Serum bactericidal activity against Helicobacter pylori in patients with hypogammaglobulinaemia

Anti-CD40L therapy prevents the formation of precursor lesions to gastric B-cell MALT lymphoma in a mouse model

Mucosa-associated lymphoid tissue (MALT) lymphoma is a B-cell tumour that develops over many decades in the stomachs of individuals with chronic Helicobacter pylori infection. We developed a new mouse model of human gastric MALT lymphoma in which mice with a myeloid-specific deletion of the innate immune molecule, Nlrc5, develop precursor B-cell lesions to MALT lymphoma at only 3 months post-Helicobacter infection versus 9-24 months in existing models. The gastric B-cell lesions in the Nlrc5 knockout mice had the histopathological features of the human disease, notably lymphoepithelial-like lesions, centrocyte-like cells, and were infiltrated by dendritic cells (DCs), macrophages, and T-cells (CD4+ , CD8+ and Foxp3+ ). Mouse and human gastric tissues contained immune cells expressing immune checkpoint receptor programmed death 1 (PD-1) and its ligand PD-L1, indicating an immunosuppressive tissue microenvironment. We next determined whether CD40L, overexpressed in a range of B-cell malignancies, may be a potential drug target for the treatment of gastric MALT lymphoma. Importantly, we showed that the administration of anti-CD40L antibody either coincident with or after establishment of Helicobacter infection prevented gastric B-cell lesions in mice, when compared with the control antibody treatment. Mice administered the CD40L antibody also had significantly reduced numbers of gastric DCs, CD8+ and Foxp3+ T-cells, as well as decreased gastric expression of B-cell lymphoma genes. These findings validate the potential of CD40L as a therapeutic target in the treatment of human gastric B-cell MALT lymphoma. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Atypical presentation of Good syndrome: acute hepatitis from hepatitis B virus reactivation

Good syndrome (GS) is a primary immunodeficiency (PID) that presents in middle aged to older adults with features of thymoma, hypogammaglobulinemia, CD4 T lymphopenia, inverted CD4/CD8+ ratio, and impaired T-cell mitogen proliferative responses. We present a patient, a 62-year-old female, who first presented with disease manifestation of acute hepatitis from hepatitis B virus (HBV) reactivation, which was subsequently complicated by recurrent hospitalizations for recurrent pneumonia and concomitant Helicobacter pylori and cytomegalovirus enteritis. She was later found to have thymoma and hypogammaglobulinemia and was diagnosed with GS. Although the well-known importance of T cell is in directing B-cell responses in the immunopathology of thymoma, low levels of natural killer and CD4+ γδ T cells may also be the cause of both low immune surveillance of tumor development and weak clearance of viral infection. Hence, the temporal sequence of opportunistic infections following HBV reactivation and thymoma discovery may reflect a loss of immune surveillance as the first manifestation of PID.

A sensitive gold-nanorods-based nanobiosensor for specific detection of Campylobacter jejuni and Campylobacter coli

BACKGROUND

Campylobacteriosis is a zoonotic infectious disease that can be mostly undiagnosed or unreported due to fastidious Campylobacter species. The aim of this study was to develop a simple, sensitive, and quick assay for the detection of Campylobacter spp. and taking advantage of the great sensitivity of gold nanorods (GNRs) to trace changes in the local environment and interparticle distance.

METHODS

Characterized GNRs were modified by specific ssDNA probes of cadF gene. First, the biosensor was evaluated using recombinant plasmid (pTG19-T/cadF) and synthetic single-stranded 95 bp gene, followed by a collection of the extracted DNAs of the stool samples. The sensing strategy was compared by culture, PCR, and real-time PCR.

RESULTS AND DISCUSSION

Analysis of 283 specimens showed successful detection of Campylobacter spp. in 44 cases (16%), which was comparable to culture (7%), PCR (15%), and real-time PCR (18%). In comparison with real-time PCR, the sensitivity of the biosensor was reported 88%, while the specificity test for all assays was the same (100%). However, it was not able to detect Campylobacter in 6 positive clinical samples, as compared to real-time PCR. The limit of detection was calculated to be the same for the biosensor and real-time PCR (10² copy number/mL).

CONCLUSIONS

Taking high speed and simplicity of this assay into consideration, the plasmonic nanobiosensor could pave the way in designing a new generation of diagnostic kits for detection of C. jejuni and C. coli species in clinical laboratories.

Emergence of Carbapenem Non-susceptible Campylobacter coli after Long-term Treatment against Recurrent Bacteremia in a Patient with X-linked Agammaglobulinemia

We herein report a case of recurrent Campylobacter coli bacteremia in a 37-year-old Japanese man with X-linked agammaglobulinemia (XLA). The patient experienced seven episodes of C. coli bacteremia over one year, with an erythematous rash intermittently emerged on the lower limbs. Although hospitalization for intravenous treatment was repeatedly recommended, he obstinately declined it. Following long-term oral antibiotic treatment with tebipenem and faropenem for the persistent infection, C. coli showed elevated minimum inhibitory concentrations to meropenem, a key drug for severe campylobacteriosis. Physicians should note that the overuse of antibiotics can lead to the emergence of carbapenem-non-susceptible Campylobacter strains.

Age-related variations in the in vitro bactericidal activity of human sera against Pseudomonas aeruginosa

The human serum is a vital component of the innate immunity of the host that acts as the first line of defence against invading pathogens. A key player in serum-mediated innate immune defence is a system of more than 35 proteins, collectively named as the complement system. After exposure of the pathogen, these proteins are activated in a cascade manner, ultimately forming a membrane attack complex (MAC) on the surface of the pathogen that directly lyses the bacterial cell. Formation of the MAC can be demonstrated in vitro by using serum bactericidal assay (SBA) that works in the absence of cellular components of blood after incubating the serum along with bacteria. Here, we describe the age-related differences in the bactericidal activity of human serum against Pseudomonas aeruginosa, an opportunistic human pathogen causing an array of hospital and community-acquired infections.

We demonstrate that adult sera were highly effective in the in vitro killing of Pseudomonas aeruginosa as compared to children and the elderly (p < 0.0001). Sera from children were seriously compromised in the killing P. aeruginosa, whereas elderly sera showed a reduced level of killing. Data revealed a positive correlation between age and serum-killing with higher coefficient of determination values of 0.34, 0.27, and 0.58 and p values of < 0.0001, < 0.001, and < 0.0001, respectively, after 60, 90, and 120 minutes of incubation. Hence, our study highlights the age-related difference in the bactericidal activity of human sera. We conclude that sera of children are totally compromised, whereas elderly sera are only partially compromised, in the killing of P. aeruginosa.

Chronic Diarrhea in Common Variable Immunodeficiency: a Case Series and Review of the Literature

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by reduced immunoglobulin serum levels and absent or impaired antibody production. Clinical manifestations, including infections, inflammatory and autoimmune diseases, and malignancies, also involve various segments of the gastrointestinal tract. Chronic diarrhea is one of the most common gastrointestinal symptoms and may cause a wide spectrum of potentially life-threatening conditions as malabsorption and protein-energy malnutrition. We describe three female CVID adult patients presenting with chronic diarrhea, weight loss, and protein-energy malnutrition due to different underlying conditions. Our review of the literature explores the various gastrointestinal involvements in CVID and points out several histopathological findings proper of the disease, thus highlighting the relevance of the endoscopic and histological assessment in CVID patients presenting with chronic diarrhea.

Epidemiology and pathophysiology of malignancy in common variable immunodeficiency?

Common variable immunodeficiency (CVID) is a diagnostic category of primary immunodeficiency (PID) which may present with heterogeneous disorders including recurrent infections, autoimmunity, granulomatous diseases, lymphoid and other types of malignancies. Generally, the incidence of malignancy in CVID patients is around 1.5-20.7% and usually occurs during the 4th-6th decade of life. Non-Hodgkin lymphoma is the most frequent malignancy, followed by epithelial tumours of stomach, breast, bladder and cervix. The exact pathological mechanisms for cancer development in CVID are not fully determined; however, several mechanisms including impaired genetic stability, genetic predisposition, immune dysregulation, impaired clearance of oncogenic viruses and bacterial infections, and iatrogenic causes have been proposed to contribute to the high susceptibility of these patients to malignancies.

Gastrointestinal Disorders Associated with Common Variable Immune Deficiency (CVID) and Chronic Granulomatous Disease (CGD)

Common variable immune deficiency (CVID) and chronic granulomatous disease (CGD) are two of the well-characterized primary immune deficiencies with distinct pathologic defects. While CVID is predominantly a disorder of the adaptive immune system, in CGD, innate immunity is impaired. In both syndromes, the clinical manifestations include an increased susceptibility to infections and a number of non-infectious, inflammatory conditions including systemic autoimmunity, as well as organ-specific pathology. Among the organ-associated disorders, gastrointestinal (GI) manifestations are one of the most intractable. As such, non-infectious inflammatory disorders of the GI tract are clinically challenging as they have protean manifestations, often resembling inflammatory bowel disease (IBD) or celiac disease, are notoriously difficult to treat, and hence are associated with significant morbidity and mortality. Therefore, assessing the pathogenesis and defining appropriate therapeutic approaches for GI disease in patients with CVID and CGD is imperative.

CD40 Ligand Deficient C57BL/6 Mouse Is a Potential Surrogate Model of Human X-Linked Hyper IgM (X-HIGM) Syndrome for Characterizing Immune Responses against Pathogens

Individuals with X-HIGM syndrome fail to express functional CD40 ligand; consequently they cannot mount effective protective antibody responses against pathogenic bacteria. We evaluated, compared, and characterized the humoral immune response of wild type (WT) and C57-CD40L deficient (C57-CD40L^−/−) mice infected with Citrobacter rodentium. Basal serum isotype levels were similar for IgM and IgG3 among mice, while total IgG and IgG2b concentrations were significantly lower in C57-CD40L^−/− mice compared with WT. Essentially IgG1 and IgG2c levels were detectable only in WT mice. C57-CD40L^−/− animals, orally inoculated with 2 × 10⁹ CFU, presented several clinical manifestations since the second week of infection and eventually died. In contrast at this time point no clinical manifestations were observed among C57-CD40L^−/− mice infected with 1 × 10⁷ CFU. Infection was subclinical in WT mice inoculated with either bacterial dose. The serum samples from infected mice (1 × 10⁷ CFU), collected at day 14 after infection, had similar C. rodentium-specific IgM titres. Although C57-CD40L^−/− animals had lower IgG and IgG2b titres than WT mice, C57-CD40L^−/− mice sera displayed complement-mediated bactericidal activity against C. rodentium. C. rodentium-infected C57-CD40L^−/− mice are capable of producing antibodies that are protective. C57-CD40L^−/− mouse is a useful surrogate model of X-HIGM syndrome for studying immune responses elicited against pathogens.

Lymphoproliferative disease and cancer among patients with common variable immunodeficiency

Innate immune deficiencies are a heterogeneous group of genetically inherited diseases affecting the innate and adaptive immune systems that confer susceptibility to infection, autoimmunity, and cancer. This review discusses the latest insights into the links between common variable immunodeficiency (CVI) and malignancies. Although Ig therapy greatly reduces the number of infections and enhances survival, it does not appear to address the development of cancer, especially lymphoma. The reasons for the increased susceptibility to lymphoid malignancies are unclear. These include genetics, immune dysregulation, radiosensitivity and chronic infections such as Helicobacter pylori, EBV, human herpes virus type 8 and cytomegalovirus. Further studies will allow us to better stratify the risk for cancer in these patients, and teach us to better prevent these complications and to better treat them.

Immunology and vaccines and nanovaccines for Helicobacter pylori infection

Helicobacter pylori infection is very common worldwide and is an important cause of gastritis, peptic ulcer disease, gastric mucosa-associated lymphoid tissue lymphoma, and gastric adenocarcinoma. Since the eradication requires treatment with multidrug regimens, prevention of primary infection by a suitable vaccine is attractive. Developing vaccines on the spot when and where an infection is breaking out might be possible, thanks to engineered nanoparticles. In this review, the nature of the host immune response to H. pylori infection is considered. We explain recent candidate vaccines and prophylactic or therapeutic immunization strategies for use against H. pylori. We also describe identification of different types of immune responses that may be related to protection against H. pylori infection. Thus, it seems that there is still a strong need to clarify the main protective immune response against H. pylori.

Gastric adenocarcinoma in common variable immunodeficiency: features of cancer and associated gastritis may be characteristic of the condition

Common variable immunodeficiency (CVID) is associated with an increased risk of gastric cancer. The aim of the study was to determine the morphological features of CVID-associated gastric adenocarcinoma (CAGA) and of the background gastritis. The population of gastric cancer patients with CVID of Mayo Clinic in the period 2000-2010 was studied; 6 cases of CVID (2 males, 4 females, average age 47 years, age range 26-71 years) were found in 5793 patients with gastric cancer in the study period. Each patient underwent gastric resection for which histology slides were reviewed. Chronic gastritis variables, CVID-related findings, and features of the adenocarcinoma were recorded. CAGA was of intestinal type, with high number of intratumoral lymphocytes (ITLs). Cancer was diagnosed in younger patients than in the overall population of gastric cancer. Severe atrophic metaplastic pangastritis with extensive dysplasia was present in the background in 4 cases, with features of lymphocytic gastritis in 2 cases. Features of CVID (plasma cells paucity in 4 of 6 cases, lymphoid nodules prominent in four cases) could be detected. In summary, gastric adenocarcinoma at young age with ITLs, accompanied by atrophic metaplastic pangastritis, should alert the pathologist of the possibility of CAGA. It follows that, in presence of those characteristics, the search of CVID-associated abnormalities should be undertaken in the nonneoplastic tissues.

Gastric ulcers due to varicella-zoster reactivation

We report on an 18-year-old man with common variable immunodeficiency presenting with abdominal pain and vomiting due to gastric ulcers caused by reactivation of varicella-zoster virus (VZV). Endoscopy revealed multiple ulcers in the gastric antrum. Fever and rash developed the next day. Skin biopsy showed multinucleated cells with intranuclear inclusions highly suggestive of VZV infection, and high-dose intravenous acyclovir was started. VZV was detected on direct immunofluorescence from skin biopsy and polymerase chain reaction from endoscopic biopsy. His course was complicated by encephalopathy, pancreatitis, hepatitis, renal impairment, and hyponatremia. After 3 weeks of antiviral therapy, he gradually improved. Skin lesions cleared within a week. He remained well on follow-up 1 year later. Disseminated zoster presenting as gastric ulcers in the absence of the classic rash is unusual but has been reported in immunosuppressed patients with a history of bone marrow and stem cell transplant. We report this rare presentation in a patient with common variable immunodeficiency and highlight the importance of considering zoster as a cause for severe abdominal pain and of seeking endoscopic diagnosis to facilitate early therapy and reduced mortality risk.

Innate immunity and stress physiology of eastern hellbenders (Cryptobranchus alleganiensis) from two stream reaches with differing habitat quality

In addition to depriving amphibians of physical habitat requirements (e.g., shelter, moisture, and food), habitat modification may also have subtle effects on the health of amphibians and potentially precipitate interactions with other deleterious factors such as pathogens, contaminants, and invasive species. The current study was designed to evaluate the physiological state of imperiled giant salamanders, the eastern hellbender (Cryptobranchus alleganiensis), experiencing different surrounding land use that influences in-stream habitat quality. When we compared hellbenders from a stream reach with greater anthropogenic disturbance to a more forested site, we found that baseline and stress-induced plasma levels of corticosterone were similar in the two areas, but were very low compared to other amphibians. Males consistently had higher plasma corticosterone levels than females, a finding congruent with the known territorial activities of males early in the breeding season. Innate immune responsiveness (measured as bactericidal ability of blood; BKA) was also similar at the two sites, but juveniles had less robust BKA than adults. We found a positive relationship between restraint time and BKA, suggesting that the bactericidal ability of hellbenders may improve following acute stress. Finally, there was a tendency for hellbenders with skin abnormalities to have higher BKA compared to individuals with normal integument, an observation consistent with patterns observed in other animals actively responding to pathogens. Our study provides foundational physiological information on an imperiled amphibian species and reveals important knowledge gaps that will be important for understanding the ecology, evolution, and conservation of hellbenders.

Review of gastric cancer risk factors in patients with common variable immunodeficiency disorders, resulting in a proposal for a surveillance programme

Common variable immunodeficiency disorders (CVIDs) are the most frequent symptomatic primary immunodeficiencies in adults. They comprise a heterogeneous group of pathologies, with frequent non-infectious complications in addition to the bacterial infections that usually characterize their presentation. Complications include a high risk of malignancy, especially lymphoma and gastric cancer. Helicobacter pylori infection and pernicious anaemia are risk predictors for gastric cancer in the general population and probably in patients with CVIDs. Screening for gastric cancer in a high-risk population appears to improve survival. Given the increased risk of gastric cancer in patients with CVIDs and prompted by a case of advanced gastric malignancy in a patient with a CVID and concomitant pernicious anaemia, we performed a review of the literature for gastric cancer and conducted a cohort study of gastric pathology in 116 patients with CVIDs under long-term follow-up in Oxford. Regardless of the presence of pernicious anaemia or H. pylori infection, patients with CVIDs have a 10-fold increased risk of gastric cancer and are therefore a high-risk population. Although endoscopic screening of all patients with CVIDs could be considered, a more selective approach is appropriate and we propose a surveillance protocol that should reduce modifiable risk factors such as H. pylori, in order to improve the management of patients with CVIDs at risk of gastric malignancy.

Campylobacter jejuni bacteremia and Helicobacter pylori in a patient with X-linked agammaglobulinemia

We describe a 15-year-old patient with X-linked agammaglobulinemia who developed malabsorption and bacteremia due to infection of Helicobacter pylori and Campylobacter jejuni. The Campylobacter bacteremia was only recognized after subculturing of blood culture bottles that failed to signal in the automated system. After 2 weeks of treatment with meropenem and erythromycin for 4 weeks, the patient developed a relapse of bacteremia 10 months later with a high level erythromycin resistant C. jejuni. Sequencing revealed an A2058C mutation in the 23 S rRNA gene associated with this resistance. Treatment with doxycycline for 4 weeks finally resulted in complete eradication. This case report illustrates the importance for physicians to use adapted culture methods and adequate prolonged therapy in patients with an immunodeficiency. A summary of published case reports and series of patients with hypogammaglobulinemia or agammaglobulinemia with Campylobacter or Helicobacter bacteremia is given.