You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["AnatomicalEntity"].

Please return the output as a JSON object of the format: {"AnatomicalEntity": ["tumor cells", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Novel mechanism for the impairment of cell proliferation in HIV-1 infection.
The synthesis of ribonucleotides is essential to cell proliferation. Defects in the relevant metabolic pathways have been demonstrated in stimulated T cells from AIDS patients and are associated with lymphocyte necrotic death. Here, Margarita Bofill and colleagues discuss the possibility that an impaired ribonucleotide metabolism might be common to all rapidly dividing cells and thus contribute to other recognized symptoms of HIV-1 infection.
{"AnatomicalEntity": ["cell", "lymphocyte", "cells", "T cells"]}