### ITGB2 Gene Overview

**Gene Symbol:** ITGB2  
**Location:** Chromosome 21  
**Protein:** Integrin beta-2 (also known as CD18)

ITGB2 encodes the integrin beta chain that pairs with various alpha chains to form integrin heterodimers. Integrins are transmembrane receptors that facilitate cell adhesion and enable cells to communicate with their extracellular environment. ITGB2 plays a crucial role in the immune system, especially in leukocyte recruitment and adhesion.

### 1. Associated Genes
Beyond the associations mentioned in the summaries, ITGB2 is also implicated in relation to other genes such as:
- **ITGAL (CD11a):** Integrin alpha L that pairs with ITGB2 to form the LFA-1 integrin complex.
- **ITGAM (CD11b):** Integrin alpha M, pairing with ITGB2 to form complement receptor type 3 (CR3).
- **ITGAX (CD11c):** Integrin alpha X, associating with ITGB2 for function in macrophage and dendritic cell adhesion.
- **ITGAD (CD11d):** Integrin alpha D, also interacts with ITGB2, particularly in leukocyte functions.
- **ICAM (Intercellular Adhesion Molecules):** ITGB2 acts as a receptor for ICAM1, ICAM2, ICAM3, and ICAM4.

### 2. Aging and Age-Related Diseases
Research has implicated integrins, including ITGB2, in various aging processes and age-related diseases:
- **Inflammation:** Aging is often associated with chronic inflammation, known as “inflammaging,” where ITGB2 may contribute to increased leukocyte adhesion and migration, affecting tissue homeostasis and repair.
- **Immunosenescence:** This term describes the decline in immune function associated with aging, where defects in ITGB2 could influence adaptive immunity and increase susceptibility to infections.
- **Cardiovascular Diseases:** Altered integrin expression and function, including ITGB2, in older adults have been linked to the pathogenesis of atherosclerosis and thrombosis.
- **Cancer:** As integrins are involved in cell signaling and migration, their dysregulation, including ITGB2, may contribute to tumor metastasis, especially in the elderly population.

### 3. Drug Interactions
While specific drugs targeting ITGB2 directly are limited, the following classes may interact with pathways involving this gene or its protein product:
- **Monoclonal Antibodies:** Such as anti-integrin therapies (e.g., natalizumab) that target integrin pathways involved in immune modulation.
- **Anti-inflammatory Drugs:** Non-steroidal anti-inflammatory drugs (NSAIDs) may indirectly affect integrin activity by modulating immune responses.
- **Immunosuppressive Agents:** Drugs like corticosteroids that influence immune cell activity and may affect integrin-mediated interactions.

### 4. Pathways and Biological Processes
ITGB2 is involved in several critical biological processes and pathways, including:
- **Leukocyte Adhesion:** ITGB2 is integral to the adhesion and migration of leukocytes during immune responses.
- **Complement Activation Pathways:** It interacts with the complement proteins iC3b and factor X, facilitating opsonization and clearance of pathogens.
- **Cell-Matrix Adhesion:** Contributes to the ability of leukocytes to adhere to extracellular matrix components during tissue infiltration.
- **Signaling Pathways:** Involves several signaling cascades like those initiated by PTK2B (PYK2) during neutrophil transmigration.
- **Apoptotic Cell Clearance:** Plays a role in the phagocytosis of apoptotic cells, particularly in resolving inflammation.

In summary, ITGB2 is a vital component of the immune response, with implications in aging and several diseases, underscoring its importance in both health and pathological states.