Intracellular J chains in lymphoproliferative diseases.

The presence of J or joining chains has been studied in formol-paraffin tissue sections from various lymphoproliferative diseases. The percentages of J chain positivity in 56 cases of multiple myeloma, in 41 of immunocytic malignant lymphoma and 35 of immunoblastic malignant lymphoma were 58.9, 70.7 and 37.1%, respectively. The ratio of kappa to lambda chain types of the monotypic Ig-s was the lowest in multiple myeloma, intermediate in immunocytic and highest in immunoblastic malignant lymphoma (ml). In 8 cases (one local immature plasmocytoma, one non-secretory multiple myeloma, one immunocytic, 4 immunoblastic and one centroblastic malignant lymphoma), only J chains were present in the tumour cells--"J chain disease". A significant difference in survival of J chain positive (26.8 months) and negative (17.7 months) multiple myeloma cases was observed. Myeloma kidney lesions were slightly more frequent in J chain negative cases. In lymphoproliferative disease J chain seems to be associated with early events of Ig synthesis. On the other hand, in two cases with biclonal Ig-s, the IgM positive immunoblastic ml cells and inclusions and the IgA positive multiple myeloma cells and inclusions were J chain positive. The IgG positive cells in both tumours and the IgG positive inclusions in the immunoblastic tumour were negative for J chains.