Individual B-cells in lymphoid tissue possess either kappa or lambda light chains, but never both together. Specific rearrangement of lambda light chain of immunoglobulins can lead to loss of some protein coding genes, which does not seem to be functionally relevant (while functionally relevant miR-650 can be overexpressed). Using immunohistochemistry, it is possible to determine the relative abundance of B-cells expressing kappa and lambda light chains. If the lymph node or similar tissue is reactive, or otherwise benign, it should possess a mixture of kappa positive and lambda positive cells. If, however, one type of light chain is significantly more common than the other, the cells are likely all derived from a small clonal population, which may indicate a malignant condition, such as B-cell lymphoma. [Wiki]

Individual B-cells in lymphoid tissue possess either kappa or lambda light chains, but never both together. Specific rearrangement of lambda light chain of immunoglobulins can lead to loss of some protein coding genes, which does not seem to be functionally relevant (while functionally relevant miR-650 can be overexpressed). Using immunohistochemistry, it is possible to determine the relative abundance of B-cells expressing kappa and lambda light chains. If the lymph node or similar tissue is reactive, or otherwise benign, it should possess a mixture of kappa positive and lambda positive cells. If, however, one type of light chain is significantly more common than the other, the cells are likely all derived from a small clonal population, which may indicate a malignant condition, such as B-cell lymphoma. [Wiki]