**Question:** Major signs included by WHO for AIDS diagnosis -

A. Persistent generalized lymphadenopathy
B. Weight loss
C. Atypical lymphocyte count
D. Skin lesions

**Core Concept:** AIDS (Acquired Immunodeficiency Syndrome) is a severe stage of HIV (Human Immunodeficiency Virus) infection, characterized by damage to the immune system, leading to opportunistic infections and malignancies. The World Health Organization (WHO) has defined a set of criteria for AIDS diagnosis.

**Why the Correct Answer is Right:**

The correct answer, A, refers to a persistent enlargement of lymph nodes (lymphadenopathy) in multiple regions of the body, often accompanied by pain and tenderness. This is one of the key features of AIDS, as the virus causes a significant decline in CD4+ T-cells, leading to the enlargement of lymph nodes as the body's immune response becomes exhausted.

**Why Each Wrong Option is Incorrect:**

Option B (weight loss) is a significant symptom in AIDS patients, but it is not specific to AIDS diagnosis. Weight loss can be due to various reasons like anorexia, malabsorption, or infections.

Option C (atypical lymphocyte count) refers to a change in the type and function of lymphocytes, particularly the decreased CD4+ T-cell count. This is not a major diagnostic criterion for AIDS but rather a supportive finding.

Option D (skin lesions) is not a major criterion for AIDS diagnosis. While skin lesions can occur in AIDS patients due to opportunistic infections or tumors, they are not essential for diagnosing AIDS.

**Clinical Pearl:** AIDS diagnosis primarily relies on symptoms, signs, and laboratory findings confirming a low CD4+ T-cell count, typically <200 cells per microliter or <14% of total lymphocytes. However, the combination of specific symptoms, including lymphadenopathy, weight loss, and opportunistic infections, can lead to a clinical suspicion of AIDS, initiating further diagnostic tests and confirmatory investigations.