Immunodeficiency-associated Hodgkin lymphoma

Immune deficiency/dysregulation -associated lymphoproliferative disorders. Revised classification and management

Significant advances in the field of lymphoma have resulted in two recent classification proposals, the International Consensus Classification (ICC) and the 5th edition WHO. A few entities are categorized differently in the ICC compared to the WHO. Nowhere is this more apparent than the immunodeficiency lymphoproliferative disorders. The three previous versions of the WHO classification (3rd, 4th and revised 4th editions) and the ICC focused on four clinical settings in which these lesions arise for primary categorization. In contrast the 2023 WHO 5th edition includes pathologic characteristics including morphology and viral status, in addition to clinical setting, as important information for lesion classification. In addition, the 2023 WHO recognizes a broader number of clinical scenarios in which these lesions arise, including not only traditional types of immune deficiency but also immune dysregulation. With this classification it is hoped that new treatment strategies will be developed leading to better patient outcomes.

Classic Hodgkin lymphoma in young people

Classic Hodgkin lymphoma (CHL) is a unique form of lymphoid cancer featuring a heterogeneous tumor microenvironment and a relative paucity of malignant Hodgkin and Reed-Sternberg (HRS) cells with characteristic phenotype. Younger individuals (children, adolescents and young adults) are affected as often as the elderly, producing a peculiar bimodal age-incidence profile that has generated immense interest in this disease and its origins. Decades of epidemiological investigations have documented the populations most susceptible and identified multiple risk factors that can be broadly categorized as either biological or environmental in nature. Most risk factors result in overt immunodeficiency or confer more subtle alterations to baseline health, physiology or immune function. Epstein Barr virus, however, is both a risk factor and well-established driver of lymphomagenesis in a significant subset of cases. Epigenetic changes, along with the accumulation of somatic driver mutations and cytogenetic abnormalities are required for the malignant transformation of germinal center-experienced HRS cell precursors. Chromosomal instability and the influence of endogenous mutational processes are critical in this regard, by impacting genes involved in key signaling pathways that promote the survival and proliferation of HRS cells and their escape from immune destruction. Here we review the principal features, known risk factors and lymphomagenic mechanisms relevant to newly diagnosed CHL, with an emphasis on those most applicable to young people.

Immunodeficiency-Associated Epstein-Barr Virus-Positive B-cell Lymphoproliferative Disorders

Sources of immune deficiency and dysregulation (IDD) are being increasingly recognized and defined, as are IDD-related B-cell lymphoproliferative lesions and lymphomas occurring in these patients. In this review, basic biology of Epstein-Barr virus (EBV) as it relates to classification of EBV-positive B-cell lymphoproliferative disorders (LPDs) is reviewed. Also discussed is the new paradigm of classification of IDD-related LPDs adopted by the fifth edition World Health Organization classification. IDD-related EBV-positive B-cell hyperplasias, LPDs, and lymphomas are discussed with particular attention to unifying and unique features that assist with recognition of these IDD-related lesions and their classification scheme.

HIV-related lymphomas

PURPOSE OF REVIEW

To summarize the recent evidence on the pathology, current standard of care and recent advances in the treatment of HIV-related lymphomas.

RECENT FINDINGS

Lymphomas remain a major cause of morbidity and mortality in people living with HIV, even in the era of combination antiretroviral therapy (cART). However, treatment outcomes for these malignancies have improved in recent decades, due to full-dose chemotherapy, effective cART and supportive care. Recent advances include the identification of novel driving signaling pathways as promising molecular targets to improve lymphoma outcomes.

SUMMARY

Patients with HIV-related lymphomas who receive effective cART should be treated like the general population.