No abstract

The organization of immunoglobulin heavy chain (IgH), light chain (kappa and lambda) and T cell receptor (TCR) beta chain gene loci in 10 patients with ocular adnexal pseudolymphoma was investigated. Eight of them showed IgH gene rearrangement in at least one of the 3 restriction enzymes-digested DNAs extracted from ocular adnexal neoplasms. In contrast, none of them exhibited clonal TCR beta chain gene rearrangement. The configuration of bcl-1, bcl-2 and c-myc oncogenes was also studied by Southern blot technique. Two patients had a rearranged joining region, IgH-containing fragment that comigrated with the rearranged bcl-1 fragment. C-myc gene rearrangement was found in only one patient who also had bcl-1 gene rearrangement. In ocular adnexal pseudolymphoma, none demonstrated bcl-2 gene rearrangement; however, in bone marrow cells, one patient with systemic lymphadenopathy exhibited both IgH and bcl-2 gene rearrangements. Three genotypic subsets of these ocular adnexal pseudolymphoma can be identified by the configuration of IgH gene and related oncogenes: with germline configuration of IgH gene and bcl-1, bcl-2 and c-myc oncogenes; with rearrangement of IgH gene but germline configuration of these oncogenes; and with recombination between rearranged IgH and bcl-1 genes. These results suggest in ocular adnexal pseudolymphoma a spectrum of clonal change evolving from polyclonal to monoclonal B-population, and further to monoclonal B-population with rearranged bcl-1, c-myc and/or bcl-2 oncogenes.

Whether the pathogenesis of polymorphic reticulosis is from T cells, B cells, or histiocytes has been controversial. In this study, the Southern blot hybridization technique was used to analyze immunoglobulin and T-cell receptor beta-chain genes and to perform the conventional surface marker analysis in two patients with polymorphic reticulosis. The immunophenotype demonstrated the presence of predominantly mature, activated T-lymphocytes, minimal B-cells, and no natural killer cells or monocytes/granulocytes. The mature T-cell phenotype could be due to either inflammatory infiltrates or neoplastic cells of peripheral T-cell type, because the two coexist in polymorphic reticulosis tumors. The value of surface marker examination is limited in the analysis of PMR tumors. However, genetic analysis revealed that only Ig genes were rearranged, with no rearrangement of the TCR beta gene. Rearrangement of immunoglobulin genes occurs in B-lineage lymphoid neoplasms and is thought to be a criterion for diagnosis of lymphoid neoplasms. Based on genetic analysis and clinicopathologic information, this study concluded that polymorphic reticulosis is a malignant lymphoma of B-cell lineage.