Eosinophilia during intestinal infection

The Potential Nexus between Helminths and SARS-CoV-2 Infection: A Literature Review

Chronic helminth infections (CHIs) can induce immunological tolerance through the upregulation of regulatory T cells. In coronavirus disease 2019 (COVID-19), abnormal adaptive immune response and exaggerated immune response may cause immune-mediated tissue damage. Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) and CHIs establish complicated immune interactions due to SARS-CoV-2-induced immunological stimulation and CHIs-induced immunological tolerance. However, COVID-19 severity in patients with CHIs is mild, as immune-suppressive anti-inflammatory cytokines counterbalance the risk of cytokine storm. Since CHIs have immunomodulatory effects, therefore, this narrative review aimed to clarify how CHIs modulate the immunoinflammatory response in SARS-CoV-2 infection. CHIs, through helminth-derived molecules, may suppress SARS-CoV-2 entry and associated hyperinflammation through attenuation of the inflammatory signaling pathway. In addition, CHIs may reduce the COVID-19 severity by reducing the SARS-CoV-2 entry points in the initial phase and immunomodulation in the late phase of the disease by suppressing the release of pro-inflammatory cytokines. In conclusion, CHIs may reduce the severity of SARS-CoV-2 infection by reducing hyperinflammation and exaggerated immune response. Thus, retrospective and prospective studies are recommended in this regard.

Parasitic Infections in Internationally Adopted Children: A Twelve-Year Retrospective Study

Parasitic infections (PIs) are among the most frequent infectious diseases globally. Previous studies reported discrepant results regarding the prevalence of PIs in internationally adopted children (IAC). Data from IAC referred to our paediatric university hospital in 2009–2021 were collected to evaluate the frequency of PIs by the use of stool microscopic examination, antigen assays for Giardia lamblia and Cryptosporidium parvum, and serological tests for Toxocara canis, Strongyloides stercoralis, Schistosoma mansoni, Echinococcus spp., Taenia solium, and Trypanosoma cruzi. Uni- and multivariate logistic regression analyses were performed to evaluate risk factors for PIs and eosinophilia. The proportion of IAC with at least one positive test was 26.83% (640/2385); 2.13% (n = 51) had positive tests for 2 or 3 parasites. A positive assay for helminthic infection was retrieved in 11.07% of children (n = 264), and 17.86% (n = 426) presented with eosinophilia. The most common positive tests were anti-Toxocara canis antibodies (n = 312; 13.8%), followed by positive stool antigen for Giardia lamblia (n = 290; 12.16%), and positive microscopic stool examination for Blastocystis hominis (n = 76; 3.19%). A statistically significant association was found between PIs and region of origin (children from Latin America and Africa were more likely to present PIs than children from Eastern Europe), age 5–14 years, and eosinophilia. No significant association was observed between PIs and gender, vitamin D deficiency, or anemia. In conclusion, PIs are relevant in IAC and an accurate protocol is needed to evaluate IAC once they arrive in their adoptive country.

Eosinophilia and parasitic infestations in patients with chronic obstructive pulmonary disease

Eosinophilia may guide response to inhaled corticosteroid treatment in patients with chronic obstructive pulmonary disease (COPD). This study aimed to determine prevalence of eosinophilia and parasitic infestations in these patients. We conducted a prospective cohort study between February 2019 and January 2020 and screened 107 stable COPD patients. A total of 77 subjects (84.4% men) were included. Age was 73.8 ± 8.9 years. Forced expiratory volume in 1 s was 66.5 ± 25.5%. Smoking history was 25.9 ± 18 pack-years. Comorbidities included cardiovascular disease (57.1%). Respiratory symptoms were assessed by modified Medical Research Council dyspnea score (1.6 ± 0.8), chronic obstructive pulmonary disease Assessment Test score (9.3 ± 4.9), and 6-min walking distance (317.2 ± 135.2 m). Patients with blood eosinophil count at least 100 cells/μL were 79.2% and at least 300 cells/μL were 33.8%. Intestinal parasites were not found. Significant positive correlations were found between high blood eosinophilia and some post-bronchodilator lung function parameters. In conclusion, eosinophilic COPD was not uncommon. No intestinal parasite was found in this population. This study suggests that stool parasite exam might be omitted for routine practice.

Clinicaltrials.in.th Number: TCTR20191129002.

A retrospective administrative database analysis of the association between clonorchiasis or helminthiasis and the development of cholelithiasis

PURPOSE

Parasite infestation (PI) is reportedly related to intrahepatic stones (IHSs) and common bile duct (CBD) stones. This study assessed the association of clonorchiasis and helminthiasis with the sub-types of cholelithiasis.

METHODS

The study cohort consisted of 713 patients who were aged ≥20 years with clonorchiasis or helminthiasis for the first time between 2000 and 2010 from the National Health Insurance Research Database. The controls without clonorchiasis and helminthiasis were randomly selected with a 1:1 propensity score matching. All patients were followed up until the end of 2011 to measure the incidence of cholelithiasis.

RESULTS

The risks of cholelithiasis in the clonorchiasis (adjusted hazard ratio [aHR] = 3.72, 95% confidence interval [CI] = 2.01-6.90) and helminthiasis (aHR = 2.27, 95% CI = 1.25-4.16) were higher than in the non-PI cohort. Patients with clonorchiasis had increased risks of gallstones without bile duct stones (aHR = 3.13, 95% CI = 1.54-6.39) and bile duct stones without gallstones (aHR = 4.75, 95% CI = 1.23-18.4). Patients with helminthiasis had an increased risk of gallstones without bile duct stones (aHR = 2.20, 95% CI = 1.11-4.33), but no higher risk of bile duct stones without gallstones was observed in helminthiasis (aHR = 2.22, 95% CI = 0.54-9.06), despite its high aHR. Neither clonorchiasis nor helminthiasis had an increased risk of concomitant gallstones and bile duct stones.

CONCLUSION

Clonorchiasis is related to the development of not only gallstones, but also bile duct stones, and helminthiasis is only associated with the development of gallstones. However, cases of PI are rare in Taiwan, and this requires more international studies to clarify the association between helminthiasis and bile duct stones.

Immunomodulation of allergic response in children and adolescents: What we can learn from lymphatic filarial infection

BACKGROUND

Although it is well known that allergic diseases involve a strong Th2 immune response, with production of high levels of specific IgE allergen, knowledge on the association between filarial infection and allergies, among paediatric patients is scarce.

OBJECTIVE

To evaluate the allergic response patterns in cases of filarial infection by comparing peripheral eosinophils, total IgE levels, immediate hypersensitivity and cytokine levels in children and adolescents in Brazil.

METHODS

This was an exploratory study with three groups: (I) with filarial infection and without allergic diseases; (II) without filarial infection and with allergic diseases; and (III) without filarial infection and without allergic diseases. The prick test and specific IgE tests for aeroallergens were performed using five antigens. Peripheral eosinophils and total IgE were also evaluated. IL-4 and IL-5 were determined using whole-blood culture stimulated by three antigens.

RESULTS

Eosinophilia and elevated levels of total IgE (≥400IU/dl) were observed in all groups. The prick test was positive in 56.6% of the cases. Group I presented hypersensitive responses similar to the allergic disease groups. In the whole-blood culture stimulated by Dermatophagoides pteronyssinus, average IL-4 production did not differ significantly among the groups, but IL5 production resulting from stimulation was greater in the allergic disease groups (p<0.05).

CONCLUSIONS

The allergic response pattern in group with filarial infection was similar to that of the groups with and without allergic diseases, but the response to IL-5 in the culture stimulated by D. pteronyssinus was an exclusive characteristic of the allergic group.

[Clinical approach to imported eosinophilia]

Eosinophilia is a common finding in international travelers and immigrants, being an helmintic infection its main etiology. The positive predictive value of eosinophilia for an helmintosis is low in travellers. Eosinophilia may be an incidental finding, or symptomatic, and it represents a clinical challenge due to the low sensitivity and specificity of direct and indirect parasitological diagnostic tests, respectively. It requires a structured approach based on geographical areas, environmental exposures and behavioral risks, and associated symptoms. The initial assessment should include a comprehensive and tailored anamnesis and physical examination, basic laboratory tests, a complete parasitological examination of stool samples and a Strongyloides stercoralis serology, supplemented with other explorations guided by epidemiological and clinical suspicion. Empiric treatment with albendazole and/or ivermectin (plus praziquantel if risk of schistosomiasis) is an option for unidentified persistent eosinophilia after study, and in persons in whom a proper assessment or follow-up can not be assured. In patients at risk for estrongiloidosis who are candidates for immunosuppressive therapies, it is indicated a prior screening and treatment to prevent a future hyperinfestation syndrome.

Comparison between PCR and larvae visualization methods for diagnosis of Strongyloides stercoralis out of endemic area: A proposed algorithm

Underdiagnosis of chronic infection with the nematode Strongyloides stercoralis may lead to severe disease in the immunosuppressed. Thus, we have set-up a specific and highly sensitive molecular diagnosis in stool samples. Here, we compared the accuracy of our polymerase chain reaction (PCR)-based method with that of conventional diagnostic methods for chronic infection. We also analyzed clinical and epidemiological predictors of infection to propose an algorithm for the diagnosis of strongyloidiasis useful for the clinician. Molecular and gold standard methods were performed to evaluate a cohort of 237 individuals recruited in Buenos Aires, Argentina. Subjects were assigned according to their immunological status, eosinophilia and/or history of residence in endemic areas. Diagnosis of strongyloidiasis by PCR on the first stool sample was achieved in 71/237 (29.9%) individuals whereas only 35/237(27.4%) were positive by conventional methods, requiring up to four serial stool samples at weekly intervals. Eosinophilia and history of residence in endemic areas have been revealed as independent factors as they increase the likelihood of detecting the parasite according to our study population. Our results underscore the usefulness of robust molecular tools aimed to diagnose chronic S. stercoralis infection. Evidence also highlights the need to survey patients with eosinophilia even when history of an endemic area is absent.

Eosinophilic Gastroenteritis: Case Report and Review in Search for Diagnostic Key Points

Eosinophilic gastroenteritis is considered an uncommon disease with a low incidence rate that remains as a diagnostic challenge for the clinician, in spite of the fact that seventy years have passed since its original description. Hereby we present the case of a 29-year-old male without history of allergies who was evaluated for unspecific gastrointestinal symptoms, without relevant findings on physical examination and presenting an initial complete blood count (CBC) with severe eosinophilia. The patient was evaluated and the diagnosis of eosinophilic gastroenteritis was confirmed by histopathological findings. The relevance of the case resides in highlighting the lack of guidelines or consensus for histological diagnosis being virtually the only one available. To a similar extent, treatment evidence is based on case series with a reasonable number of patients and case reports.

Helminth-associated systemic immune activation and HIV co-receptor expression: response to albendazole/praziquantel treatment

Background

It has been hypothesized that helminth infections increase HIV susceptibility by enhancing systemic immune activation and hence contribute to elevated HIV-1 transmission in sub-Saharan Africa.

Objective

To study systemic immune activation and HIV-1 co-receptor expression in relation to different helminth infections and in response to helminth treatment.

Methods

HIV-negative adults with (n = 189) or without (n = 57) different helminth infections, as diagnosed by Kato-Katz, were enrolled in Mbeya, Tanzania. Blinded to helminth infection status, T cell differentiation (CD45RO, CD27), activation (HLA-DR, CD38) and CCR5 expression was determined at baseline and 3 months after Albendazole/Praziquantel treatment. Plasma cytokine levels were compared using a cytometric bead array.

Results

Trichuris and Ascaris infections were linked to increased frequencies of “activated” CD4 and/or CD8 T cells (p<0.05), whereas Hookworm infection was associated with a trend towards decreased HLA-DR⁺ CD8 T cell frequencies (p = 0.222). In Trichuris infected subjects, there was a linear correlation between HLA-DR⁺ CD4 T cell frequencies and the cytokines IL-1β and IL-10 (p<0.05). Helminth treatment with Albendazole and Praziquantel significantly decreased eosinophilia for S. mansoni and Hookworm infections (p<0.005) but not for Trichuris infection and only moderately modulated T cell activation. CCR5 surface density on memory CD4 T cells was increased by 1.2-fold during Trichuris infection (p-value: 0.053) and reduced after treatment (p = 0.003).

Conclusions

Increased expression of T cell activation markers was associated with Trichuris and Ascaris infections with relatively little effect of helminth treatment.

Helminth infections are common in sub-Saharan Africa where about half of the population may be infected with one or more helminth species. HIV infection is also highly prevalent in this region. Because of the geographic overlap of helminth and HIV infections, it has been hypothesized that helminth infections may increase susceptibility to HIV by increasing systemic immune activation, which has been linked to increased HIV susceptibility. We therefore investigated the profile of T cell activation in individuals infected with different helminth species before and after helminth treatment within the WHIS cohort in Mbeya, Tanzania. Our study shows that systemic T cell activation differs between infections with different helminths. Particularly Trichuris but also Ascaris and S. mansoni infections were linked to increased frequencies of activated, HLA-DR⁺ T cells with relatively little effect of helminth treatment. Hookworm infection was associated with a trend towards decreased frequencies of activated, HLA-DR⁺ CD8⁺ T cells. Our study supports the concept that helminth infections, which are linked to systemic immune activation, could potentially also contribute to increased HIV transmission.

Population dynamics and host reactions in young foxes following experimental infection with the minute intestinal fluke, Haplorchis pumilio

BACKGROUND

Infections with fish-borne zoonotic trematodes (FZT) including the minute intestinal fluke, Haplorchis pumilio, are highly prevalent in Southeast Asia. However, little is known about the infection dynamics and clinical symptoms in the final hosts which include a range of animal species and man. We aimed to generate such information using an experimental model with H. pumilio in foxes.

METHOD

Eight commercially bred foxes were each orally infected with 2000 H. pumilio metacercariae. Another three foxes served as uninfected controls. Faecal examination for eggs was performed twice weekly. The body weight was measured, standard haematological and biochemical analysis were performed regularly. All foxes were euthanized at day 56 post infection (p.i.). Adult worms were quantified and location in the small intestine noted.

RESULTS

Anorexia was observed in all infected foxes starting day 12 p.i. and lasting for approximately a week. A weight loss was noticed in the infected group in weeks 3-6 p.i. Five of eight infected foxes excreted H. pumilio eggs day 9 p.i. onwards, the remaining three started on day 13 p.i. Mean (± SD) faecal egg counts showed an initial peak at day 16-20 with a maximum of 1443 ± 1176 eggs per gram of faeces (epg), where after a stable egg output around 4-500 epg was seen. Worm burdens ranged between 116-2070 adult flukes with a mean (± SD) worm recovery of 948 ± 666. The majority of worms were found in the lower part of the jejunum. Total white blood cell and lymphocyte counts were significant lower in the infected group from first week p.i. onwards and throughout the study period. A significantly lower level of eosinophils was found in week 2 p.i. and transient anaemia was seen in week 2 and 4 p.i.

CONCLUSION

This study showed a short prepatency period, an initial peak in egg excretion, establishment of infection in all animals with predilection site in the lower jejunum and a marked but transient clinical effect of the infection. The findings on egg output and prepatency should be taken into consideration when control programs targeting dogs and other reservoir hosts are to be established.

Clinical value of duodenal biopsies--beyond the diagnosis of coeliac disease

At upper gastrointestinal endoscopy to investigate unexplained diarrhea and iron deficiency anemia, duodenal biopsies are often taken to exclude a diagnosis of coeliac disease. While histology remains the gold standard for this diagnosis, recent developments in serological testing may overtake this as a first line test and biopsy restricted to confirming the diagnosis. Established coeliac disease on biopsy is straightforward, but early lesions may pose a challenge. Newer endoscopic procedures such as push-pull enteroscopy (balloon enteroscopy) with biopsy allow access to the small bowel beyond the second part of the duodenum. Controversy remains as to what constitutes the normal histology of the duodenum, and small bowel. Lymphocytic duodenosis (increased intraepithelial lymphocytes with normal villous architecture) in patients with negative coeliac serology can be associated with Helicobacter pylori, drugs, autoimmune and other diseases including food allergy. Full thickness small intestinal biopsies can aid in investigation of enteric neuropathies in severe dysmotility disorders. Biopsies are also taken to investigate malabsorption due to suspected infectious and metabolic disorders. Despite highly active anti-retroviral therapy (HAART), immunosuppressed patients may be affected by duodenal pathogens. The histology of duodenal mucosa in acid related disorders reflects the damage seen at endoscopy. Although the prevalence of duodenal ulcer disease is decreasing, drugs causing ulceration remain an important disease entity. Recent observations in functional bowel disorders suggest that the duodenum may be a key site for pathology. In functional dyspepsia, patients with early satiety may have excess eosinophil infiltration, and the mast cell is probably a key player in the irritable syndrome in the small intestine.

Activity and turnover of eosinophil and neutrophil granulocytes are altered in visceral leishmaniasis

Visceral leishmaniasis (VL) is a health issue in Sudan. Our aim was to investigate the involvement of eosinophils and neutrophils in VL by serum and plasma measurements of eosinophil cationic protein (ECP) and myeloperoxidase (MPO) and some key cytokines and chemokines. Blood was collected from 125 VL patients and 181 healthy Sudanese controls from the same rural area. Results showed reduced eosinophil and neutrophil counts in the VL group (P=0.0001 and P=0.002, respectively). Serum-ECP levels were higher in the controls (P<0.0001), while plasma MPO levels were higher in the VL group (P<0.0001). Levels of IL-5, granulocyte macrophage-colony stimulating factor (GM-CSF) and IL-17 were increased among the VL group (P<0.0001, P=0.017 and P=0.03, respectively), whereas eotaxin and IL-8 levels were reduced (P<0.0001 and P=0.002, respectively). Positive correlations were found between IL-8 and ECP/MPO (P<0.0001). We conclude that eosinophil and neutrophil turnover and activity are increased in subjects in rural areas of Sudan. In VL the turnover was further increased, but the relatively low secretory activity of eosinophils and neutrophils in VL may relate to the reduced production and availability of the chemokines eotaxin and IL-8. The combined assay of ECP and MPO in serum and plasma provides further insight into the mechanisms of eosinophil and neutrophil involvement in disease and constitutes a novel approach to the study of disease processes.

Interactions between immunity and metabolism - contributions from the metabolic profiling of parasite-rodent models

A combined interdisciplinary research strategy is even more crucial in immunology than in many other biological sciences in order to comprehend the closely linked interactions between cell proliferation, molecular signalling and gene rearrangements. Because of the multi-dimensional nature of the immune system, an abundance of different experimental approaches has developed, with a main focus on cellular and molecular mechanisms. The role of metabolism in immunity has been underexplored so far, and yet researchers have made important contributions in describing associations of immune processes and metabolic pathways, such as the central role of the l-arginine pathway in macrophage activation or the immune regulatory functions of the nucleotides. Furthermore, metabolite supplement studies, including nutritional administration and labelled substrates, have opened up new means of manipulating immune mechanisms. Metabolic profiling has introduced a reproducible platform for systemic assessment of changes at the small-molecule level within a host organism, and specific metabolic fingerprints of several parasitic infections have been characterized by 1H NMR spectroscopy. The application of multivariate statistical methods to spectral data has facilitated recovery of biomarkers, such as increased acute phase protein signals, and enabled direct correlation to the relative cytokine levels, which encourages further application of metabolic profiling to explore immune regulatory systems.

Gastrointestinal eosinophils in health, disease and functional disorders

Eosinophils are potent innate immune cells that home to the gastrointestinal tract where they participate in host immunity to luminal pathogens, and help to maintain intestinal epithelial homeostasis. However, these cells are now recognized to have key functions in the pathogenesis of numerous other disorders of the gastrointestinal tract, including primary eosinophilic gastrointestinal disease, common functional conditions, such as dyspepsia, and also in gastrointestinal disorders in patients with allergic disease. We are just beginning to understand the potential pathological role of eosinophils in gastrointestinal disease, and it is increasingly likely that gastroenterologists and histopathologists will need to account for the presence of gastrointestinal eosinophils and relate their presence to gastrointestinal symptoms. This Review discusses the role of gastrointestinal eosinophils in health and disease, including their associations with functional and allergic disorders.

Childhood nephrotic syndrome in Cambodia: an association with gastrointestinal parasites

OBJECTIVES

To describe childhood nephrotic syndrome (NS) in Cambodia and to evaluate whether initial presentation or relapse is associated with gastrointestinal parasitic infection.

STUDY DESIGN

We reviewed the records of 112 children with NS. A retrospective cross-sectional study compared 99 stool exams from 63 children with NS with 12 365 stool exams from 9495 controls.

RESULTS

The male-to-female ratio was 1.7; the mean age of presentation was 8.95 years--44% were hypertensive, 44% had microscopic hematuria, 40% had eosinophilia, and 41% had acute renal failure; 92.7% were steroid sensitive, 12.7% were steroid dependent, and 8.9% were frequent relapsers. Peritonitis and death were rare outcomes. Giardia lamblia (OR, 3.62; 95% CI, 2.0 to 6.1), Strongyloides stercoralis (OR, 3.59; 95% CI, 1.3 to 8.2), and Hookworm species (OR, 2.57; 95% CI, 1.0 to 5.5) were more likely to be isolated from the children with NS than the controls.

CONCLUSIONS

The clinical course of childhood NS in Cambodia is similar to the developed world. Differences at presentation included older age and increased prevalence of microscopic hematuria, hypertension, eosinophilia, and acute renal failure. This study demonstrates an association between G lamblia, S stercoralis, and possibly Hookworm species and the onset of NS.

Eosinophilia in returning travelers and migrants

INTRODUCTION

Eosinophilia in travelers returning from tropical countries is often caused by helminths. The high eosinophil counts arise particularly from tissue migration of invasive larvae.

METHODS

Review of literature selected by means of a Medline search using the MeSH terms "eosinophilia" and "helminth."

RESULTS

The patient's geographic and alimentary history may suggest infection with particular parasitic worms. A targeted diagnostic approach is suggested. The physician should concentrate on the principal signs and be guided by the geographic and alimentary history. Elaborate diagnostic measures are seldom indicated.

DISCUSSION

Although eosinophilia alone has low positive predictive value for a worm infection, it points clearly to helminthosis if the patient has recently returned from the tropics and the eosinophilia is new.