Disclosed are microarrays comprising a plurality of oligonucleotide species capable of hybridizing to a polynucleotide comprising a sequence encoding at least a portion of a light chain variable region or a complement thereof. Also disclosed are methods of identifying light chain variable genes associated with a disease, methods of diagnosing a disease and methods of monitoring a disease. Methods of evaluating the ability of a therapeutic agent or a treatment to alter expression of the light chain variable gene are also provided.