The CD21(low) V(H)1-69(+) B cells of MC patients, like those of CVID and HIV patients, are anergic to BCR and TLR9 stimulation and display deregulation of several anergy-related genes; proliferative anergy is also observed in CD21(high) MZ-like V(H)1-69(+) B cells, that over-express the antiproliferative transcriptional repressor Stra13.
The CD21(low) B cells have been shown to be profoundly anergic, and defects of BCR-mediated calcium signaling and of T cells have been described in CVID 1a.