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The Inducible System: Antigens
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Vertebrates are large, complex multicellular animals. They are colonies of cells, the individual cells of which are highly integrated and tightly controlled. The defense against an invader can only occur if this system of cells can distinguish the invader from itself. The ability to distinguish between self and the invader and then to take action against the foreign agent alone is the measure of immunocompetence. As parasites are constructed of proteins, lipids, carbohydrates, and nucleic acids, just like their hosts, recognition of the parasite as foreign depends on the recognition of fine points of difference between the molecules of the parasite and the host.
AIDS-Related Malignancy
Published in Pat Price, Karol Sikora, Treatment of Cancer, 2020
Mark Bower, Elena Gervasi, Alessia Dalla Pria
Primary central nervous system lymphoma (PCL) is defined as non-Hodgkin lymphoma (NHL) that is confined to the cranio-spinal axis without systemic involvement. This diagnosis is rare in immunocompetent patients but occurs more frequently in patients with both congenital and acquired immunodeficiency. Since 1985 high-grade B-cell NHL including PCL has been an AIDS-defining diagnosis. AIDS-related PCL occurs equally frequently across all ages and transmission risk groups. A meta-analysis of cohort studies has shown a significant decline in the incidence of PCL following the introduction of highly active antiretroviral therapy (HAART) (relative risk 0.42)30 which is attributed to the protective effects of HAART.31
Non-Resolving Pneumonia
Published in Firza Alexander Gronthoud, Practical Clinical Microbiology and Infectious Diseases, 2020
In immunocompetent individuals without comorbidities, clinical improvement is relatively rapid and precedes radiographic improvement. It may take several days for the temperature to completely settle, with a minority remaining febrile beyond 20 days. Clinical improvement is delayed in severe presentation, multilobar disease and infection with drug-resistant organisms.Radiographic improvement is often much slower, with 20%–30% of patients demonstrating no radiographic improvement after one week. Initial worsening of the chest radiograph is common. Risk factors for delayed radiographic resolution include bacteraemia, persistent fever or leucocytosis beyond 6 days, advanced age, chronic obstructive pulmonary disease, alcoholism and HIV.Radiographic clearing occurs by 1–3 months in nonbacteraemic cases and 3–5 months in bacteraemic cases. Residual radiographic abnormalities are rare in nonbacteraemic cases but are present in up to 35% of bacteraemic cases.
Expert review of global real-world data on COVID-19 vaccine booster effectiveness and safety during the omicron-dominant phase of the pandemic
Published in Expert Review of Vaccines, 2023
Rontgene Solante, Carlos Alvarez-Moreno, Erlina Burhan, Suwat Chariyalertsak, Nan-Chang Chiu, Sunate Chuenkitmongkol, D. V. Dung, Kao-Pin Hwang, Javier Ortiz Ibarra, Sasisopin Kiertiburanakul, Prasad S. Kulkarni, Christopher Lee, Ping-Ing Lee, Rommel Crisenio Lobo, Alejandro Macias, Cao Huu Nghia, Anna Lisa Ong-Lim, Alfonso J. Rodriguez-Morales, Rosana Richtmann, Marco Aurélio Palazzi Safadi, Hindra Irawan Satari, Guy Thwaites
To formulate the optimal vaccination strategy, decision-makers need sufficient data on VE in higher risk populations (e.g. the elderly, those with comorbidities, immunocompromised) that may need to be prioritized. One systematic review and meta-analysis [101] of eleven vaccines (including mRNA-1273, BNT162b2, AZD1222, Ad26.COV2.S, CoronaVac, and BBIBP-CorV) found that VE was 59.7% (95%CI: 45.00, 70.40) in older adults. Another review [102] of BNT162b2, mRNA-1273, Ad26.COV2.S and AZD1222 in immunocompromised groups found a wide range in VE – 64% to 90% against infection, 73% to 84% against symptomatic disease, 70% to 100% against severe disease, and 63% to 100% against hospitalizations. Of note, VE in immunocompromised populations was usually lower than in immunocompetent populations, and importantly, was not significantly influenced by age, vaccine type or time of evaluation, but varied considerably among immunocompromised patient subgroups [103].
Polybia occidentalis and Polybia fastidiosa venom: a cytogenotoxic approach of effects on human and vegetal cells
Published in Drug and Chemical Toxicology, 2021
Marcel José Palmieri, Amanda Ribeiro Barroso, Larissa Fonseca Andrade-Vieira, Marta Chagas Monteiro, Andreimar Martins Soares, Pedro Henrique Souza Cesar, Mariana Aparecida Braga, Marcus Vinicius Cardoso Trento, Silvana Marcussi, Lisete Chamma Davide
The immune system plays a major role in maintaining the body healthy, responding to invading microorganisms, macromolecules, neutralizing defective cells, and controlling cellular processes. In order to maintain immunocompetence, our organism relies on many compensatory mechanisms to avoid its impairment facing a toxic agent. Here, we evaluated the effect of two Polybia venoms upon whole blood nucleated cells (Baniyash 2006). Although the effects observed here are not specifically immunotoxic, they can lead to alterations in immune system functioning. These alterations could result in both immunosuppression or to an exaggeration in immune responses. Despite the compensatory mechanisms, there is no secure levels of such adverse effects for our healthy (Descotes 2006). Our concerns involved events which the individual are exposed to multiple stings at once, or exposed daily being often stinged. In these cases, the individuals would be more susceptible to infectious diseases, could present hypersensitivity reactions, and a immune system less consistent, besides the possibility of abnormal cell divisions occurring more frequently.
Mediastinal lymphadenopathy: a practical approach
Published in Expert Review of Respiratory Medicine, 2021
Hariharan Iyer, Abhishek Anand, PB Sryma, Kartik Gupta, Priyanka Naranje, Nishikant Damle, Saurabh Mittal, Neha Kawatra Madan, Anant Mohan, Vijay Hadda, Pawan Tiwari, Randeep Guleria, Karan Madan
Histoplasmosis is an endemic disease in certain regions of the United States of America with a wide range of clinical presentation, ranging from a self-limiting symptomatic flu-like illness to a progressively disseminated form of the disease. Although more common in immunocompromised individuals, it has been reported in immunocompetent individuals as well [16]. In acute histoplasmosis, there may be the presence of granulomatous mediastinal lymphadenopathy [17]. Usually, mediastinal adenitis due to histoplasmosis is asymptomatic; however, clinical features may be present due to compression of the mediastinal structures by the enlarged lymph nodes [18]. The usual course of such lymph nodes is shrinkage over time. However, rarely there may be excessive fibrosis during the healing phase, which may lead to the formation of a mediastinal granuloma or fibrosing mediastinitis [18].