**Question:** True regarding anaemia of chronic diseases are A/E -

A. Reduced erythropoietin production
B. Decreased number of red blood cells (RBCs)
C. Increased destruction of RBCs
D. Increased RBC life span

**Core Concept:** Anaemia of chronic diseases (ACD) is a type of anaemia that occurs as a consequence of persistent inflammation or tissue injury. It is characterized by a decrease in RBC production due to various mechanisms.

**Why the Correct Answer is Right:** In ACD, erythropoietin (EPO) is reduced due to the negative feedback mechanism. When there is chronic inflammation or tissue injury, cytokines like interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) are released. These cytokines suppress EPO production by the kidneys, leading to decreased RBC production.

**Why Each Wrong Option is Incorrect:**

A. Decreased number of red blood cells (RBCs): Although ACD results in reduced RBC production, it does not directly affect the number of RBCs in the blood as they are already present.

B. Increased RBC life span: ACD does not increase RBC life span. Instead, it results in a compensatory mechanism where RBCs are more resistant to destruction, leading to reduced haemolysis and thus, a decrease in circulating RBC count.

C. Increased destruction of RBCs: ACD does not cause an increased destruction of RBCs. Instead, it is characterized by a decreased production of new RBCs, resulting in a lower overall RBC count.

**Increased RBC life span** is not a correct answer because it is not a defining feature of ACD. Instead, ACD results in a decrease in circulating RBC count due to decreased erythropoiesis (red blood cell production) and the compensatory mechanism of increased RBC resistance to destruction. This helps to differentiate ACD from other types of anaemia where increased RBC destruction is a primary feature.