Spontaneous reduction of leukemic lymphoma cells possibly by anti-tumor antibody-mediated phagocytosis; a κ λ-dual-positive B cell lymphoma

Abstract

We have investigated the possible role of anti-tumor antibody detected in a case of follicular lymphoma which demonstrated the spontaneous reduction of leukemic tumor cells. The tumor cells genotypically had monoclonal rearrangements of the immunoglobulin J H and C genes, but phenotypically exhibited surface IgG, A, and ( dual positivity). The culture study revealed that IgG , at least, was derived from the serum, and IgA was expressed intrinsically. Furthermore, the positive correlation between the densities of both surface light chains on two-color flow cytometry, the rosette formation study and its inhibition test by the Fc␥ fragment suggested that the serum IgG combined with some antigens on the tumor-cell surface via its Fab portion and with the Fc␥ receptor of macrophages via its Fc portion. From these findings, we regarded the present case as an anti-tumor antibody-coated lymphoma. In addition, the phagocytic study disclosed that the serum-derived IgG , at least, might have induced the phagocytosis of circulating lymphoma cells by macrophages. In conclusion, the existence of the anti-tumor antibody-coated lymphoma may be helpful in clarifying the immunological mechanism of the spontaneous regression occasionally seen in lymphomas.

Ordered recombination of immunoglobulin light chain genes occurs at the IGK locus but seems less strict at theIGL locus

“…Although we did not find dual Ig/Ig chain expression in our CBL series (Figure 1), it has been described as occurring in normal and malignant human B lymphocytes. [21][22][23]26 RT-PCR indicates reverse transcriptase-polymerase chain reaction. *The junctional region is described as the number of bases lost at the 3Ј end of the V segment followed by randomly inserted nucleotides and the number of bases lost from the 5Ј end of the J segment.…”

“…However, during the last few years, several reports have indicated that dual receptor expression might occur in B lymphocytes as well as in T lymphocytes because of ongoing rearrangements after a functional receptor gene has been formed and expressed. [21][22][23][24][25][26] It was found that a single T lymphocyte might express 2 different T-cell receptor (TCR)␤ chains and 2 different TCR␣ chains, indicating that both TCRB alleles as well as both TCRA alleles are functionally rearranged and expressed. 24,25 By analogy, Giachino et al demonstrated that in 0.2% to 0.5% of human B lymphocytes dual expression of Ig and Ig occurs.…”