Therapeutic monoclonal antibodies (MAbs) — Identify the incorrect statement about clinical uses and disease areas.

Introduction / Context:
Monoclonal antibodies (MAbs) are versatile biologics used across oncology, autoimmunity, infectious disease, transplantation, and even endocrine-related conditions. The question tests awareness of the breadth of indications and the misconception that MAbs are limited to infections or cancer only.

Given Data / Assumptions:

• MAbs can be conjugated for imaging (tumor scanning) or engineered for therapy (naked, ADCs, radioimmunotherapy).
• Diagnostic, prognostic, and therapeutic uses span multiple specialties.
• Endocrine and metabolic disorders can involve MAbs (e.g., anti-PCSK9 for lipid disorders; antibodies targeting IGF-1 receptor pathways in research/therapy).

Concept / Approach:
Determine which statement artificially restricts MAb utility. Because MAbs are used beyond infectious diseases (e.g., Graves’ ophthalmopathy treatments, metabolic and lipid disorders), any claim that they “cannot be used” in non-infectious endocrine contexts is incorrect.

Step-by-Step Solution:

Verification / Alternative check:
Approved and investigational antibodies target endocrine axes or metabolic pathways, confirming cross-disciplinary applications.

Why Other Options Are Wrong:

• a/b/c/e: All describe legitimate applications of MAbs in modern medicine.

Common Pitfalls:
Assuming antibodies are only anti-infective or anti-tumor; in reality, modulation of signaling pathways by MAbs is broadly therapeutic.

Final Answer:
Monoclonal antibodies cannot be used in non-infectious diseases such as endocrine disorders.