Haematology and the immune system: Understanding the link between blood disorders and immunity

Haematology, the study of blood, plays a crucial role in understanding the body’s immune system. Blood is not just responsible for transporting oxygen and nutrients; it also serves as a critical component of our defense mechanism against infections, diseases, and other threats.

The link between haematology and the immune system becomes particularly significant when examining blood disorders and how they can impact immunity. In this article, revered consultant haematologist, Dr Vishal Jayakar, delves further into the relationship between blood disorders and the immune system. 

Blood consists of several vital components, including red blood cells, white blood cells, platelets, and plasma. Among these, white blood cells (WBCs) are the most essential to the immune response. They include different types such as neutrophils, lymphocytes (including B and T cells), monocytes, and eosinophils, each playing a unique role in identifying and attacking foreign invaders like bacteria, viruses, and other harmful microorganisms.

A well-functioning immune system relies on healthy white blood cells to maintain a balance between fighting off infections and preventing harmful inflammation or autoimmune reactions. However, when blood disorders arise, this balance can be disrupted, leading to weakened immunity or an overactive immune response.

One example of a blood disorder affecting the immune system is leukaemia, a type of cancer that originates in the bone marrow where blood cells are produced. In leukemia, the body generates abnormal white blood cells, impairing the immune system’s ability to defend against infections. Another condition, anaemia, particularly when caused by nutritional deficiencies or chronic diseases, can weaken the body’s immune response, making it harder to fight infections.

Autoimmune diseases like lupus also highlight the interplay between haematology and immunity. In lupus, the immune system mistakenly attacks healthy blood cells, leading to anaemia, clotting issues, or even low platelet counts (thrombocytopenia), which can cause a range of symptoms and complications.

Understanding the link between haematology and the immune system allows medical professionals to better diagnose and treat blood disorders while addressing the immune system's role. Continued research into this connection offers hope for improved treatments, early interventions, and better management of both blood disorders and immune-related conditions.