Total RNA was manually extracted from the whole blood using RNA-BEE (Tel Test) and purified by Dynal magnetic beads (Invitrogen) to obtain messenger RNA (mRNA). The purified mRNA was amplified with the use of six-sense IGHV family-specific (HV1–HV6) leader primers and an antisense μ-chain constant-region primer in one multiplex one-step reverse-transcriptase–polymerase-chainreaction (RT-PCR) assay.
