Immunoglobulin heavy- and light-chain gene rearrangements examined by single-cell PCR. CD19 bright/CD38 bright (A) and CD19 dimmer/CD38 dimmer (B) B cells from a healthy control and patient 3 were analyzed by single-cell RT-PCR. Each lane contains the PCR product from a single cell. Lanes containing positive (+) and negative (−) controls are marked. Igα (CD79a) was amplified from wells to document that the wells from patient 3 contained B cells.