© 1994 British Society for Rheumatology
research-article |
1-ANTICHYMOTRYPSIN, C-REACTIVE PROTEIN AND ERYTHROCYTE SEDIMENTATION RATE IN POLYMYALGIA RHEUMATICA AND GIANT CELL ARTERITIS
*Rheumatology Research Unit, Addenbrooke's Hospital Cambridge CB2 2QQ
Department of Clinical Biochemistry, Addenbrooke's Hospital Cambridge CB2 2QQ
Forty-four patients with polymyalgia rheumatica and/or giant cell arteritis (PMR/GCA) were followed from presentation, through remissions and relapses for a median duration of 36 months. Clinical disease activity, ESR, CRP and 
1-antichymotrypsin (1-ACT) were measured.
Before treatment ESR, CRP and 1-ACT were all significantly raised, compared with age- and sex-matched controls.
On clinical remission with prednisolone treatment, ESR and CRP fell to control levels but 1-ACT behaved quite differently, remaining raised for 18 months or until prednisolone treatment could be withdrawn. At 18 month follow-up of PMR/GCA, an 1-ACT level of 
0.7 g/1 was associated with a reduced risk of subsequent relapse (P = 0.006).
At clinical relapse during treatment, ESR was not raised compared with controls, and CRP, although significantly higher than controls (P = 0.015), remained less than 6 mg/1 in the majority of patients.
The three laboratory investigations were, therefore, of limited value in confirming relapses of PMR/GCA during prednisolone treatment, but 1-ACT may be useful as an indicator of underlying disease activity and hence as a guide to the speed that the prednisolone dosage should be reduced.
KEY WORDS: 1-Antichymotrypsin, Erythrocyte sedimentation rate, C-Reactive protein, Polymyalgia rheumatica, Giant cell arteritis