The etiology of non-Hodgkin's lymphomas (NHL) remains a controversial
matter, but, in the last few years, considerable evidence suggests tha
t aberrations of the immune system and viruses may act as etiologic ag
ents, in at least some cases of NHL. In fact, patients with primary im
muno-deficiencies, or those suffering from diseases characterized by a
utoimmune dysfunction, show an increased risk for the development of N
HL. Several viruses have been identified as possible etiologic agents
for NHL; one of the best studied is the Epstein-Barr virus, which was
detected in cultures of tumor cells from patients with Burkitt's lymph
oma. The pathogenetic potential of this virus is illustrated by it's a
ssociation with an increasing number of malignant diseases. In additio
n, the human T-cell lymphotropic virus family (HTLV), was also recogni
zed as possible etiologic agents for several lymphomas, such as cutane
ous T-cell lymphoma and T-cell leukemia-lymphoma syndrome (HTLVI), and
T-cell hairy cell leukemia (HTLV-II). Recently, the presence of hepat
itis C virus infection has also been recognized in several hematologic
al malignancies such as mixed cryoglobulinemia, low-grade malignant ly
mphomas and Waldenstrom's disease. The possible etiopathogenethic role
of this virus in non-Hodgkin's lymphomas is discussed on the basis of
molecular, clinical, and epidemiological considerations.