B cell receptor light chain repertoires show signs of selection with differences between groups of healthy individuals and SLE patients

We have developed a microarray to study the expression of L-chain V genes (VL genes) in healthy and SLE patient peripheral κ- and λ-sorted B cells. In all repertoires tested, one VL gene accounts for over 10% of all gene VL expression, consistent with positive selection acting on L-chains. While a few VL genes were highly expressed in all individuals, most VL genes were expressed at different levels. Some VL genes (5 out of a total of 78) were not detected. We attribute their absence from the repertoire to negative selection. Positive selection and negative selection were also found in SLE repertoires, but expression of VL genes was different; the differences point to less regulation of VL gene repertoires in SLE. Our data shows that VL gene expression is variable and supports a model where the L-chain repertoire is generated by both positive and negative selection on L-chains.

► We developed a microarray to study B cell receptor light chain V gene repertoires. ► Negative and positive selection acts on light chains to shape the B cell repertoire. ► κ and λ B cells are selected differently. ► Certain light chain V genes are expressed at different levels in SLE patients.