To gain insight into the process of lymphomagenesis in AIDS and to investigate a possible pathogenetic relationship between LAS and NHL, we investigated the clonality of the B or T lymphoid populations by Ig or T beta gene rearrangement analysis, the presence of rearrangements involving the c-myc oncogene locus, and the presence of human immunodeficiency virus (HIV) sequences in both LAS and B-NHL biopsies.
However, only one of the B cell clones, identified by Ig gene rearrangements carries a c-myc gene rearrangement, suggesting that only one clone carries the genetic abnormality associated with malignant B cell lymphoma.
With the exception of some lymphoblastic lymphomas, high-grade B-cell lymphomas normally expressed the pan B-cell antigens CD19 and CD22 but only immunoblastic lymphomas consistently expressed the pan B marker CD20.
The frequent rearrangement of bcl-2 in a variety of B cell lymphomas of diffuse morphology (small cleaved cell, large cell, small noncleaved cell and immunoblastic) is noteworthy.
Immunocytochemistry has shown that all cases of enteropathy-associated T cell lymphoma studied are HML-1 positive and all peripheral T cell lymphomas and mucosal B cell lymphomas are HML-1 negative.
Ninety-six percent of B-cell lymphomas reacted with one or more of the B-cell-associated antibodies, whereas 100% of T-cell lymphomas reacted either with MT1, UCHL1, or both antibodies.
Immunocytochemistry has shown that all cases of enteropathy-associated T cell lymphoma studied are HML-1 positive and all peripheral T cell lymphomas and mucosal B cell lymphomas are HML-1 negative.
These data indicate that primary cutaneous lymphomas of B-cell origin share morphological and phenotypic similarities with the nodal B-cell lymphomas of follicular histotype, are proliferating, and express in 45% of cases clear monoclonal immunoglobulin light chain; the molecular analysis confirms the B-cell derivation and the monoclonal nature of this neoplasia; it also shows that neither bcl-2 nor c-myc oncogenes are involved and that no inappropriate rearrangements of the T-cell receptor genes are found in this lymphoma.
The human bcl-2 gene is a oncogene candidate which is involved in the t(14;18) translocation specifically associated with follicular and diffuse B cell lymphomas.