Study on the expression of high mobility group box chromosomal protein 1 in skin lesions in patients with lupus erythematosus / 中华风湿病学杂志

ABSTRACT

Objective To study the expression of high mobility group box chromosomal protein 1(HMGB-1) in the skin lesions of patients with lupus erythematosus and investigate the role of HMGB-1 in the pathogenesis of lupus erythematosus. Methods Immunohistochemical assay and Western-blot were used to test the expression of HMGB-1 in skin lesions from 20 discoid lupus erythematosus (DLE) patients, 25 systemic lupus erythematosus (SLE) patients and 20 healthy controls. Results In healthy controls, H MGB-1 was mainly expressed in the nucleus of keratinocytes. In skin lesions of DLE patients, HMGB-1 was mainly expressed in mononuclear cells of dermis, but the percentage of positive keratinocytes in epidermis of lesion area was decreased than that of healthy controls (t=11.315, P<0.01). In skins that were not involved,HMGB-1 was also expressed in the nucleus of keratinocytes and there was no difference in the percentage of positive keratinocytes between DLE and healthy controls (P>0.05). By Western-blot, there was no stati-stical significance in total protein between DLE and healthy controls (t=0.681, P>0.05). In SLE, besides the mononuclear cells, HMGB-1 could be detected both in the cytoplasmic and extracellular space in dermis,while the HMGB-1 nuclear expressions in keratinocytes'of epidermis were decreased than those of DLE (t=6.821, P<0.01), and in un-involved skin, HMGB-1 was also expressed in the nucleus of keratinocytes and there was no difference in the percentage of positive keratinocytes with healthy controls (P>0.05). The total protein was increased in SLE than that of healthy controls and DLE patients (t=15.494, P<0.01 ; t=13.221, P<0.01, respectively). The intensity of HMGB-1 was con'elated with SLEDAI and proteinuria (r=0.565, P<0.01,OR=1.027, P<0.05, respectively). Conclusion Compared with healthy controls, there is translocation and alteration of HMGB-1 expression in patients with lupus erythematosus, which indicates that HMGB-1 may be involved in the inflammation of lupus erythematosus.