FCRL4 and neoplasm: CD20&lt;sup&gt;+&lt;/sup&gt;FCRL4&lt;sup&gt;+&lt;/sup&gt; B Cells Activate CD8&lt;sup&gt;+&lt;/sup&gt; T Cells via MHC-I Restriction in Nasopharyngeal Carcinoma Anti-Tumor Immunity.