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Cellular Classification
Pathologically, AIDS-related lymphomas are comprised of a narrow spectrum of
histologic types consisting almost exclusively of B-cell tumors of aggressive
type. These include:
- Diffuse large B-cell lymphoma.
- B-cell immunoblastic lymphoma.
- Small
noncleaved lymphoma, either Burkitt or Burkitt-like.
All three pathologic types are
equally distributed and represent aggressive disease.
AIDS-related lymphomas, though usually of B-cell origin as demonstrated by
immunoglobulin heavy-chain gene rearrangement studies, have also been shown to
be oligoclonal and polyclonal as well as monoclonal in origin. Although HIV
does not appear to have a direct etiologic role, HIV infection does lead to an
altered immunologic milieu. HIV generally infects T lymphocytes whose loss of
regulation function leads to hypergammaglobulinemia and polyclonal B-cell
hyperplasia. B cells are not the targets of HIV infection. Instead,
Epstein-Barr virus (EBV) is thought to be at least a cofactor in the etiology
of some of these lymphomas. The EBV genome has been detected in varying
numbers of patients with AIDS-related lymphomas; molecular analysis suggests
that the cells were infected before clonal proliferation began.[1] EBV is
detected in 30% of patients with small, noncleaved lymphomas and in 80% of patients with
diffuse, large cell lymphomas. The rare, primary effusion lymphoma consistently
harbors human herpes virus type-8 and frequently contains EBV.[2] HIV-related T-cell
lymphomas have also been identified and appear to be associated with EBV
infection.[3]
References
-
Thorley-Lawson DA, Gross A: Persistence of the Epstein-Barr virus and the origins of associated lymphomas. N Engl J Med 350 (13): 1328-37, 2004.
[PUBMED Abstract]
-
Simonelli C, Spina M, Cinelli R, et al.: Clinical features and outcome of primary effusion lymphoma in HIV-infected patients: a single-institution study. J Clin Oncol 21 (21): 3948-54, 2003.
[PUBMED Abstract]
-
Thomas JA, Cotter F, Hanby AM, et al.: Epstein-Barr virus-related oral T-cell lymphoma associated with human immunodeficiency virus immunosuppression. Blood 81 (12): 3350-6, 1993.
[PUBMED Abstract]
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