Changes in the immune system of untreated patients with chronic lymphocytic leukaemia - Part 1: Adaptive immunity
Abstract
CChronic lymphocytic leukaemia, the most common leukaemia of adults in the western world, is associated with significant combined immunodeficiency. Even treatment-naive patients with early stages of the disease can have immunoglobulin deficiency.
IgA hypogammaglobulinemia was shown to be a negative prognostic factor, leading to a higher frequency of bacterial infections. There are changes in both the number and immunophenotype of T-cells with inversion of the CD4+/ CD8+ ratio and an increase in regulatory T-cells.
Changes in T-cell function are described as pseudo-exhaustion, characterised by the inability to form immunological synapses. Furthermore, the cytokine spectrum and immune cell differentiation indicate a shift towards Th2 immune response.
These changes lead to increased susceptibility to opportunistic and viral infections. There are changes of innate immunity as well - NK cells, neutrophils, monocytes/ macrophages and the complement system are all affected.
In this article, major adaptive immunity changes in treatment-naive patients are summarized.