Neurology — MCQs

Question 1: Which of the following is NOT associated with AIDS?

• A. Increased p 24 antibody
• B. Hypogammaglobulinemia (Correct Answer)
• C. Abnormal mitogen assay
• D. Anergy

Explanation: **Explanation:** In AIDS, the hallmark of the disease is the progressive depletion of CD4+ T-helper cells [1], leading to profound immune dysregulation. **Why Hypogammaglobulinemia is the Correct Answer:** Patients with AIDS typically exhibit **Hypergammaglobulinemia** (specifically polyclonal gammaglobulinemia), not hypogammaglobulinemia. This occurs because of chronic, non-specific B-cell activation. Although the B-cells are increased in number and produce high levels of immunoglobulins (IgG and IgA), they are functionally defective and fail to mount an effective antibody response to new antigens or vaccines. **Analysis of Incorrect Options:** * **A. Increased p24 antibody:** In the early stages of HIV infection (seroconversion), the body produces antibodies against the p24 capsid antigen [2]. While p24 *antigen* levels rise during acute infection and late-stage AIDS, p24 *antibodies* are characteristic of the asymptomatic phase. * **C. Abnormal mitogen assay:** Since T-cell function is severely compromised, there is a decreased proliferative response to mitogens (like Phytohemagglutinin/PHA). This is a classic laboratory finding in cellular immunodeficiency. * **D. Anergy:** This refers to the lack of a delayed-type hypersensitivity (DTH) response to common recall antigens (e.g., Tuberculin/PPD). It occurs due to the profound loss of effector T-cells [1]. **High-Yield NEET-PG Pearls:** * **CD4:CD8 Ratio:** In healthy individuals, the ratio is ~2:1. In AIDS, this ratio **inverts** to <1:1 [1]. * **B-cell paradox:** AIDS is characterized by high quantitative globulins but poor qualitative function (increased risk of infections by encapsulated bacteria like *S. pneumoniae*). * **Window Period:** The time between infection and the appearance of detectable antibodies (usually 2-12 weeks). The p24 antigen is the earliest marker detectable during this phase [2].