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Normal human lymph node T follicular helper cells and germinal center B cells accessed via fine needle aspirations

Germinal centers (GC) are critically important for the maturation of the antibody response and the generation of memory B cells, which are the basis for long-term protection from pathogens. Germinal centers only occur in lymphoid tissue, such as lymph nodes, and are not present in blood. Therefore, cells of the germinal center, including GC B cells and GC T follicular helper (TFH) cells, are not well-studied in humans under normal healthy conditions, due to the limited availability of healthy lymph node samples. We used a minimally invasive, routine clinical procedure, lymph node fine needle aspirations (LN FNAs), to obtain lymph node cells from healthy human subjects to establish benchmarks of GC cells under noninflammatory conditions. This study of 50 lymph nodes demonstrates that human LN FNAs are a safe and feasible technique for immunological research, and defines benchmarks for human GC biology. The findings indicate that assessment of the GC response via LN FNAs will have application to the study of human vaccination, allergy, and autoimmune disease.