High Concentration of Soluble HLA-DR in the Synovial Fluid: Generation and Significance in “Rheumatoid-like” Inflammatory Joint Diseases

Proteomic analysis of synovial fluid: insight into the pathogenesis of knee osteoarthritis

“…In addition, a protective effect of DERAA-containing HLA-DRB1 alleles on RA development has been previously reported [31]. Elevated SF sHLA-DR may be related to various HLA-DR turnover rates or differently regulated release mechanisms, allele-specific "secretor types", and proteolytic cleavage of cell-bound counterparts may also contribute to the increase [32]. HLA-DR may modulate T-cell activation in at least two ways: On the one hand, sHLA-DR may suppress T-cell activation by competing with their cell-bound counterparts for TCR and/or CD4 binding.…”

“…HLA-DR may modulate T-cell activation in at least two ways: On the one hand, sHLA-DR may suppress T-cell activation by competing with their cell-bound counterparts for TCR and/or CD4 binding. The appearance of smaller sized sHLA-DR may be an attempt of the immune system to counteract the expansion of CD4 T lymphocytes as a result of the disease [32]. On the other hand, autologous sHLA-DR presented by antigenpresenting cells (APCs) can trigger a vicious circle of immunostimulation and promote the spontaneous proliferation of SF monocytes in a manner analogous to the autologous mixed lymphocyte reaction under pathological conditions [33].…”

Soluble major histocompatibility complex molecules in immune regulation: highlighting class II antigens

“…Reported levels of sHLA‐DR in sera of healthy donors vary significantly from 0·31 ng/ml to 1400 ng/ml . Other studies place that range from 0·02 ng/ml to 100 ng/ml . Such variations, however, are possibly due to the use of different monoclonal antibodies or cross‐reactivity with other serum proteins.…”

“…Such variations, however, are possibly due to the use of different monoclonal antibodies or cross‐reactivity with other serum proteins. Regardless of the physiological levels of sMHC‐II proteins in the serum of healthy individuals, many pathological conditions including viral encephalitis, rheumatoid arthritis, pathological pregnancies, asthma, AIDS, chronic hepatitis C and acute chronic uveitis have been shown divergence of sMHC‐II levels from control values. By the same token, the reported levels of sHLA‐I in healthy individuals vary from 357 ng/ml to 1·06 μg/ml, while they significantly increase in AIDS patients, as well as in cases of rheumatoid arthritis, systemic lupus erythematosus (SLE), Sjogren's syndrome and multiple sclerosis (MS) …”

Soluble HLA class I molecules in malignant pleural and peritoneal effusions and its possible role on NK and LAK cytotoxicity

“…In recent studies, investigators have evaluated the amount of sHLA-I in cancerous patients and various levels of circulating sHLA-I have been reported in patients with melanoma ), brain tumors (Turowski et al 1996), pancreatic cancer (Shimura et al 2001), lymphoma (Nocito et al 1997), and gastric cancer (Shimura et al 1994). These studies have focused on the sHLA-I value in serum of cancerous patients whereas; the presence of sHLA-I in other body fluids in normal and pathological conditions has been reported (Zavazava et al 1994;Wobst et al 1998;Claus et al 2000). In the present work the value of sHLA-I in the peritoneal and pleural effusions of patients with malignancy, infection, and other diseases was examined.…”