Predicted limited redistribution of T cells to secondary lymphoid tissue correlates with increased risk of haematological malignancies in asplenic patients.

The spleen, a secondary lymphoid tissue (SLT), has an important role in generation of adaptive immune responses. Although splenectomy remains a common procedure, recent studies reported poor prognosis and increased risk of haematological malignancies in asplenic patients. The high baseline trafficking of T lymphocytes to splenic tissue suggests splenectomy may lead to loss of blood-borne malignant immunosurveillance that is not compensated for by the remaining SLT. To date, no quantitative analysis of the impact of splenectomy on the human T cell trafficking dynamics and tissue localisation has been reported. We developed a quantitative computational model that describes organ distribution and trafficking of human lymphocytes to explore the likely impact of splenectomy on immune cell distributions. In silico splenectomy resulted in an average reduction of T cell numbers in SLT by 35% (95%CI 0.12-0.97) and a comparatively lower, 9% (95%CI 0.17-1.43), mean decrease of T cell concentration in SLT. These results suggest that the surveillance capacity of the remaining SLT insufficiently compensates for the absence of the spleen. This may, in part, explain haematological malignancy risk in asplenic patients and raises the question of whether splenectomy has a clinically meaningful impact on patient responses to immunotherapy.

Methamphetamine facilitates pulmonary and splenic tissue injury and reduces T cell infiltration in C57BL/6 mice after antigenic challenge.

Methamphetamine (METH) is a strong addictive central nervous system stimulant. METH abuse can alter biological processes and immune functions necessary for host defense. The acquisition and transmission of HIV, hepatitis, and other communicable diseases are possible serious infectious consequences of METH use. METH also accumulates extensively in major organs. Despite METH being a major public health and safety problem globally, there are limited studies addressing the impact of this popular recreational psychostimulant on tissue adaptive immune responses after exposure to T cell dependent [ovalbumin (OVA)] and independent [lipopolysaccharide (LPS)] antigens. We hypothesized that METH administration causes pulmonary and splenic tissue alterations and reduces T cell responses to OVA and LPS in vivo, suggesting the increased susceptibility of users to infection. Using a murine model of METH administration, we showed that METH causes tissue injury, apoptosis, and alters helper and cytotoxic T cell recruitment in antigen challenged mice. METH also reduces the expression and distribution of CD3 and CD28 molecules on the surface of human Jurkat T cells. In addition, METH decreases the production of IL-2 in these T-like cells, suggesting a negative impact on T lymphocyte activation and proliferation. Our findings demonstrate the pleotropic effects of METH on cell-mediated immunity. These alterations have notable implications on tissue homeostasis and the capacity of the host to respond to infection.

Selenium deficiency causes immune damage by activating the DUSP1/NF-κB pathway and endoplasmic reticulum stress in chicken spleen.

Selenium (Se) is an essential trace element and its deficiency can lead to immune dysfunction. Many studies have investigated the immune damage caused by Se deficiency in chickens, but its mechanism still needs to be explored. In this study, we fed 1-day-old Hyline male chickens with Se deficient diets (the Se content was 0.008 mg kg-1 of diet) and a basal diet (the Se content was 0.15 mg kg-1 of diet). The spleen was collected at the sixth week and used for subsequent experiments. The pathological analysis showed that Se deficiency leads to the destruction of the normal nuclear structure of the spleen cell, and we can observe obvious chromatin condensation and nuclear debris. We constructed a transcriptome database and analyzed the abundance of various genes in the spleen by transcriptome sequence. The analysis of differentially expressed genes (DEGS) showed significant changes in 337 genes, including 210 up-regulations and 127 down-regulations after feeding Se deficient diets. Se deficiency can significantly change oxidative stress and inflammatory response genes in chicken spleen. This study confirmed that Se deficiency increased the IL-2 levels, whereas it down-regulated IL-17, IFN-γ and Foxp3, which indicates that the immune dysfunction of the spleen and Th1/Th2 is imbalanced. We also found that Se deficiency down-regulated some related genes for endoplasmic reticulum Ca2+ transport, leading to endoplasmic reticulum stress (ERS). Moreover, we determined that Se deficiency triggered the low expression of DUSP1/NF-κB. In summary, our results indicate that Se deficiency can inhibit the spleen immune function of chickens by regulating the DUSP1/NF-κB pathway and ERS, leading to spleen damage in chickens. Based on transcriptomics research, our results will help further study the harmful effects of Se deficiency.

The effects of aqueous extract of Maca on energy metabolism and immunoregulation.

BACKGROUND: In the present work, we investigated the effects of aqueous extract of Maca (AEM) on energy metabolism and immunoregulation in spleen-deficient mice. METHOD: We established a cyclophosphamide-induced spleen-deficiency model with ginseng, a herb that strengthens splenic function, as a control. Sixty male Kunming mice were randomly divided among 5 groups: normal, model, ginseng control (1.5 g/kg), AEM high dose (1.5 g/kg), and AEM low dose (0.75 g/kg). All animals, except those in the normal group, were injected with cyclophosphamide to induce spleen deficiency. Furthermore, we investigated differences in the thermotropic behaviors of mice using the Animal Thermotropism Behavior Surveillance System to detect energy metabolism-related assays and immune regulation assays. RESULTS: Mice given AEM exhibited tropism in response to hot plate exposure. AEM inhibited loss of body weight and immune organ atrophy caused by cyclophosphamide, increased the cAMP/cGMP ratio in blood, and enhanced the activities of Na+-K+-ATPase, Ca2+-Mg2+-ATPase, lactate dehydrogenase, and hepatic glycogen. AEM significantly reversed declining white blood cells and platelet counts, and increased the hemoglobin content within peripheral blood cells. AEM improved the protein levels of IFN-γ, TNF-ß, IL-2, and IL-4 in the spleen. CONCLUSIONS: Maca possesses the Traditional Chinese Medicine (TCM) property of warm and appears to strengthen spleen function.

Comparisons of Stereological and Other Approaches for Quantifying Macrophage Aggregates in Piscine Spleens.

Macrophage aggregates (MAs) are focal accumulations of pigmented macrophages in the spleen and other tissues of fish. A central role of MAs is the clearance and destruction of degenerating cells and recycling of some cellular components. Macrophage aggregates also respond to chemical contaminants and infectious agents and may play a role in the adaptive immune response. Tissue damage or physiological stress can result in increased MA accumulation. As a result, MAs may be sensitive biomarkers of environmental stress in fish. Abundance of MAs in tissues has been reported in a variety of ways-most commonly as density, mean size, and relative area-but the utility of these estimates has not been compared. In this study, four different types of splenic MA abundance estimates (abundance score, density, relative area, and total volume) were compared in two fish populations (Striped Bass Morone saxatilis and White Perch M. americana) with a wide range in ages. Stereological estimates of total volume indicated an increase in MA abundance with spleen volume, which generally corresponded to fish age, and with splenic infections (mycobacteria or trematode parasites). Abundance scores were generally limited in the ability to detect changes in MA abundance by these factors, whereas density estimates were greatly influenced by changes in spleen volume. In some instances, densities declined while the total volume of MAs and spleen volume increased. Experimentally induced acute stress resulted in a decrease in spleen volume and an increase in MA density, although the total volume of MAs remained unchanged. Relative area estimates accounted for the size and number of MAs but not for changes in organ volume. Total volume is an absolute measure of MA abundance irrespective of changes in organ volume or patterns of accumulation and may provide an improved means of quantifying MAs in the spleens of fish.

Hepatosplenic Fungal Infections in Children With Leukemia-Risk Factors and Outcome: A Multicentric Study.

BACKGROUND: Invasive fungal infections, including hepatosplenic fungal infections (HSFI), cause significant morbidity and mortality in children with leukemia. There are not enough data to support for the best approach to diagnosis of HSFI in children, nor for the best treatment. PROCEDURE: In this multicentric study, we assessed the demographic data, clinical and radiologic features, treatment, and outcome of 40 children with leukemia and HSFI from 12 centers. RESULTS: All cases were radiologically diagnosed with abdominal ultrasound, which was performed at a median of 7 days, of the febrile neutropenic episode. Mucor was identified by histopathology in 1, and Candida was identified in blood cultures in 8 patients. Twenty-two had fungal infection in additional sites, mostly lungs. Nine patients died. Four received a single agent, and 36 a combination of antifungals. CONCLUSIONS: Early diagnosis of HSFI is challenging because signs and symptoms are usually nonspecific. In neutropenic children, persistent fever, back pain extending to the shoulder, widespread muscle pain, and increased serum galactomannan levels should alert clinicians. Abdominal imaging, particularly an abdominal ultrasound, which is easy to perform and available even in most resource-limited countries, should be recommended in children with prolonged neutropenic fever, even in the absence of localizing signs and symptoms.

Incidence and risk factors for sepsis after childhood splenectomy.

BACKGROUND: Children who have undergone splenectomy may develop impaired immunologic function and heightened risk of overwhelming postsplenectomy infection. We sought to define the long-term rate of and risk factors for postsplenectomy sepsis. METHODS: We leveraged the Military Health System Data Repository, a nationally representative claims database including >3 million children registered as dependents of members of the United States Armed Services (2005-2014). Inclusion criterion was splenectomy at age 18 years or prior. The primary outcome was hospitalization for sepsis. RESULTS: Among 195 children who underwent splenectomy, 7% (n = 13) were hospitalized with sepsis, with an incidence of 1.8 (95% CI = 1.0-3.1) events per 100 person-years. The median time to sepsis was 224 days (IQR = 109-606) and 38% (5/13) of events occurred within the first postsplenectomy year. The postsplenectomy mortality rate was 1% (n = 3). After adjusting for underlying diagnosis, older age at splenectomy (HR = 0.90 per year, 95% CI = 0.81-0.99) was associated with decreased hazard of sepsis. CONCLUSIONS: In a contemporary national cohort, the prevalence of postsplenectomy sepsis was 7% (1.8 events per 100 person-years). Although most presented during the first year after splenectomy, many (62%) sepsis events occurred later, suggesting that postsplenectomy immunologic dysfunction persists beyond one year. The immunologic consequences of asplenia must continue to be acknowledged, as postsplenectomy sepsis remains a serious concern. TYPE OF STUDY: Prognosis study. LEVEL OF EVIDENCE: Level III.

Doxorubicin triggers splenic contraction and irreversible dysregulation of COX and LOX that alters the inflammation-resolution program in the myocardium.

Doxorubicin (DOX) is a widely used drug for cancer treatment as a chemotherapeutic agent. However, the cellular and integrative mechanism of DOX-induced immunometabolism is unclear. Two-month-old male C57BL/6J mice were divided into high- and low-dose DOX-treated groups with a maintained saline control group. The first group was injected with a high dose of DOX (H-DOX; 15 mg·kg-1·wk-1), and the second group was injected with 7.5 mg·kg-1·wk-1 as a latent low dose of DOX (LL-DOX). H-DOX treatment led to complete mortality in 2 wk and 70% survival in the LL-DOX group compared with the saline control group. Therefore, an additional group of mice was injected with an acute high dose of DOX (AH-DOX) and euthanized at 24 h to compare with LL-DOX and saline control groups. The LL-DOX and AH-DOX groups showed obvious apoptosis and dysfunctional and structural changes in cardiac tissue. Splenic contraction was evident in AH-DOX- and LL-DOX-treated mice, indicating the systems-wide impact of DOX on integrative organs of the spleen, which is essential for cardiac homeostasis and repair. DOX dysregulated splenic-enriched immune-sensitive lipoxygenase and cyclooxygenase in the spleen and left ventricle compared with the saline control group. As a result, lipoxygenase-dependent D- and E-series resolvin precursors, such as 16HDoHE, 4HDoHE, and 12-HEPE, as well as cyclooxygenase-mediated PG species (PGD2, PGE2, and 6-keto-PG2α) were decreased in the left ventricle, suggestive of defective immunometabolism. Both AH-DOX and LL-DOX induced splenic contraction and expansion of red pulp with decreased CD169+ metallophilic macrophages. AH-DOX intoxicated macrophages in the spleen by depleting CD169+ cells in the acute setting and sustained the splenic macrophage loss in the chronic phase in the LL-DOX group. Thus, DOX triggers a vicious cycle of splenocardiac cachexia to facilitate defective immunometabolism and irreversible macrophage toxicity and thereby impaired the inflammation-resolution program. NEW & NOTEWORTHY Doxorubicin (DOX) triggered splenic mass loss and decreased CD169 with germinal center contraction in acute and chronic exposure. Cardiac toxicity of DOX is marked with dysregulation of immunometabolism and thereby impaired resolution of inflammation. DOX suppressed physiological levels of cytokines and chemokines with signs of splenocardiac cachexia.

Cellular immunodeficiency related to chronic dermatophytosis in a patient with Schistosoma mansoni infection: can schistosomiasis induce immunodeficiency?

Here, we describe a case of hepatosplenic schistosomiasis that progressed to widespread persistent dermatophytosis. Significant T and B lymphocytopenia was confirmed. T-cell deficit is associated with increased susceptibility to fungal infections of skin and mucous membranes. The accumulation of a large amount of blood cells in the spleen could have played a crucial role in the development of lymphocytopenia in the present case. Alternatively, the schistosomiasis-induced increase in prostaglandin E2 levels could have inhibited the production of interferon-γ, a cytokine fundamental to fungal resistance. This case shows the potential of hepatosplenic schistosomiasis to impair the immune response.

Cellular immunodeficiency related to chronic dermatophytosis in a patient with Schistosoma mansoni infection: can schistosomiasis induce immunodeficiency?

Abstract: Here, we describe a case of hepatosplenic schistosomiasis that progressed to widespread persistent dermatophytosis. Significant T and B lymphocytopenia was confirmed. T-cell deficit is associated with increased susceptibility to fungal infections of skin and mucous membranes. The accumulation of a large amount of blood cells in the spleen could have played a crucial role in the development of lymphocytopenia in the present case. Alternatively, the schistosomiasis-induced increase in prostaglandin E2 levels could have inhibited the production of interferon-γ, a cytokine fundamental to fungal resistance. This case shows the potential of hepatosplenic schistosomiasis to impair the immune response.

Ferulic acid (FA) abrogates ionizing radiation-induced oxidative damage in murine spleen.

PURPOSE: The spleen is a crucial organ manifesting immune functions. Thus, radiation-induced oxidative challenge is vulnerable for the spleen. Our major objective was to protect the spleen from radiation-induced anomalous situations and to identify the signaling pathways involved. MATERIALS AND METHODS: Swiss albino mice were treated with ferulic acid (FA) once in a day at a dose of 50 mg/kg body weight for 5 consecutive days before exposing them to single dose of 10 Gy irradiation. The ROS generation and MMP change were determined by flow cytometry. The expression of different signaling proteins was investigated by immunoblotting and immunocytochemistry. RESULTS: FA pretreatment significantly prevented radiation-induced oxidative stress by downregulating TBARS formation and by upregulating SOD and catalase activity. FA scavenged ROS, prevented the alteration of MMP and downregulated the expression of stress marker Cdc42 and apoptotic markers p53, p21, Bax and PTEN. Cell cycle analysis showed DNA damage induced arrest of cells at subG0/G1 phase. Moreover, pretreatment with FA augmented Bcl2 expression and also increased the level of p-PI3K. CONCLUSION: FA prevented the activation of apoptotic signaling events in the spleen by interfering with the free radical chain reaction and by scavenging superfluous ROS. This is perhaps the first comprehensive study with a mechanistic viewpoint that FA can protect the spleen from ionizing radiation.

Distinct surveillance pathway for immunopathology during acute infection via autophagy and SR-BI.

The mechanisms protecting from immunopathology during acute bacterial infections are incompletely known. We found that in response to apoptotic immune cells and live or dead Listeria monocytogenes scavenger receptor BI (SR-BI), an anti-atherogenic lipid exchange mediator, activated internalization mechanisms with characteristics of macropinocytosis and, assisted by Golgi fragmentation, initiated autophagic responses. This was supported by scavenger receptor-induced local increases in membrane cholesterol concentrations which generated lipid domains particularly in cell extensions and the Golgi. SR-BI was a key driver of beclin-1-dependent autophagy during acute bacterial infection of the liver and spleen. Autophagy regulated tissue infiltration of neutrophils, suppressed accumulation of Ly6C+ (inflammatory) macrophages, and prevented hepatocyte necrosis in the core of infectious foci. Perifocal levels of Ly6C+ macrophages and Ly6C- macrophages were unaffected, indicating predominant regulation of the focus core. SR-BI-triggered autophagy promoted co-elimination of apoptotic immune cells and dead bacteria but barely influenced bacterial sequestration and survival or inflammasome activation, thus exclusively counteracting damage inflicted by immune responses. Hence, SR-BI- and autophagy promote a surveillance pathway that partially responds to products of antimicrobial defenses and selectively prevents immunity-induced damage during acute infection. Our findings suggest that control of infection-associated immunopathology can be based on a unified defense operation.

Upregulated expression of CD30 protein in sclerosing angiomatoid nodular transformation (SANT): studies of additional 4 cases and analyses of 6 cases previously published cases.

Sclerosing angiomatoid nodular transformation (SANT) of spleen is a benign lesion with a distinct morphological and immunohisochemical characteristics. Only Weinred I et al (Virchow Arch 451: 73-9, 2007) reported 6 cases of SANT expressing CD30, of which positive for EBV by in situ hybridization (EBER). 4 cases of SANT were added to investigate the clinicopathological features and focused on the expression of CD30 and EBER combined with the previously published literature. Histologically, individual angiomatoid nodules were sharply delineated by fibrocollagenous stroma with numerous vascular lumens and surrounded by a different population of spindle and ovoid cells. Angiomatoid nodules of all of the 4 cases heterogeneously expressed CD34, CD8, CD68 and diffusely demonstrated CD31 and CD30, but none were positive for EBER. We added these cases with reviewed literature to emphasize and verify the fact that upregulated expression of CD30 in SANT is quite common, which should be taken into consideration when making differential diagnosis.

Prolonged fever and splenic lesions caused by Malassezia restricta in an immunocompromised patient.

Malassezia species are commonly found on human skin as commensals but can cause invasive infections in premature infants and immunocompromised hosts. Due to their fastidious growth, diagnosis of Malassezia infections can prove challenging. Molecular techniques can aid in diagnosis and treatment of invasive infections. We describe the case of a pediatric oncology patient with splenic lesions secondary to Malassezia restricta.

Spontaneous rupture of a splenic hydatid cyst with anaphylaxis in a patient with multi-organ hydatid disease.

Hidatid cysts of the spleen are a rare occurrence, the spleen being the third most common organ for the development of Echinococcus Granulosus. Splenic hydatid cysts are commonly part of multi-organ hydatid disease. Diagnosis is often established when investigating a splenomegaly or by chance during an unrelated consult. It can also be diagnosed after rupture, be it following trauma (the most common occurrence)or spontaneous. Splenic hydatid cyst rupture requires immediate action and is a life-threatening condition. It results, most often, in splenectomy. We present the case of a patient with multi-organ hydatid disease that presented with a ruptured splenic cyst and developed anaphylaxis. The case was resolved by splenectomy and recovered well.

Sclerosing angiomatoid nodular transformation of the spleen.

Sclerosing Angiomatoid Nodular Transformation (SANT) of the spleen is a rare benign lesion of the spleen with unknown etiology. SANT is classically considered to be a female-predominant disease, with most of the patients in the 30- to 60-year age group. Most lesions are found incidentally on imaging. Although SANT has specific imaging findings, the differential diagnosis from other splenic tumors or malignant lesions is very difficult. Histopathologically, these tumors reveal multiple confluent angiomatoid nodules; these nodules are surrounded by concentric collagen fibers exhibiting an inflammatory and myofibroblastic response and are accompanied by numerous erythrocytes and siderophages. The nodules are populated by endothelial cells, phenotypically recapitulating normal splenic vasculature, such as sinusoids, capillaries, and small veins. Nuclear atypia is minimal, mitotic figures are extremely rare, and necrosis is consistently absent. This lesion has a unique immunohistochemical profile characterized by CD34(-)CD31(+)CD8(+) sinusoids, CD34(+)CD31(+)CD8(-) capillaries, and CD34(-)CD31(+)CD8(-) small veins. CD68 is positive in macrophages. Splenectomy is a useful and effective technique for the management of SANT. SANT patients have a good prognosis, with no recurrence after splenectomy. In this review, we discuss the current knowledge of SANT of the spleen and its clinical relevance.

[Changes in the immune status of patients operated for splenic lesions in the late postoperative period and their relation to the development of complications].

This analysis of changes in the immune status of patients operated for splenic lesions is based on the observations of 126 subjects. Fifty of them underwent autolientransplantation and 26 conservative surgery. The main parameters of humoral and cellular immunity were measured along with changes in the microflora. Splenectomy was shown to cause changes in the characteristics of both cellular and humoral immunity. Autolientransplantation caused a significant decrease in the serum level of total complement and its C3- and C-4 fractions while the amount of circulating immune complexes increased All other parameters of the immune status remained unaltered The best outcome of the treatment was documented after conservative surgery.

Isolated splenic peliosis in an immunocompromised patient.

BACKGROUND: Peliosis is a rare condition characterised by multiple cyst-like, blood-filled cavities within the parenchyma of solid organs, most commonly affecting the liver. Isolated splenic peliosis is an even more unusual phenomenon. Patients with AIDS may develop peliosis in association with bacillary angiomatosis. This is due to secondary infection with Bartonella henselae or a similar organism, Rochalimaea henselae. CASE PRESENTATION: A 45-year-old HIV-positive man on antiretroviral therapy presented with a left hypochodrial abdominal mass. Radiological and histopathological examination confirmed splenic peliosis.