Change in the expression of body fluid proteins is caused by many diseases or environmental disturbances. The changes in tear proteins are also associated with various pathological eye conditions. Especially, chronic blepharitis is one of the most common conditions seen in the ophthalmologist's office. However, there are no specific clinical diagnostic tests for blepharitis, and it is difficult to treat effectively. Therefore, the aim of this study was to screen prognostic or diagnostic marker tear proteins for blepharitis and investigate pathogenesis of this disease using proteomics techniques. The tear proteins expressed in patients suffering from blepharitis (patient, n=19) and healthy volunteers (control, n=27) were analyzed using the two-dimensional electrophoresis (2-DE) technique. The differentially expressed proteins in patients were identified with ESI-Q-TOF (electrospray-quadrupole-time-of-flight) mass spectrometry and confirmed with western blotting. Nine proteins in patient were down regulated about 50% compared to those of the control: serum albumin precursor, alpha-1 antitrypsin, lacritin precursor, lysozyme, Ig-kappa chain VIII, prolactin inducible protein (PIP/GCDFP-15), cystatin-SA III, pyruvate kinase, and an unnamed protein. The use of the two-dimensional eletrophoretic technique could give more insight into the disease-related protein expression changes in tear fluids. Our findings reveal that the composition of tear proteins in blepharitis patients is different from that of healthy subjects and may provide further insights into the pathogenesis of blepharitis.

The major house-dust mite allergen, Der f 2, stimulates the phospholipase D (PLD) in T lymphocytes from Dermatophagoides farinae specific allergic individuals. PLD activity increased more than two-fold in T cells from allergic patients compared with those cells from normal controls with maximal responses within 30 min after exposure of Der f 2. A well-known PLD activator PKC-alpha was found to be translocated to membrane from cytosol in Der f 2-treated T cells from Dermatophagoides farinae specific allergic individuals. Down-regulation of PKC-alpha with phorbol myristate acetate pretreatment for 24 h abolished Der f 2-induced PLD activation. Ro 320432, PKC inhibitor also reduced the effects of Der f 2-induced PLD activation suggesting that PKC-alpha acts as upstream activator of PLD in Der f 2-treated T cells. Taken together, the present data suggest that Der f 2 can stimulate PLD activity through the PKC-alpha activation in T cells from Dermatophagoides farinae allergic individuals.