Immunogenesis in White Mice Infected with Yersinia pestis with Different Plasmid Composition.

Morphological changes in the immunocompetent organs of white mice with experimental plague infection manifested in activation of the immune response of different degree and pathological process of different severity that depended on the plasmid composition of Y. pestis. Widening of the T-dependent zones in the immune organs of white mice infected with isogenic strains of Y. pestis with different plasmid composition attests to activation of cellular immunity. Our findings allow considering Y. pestis subsp. altaica I-2948/3, Y. pestis subsp. pestis I-3479 and Y. pestis subsp. pestis I-3480 as promising candidates for vaccine strains.

Eosinophils may play regionally disparate roles in influencing IgA(+) plasma cell numbers during large and small intestinal inflammation.

BACKGROUND: Eosinophils are innate immune cells present in the intestine during steady state conditions. An intestinal eosinophilia is a hallmark of many infections and an accumulation of eosinophils is also observed in the intestine during inflammatory disorders. Classically the function of eosinophils has been associated with tissue destruction, due to the release of cytotoxic granule contents. However, recent evidence has demonstrated that the eosinophil plays a more diverse role in the immune system than previously acknowledged, including shaping adaptive immune responses and providing plasma cell survival factors during the steady state. Importantly, it is known that there are regional differences in the underlying immunology of the small and large intestine, but whether there are differences in context of the intestinal eosinophil in the steady state or inflammation is not known. RESULTS: Our data demonstrates that there are fewer IgA(+) plasma cells in the small intestine of eosinophil-deficient ΔdblGATA-1 mice compared to eosinophil-sufficient wild-type mice, with the difference becoming significant post-infection with Toxoplasma gondii. Remarkably, and in complete contrast, the absence of eosinophils in the inflamed large intestine does not impact on IgA(+) cell numbers during steady state, and is associated with a significant increase in IgA(+) cells post-infection with Trichuris muris compared to wild-type mice. Thus, the intestinal eosinophil appears to be less important in sustaining the IgA(+) cell pool in the large intestine compared to the small intestine, and in fact, our data suggests eosinophils play an inhibitory role. The dichotomy in the influence of the eosinophil over small and large intestinal IgA(+) cells did not depend on differences in plasma cell growth factors, recruitment potential or proliferation within the different regions of the gastrointestinal tract (GIT). CONCLUSIONS: We demonstrate for the first time that there are regional differences in the requirement of eosinophils for maintaining IgA+ cells between the large and small intestine, which are more pronounced during inflammation. This is an important step towards further delineation of the enigmatic functions of gut-resident eosinophils.

Paediatric nodal marginal zone B-cell lymphadenopathy of the neck: a Haemophilus influenzae-driven immune disorder?

Many hyperplasias and lymphomas of marginal zone B-cells are associated with infection. We identified six children and one adolescent with cervical lymphadenopathy showing prominent polyclonal nodal marginal zone hyperplasia (pNMZH) and four adolescents with monoclonal paediatric nodal marginal zone lymphoma (pNMZL). The clonality status was assessed using BIOMED-2-IG PCR analysis. Haemophilus influenzae was identified in all six cases of pNMZH that could be tested by direct culture (N = 3) or a very sensitive PCR for the H. influenzae gyrase gene in frozen materials (N = 5). H. influenzae was not detected in three pNMZLs and 28 non-specific reactive cervical lymph nodes of age-matched controls, except for a single control node that was obtained during oropharyngeal surgery for a cleft palate showing very low copy numbers of H. influenzae. pNMZH patients were younger than pNMZL patients (median age 12 versus 21 years). pNMZH showed a prominent nodular appearance with variable fibrosis without acute inflammation. Within the nodules, the expanded germinal centres and variably sized marginal zones were colonized by activated B-cells with weak expression of IgD and lack of CD10 and/or BCL6 expression. Some areas showed skewed light chain expression in plasma cells (4/5 cases lambda). In four cases tested, this was confirmed by flow cytometry for surface Ig (3/4 cases lambda). In contrast, pNMZL showed more extensive expansion of marginal zones by centrocytoid cells and often expression of BCL2 protein. Several H. influenzae strains are known to interact with the constant part of IgD on human B-cells, leading to their polyclonal proliferation and activation. We speculate that in vivo stimulation of IgD+ marginal zone B-cells by this bacterium may be implicated in this particular lymphadenopathy that should be distinguished from monoclonal pNMZL.

Impact of dietary deviation on disease progression and gut microbiome composition in lupus-prone SNF1 mice.

Environmental factors, including microbes and diet, play a key role in initiating autoimmunity in genetically predisposed individuals. However, the influence of gut microflora in the initiation and progression of systemic lupus erythematosus (SLE) is not well understood. In this study, we have examined the impact of drinking water pH on immune response, disease incidence and gut microbiome in a spontaneous mouse model of SLE. Our results show that (SWR × NZB) F1 (SNF1 ) mice that were given acidic pH water (AW) developed nephritis at a slower pace compared to those on neutral pH water (NW). Immunological analyses revealed that the NW-recipient mice carry relatively higher levels of circulating autoantibodies against nuclear antigen (nAg) as well as plasma cells. Importantly, 16S rRNA gene-targeted sequencing revealed that the composition of gut microbiome is significantly different between NW and AW groups of mice. In addition, analysis of cytokine and transcription factor expression revealed that immune response in the gut mucosa of NW recipient mice is dominated by T helper type 17 (Th17) and Th9-associated factors. Segmented filamentous bacteria (SFB) promote a Th17 response and autoimmunity in mouse models of arthritis and multiple sclerosis. Interestingly, however, not only was SFB colonization unaffected by the pH of drinking water, but also SFB failed to cause a profound increase in Th17 response and had no significant effect on lupus incidence. Overall, these observations show that simple dietary deviations such as the pH of drinking water can influence lupus incidence and affect the composition of gut microbiome.

BH3-only protein Bim is associated with the degree of Helicobacter pylori-induced gastritis and is localized to the mitochondria of inflammatory cells in the gastric mucosa.

BH3-only protein, Bim, is a pro-apoptotic protein that mediates mitochondria-dependent cell death. However, the role of Bim in Helicobacter pylori-associated gastritis remains unclear. This study aimed to assess the cellular localization of Bim and its possible role in H. pylori-induced gastritis. The study was conducted on biopsy specimens obtained from 80 patients who underwent upper gastrointestinal endoscopy (H. pylori-negative: n=30, positive: n=50). Association between Bim mRNA expression and severity of gastritis was evaluated and the localization of Bim was examined by immunofluorescence. Bim mRNA expression was positively correlated with the degree of gastritis, as defined by the Sydney system. Immunohistochemical analysis confirmed increased Bim expression in H. pylori-infected gastric mucosa compared with uninfected mucosa in both humans and mice. Bim localized in myeloperoxidase- and CD138-positive cells of H. pylori-infected lamina propria and submucosa of the gastric tract, indicating that this protein is predominantly expressed in neutrophils and plasma cells. In contrast, Bim did not localize in CD20-, CD3-, or CD68-positive cells. Bim was expressed in the mitochondria, where it was partially co-localized with activated Bax and cleaved-PARP. In conclusion, Bim is expressed in neutrophils and plasma cells in H. pylori-associated gastritis, where it may participate in the termination of inflammatory response by causing mitochondria-mediated apoptosis in specific leucocytes.

IgM production by bone marrow plasmablasts contributes to long-term protection against intracellular bacterial infection.

IgM responses are well known to occur early postinfection and tend to be short-lived, which has suggested that this Ig does not significantly contribute to long-term immunity. In this study, we demonstrate that chronic infection with the intracellular bacterium Ehrlichia muris elicits a protective, long-term IgM response. Moreover, we identified a population of CD138(high)IgM(high) B cells responsible for Ag-specific IgM production in the bone marrow. The IgM-secreting cells, which exhibited characteristics of both plasmablasts and plasma cells, contributed to protection against fatal ehrlichial challenge. Mice deficient in activation-induced cytidine deaminase, which produce only IgM, were protected against fatal ehrlichial challenge infection. The IgM-secreting cells that we have identified were maintained in the bone marrow in the absence of chronic infection, as antibiotic-treated mice remained protected against challenge infection. Our studies identify a cell population that is responsible for the IgM production in the bone marrow, and they highlight a novel role for IgM in the maintenance of long-term immunity during intracellular bacterial infection.

Acrodermatitis chronica atrophicans with pseudolymphomatous infiltrates.

In this study, we describe the clinicopathologic features of pseudolymphomatous infiltrates found within lesions of acrodermatitis chronica atrophicans (ACA). We studied 11 patients (10 females, 1 male, age range 60-88 years). The diagnosis of ACA in all cases was confirmed by clinicopathologic correlation and positive serology for Borrelia. Histopathologic examination revealed prominent, pseudolymphomatous inflammatory cell infiltrates in all cases, with 2 distinct patterns. Eight of 11 cases showed a band-like lymphocytic infiltrate, exocytosis of lymphocytes and a fibrotic papillary dermis, similar to features seen in mycosis fungoides. The other 3 cases showed dense, nodular-diffuse dermal infiltrates with many plasma cells and without germinal centers. The plasma cells expressed both kappa and lambda immunoglobulin light chains with a polyclonal pattern in all 3 cases. In conclusion, ACA may present with pseudolymphomatous infiltrates showing both a T-cell and, less frequently, a B-cell pattern. These lesions need to be distinguished from a cutaneous lymphoma. In the context of the knowledge of Borrelia-associated cutaneous lymphomas, follow-up seems advisable in these cases.

Solitary plasmacytoma of the tonsillar site associated with actinomyces infection: the possible role of IL-6.

ExtraMedullary Plasmacytoma (EMP) is a rare plasma cell tumor. It can occur in the upper aerodigestive tract and presents as a large nodule causing local compressive symptoms. A 79-year old woman presented to Otorhinolaryngology Department with progressive hearing loss and no other symptoms. Following PET/TC examination due to the suspicion of a lymphoproliferative disease, the patient underwent tonsillectomy and the diagnosis of solitary EMP was formulated. In addition to that, the histological examination of the tonsillar tissue revealed large colonies of filamentous bacteria, showing abundant sulphur granules and Splendore-Hoeppli phenomenon; these evidences indicating the presence of a chronic Actinomyces infection. Immunohistochemical analysis demonstrated a marked IL-6 immunoreactivity of the neoplastic plasma cells. Interestingly, a marked IL-6 immunoreactivity was also found in the tissue surrounding the Actinomyces colonies. In the present study we report for the first time a solitary EMP associated with Actinomycosis. It is tempting to speculate that the unsuspected and untreated Actinomyces infection, through chronic IL-6 production, could contribute to the neoplastic transformation of plasma cells.

Objective Visual Analog Scale for Biopsy Diagnosis of Helicobacter pylori Infection in Clinical Practice.

Historic and current pathology society guidelines recommend using visual gestalt to identify substantial inflammatory cell infiltrate in Helicobacter pylori gastritis, but these scales were subjectively designed. This study aims to objectively investigate the density of inflammation that justifies additional workup for H. pylori infection. We retrospectively identified 2 patient cohorts who had undergone endoscopy with gastric biopsies; 1 with H. pylori infection (n=66), confirmed with a positive stool antigen test and/or Campylobacter-like organism test, and 1 without infection (n=81). Antral and body biopsies were selected from each case, if available, and stained with MUM-1 to highlight mucosal plasma cells. Digital analysis was performed to calculate the number of plasma cells/mm2, termed the "inflammatory score" (IS). Patients with H. pylori infection had an average of 1289 plasma cells/mm2 in the antrum and 835 plasma cells/mm2 in the body, compared with 346 plasma cells/mm2 in the antrum and 178 plasma cells/mm2 in the body in patients without infection. IS cut-off values for a positive infection were 714 plasma cells/mm2 in the antrum and 316 plasma cells/mm2 in the body, with high sensitivities and specificities in both the antrum (92%, 92%) and body (85%, 84%), respectively. A visual analog scale was created to provide a histologic correlate of the observed IS ranges and cut-offs. This practical and objective scale is associated with a high sensitivity and specificity for diagnosing H. pylori infection and justifies moving away from upfront universal H. pylori testing in routine clinical practice.

Decreased IgA antibody production in the stomach of gastric adenocarcinoma patients.

Gastric adenocarcinoma is closely associated with Helicobacter pylori infection. It is also much more frequent in patients with common variable immunodeficiency or selective IgA-deficiency than in the general population. To investigate a possible link between local antibody production and gastric tumors, we studied gastric B cell infiltration and local IgA production in patients with H. pylori induced gastric adenocarcinomas. These studies showed that total and H. pylori-specific IgA antibody levels were substantially lower in gastric tissue from the cancer patients compared to those from asymptomatic H. pylori carriers. However, serum IgA levels were similar in the cancer patients and asymptomatic carriers. As could be expected, H. pylori infected asymptomatic carriers had considerably increased IgA antibody levels compared to uninfected subjects. We conclude that patients suffering from gastric adenocarcinoma have a dramatically decreased local IgA production in the stomach compared to asymptomatic H. pylori infected individuals.

Possible relationship between intestinal barrier function and formation of pigment gallstones in hamsters.

BACKGROUND: The presence of bacteria in bile is an important factor in the formation of pigment gallstones. The bile of healthy people is sterile and bacteria in the biliary system come from endogenous infection from the gut. Yet, the route of bacterial translocation into the bile duct is still unclear. Theoretically, two routes exist: one is through the intestinal barrier and the other is by direct reflux from the sphincter of Oddi. This study was undertaken to explore the relationship between the effectiveness of intestinal barrier and the formation of pigment gallstones in hamsters. METHODS: Thirty-two hamsters were divided into an experimental and a control group, with 16 hamsters in each group. A low protein and high cellulose diet was given for 6 weeks to induce the formation of pigment gallstones in the experimental group (PS) and a normal diet was given to the control group (CON). Morphological changes, changes in the levels of serum endotoxin and diamine oxidase, and changes in the numbers of B lymphocytes, plasma cells and secretory immunoglobin A (sIgA) in the intestinal mucosa were assessed after 6 weeks. RESULTS: Four hamsters died during lithogenesis and body weight decreased in the PS group. Pigment gallstones were found in 11 hamsters at the end of the experiment, giving a lithogenesis rate of 91.67%. The serum endotoxin level before and after gallstone formation in the PS group was 0.2960+/-0.1734 U/ml and 8.2964+/-4.6268 U/ml, respectively (P<0.05). The blood diamine oxidase level before and after gallstone formation in the PS group was 2.6333+/-0.8037 U/ml and 3.3642+/-0.9545 U/ml, respectively (P<0.05). The numbers of B lymphocytes, plasma cells and sIgA in the intestinal mucosa in the PS group were 71.56+/-2.89, 68.65+/-2.09 and 27.56+/-1.07, respectively, and were significantly decreased compared with the corresponding values in the CON group (94.25+/-3.69, 93.47+/-3.98 and 42.57+/-1.96, respectively, P<0.05). CONCLUSIONS: A low protein and high cellulose diet can markedly reduce intestinal barrier function and facilitate the formation of pigment gallstones. The decrease of intestinal barrier function may take part in the formation of pigment gallstones.

Syphilis of the Aerodigestive Tract.

Syphilis, a sexually transmitted infection caused by the Gram-negative bacterium Treponema pallidum, is increasing in prevalence in the United States. It has been our experience that primary and secondary syphilis of the aerodigestive tract can afflict a large age spectrum with varied clinical and histopathologic findings, which can lead to diagnostic problems and frequent misdiagnosis. In this study, we describe the histopathologic patterns of syphilis of the aerodigestive tract to expand awareness of its varied appearance. We identify 3 patterns of inflammatory response to syphilis: plasma cell-rich, lymphohistiocytic, and lymphoma-like. We also report the presence of immunoglobulin G4-predominant plasma cells in the inflammatory response as a potential mimicker of immunoglobulin G4-related disease. Lastly, we found that use of T. pallidum immunohistochemical stain is more reliable than Steiner silver stain at the identification of spirochetes. Our study highlights that despite convention, plasma cells are not always abundant in syphilis. Awareness of the histopathologic range of syphilis in the aerodigestive tract by the surgical pathologist can lead to the correct diagnosis and guide appropriate treatment.

Increased plasmacytic differentiation in gastric mucosa-associated lymphoid tissue lymphomas: Helicobacter pylori eradication response and IgG4+ plasma cell association.

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a rare extranodal marginal zone B-cell lymphoma that is often associated with plasmacytic differentiation. However, the clinicopathological characteristics of gastric MALT lymphoma with increased plasmacytic differentiation have not yet been studied. To assess the clinicopathological implications of gastric MALT lymphoma with increased plasmacytic differentiation, 36 cases with increased plasmacytic differentiation and a control group of 16 cases with minimal plasmacytic differentiation were retrospectively collected from 65 primary gastric MALT lymphomas (2010-2012). The hematoxylin and eosin slides were reviewed, and IgG, IgG4, and κ and λ immunohistochemical staining was performed. Clinicopathological differences between the 2 groups were compared using the χ2 test and odds ratios. Logistic regression analyses were used to evaluate resistance to Helicobacter pylori eradication therapy. Increased plasmacytic differentiation is significantly correlated with the H pylori eradication response (94.4% versus 66.7%, P=.018), lower frequency of relapse (5.6% versus 35.7%, P=.014), the presence of more than one IgG4+ cell per high-power field (27.8% versus 0%, P=.022), and light-chain restriction (33.3% versus 6.2%, P=.044). Univariable logistic regression indicated that negative H pylori status (P=.016) and minimal plasmacytic differentiation (P=.019) were statistically significant predictive factors for resistance to H pylori eradication. Multivariable logistic regression analyses identified no statistically significant predictive factors. However, H pylori negativity and minimal plasmacytic differentiation showed a statistical trend toward significance (P=.078 and P=.09). Gastric MALT lymphomas with increased plasmacytic differentiation have different clinicopathological characteristics, and plasmacytic differentiation is associated with H pylori eradication response.

Russell body gastritis associated with Helicobacter pylori infection: a case report.

An unusual and rare gastric mucosal lesion histologically consisting of a localised accumulation of Russell bodies and Russell body-containing plasma cells, the so-called Mott cells, has been recognised only recently and termed as "Russell body gastritis". This lesion, despite its densely monomorphous appearance is easily confirmed to be non-neoplastic by its polyclonal immunoreactive pattern to immunoglobulin light chains. However, the aetiology of Russell body gastritis is controversial and hence the optimal treatment for this disease has not been established. Two cases of Russell body gastritis associated with Helicobacter pylori infection are reported, and the possible role of H pylori infection in the pathogenesis is discussed.

Invasion and destruction of mucosal plasma cells by Tropheryma whippelii.

Whipple's disease is a poorly understood systemic disorder associated with the bacillus, Tropheryma whippelii. An early stage of Whipple's disease is studied by using electron microscopy (ELMI) and immunohistochemistry. The diagnosis was confirmed by polymerase chain reaction-amplification and sequencing of the 16S ribosomal-RNA of the bacterium. By using ELMI, Tropheryma whippelii was found in plasma cells and macrophages in the jejunal mucosa. The immunoglobulin (Ig)A-positive plasma cells were focally destructed and their number significantly reduced. However, the bacilli in the plasma cells were morphologically intact. In contrast, the macrophages showed no signs of cell destruction, but contained bacilli in various stages of disintegration. A cytopathic effect of Tropheryma whippelii to IgA plasma cells may be the reason for the commonly found plasma cell reduction in the small intestine mucosa and an important pathogenic mechanism contributing to the evasion of the bacilli from local immune response.

Chronic plasma cell cervicitis simulating a cervical malignancy: a case report.

BACKGROUND: Only one case of plasma cell cervicitis, a rare variant of chronic cervicitis, has been reported. We report a second case and present data supporting the detection of human papillomavirus (HPV) outside of epithelial tissues. CASE: A 67-year-old woman was found to have a large cervical tumor. Extensive diagnostic evaluation failed to reveal a suspected cervical cancer; subsequently, a hysterectomy was performed. Light microscopic studies confirmed plasma cell cervicitis. Standard virologic tests were used to confirm the presence of HPV 16 in cervical sections. Retrospective study of the first reported case also demonstrated HPV. CONCLUSION: Fulminant cases of chronic cervicitis, presenting with clinical features similar to cervical cancer, are unusual. Even more interesting is the detection of HPV outside of the epithelium; this is the first case that clearly demonstrates HPV in plasma cells.

Plasma cell quantitation in the gland of Harder during infectious bursal disease virus infection of 3-week-old broiler chickens.

Histopathologic changes in the gland of Harder (GH) and bursa of Fabricius (BF) were studied during and after infection of 3-week-old broiler chickens with a pathogenic strain of infectious bursal disease virus (IBDV). Plasma cell (PC) necrosis in the GH was seen from 5 to 14 days postinoculation (PI), BF follicular necrosis was observed from 1 to 7 days PI. PC numbers within the GH, counted for 28 days after inoculation, declined and were reduced (P less than 0.01) by 51% at 7 days after inoculation, which coincided with PC necrosis and heterophil infiltration. After 14 days PI, however, PC numbers were equal to those in uninfected controls. Since the GH is a major antibody-producing site in the paraocular area, the reduction in PC number at 7 days PI might indicate compromise of local immunity in the paraocular region and upper respiratory tract associated with IBD.

Respiratory scleroma: a clinicopathologic and ultrastructural study.

Respiratory scleroma (rhinoscleroma) is a chronic granulomatous infection produced by Klebsiella rhinoscleromatis, a gram-negative aerobic coccobacillus. This disease is endemic to Africa, Central and South America, South Central and Eastern Europe, the Middle East, and China. Sporadic cases have been reported in the United States, especially in persons who migrated from the aforementioned areas. The majority of cases affect the nose, but extension to the soft and hard palate, upper lip, and maxillary sinuses also is frequent. This study comprises 11 patients (6 females and 5 males) with respiratory scleroma identified over a 6-year period in Guatemala. Their ages ranged from 16 to 60 years. Light microscopy showed a dense plasmacytic infiltrate, Mikulicz histiocytes, and Russell bodies within the plasma cells. Ultrastructural study revealed Mikulicz histiocytes, cytoplasmic vacuoles containing bacilli, and so-called A and B granules. We favor the term respiratory scleroma for this lesion because it affects not only the nose but also the upper and lower respiratory tracts as well as the mouth.