A 50-year-old female presented with mild to moderate unilateral headache which becomes severe occasionally along with fever, jaw pain and visual disturbances, malaise, fatigue and weight loss. On examination, scalp tenderness was noted. Lab findings revealed normocytic normochromic anemia, elevated ESR and raised ANA titers. Biopsy was taken from the temporal aery. Which of the following cells are most impoantly involved in the pathogenesis of the above disease: -

This is a case of Giant-cell aeritis. HPE image shows panaeritis with presence of mononuclear cells and giant cells along with proliferation of the intima and fragmentation of the internal elastic lamina. Giant cell aeritis (GCA)/Temporal aeritis, Systemic inflammatory vasculitis Occurs in older persons Most common form of systemic vasculitis in adults. It is initiated in the adventitia. CD4+ T cells enter through the vasa vasorum, become activated, and orchestrate macrophage differentiation.