CD40 and Sjogren syndrome: Conjunctival biopsy specimens from patients with both Sjögren’s syndrome keratoconjunctivitis sicca (SS-KCS) and non-Sjögren’s syndrome keratoconjunctivitis sicca (NS-KCS) display lymphocytic infiltration and increased immunoreactivity for various markers of inflammation and immune activation, including human leukocyte antigen-DR (HLA-DR), HLA-DQ, intracellular adhesion molecule 1 (ICAM-1), CD40, CD40 ligand and apoptotic marker APO2.7 [3,4].