DNA was isolated from cells using the QIAmp system (Qiagen). The concentration of DNA was estimated using the NanoDrop ND-1000 spectrophotometer. DNA quality was assessed using Agilent 2100 Bioanalyser (Agilent Technologies, Santa Clara, CA, USA). PCR primer sequences for IGHV gene framework region 3 (FR3) were designed as previously reported (Kummalue et al, 2010 (link)). PCR of the IGH genes to assess clonality used the BIOMED-2 system. Master mixes were purchased from Invivoscribe Technologies (San Diego, CA, USA), and the PCR was done as per manufacturer’s instructions and used HotStart Taq DNA polymerase (Qiagen) (Burack et al, 2010 (link)).