Osteoprotegerin and receptor activator of nuclear factor kappa b ligand surface expression in ra & oa patients

الملخص EN

Objective : to demonstrate RANKL surface expression on T lymphocytes and the level of OPG in the peripheral blood and synovial fluid of RA and OA, also to determine the level of osteoplastic bone desorption by the ratio of RANKL to OPG and detect any relation between the findings with disease activity and/or radiological grades in both group of the study.

Subjects : the study was performed on 30 patients.

Group I included 15 RA patients divided according to DAS into 2 subgroups.

Subgroup A: 9 active RA patients, subgroup B: 6 inactive RA patients.

Group II included 15 OA classified according to degree of activity of knee into subgroup C : 8 active OA and subgroup D : 7 inactive OA patients.

All the patients had effusion of the knee.

Methodology : Full history taking, complete clinical examination, assessment of disease activity using DAS in RA group and the degree of knee activity in OA group.

Laboratory investigations including detection of CD3+ CD4+ RANKL+ expression and the level of OPG in the peripheral blood and synovial fluid in both group of the study.

Quantitative measurement of CRP and RF.

Radiological progression assessment with plain x-rays on both hand and feet for RA group to calculate Ratingen score and plain X-rays on knee to detect radiological progression in OA group.

Results : there was increased numbers of CD3+ CD4+ RANKL+ lymphocytes in the synovial fluid of subgroup A more than other subgroups and more than the increase in the peripheral blood but it didn't reach to statistical significant difference.

Also, OPG level was reduced in SF of active RA (subgroup A) more than the reduction in the serum and in the other subgroups but also no significant difference was observed.

There was a statistical significant difference in measuring RANKL / OPG ratio in SF between subgroups and this significance is obvious when compared active RA with other subgroups, which indicate significant association between this ratio and disease activity in RA patients.

No significant correlation between measuring CD3+ CD4+ RANKL+ surface expression in peripheral blood or SF with various clinical, radiological and laboratory parameters in both group of the study, also no correlation was observed between measured parameters in OA group, while serum OPG showed highly significant correlation with Ratingen score in RA subgroup A and negative correlation between the level of OPG in SF and serum CRP was observed in the same subgroup A.

Conclusion : the induction of bone destruction and erosion may depend on RANKL surface expression on T lymphocytes and deficiency of OPG expression.

Also the relative level of RANKL and OPG is a key factor in determining bone loss in RA and significant association between it and activity was observed, so the use of therapy that modulate RANKL / OPG system may be benefit in preventing bone erosions in RA and further study was needed to evaluate these therapies by measuring RANKL / OPG ratio before and after treatment.