CD40LG and lymphoma: Laboratory predictors of lymphoma development include anemia, lymphopenia, neutropenia [34], low concentrations of complement factor C3 and/or C4, high serum β-2 microglobulin concentrations, low serum IgM concentrations, the disappearance of a previously positive RF antibodies (RFs) [39], and cryoglobulinemia, especially mixed monoclonal cryoglobulinemia (MMC) [40].