Pernicious Anemia

Posted: January 5th, 2023

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Abstract

Over the recent past, there has been a rise in the pernicious anemia associated with Vitamin B. 12. Vitamin B. 12 is essential for the manufacture of the red blood cells in the body; hence the deficiency interferes with normal body function. This paper, in relation to a  case study involving Teri suffering from Pernicious anemia, will address the parietal cell destruction, the correlation between parietal cell destruction and vitamin B. 12 destruction, lack of pepsin as in the case of Teri, and illustration of the normal healthy Red Blood Cells (RBC). The paper will also expound on the hematocrit, how oxygen levels create RBCs and protein transportation of oxygen in the body. The report will further detail cells secreting the antibodies and their functions in addition to the illustration of the different types of immunoglobulins and the structure of immunoglobulin.

Pernicious Anemia

Parietal Cell Destruction

Vitamin B.12 is associated with Pernicious anemia, whereby the loss of parietal cells leads to the reduction in gastric acid secretion in the body and essential for the inorganic iron. Therefore, since Teri is experiencing Parietal destruction, she is suffering from iron deficiency.

Correlation between the Destruction of Parietal Cells and Vitamin B 12 Deficiency

The various individuals who have been diagnosed with pernicious anemia have been diagnosed with a reduction in Vitamin B12 levels. The stomach acidic environment determines the vitamin B12 release from the dietary protein-bound form. Gastric parietal cell mass loss culminates in the hypochlorhydria as well as the reduction in the absorption of Vitamin B 12 into the body. The various instances of intrinsic factor production have also been associated with vitamin B 12 deficiency in the body (Melo et al., 2021). The multiple individuals diagnosed with pernicious anemia have been documented to present increased chances of gastric carcinoid tumors as well as adenocarcinoma, attributed to hypochlorhydria. The hypochlorhydria, which has been linked to pernicious anemia, culminates in the hyperplasia of the various G cells alongside hypergastrinemia within the body.

Lack of Pepsin

Pepsin is an essential product in the body upon absorption into the bloodstream. It aids in the breakdown of the larger, partially digested, and fragments of proteins absorbed by the body on the small intestine (Melo et al., 2021). The breakdown of the protein-bound state is thus aided when the protein concentration is high; hence low pepsin leads to reduced protein fragments which can be broken down to release Vitamin B. 12 in which Teri is lacing.

Red Blood Cells

The red blood cells are also described as erythrocytes and constitute the predominant type of cells within a blood smear. The shape of healthy red blood cells is described as biconcave but with a flattened center on both sides, which assumes the form of shallow bowl-like indentations (Seo et al., 2019). The shape is also supported by the theoretical framework, which includes the bending energy as well as elasticity. The biconcave shape is uniform, with the size being approximately 7.2 microns lacing any organelles as well as granules (Seo et al., 2019). Erythropoietin production from the kidney helps in the regulation of red blood cell production. 

Hematocrit

Hematocrit is also described as a packed-cell (PCV) volume test, usually carried out as a blood test. The test is used as a measure of the red blood cell proportion within the blood. The red blood cells function to distribute oxygen throughout the body; hence too few or higher proportion acts as an indication of a particular disease.

Red Blood Cell Production

Hypoxia is the condition in which oxygen is a delimiting factor in the body. It induces an increase in the erythropoietin levels hence stimulating the mature RBCs production within the bone marrow (Seo et al., 2019). In response to the hypoxia, the RBCs, through the Oxygen-dependent metabolic control, entail the competitive attachment with the deoxyhemoglobin and glycolytic enzymes to the N-terminal cytosolic domains of the band.

Oxygen Transportation

The protein hemoglobin molecule usually carries out oxygen transportation throughout the body. The hemoglobin molecule is composed of four various building frameworks, with each containing a heme group as well as a globin chain (Choudhury, 2018). The heme group subunit posses a porphyrin ring containing an iron atom that is centrally located. The hemoglobin structure is described as quaternary, consisting of two proteins, α and β chains with 141 and 146 amino acids (Choudhury, 2018). The heme molecule acts as a covalent link between each of the subunits.

Anti-bodies

The white blood cells, described explicitly as B-lymphocytes, perform the primary production of the white blood cells. Upon binding the antigen to the B-Cell surface, stimulation of the B-cell division and maturity constitute the identical cells commonly referred to as clones (Chiu et al., 2019). The mature B-cells are commonly referred to as plasma cells and are usually tasked with the secretion of antibodies into the bloodstream as well as the lymphatic system.

Functions

The antibodies perform the function of neutralization of the infectivity as well as toxins. This occurs whenever the antibodies are discharged into the blood as well as mucosa s. They block the infectivity region of the pathogens hence inactivating any foreign pathogens and toxins. The neutralization is due to the interference of the organism’s attachment to the various host sites.

The antibodies act as facilitators to foreign substances through the opsonization process (Chiu et al., 2019). The process of internalization, as well as antibody-coated pathogen degradation, occurs through the aid of the macrophages and neutrophils, thereby leading to the foreign pathogen clearance in the FcRs. 

The antibodies are also vital in the complement-mediated lysis for the various pathogens as well as infected cells. This can be illustrated by activating the complement system by the antibodies such as IgM and IgG (Chiu et al., 2019). C3b, a primary byproduct aids in the binding to the various cells in the form of Ag-Ab complexes.

 The transcytosis process is achieved through the IgA moving along the epithelial cells in the secretory. The IgA, however, travels across the mucosal surfaces of respiratory, gastrointestinal as well as urogenital tracts within the body (Chiu et al., 2019). The IgG in mammals can cross via a placental barrier, hence the mother’s antibody repertoire’s conference, thus protecting the fetus from the pathogens. Therefore, this constitutes passive immunization, which takes place during the gestation period.

Types of Anti-bodies

There are five types of antibodies swerving different functions. IgG is the most profuse within the plasma and can transference to the fetus via the placenta for passive immunity until the baby develops its immune system to function. IgM accounts for 10% of the total human immunoglobulins and assumes the pentameric structure where the Y-shaped molecules are lined together (Chiu et al., 2019). This structure explains the higher avidity as compared to IgG though it has a lower affinity for antigens. IgA is highly abundant within the serum, nasal mucus, and saliva, accounting for 10-15% of the human immunoglobulins. It is constituted of the dimer that is a combination of two-lined IgA. IgA offers the neonates protection from pathogens in the gastrointestinal tract. IgE occurs in minute proportions and primarily provides protection against the parasites (Chiu et al., 2019). IgD also accounts for 1% of the human immunoglobulin and is thus tasked with the induction of antibody production within B cells.

Immunoglobulin Structure

Immunoglobulins are defined as heterodimeric proteins which are comprised of both heavy and light chain pairs in structure. The chains are separable on functionality, variable domains that bind the antigens, and constant domains specifying the various effector significance (Nezlin, 2019). These effector significances include the initiation of both complement and attachment onto the Fc receptors. The variable realms are constructed through a composite sequence of gene reorganization; hence, subjected to somatic hypermutation following the antigen exposure. Nezlin (2019) affirms that the variable domain is divided into three sub-regions; complementary determining regions (CDRs) and four framework regions (FRs). The 3 CDRs of the H chain are attached to three CDRs of the L chain to constitute the antigen-binding site. IgM, IgA, IgG, IgE, as well as IgD form of the Heavy chain C domains.

References

Chiu, M. L., Goulet, D. R., Teplyakov, A., & Gilliland, G. L. (2019). Antibody structure and function: the basis for engineering therapeutics. Antibodies, 8(4), 55.

Choudhury, R. (2018). Hypoxia and hyperbaric oxygen therapy: a review. International journal of general medicine, 11, 431.

Melo, T., dos Santos, L. R., Martins, P., & Vilas, A. P. (2021). A case of vitamin B12 deficiency with some unusual features. European Journal of Medical Case Reports, 5(1), 1-3.

Nezlin, R. (2019). Dynamic aspects of the immunoglobulin structure. Immunological investigations, 48(8), 771-780.

Seo, Y., Shin, K. H., Kim, H. H., & Kim, H. S. (2019). Current advances in red blood cell generation using stem cells from diverse sources. Stem cells international, 2019.