HLA is group of

Options

A. Proteins
B. Genes
C. Polypeptides
D. Chromosomes

Answer

### Step-by-Step Solution:

1. **Understanding HLA**: HLA stands for Human Leukocyte Antigen. It is a crucial component of the immune system in humans.

2. **HLA as a Gene Complex**: HLA is part of a gene complex known as the Major Histocompatibility Complex (MHC). This complex includes various genes that encode proteins essential for the immune response.

3. **Function of HLA**: The proteins produced by HLA genes are located on the surface of cells and play a vital role in regulating the immune system. They help the body recognize which cells are its own and which are foreign.

4. **HLA and Organ Transplants**: HLA is significant in organ transplantation because differences in HLA between the donor and recipient can lead to organ rejection. The immune system may attack the transplanted organ if it recognizes the HLA proteins as foreign.

5. **HLA and Autoimmune Diseases**: Mutations or variations in HLA genes can be associated with autoimmune diseases, where the immune system mistakenly attacks the body’s own cells.

6. **Conclusion**: Given the information, HLA is classified as a group of genes.

### Final Answer:
HLA is a group of genes.

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