Cytomegalovirus aggravates the autoimmune phenomenon in systemic autoimmune diseases

Human Cytomegalovirus (CMV), because of its ability to extensively manipulate host immunity during active infection, has been suggested to be involved in autoimmunity. However, its influence on T-cells and cytokines in systemic autoimmune diseases like systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) is indistinct.

We investigated the in-vitro response of T lymphocytes from SLE and SSc patients to CMV antigen. Functional activity of T lymphocytes was determined by estimating Th1 (IL-2 and IFN-γ) and Th2 (IL-4 and IL-10) cytokines.

We observed that CMV antigen stimulation in-vitro resulted in significant increase in CD4:CD8 T-cell ratio in peripheral blood mononuclear cells (PBMCs) from SLE and SSc patients; response dominated by CD4⁺ than CD8⁺ memory T-cells. SSc T-cell response was differentiated by aberrant increase in CD4⁺CD25⁺ T-cells. CMV antigen caused elevation in IL-4 and IFN-γ production in both patient PBMCs, whereas IL-2 was also raised in SLE PBMCs. The development of large pool of memory T-cells and overproduction of IFN-γ may result in flare-up of autoimmunity in these patients.

Our study provides an insight into the immunopathological potential of CMV-reactive immune cells to develop new potential strategies for targeted therapeutic intervention.