Abstract
Haematological malignancies represent a heterogenous group of diseases, encompassing lymphomas, leukaemia, and multiple myeloma. Among these, the involvement of human endogenous retroviruses (HERVs) has been most consistently reported in lymphoma, while their role in leukaemia and multiple myeloma remains limited. This study investigated the humoral response to the envelope proteins of HERV-K and HERV-H in the peripheral blood of patients with multiple myeloma and non-Hodgkin lymphoma and assessed HERV-K envelope gene expression through an approach combining indirect ELISA and quantitative PCR. The study revealed an increased humoral response against the HERV-K envelope epitope in patients with non-Hodgkin lymphoma compared to matched healthy controls. However, no differences were observed in patients with multiple myeloma. Although limited to the humoral level, these findings support the relevance of HERV-K specific immune responses in non-Hodgkin lymphoma and provide a rationale for further investigation.