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Hematology. American Society of... Dec 2020An estimated 1 million people in the United States have functional or anatomic asplenia or hyposplenia. Infectious complications due to encapsulated organisms such as...
An estimated 1 million people in the United States have functional or anatomic asplenia or hyposplenia. Infectious complications due to encapsulated organisms such as Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae can lead to fulminant sepsis and death, particularly in young children, in the period shortly after splenectomy, and in immunocompromised patients. Patients with asplenia are also at risk for less common infections due to Capnocytophaga, Babesia, and malaria. Antibiotic prophylaxis, vaccines, and patient and family education are the mainstays of prevention in these at-risk patients. Recommendations for antibiotic prophylaxis typically target high-risk periods, such as 1 to 3 years after splenectomy, children ≤5 years of age, or patients with concomitant immunocompromise. However, the risk for sepsis is lifelong, with infections occurring as late as 40 years after splenectomy. Currently available vaccines recommended for patients with asplenia include pneumococcal vaccines (13-valent pneumococcal conjugate vaccine followed by the 23-valent pneumococcal polysaccharide vaccine), meningococcal vaccines (meningococcal conjugate vaccines for serogroups A, C, Y and W-135 and serogroup B meningococcal vaccines), H. influenzae type b vaccines, and inactivated influenza vaccines. Ongoing booster doses are also recommended for pneumococcal and meningococcal vaccines to maintain protection. Despite the availability of prevention tools, adherence is often a challenge. Dedicated teams or clinics focused on patient education and monitoring have demonstrated substantial improvements in vaccine coverage rates for individuals with asplenia and reduced risk of infection. Future efforts to monitor the quality of care in patients with asplenia may be important to bridge the know-do gap in this high-risk population.
Topics: Adult; Anti-Bacterial Agents; Bacterial Capsules; Bacterial Infections; Child; Haemophilus Vaccines; Humans; Infection Control; Infections; Meningococcal Vaccines; Pneumococcal Vaccines; Primary Immunodeficiency Diseases; Spleen; Splenectomy; Vaccination
PubMed: 33275684
DOI: 10.1182/hematology.2020000117 -
The Indian Journal of Medical Research Apr 2019
Topics: Burkholderia pseudomallei; Female; Gram-Negative Bacteria; Humans; Liver; Magnetic Resonance Imaging; Melioidosis; Spleen; Young Adult
PubMed: 31411183
DOI: 10.4103/ijmr.IJMR_2018_17 -
Journal of Leukocyte Biology Oct 2021The spleen is a complex secondary lymphoid organ that plays a crucial role in controlling blood-stage infection with Plasmodium parasites. It is tasked with sensing and... (Review)
Review
The spleen is a complex secondary lymphoid organ that plays a crucial role in controlling blood-stage infection with Plasmodium parasites. It is tasked with sensing and removing parasitized RBCs, erythropoiesis, the activation and differentiation of adaptive immune cells, and the development of protective immunity, all in the face of an intense inflammatory environment. This paper describes how these processes are regulated following infection and recognizes the gaps in our current knowledge, highlighting recent insights from human infections and mouse models.
Topics: Animals; Erythrocytes; Hematopoiesis; Humans; Immunity; Malaria; Plasmodium; Spleen
PubMed: 33464668
DOI: 10.1002/JLB.4RI1020-713R -
Journal of Visceral Surgery Aug 2016The spleen and pancreas are at risk for injury during abdominal trauma. The spleen is more commonly injured because of its fragile structure and its position immediately... (Review)
Review
The spleen and pancreas are at risk for injury during abdominal trauma. The spleen is more commonly injured because of its fragile structure and its position immediately beneath the ribs. Injury to the more deeply placed pancreas is classically characterized by discordance between the severity of pancreatic injury and its initial clinical expression. For the patient who presents with hemorrhagic shock and ultrasound evidence of major hemoperitoneum, urgent "damage control" laparotomy is essential; if splenic injury is the cause, prompt "hemostatic" splenectomy should be performed. Direct pancreatic injury is rarely the cause of major hemorrhage unless a major neighboring vessel is injured, but if there is destruction of the pancreatic head, a two-stage pancreatoduodenectomy (PD) may be indicated. At open laparotomy when the patient's hemodynamic status can be stabilized, it may be possible to control splenic bleeding without splenectomy; it is always essential to search for injury to the pancreatic duct and/or the adjacent duodenum. Pancreatic contusion without ductal rupture is usually treated by drain placement adjacent to the injury; ductal injuries of the pancreatic body or tail are treated by resection (distal pancreatectomy with or without splenectomy), with generally benign consequences. For injuries of the pancreatic head with pancreatic duct disruption, wide drainage is usually performed because emergency PD is a complex gesture prone to poor results. Postoperatively, the placement of a ductal stent by endoscopic retrograde catheterization may be decided, while management of an isolated pancreatic fistula is often straightforward. Non-operative management is the rule for the trauma victim who is hemodynamically stable. In addition to the clinical examination and conventional laboratory tests, investigations should include an abdominothoracic CT scan with contrast injection, allowing identification of all traumatized organs and assessment of the severity of injury. In this context, non-operative management (NOM) has gradually become the standard as long as the patient remains hemodynamically stable and there is no suspicion of injury to hollow viscera, with the patient being carefully monitored on a surgical service. The development of arteriography with splenic artery embolization has increased the rate of splenic salvage; this can be performed electively based on specific indications (blush on CT, pseudoaneurysm, arteriovenous fistula), and may also be considered for severe splenic injury, abundant hemoperitoneum, or severe polytrauma. For pancreatic injury, in addition to CT scan, magnetic resonance pancreatography (MRCP) or even endoscopic retrograde cholangiopancreatography (ERCP) may be necessary to identify a ductal rupture. If the pancreatic duct is intact, laboratory and CT imaging surveillance is performed just as for splenic injury. In case of pancreatic ductal injury, ERCP stenting can be considered. However, if this is unsuccessful, the therapeutic decision can be difficult: while NOM can still be successful, complications may arise that are difficult to treat while distal pancreatectomy, although initially more agressive may avoid these complications if performed early.
Topics: Abdominal Injuries; Angiography; Embolization, Therapeutic; Hemoperitoneum; Humans; Infections; Laparotomy; Pancreas; Pancreaticoduodenectomy; Postoperative Complications; Spleen; Splenectomy
PubMed: 27402320
DOI: 10.1016/j.jviscsurg.2016.04.005 -
Frontiers in Cellular and Infection... 2018The spleen is a secondary lymphoid organ responsible for immune surveillance against blood-circulating pathogens. Absence of the spleen is associated with increased... (Review)
Review
The spleen is a secondary lymphoid organ responsible for immune surveillance against blood-circulating pathogens. Absence of the spleen is associated with increased susceptibility to systemic spread and fatal infection by different pathogens. Severe forms of visceral leishmaniasis are associated with disorganization of spleen compartments where cell interactions essential for splenic immunological function take place. White pulp atrophies, secondary lymphoid follicles and marginal zones vanish, and the boundaries separating white and red pulp blur. Leukocyte populations are reduced or disappear or are replaced by plasma cells. In this paper, we review the published data on spleen disorganization in severe forms of visceral leishmaniasis and propose a histological classification to help the exchange of information among research groups.
Topics: Animals; Chronic Disease; Humans; Leishmania infantum; Leishmaniasis, Visceral; Leukocytes; Spleen
PubMed: 30483481
DOI: 10.3389/fcimb.2018.00394 -
PLoS Medicine May 2021A very large biomass of intact asexual-stage malaria parasites accumulates in the spleen of asymptomatic human individuals infected with Plasmodium vivax. The mechanisms...
BACKGROUND
A very large biomass of intact asexual-stage malaria parasites accumulates in the spleen of asymptomatic human individuals infected with Plasmodium vivax. The mechanisms underlying this intense tropism are not clear. We hypothesised that immature reticulocytes, in which P. vivax develops, may display high densities in the spleen, thereby providing a niche for parasite survival.
METHODS AND FINDINGS
We examined spleen tissue in 22 mostly untreated individuals naturally exposed to P. vivax and Plasmodium falciparum undergoing splenectomy for any clinical indication in malaria-endemic Papua, Indonesia (2015 to 2017). Infection, parasite and immature reticulocyte density, and splenic distribution were analysed by optical microscopy, flow cytometry, and molecular assays. Nine non-endemic control spleens from individuals undergoing spleno-pancreatectomy in France (2017 to 2020) were also examined for reticulocyte densities. There were no exclusion criteria or sample size considerations in both patient cohorts for this demanding approach. In Indonesia, 95.5% (21/22) of splenectomy patients had asymptomatic splenic Plasmodium infection (7 P. vivax, 13 P. falciparum, and 1 mixed infection). Significant splenic accumulation of immature CD71 intermediate- and high-expressing reticulocytes was seen, with concentrations 11 times greater than in peripheral blood. Accordingly, in France, reticulocyte concentrations in the splenic effluent were higher than in peripheral blood. Greater rigidity of reticulocytes in splenic than in peripheral blood, and their higher densities in splenic cords both suggest a mechanical retention process. Asexual-stage P. vivax-infected erythrocytes of all developmental stages accumulated in the spleen, with non-phagocytosed parasite densities 3,590 times (IQR: 2,600 to 4,130) higher than in circulating blood, and median total splenic parasite loads 81 (IQR: 14 to 205) times greater, accounting for 98.7% (IQR: 95.1% to 98.9%) of the estimated total-body P. vivax biomass. More reticulocytes were in contact with sinus lumen endothelial cells in P. vivax- than in P. falciparum-infected spleens. Histological analyses revealed 96% of P. vivax rings/trophozoites and 46% of schizonts colocalised with 92% of immature reticulocytes in the cords and sinus lumens of the red pulp. Larger splenic cohort studies and similar investigations in untreated symptomatic malaria are warranted.
CONCLUSIONS
Immature CD71+ reticulocytes and splenic P. vivax-infected erythrocytes of all asexual stages accumulate in the same splenic compartments, suggesting the existence of a cryptic endosplenic lifecycle in chronic P. vivax infection. Findings provide insight into P. vivax-specific adaptions that have evolved to maximise survival and replication in the spleen.
Topics: Adolescent; Adult; Asymptomatic Infections; Female; Humans; Indonesia; Malaria, Vivax; Male; Middle Aged; New Guinea; Plasmodium vivax; Prospective Studies; Reticulocytes; Spleen; Splenectomy; Young Adult
PubMed: 34038413
DOI: 10.1371/journal.pmed.1003632 -
Annals of Surgery Mar 1994
Topics: Humans; Infections; Spleen; Splenectomy
PubMed: 8147603
DOI: 10.1097/00000658-199403000-00001 -
Revista Do Colegio Brasileiro de... Jul 2018Trauma is a public health problem and the most common cause of death in people under the age of 45. In blunt abdominal trauma, the spleen is the most commonly injured... (Review)
Review
Trauma is a public health problem and the most common cause of death in people under the age of 45. In blunt abdominal trauma, the spleen is the most commonly injured organ. Splenectomy remains the most common treatment, especially in high-grade lesions, despite increased nonoperative treatment. Removal of the spleen leads to increased susceptibility to infections due to its role in the immune function. Postsplenectomy sepsis is an important complication and presents a high mortality rate. Patients undergoing splenectomy should be immunized for encapsulated germs, as these are the agents most commonly associated with such infections. Splenic autotransplantation is a simple procedure, which can be an alternative to reduce infection rates consequent to total splenectomy, and reduce costs related to hospitalizations. This review aims to provide evidence-based information on splenic autotransplantation and its impact on the prognosis of patients undergoing total splenectomy. We searched the Cochrane Library, Medline/PubMed, SciELO and Embase, from January 2017 to January 2018 and selected articles in English and Portuguese, dated from 1919 to 2017. We found that the adjusted risk of death in splenectomized patients is greater than that of the general population, and when total splenectomy is performed, splenic autotransplantation is the only method capable of preserving splenic function, avoiding infections, especially postsplenectomy sepsis. Health professionals should be familiar with the consequences of the method chosen to manage the patient suffering from splenic trauma.
Topics: Humans; Infections; Medical Illustration; Postoperative Complications; Risk Factors; Spleen; Splenectomy; Transplantation, Autologous
PubMed: 29995152
DOI: 10.1590/0100-6991e-20181850 -
The American Journal of Pathology Aug 2016The effects of HIV infection on spleen and its cellular subsets have not been fully characterized, particularly for macrophages in which diverse populations exist. We...
The effects of HIV infection on spleen and its cellular subsets have not been fully characterized, particularly for macrophages in which diverse populations exist. We used an accelerated SIV-infected macaque model to examine longitudinal effects on T-cell and macrophage populations and their susceptibilities to infection. Substantial lymphoid depletion occurred, characterized by follicular burn out and a loss of CD3 T lymphocytes, which was associated with cellular activation and transient dysregulations in CD4/CD8 ratios and memory effector populations. In contrast, the loss of CD68 and CD163(+)CD68(+) macrophages and increase in CD163 cells was irreversible, which began during acute infection and persisted until terminal disease. Mac387 macrophages and monocytes were transiently recruited into spleen, but were not sufficient to mitigate the changes in macrophage subsets. Type I interferon, M2 polarizing genes, and chemokine-chemokine receptor signaling were up-regulated in spleen and drove macrophage alterations. SIV-infected T cells were numerous within the white pulp during acute infection, but were rarely observed thereafter. CD68, CD163, and Mac387 macrophages were highly infected, which primarily occurred in the red pulp independent of T cells. Few macrophages underwent apoptosis, indicating that they are a long-lasting target for HIV/SIV. Our results identify macrophages as an important contributor to HIV/SIV infection in spleen and in promoting morphologic changes through the loss of specific macrophage subsets that mediate splenic organization.
Topics: Animals; Immunohistochemistry; In Situ Hybridization; Macaca nemestrina; Macrophages; Oligonucleotide Array Sequence Analysis; Simian Acquired Immunodeficiency Syndrome; Spleen; T-Lymphocytes
PubMed: 27322772
DOI: 10.1016/j.ajpath.2016.03.019 -
Frontiers in Immunology 2020(Mtb) infects alveolar macrophages (AMs), causing pulmonary tuberculosis (PTB), the most common form of the disease. Less frequently, Mtb is disseminated to many other...
(Mtb) infects alveolar macrophages (AMs), causing pulmonary tuberculosis (PTB), the most common form of the disease. Less frequently, Mtb is disseminated to many other organs and tissues, resulting in different extrapulmonary forms of TB. Nevertheless, very few studies have addressed the global mRNA response of human AMs, particularly from humans with the active form of the disease. Strikingly, almost no studies have addressed the response of human extrapulmonary macrophages to Mtb infection. In this pilot study, using microarray technology, we examined the transcriptomic response of AMs from PTB patients (AMTBs) and AMs from control subjects (AMCTs) infected with two clinical isolates of Mtb. Furthermore, we also studied the infection response of human splenic macrophages (SMs) to Mtb isolates, as a model for extrapulmonary infection, and compared the transcriptomic response between AMs and SMs. Our results showed a striking difference in global mRNA profiles in response to infection between AMs and SMs, implicating a tissue-specific macrophage response to Mtb.
Topics: Adult; Case-Control Studies; Female; Gene Expression Profiling; Gene Regulatory Networks; Host Microbial Interactions; Humans; Macrophages, Alveolar; Male; Middle Aged; Mycobacterium tuberculosis; Pilot Projects; RNA, Messenger; Spleen; Transcriptome; Tuberculosis, Pulmonary; Young Adult
PubMed: 32373118
DOI: 10.3389/fimmu.2020.00630