Specific and non-specific autoreactive immunity

Activation of Complement Following Total Hip Replacement

The aim of this study was to investigate whether complement activation, via the classical and alternative pathways, occurs following a cemented total hip replacement (THR) surgery due to osteoarthritis. Blood samples were collected systematically from 12 patients - six male and six women, with a median age of 75 (range: 59-90 years) - preoperatively, 6 h post-operatively and on the first, second and third post-operative day. Total function of classical (CH50) and alternative pathways (AH50) was evaluated, along with the determination of serum concentrations of the complement proteins C3, C4, C3d, the soluble terminal complement complex (sTCC) sC5b-9, as well as C-reactive protein (CRP) and albumin. Measurements of CRP and albumin levels elucidated a marked inflammatory response following the operation. The CH50, AH50 and C3 and C4 levels were significantly lower 6 h after the surgery compared with the preoperative levels, but elevated above the preoperative levels during the following 3 days. The complement activation product C3d levels increased continually during the whole observation period, from 13.5 AU/ml (range: 8-19 AU/ml) preoperative to 20 AU/ml (range: 12-34 AU/ml) on the third post-operative day. Furthermore, we observed an increase in the sC5b-9 levels between the preoperative and the third post-operative day. These results demonstrate a significant activation of the complement system following cemented THR. Further studies are needed to elucidate the time frame and the pathogenic role of this observed complement activation.

Inflammatory cytokines in relation to adrenal response following total hip replacement

Our objective was to investigate the initiation and course of pro- and anti-inflammatory cytokines in early inflammatory response and to elucidate the cytokine system in relation to the adrenal response caused by stress. Seven blood samples were collected, pre- and postoperatively (0-72 h) after total hip replacement (THR) due to osteoarthritis. The following cytokines were measured using Cytometric Bead Array: interleukin-1beta (IL-1beta), IL-6, tumour necrosis factor-alpha, IL-8, IL-12 and IL-10 (B&D). Thirteen patients took part in the study (67 +/- 9 years). C-reactive protein increased from <6 to over 200 mg/l on the second post-op day. The concentration of IL-6 increased 10-fold just 3 h post-op (4-47 pg/ml) and reached its maximum value 6 h post-op (77 pg/ml; Wilcoxon test P < 0.01) Repeated measurements were also significant (Friedman P < 0.05). The concentration of IL-8 doubled the day of surgery but did not reach a significant level (Friedman test =0.069). None of the other cytokines showed any significant changes. The diurnal cortisol rhythm was interrupted after the surgery and there was a significant correlation between the cortisol secretion and IL-6 response. This study demonstrates an isolated elevation in IL-6 levels with only a minor elevation in IL-8 following THR. This pro-inflammatory response seemed to decline without activation of anti-inflammatory cytokines (IL-10), but cortisol seemed to play a complicated role in halting the acute inflammatory response.

Cytokine autoantibodies in rheumatoid arthritis

Sera from 42 patients with rheumatoid arthritis (RA) and 40 healthy controls (HC) were examined for cytokine autoantibodies (CK-aAb) by accurate and sensitive radioimmunoassays. The prevalences of detectable CK-aAb in RA (HC) were: aAb-IL-1 alpha = 36% (38%); aAb-IL-6 = 29% (13%), p = 0.06; aAb-IL-8 = 0% (0%); aAb-IFN alpha = 12% (3%), p = 0.11. The levels of the individual CK-aAb did not correlate, and there were no correlations between CK-aAb levels and clinical or laboratory variables. CK-aAb levels remained constant in 8 RA patients tested over a period of 6 months. With regard to alterations in aAb-IL-1 alpha levels, 4/11 HC were consistently positive over 18-36 months; 2/11 converted and became highly positive. The levels of aAb-IFN alpha and aAb-IL-6, but not aAb-IL-1 alpha, tended to be increased in RA patients; aAb-IL-8 were undetectable in both RA and HC.