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Toxic Shock Syndrome and Other Related Severe Infections
Published in Botros Rizk, A. Mostafa Borahay, Abdel Maguid Ramzy, Clinical Diagnosis and Management of Gynecologic Emergencies, 2020
The pathogenesis resulting from invasive GAS infections is due to virulence factors associated with this microorganism. These factors enable GAS to attach to the host tissue, evade the immune response, and spread by penetrating host tissue layers. There are several virulence factors, all of which have unique pathologic features that result in invasive disease [124]. However, of these factors, M protein is considered the major somatic virulence factor. This protein allows GAS to adhere to endothelium of blood vessels, causing vascular leakage and hypercoagulability. Even with treatment, this protein can cause DIC, multiorgan failure, and death. In addition, M protein resists the human immune response by preventing macrophage phagocytosis. It is not clear why some patients with GAS progress to widespread disseminated invasive disease while others do not. With the right environment and specific trigger, such as surgery or a vaginal laceration after a delivery, GAS can release its virulence factors and quickly progress to an acute highly lethal state.
Multiple Myeloma
Published in Pat Price, Karol Sikora, Treatment of Cancer, 2020
The diagnosis of myeloma is usually made by the demonstration of a monoclonal protein (M-protein/paraprotein) in the serum or urine and/or lytic lesions on X-ray/cross-sectional imaging together with an increased number of plasma cells in the bone marrow. The definition of myeloma was given by the IMWG in 2014 (Table 31.2). There are many other conditions in which an M-protein may be present (MGUS, AL amyloidosis, plasmacytoma, any B cell non-Hodgkin lymphoma, chronic lymphocytic leukemia, connective tissue disorders). An IgM monoclonal protein is usually associated with Waldenstroms macroglobulinemia or IgM MGUS, although rare cases of IgM myeloma do occur.
The Non-Hodgkin’s Lymphomas and Plasma Cell Dyscrasias
Published in Harold R. Schumacher, William A. Rock, Sanford A. Stass, Handbook of Hematologic Pathology, 2019
Lynne V. Abruzzo, L. Jeffrey Medeiros
Most patients with MGUS have an M-protein on serum electrophoresis that ranges in amount from 0.3 to 3 g/dL, rarely higher. A minority have free light chain in the urine, usually less than 1 g/24 hr. The M-protein is usually IgG, but may be IgM or IgA; the light chain may be either k or λ. Polyclonal serum immunoglobulins are usually present in normal amounts, but may be decreased in up to one-third of patients. Blood counts are normal, although rouleaux may be seen. About half of patients with MGUS have slightly increased numbers of plasma cells in the bone marrow, less than 10%. The plasma cells are morphologically normal and may be scattered through the marrow or in small clusters, usually adjacent to blood vessels, Immunohistochemical stains show a polyclonal plasmacytosis in most cases; a minority of cases are monoclonal.
Targeting viral proteins for restraining SARS-CoV-2: focusing lens on viral proteins beyond spike for discovering new drug targets
Published in Expert Opinion on Drug Discovery, 2023
Tao Yang, Si Chun Wang, Linyan Ye, Yasen Maimaitiyiming, Hua Naranmandura
The membrane glycoprotein (M protein), the most abundant protein in the coronavirus virion, exhibits multiple functions in the process of viral life cycle including viral modification, protein trafficking, virion assembly and secretion [115]. M protein also contributes to compromise the host innate immunity as an interferon antagonist [116]. The M protein of SARS-CoV-2 is a 222-amino acid protein that shares 90.5% sequence identity with the M protein of SARS-CoV [117]. It contains three domains, namely, a short N-terminal domain, a triple transmembrane domain and a longer C-terminal domain (Figure 2(g)). The M protein related assembly process includes multiple steps: first, the M protein self-associates and is mainly localized in the ER and Golgi apparatus; second, the M protein interacts with the N protein and forms a complex in Golgi or ER-Golgi compartment, enabling further binding of viral RNA to the N protein [112]; third, the M protein recruits spike protein and other factors to enable viral release and budding process.
Ravaging SARS-CoV-2: rudimentary diagnosis and puzzling immunological responses
Published in Current Medical Research and Opinion, 2021
Tapan Kumar Mukherjee, Parth Malik, Radhashree Maitra, John R. Hoidal
The coronavirus genome remains the largest of all RNA viruses, comprising multiple ORFs, followed by the Nucleocapsid (N), Spike (S), Envelope (E) and Matrix (M) proteins (Figure 1)10. The S protein is divergent with less than 75% nucleotide sequence similarity to previously identified SARS-associated coronaviruses11. The N, E and M structural proteins are more conserved and are essential for virus survival. These proteins encase the RNA and are essential for budding, envelope formation and pathogenesis12–14. The M protein binds the nucleocapsid, facilitating viral assembly and generation of new virus particles. The E protein is implicated in morphogenesis, liberation, and pathogenesis while the S protein develops the homotrimeric spikes which recognize receptor(s) through which invasion to a potential host is mediated12,15,16. A notable aspect herein pertains to distinctive M protein prevalence in elongated and compact forms. While the former contributes to rigidity via acting on clustered spikes and a rather unconventional narrow membrane curvature domain, the latter regulates the flexibility and S protein interactions. The M protein regulates the virion size via interaction with S, N proteins and genomic RNA, facilitating their involvement in virus assembly12.
Sequential change in serum VEGF levels in a case of tocilizumab-resistant TAFRO syndrome treated effectively with rituximab
Published in Modern Rheumatology Case Reports, 2021
Risa Wakiya, Tomohiro Kameda, Yohei Takeuchi, Hiroki Ozaki, Shusaku Nakashima, Hiromi Shimada, Norimitsu Kadowaki, Hiroaki Dobashi
Laboratory examinations on admission yielded the following results (Table 1). He had decreased total protein (5.5 g/dl) and albumin (1.8 g/dl). His serum immunoglobulin (Ig) G level was 1,297 mg/dl, with no detectable M-protein. His serum complement level was within normal limits. Results for antinuclear, anti-double-stranded DNA, anti-ribonucleoprotein, anti-Smith, anti-Sjögren’s syndrome antigen (SS)-A and SS-B antibodies were negative. Proteinase 3 antineutrophil cytoplasmic antibodies (ANCA) and myeloperoxidase ANCA were not elevated. The platelet-associated IgG (PAIgG) level was 47.7 ng/107 cells. The lupus anticoagulant ratio was 1.86, and the anticardiolipin antibody, thyroglobulin antibody and thyroid peroxidase antibody levels were 69.4, 101.0 and 540.2 IU/ml, respectively. Thyroid-stimulating hormone was 10.01 µIU/ml and soluble IL-2 receptor (sIL-2R) was 2,130 U/ml, both of which were high. His serum IL-6 and plasma VEGF levels were elevated at 14.4 and 161 pg/ml. IL-6 and VEGF levels in ascites (3540 and 444 pg/ml, respectively) were higher than those in the serum and plasma. T-SPOT-TB and β-d-glucan test results were both negative. Moreover, PCR tests did not detect the presence of human herpes virus 8 in the patient’s blood (Table 1).