Question 1

What is the Meaning of HLA-B 15: 02?

Accepted Answer

HLA-B 15:02 denotes a specific allele of the Human Leukocyte Antigen B gene, a component of the Major Histocompatibility Complex Class I. This particular genetic variant encodes a protein found on the surface of most nucleated cells, playing a critical role in the immune system's ability to recognize self from non-self by presenting peptide fragments to T-lymphocytes.

Question 2

What is the Context of HLA-B 15: 02?

Accepted Answer

Within the human physiological landscape, HLA-B 15:02 functions as a cell surface glycoprotein, integral to immune surveillance. It operates within the adaptive immune system, where its primary biological environment is the cellular membrane, allowing it to interact directly with circulating T-cells. This interaction is fundamental for initiating targeted immune responses against intracellular pathogens or aberrant cells.

Question 3

What is the Significance of HLA-B 15: 02?

Accepted Answer

The clinical importance of HLA-B 15:02 is substantial due to its strong association with severe cutaneous adverse reactions (SCARs), notably Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN). For patients, particularly those of certain Asian ancestries, carriage of this allele significantly increases the risk of these life-threatening skin conditions when exposed to specific medications like carbamazepine. Recognizing this genetic predisposition allows clinicians to modify treatment strategies, thereby improving patient safety and overall health outcomes.

Question 4

What is the Mechanism of HLA-B 15: 02?

Accepted Answer

The mechanism by which HLA-B 15:02 exerts its effect involves aberrant drug presentation. Certain drugs or their metabolites, when administered, can bind non-covalently or covalently to the antigen-binding groove of the HLA-B 15:02 protein. This altered HLA-drug complex is then presented on the cell surface, mimicking a foreign antigen. Subsequently, specific cytotoxic T-lymphocytes recognize this complex as foreign, triggering an immune cascade that leads to widespread epidermal necrosis and severe systemic inflammation.

Question 5

What is the Application of HLA-B 15: 02?

Accepted Answer

In clinical practice, the presence of HLA-B 15:02 is primarily assessed through pharmacogenomic testing before initiating specific drug therapies. For instance, the US Food and Drug Administration (FDA) recommends screening for this allele in patients of Asian descent prior to prescribing carbamazepine. This pre-emptive genetic screening allows healthcare providers to identify at-risk individuals and select alternative medications, thereby mitigating the risk of severe adverse drug reactions and guiding personalized therapeutic approaches.

Question 6

What is the Metric of HLA-B 15: 02?

Accepted Answer

The determination of HLA-B 15:02 status is achieved through genetic testing. This diagnostic procedure typically involves collecting a blood sample or a buccal swab from the patient. Laboratory methods, such as polymerase chain reaction (PCR) or DNA sequencing, are then employed to identify the specific genetic sequence corresponding to the HLA-B 15:02 allele. The result is reported as positive or negative for the presence of this allele.

Question 7

What is the Risk of HLA-B 15: 02?

Accepted Answer

The primary clinical risk associated with HLA-B 15:02 is the elevated susceptibility to developing severe cutaneous adverse reactions, including SJS and TEN, upon exposure to specific drugs like carbamazepine, oxcarbazepine, and phenytoin. Improper application involves prescribing these medications to individuals known to carry the allele without considering the heightened risk. Mismanagement includes a failure to screen high-risk populations or overlooking the established guidelines for pharmacogenetic testing, which can lead to severe, potentially fatal, dermatological and systemic complications.

HLA-B 15: 02

Meaning

Context

Significance

Mechanism

Application

Metric

Risk

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