also systemic infection, and presents difficulties in treatment because of its high resistance to antifungal compounds.

First report of Paracoccidioides brasiliensis infection in fish.

The thermodimorphic fungus Paracoccidioides brasiliensis is the etiological agent of paracoccidioidomycosis (PCM), a deep mycosis endemic in Latin American countries that affects mainly male rural workers. Infection by P. brasiliensis has also been reported in several species of terrestrial animals; however, the capacity of the fungus to infect aquatic organisms is poorly known. The aim of this study was to detect P. brasiliensis in a fish species, Nile tilapia (Oreochromis niloticus), the most farmed and widely distributed fish in endemic areas for human PCM in Brazil. As a first step, the humoral immune response against the fungus was evaluated in an experimental group of three fish immunized with inactivated P. brasiliensis yeast cells. For the seroepidemiological study, serum samples of Nile tilapia raised in cages (n = 109) and in ponds (n = 105), collected from a fish slaughterhouse, were analyzed for P. brasiliensis antibodies by ELISA using gp43 as antigen. All the inoculated fish produced antibodies against the fungus. The seropositivity observed in fish raised in cages and ponds was 17.4 and 5.7%, respectively. Due to the higher seropositivity observed in caged fish, 100 tissue samples (encephalon, liver, and kidney), from another group of tilapia raised in cages, were analyzed by polymerase chain reaction (PCR; Pb-ITSR and Pb-ITSE). Three tissue samples (liver n = 1, kidney n = 1, and enchepahlon n = 1) from three different fish resulted positive to PCR. This is the first report to show serological and molecular evidence of P. brasiliensis infection in a fish species.

Immunohistochemical Cross-Reactivity Between Arthrographis kalrae and Highly Pathogenic Coccidioides posadasii, Histoplasma capsulatum, and Paracoccidioides Fungal Species.

Recently, we have reported serological cross-reactivity between paracoccidioidomycosis ceti and paracoccidioidomycosis, histoplasmosis, and coccidioidomycosis. However, data on the interaction of Arthrographis kalrae with the above pathogenic fungal infections are lacking. A. kalrae is a widely occurring ascomycetous fungus; causes superficial and deep mycoses; shows thermally dependent dimorphism; and has a genomic profile related to the above-mentioned fungal species. Our study aims to investigate cross-reactivity using eight murine sera, obtained from experimental infection with two A. kalrae isolates. The murine sera were incubated with fungal cells of A. kalrae, Coccidioides posadasii, Histoplasma capsulatum, Paracoccidioides sp., and P. brasiliensis. Thirty murine sera, obtained from experimental infection with six isolates of H. capsulatum, sera from three cases of dolphin paracoccidioidomycosis ceti, two human sera from patients with paracoccidioidomycosis, and a serum sample from a healthy person with a history of coccidioidomycosis, were also incubated with A. kalrae fungal cells and the respective fungal cells that caused the infection as positive controls. Sera derived from the mice infected with A. kalrae reacted strongly when incubated with the Paracoccidioides sp., P. brasiliensis, and C. posadasii, but no positive reaction was observed against the fungal cells of H. capsulatum. The murine sera infected with three out of six isolates of H. capsulatum, and all cetacean and human serum samples reacted positively with the fungal cells of A. kalrae. The present study demonstrated serological cross-reactions among A. kalrae infection, coccidioidomycosis, paracoccidioidomycosis, paracoccidioidomycosis ceti, and histoplasmosis.

Effects of Subcutaneous Ochratoxin-A Exposure on Immune System of Broiler Chicks.

Ochratoxin A (OTA), an immunosuppressive mycotoxin, can increase the risk of many infectious diseases and contribute to economic losses to the poultry industry. The immunosuppressive effect has mainly been investigated through oral exposure; however, birds may also be contaminated through skin absorption. The present study investigated the influence of OTA exposure on the defense system of broiler chicks through the subcutaneous route and including low doses. Groups of broiler chicks (Cobb), 05 days old, were exposed to subcutaneous inoculation of OTA at concentrations of 0.1; 0.5; 0.9; 1.3; and 1.7 mg OTA/kg body weight. The size of the lymphoid organs, circulating immune cells, and total IgY and IgA levels were evaluated 21 days post inoculation. Subcutaneous OTA exposure decreased the weight of the thymus, spleen, and bursa of Fabricius, and leukocytopenia (p < 0.05) was detected in chicks of the OTA treated groups. In a dose-dependent way, decreased levels of circulating lymphocytes and heterophils (p < 0.05), and increased levels of monocytes (p < 0.05) were detected. Decreased IgY and IgA serum concentrations were noted in the OTA treated groups (p < 0.05). In conclusion, subcutaneous OTA exposure induces immunosuppression even at low levels.

Immunohistochemical Cross-Reactivity Between Paracoccidioides sp. from Dolphins and Histoplasma capsulatum.

Paracoccidioidomycosis ceti is a cutaneous disease of cetaceans caused by uncultivated Paracoccidioides brasiliensis or Paracoccidioides spp. Serological cross-reactions between paracoccidioidomycosis ceti and paracoccidioidomycosis, paracoccidioidomycosis and histoplasmosis, and paracoccidioidomycosis and coccidioidomycosis have been reported before. The present study aimed to detect immunohistochemical cross-reaction between antibodies to Paracoccidioides sp. and Histoplasma capsulatum, and vice versa. Thirty murine sera, obtained from experimental infections of 6 isolates of H. capsulatum, were reacted with paraffin-embedded yeast-form cells of Paracoccidioides sp. derived from a case of paracoccidioidomycosis ceti in Japan. The murine sera were also reacted with human isolates of H. capsulatum yeast cells, with P. brasiliensis yeast cells, and with fungal cells of Coccidioides posadasii. Three dolphins' sera from cases of paracoccidioidomycosis ceti, two human sera from patients with paracoccidioidomycosis, and a serum from a healthy person with a history of coccidioidomycosis were used in order to determine that the tested fungal cells reacted properly. Sera derived from mice infected with an isolate of H. capsulatum reacted positively against yeast cells of Paracoccidioides sp., yeast cells of P. brasiliensis, and fungal cells of C. posadasii, while those derived from other strains were negative. The present study recorded for the first time the cross-reaction between the yeast cells of H. capsulatum and antibodies against Paracoccidioides spp., the yeast cells of Paracoccidioides sp. and antibodies against H. capsulatum, the yeast cells of Paracoccidioides sp. and antibodies against Coccidioides sp., and fungal cells of C. posadasii and antibodies against Paracoccidioides spp.

Low Doses of Ochratoxin-A Decrease IgY and IgA Production in Broiler Chicks.

The mycotoxin, ochratoxin-A (OTA), produced by some fungi, and is a natural contaminant of many foods and animal feeds worldwide. Due to its toxic effects, the recommended maximum daily intake of OTA for poultry feeds is 0.1 mg OTA/kg (ECR2006/575/EC); this dose does not induce changes in hepatic/renal parameters, but decreases thymus size and serum globulin concentrations. Accordingly, in this study, we assessed quantitatively the total circulating IgY and IgA serum levels, in chicks consuming a 0.1 mg OTA/kg diet (limit) and higher doses (0.3⁻1.1 mg OTA/kg diet) for 14 or 21 days. We also evaluated other immunological parameters (thymus, bursa of Fabricius, and spleen weights and leukocyte profiles) at day 21. Decreased IgY serum levels were observed in all OTA-treated groups (p < 0.05). In the low-dose group, IgA levels were decreased on day 21, but not on day 14. The size of the thymus and the bursa of Fabricius was decreased in all OTA-treated groups (p < 0.05), whereas reduced spleen size and altered leukocyte profiles were detected only in the high-dose group (p < 0.05). We concluded that chronic exposure to OTA, even at the recommended highest dose, affected IgY and IgA production in chicks.

Polyclonal antibodies to Paracoccidioides brasiliensis are able to recognise antigens from different strains from Paracoccidioides species complex, including Paracoccidioides lutzii LDR2.

Since the new species Paracoccidioides lutzii emerged in 2009, much has been researched on strains previously considered atypical. Still, there is no consensus about recognition of antigens from P. lutzii by antibodies directed to other Paracoccidioides species, which can have great impact on Paracoccidioidomycosis (PCM) diagnosis. Current research investigated soluble protein/carbohydrate epitopes from P. lutzii LDR2, Paracoccidioides restrepiensis B339 and Paracoccidioides americana LDR3 recognised by IgG directed to Paracoccidioides brasiliensis. Cell free antigens (CFA) were analysed by: (a)silver and periodic acid-Schiff staining of SDS-PAGE; (b)immunoblot (IB) with rabbit IgG anti-P. brasiliensis Pb18; (c)IB and ELISA with a pool of PCM patients' sera before and after treatment with sodium metaperiodate (SMP) to oxidise carbohydrate epitopes. Both rabbit and human immune sera recognised several antigens of P. lutzii LDR2, P. restrepiensis B339 and P. americana LDR3. P. lutzii's gp43 was not observed in IB or silver/PAS staining. SMP treatment affected reactions with all 3 CFAs, but more intensely with antigens from P. lutzii LDR2. In conclusion, antibodies directed to P. brasiliensis recognised antigens from P. lutzii LDR2. The use of any of the recognised antigens in a broad spectrum diagnostic model for Paracoccidioides species complex needs to be further investigated.

Paracoccidioides restrepiensis B339 (PS3) and P. lutzii LDR2 yeast cells and soluble components display in vitro hemolytic and hemagglutinating activities on human erythrocytes.

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by thermodimorfic fungi of Paracoccidioides species complex. Several pathogenic fungi produce hemagglutinins and hemolysins, which are virulence factors involved in adhesion of pathogens to host tissues or cells and in destruction of erythrocytes. The present research investigated hemolytic and hemagglutinating activities of yeast cells and soluble components from P. restrepiensis (PS3; former P. brasiliensis B339) and P. lutzii (LDR2). Different concentrations of live and heat-killed yeast cells and soluble components from cell free antigen preparation (CFA) (native or heated - 56 and 100 °C, 30 min) were mixed with 1% human erythrocyte suspension. Yeast cells from both species caused hemolysis, but P. lutzii LDR2 was more hemolytic than P. restrepiensis B339, while the opposite phenomena occurred with soluble components in most conditions. Live or heat-killed yeast cells of both fungi agglutinated erythrocytes, but only heated soluble components from P. restrepiensis B339 showed hemagglutinating activity. In conclusion, yeast cells of P. restrepiensis B339 and P. lutzii LDR2 produce hemolysins and hemagglutinins, which most likely are more restricted to yeast cells in P. lutzii LDR2 and are more released in soluble form byP. restrepiensis B339, requiring further study.

External apical root resorption diagnosis by using FII human dentine fraction and salivary IGg.

BACKGROUND: External apical root resorption as a consequence of orthodontic treatment is an inflammatory pathological process that results in permanent loss of tooth structure from the root apex. OBJECTIVES: This study aimed to investigate the diagnostic potential of human dentine fractions and salivary IgG in external apical root resorption. PATIENTS AND METHODS: Saliva samples were collected from 10 patients before (T0) and after 3 (T3), 6 (T6) and 12 (T12) months of orthodontic treatment. The total dentinal extract, obtained from human third molars, was fractioned by gel filtration chromatography in three fractions denominated FI, FII and FIII. The root resorption analysis of the upper central incisors was performed by digital image subtraction method. Reactivity of salivary IgG to antigenic fractions of dentine was determined by enzyme-linked immunosorbent assay (Elisa). RESULTS: Regardless of treatment, FI dentin fraction with high MM (<300kDa) was the one that presented highest reactivity with salivary IgG. However, it was found higher salivary IgG reactivity for FII (69 to 45 kilodalton [kDa]) as compared to FIII (<45kDa) at (T6) and (T12), (P<0.05), the same periods in that the root resorptions were detected. CONCLUSION: Our results suggest that FII human dentine fraction and salivary IgG have potential to be used in diagnosis and monitoring of external apical root resorption. The development of a practical and accessible biochemical test using saliva and FII dentine fraction may help in the prevention of severe root resorption.