Acute phase proteins in the monitoring of inflammatory disorders

ITIH4 (inter-alpha-trypsin inhibitor heavy chain 4) is a new acute-phase protein isolated from cattle during experimental infection

We have isolated from calf serum a protein with an apparent M(r) of 120,000. The protein was detected by using antibodies against major acute-phase protein in pigs with acute inflammation. The amino acid sequence of an internal fragment revealed that this protein is the bovine counterpart of ITIH4, the heavy chain 4 of the inter-alpha-trypsin inhibitor family. The response of this protein in the sera was determined for animals during experimental bacterial and viral infections. In the bacterial model, animals were inoculated with a mixture of Actinomyces pyogenes, Fusobacterium necrophorum, and Peptostreptococcus indolicus to induce an acute-phase reaction. All animals developed moderate to severe clinical mastitis and exhibited remarkable increases in ITIH4 concentration in serum (from 3 to 12 times the initial values, peaking at 48 to 72 h after infection) that correlated with the severity of the disease. Animals with experimental infections with bovine respiratory syncytial virus (BRSV) also showed increases in ITIH4 concentration (from two- to fivefold), which peaked at around 7 to 8 days after inoculation. Generally, no response was seen after a second infection of the same animals with the virus. Because of the significant induction of the protein in the animals in the mastitis and BRSV infection models, we can conclude that ITIH4 is a new positive acute-phase protein in cattle.

Relationship between some acute phase reactants and the Bath Ankylosing Spondylitis Disease Activity Index in patients with ankylosing spondylitis

OBJECTIVES

The aims of this study were to investigate a possible relationship between the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and some acute phase reactant (APR) levels in patients with ankylosing spondylitis (AS).

METHODS

Twenty outpatients who fulfilled the modified New York criteria for AS were included in the study. Laboratory activity was assessed by examining erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), haptoglobin (Hp), and beta2 microglobulin (beta2MG). Disease activity was assessed according to the BASDAI, which includes a 10-point visual analogue scale to measure pain, fatigue, morning stiffness, swelling, and areas of local tenderness.

RESULTS

When APR values were analyzed for the BASDAI, a positive correlation between CRP and BASDAI was observed (r = 0.556, P < 0.05). There was no clear, statistically significant correlation between BASDAI and the other APRs (ESR, r = 0.328, P > 0.05; Hp, r = 0.035, P > 0.05; and beta2MG, r = -0.190, P > 0.05).

CONCLUSIONS

Our data suggest that CRP is a better marker of disease activity than ESR, Hp, and beta2MG.

Levels of some acute-phase proteins in the serum of patients with cancer during radiotherapy

The acute phase response involves changes in serum concentrations of a number of liver-synthesized proteins. Among these are C-reactive protein (CRP), ferritin (FER), transferrin (Trf) and ceruloplasmin (Cp). Determination of serum CRP, FER, Trf, and Cp was performed in 52 patients with inoperable head and neck cancer (n=11), inoperable esophageal cancer (n=10), rectal cancer (n=9; operation was performed=5, inoperable=4), and lung cancer (n=22), all of whom were treated with radical radiotherapy (RT). Post-radiotherapy CRP levels were significantly higher compared to the preradiotherapy levels (p<0.001). We found decreased serum Trf levels during the irradiation period, while acute-phase proteins such as CRP, FER, and Cp levels increased during the RT period. Further studies on the roles of other acute phase reactants and the above mentioned parameters in a large-patients-with cancer group during radiotherapy are required to understand the role of markers, which are altered during radiotherapy.

Relationship between levels of serum C-reactive protein, leucocyte count and carotid plaque in patients with ischemic stroke

In order to study the relationship between serum C-reactive protein (CRP) levels, leukocyte count and carotid plaque in patients with ischemic stroke, carotid duplex examination was performed by high-definition imaging (HDI) 5000 triplex system. Serum CRP was measured by nephelometry within 72 h after index ischemic stroke. A lesion was considered a plaque in the presence of a maximum intimal-medial wall thickness (IMT) 1.2 mm. Results of carotid ultrasonography were divided into two groups: M1, normal (IMT < 1.2 mm) and M2, abnormal (IMT > or = 1.2 mm). The results showed that the mean age of M2 was significantly older than that of M1 (69.7 +/- 10.4 versus 62.5 +/- 9.6, P = 0.001). The patients with hypertension and diabetes mellitus (78%, 35% respectively) in M2 were significantly more than those (52%, 18% respectively) in M1 (P < 0.01, P < 0.05). There were 32 (65%) patients with elevated CRP levels in M2, but 33 (46%) patients with elevated CRP levels in M1, with the difference being significant between the two groups (P < 0.05). The levels of serum glucose and leukocyte count (8.1 +/- 5.5, 10.3 +/- 4.0, respectively) in abnormal CRP group were significantly higher than that of normal CRP group (6.4 +/- 2.8, 8.7 +/- 3.4) (P < 0.05, P < 0.05); elevated CRP levels was found in 42 (62%) patients with territory infarction and 23 (43%) patients with lacunar infarction respectively, with the difference being significant between these two groups (P < 0.05). It was concluded that the elevation of CRP levels was an significant clinical index for carotid plaque in patients with acute cerebral infarction.

Interleukin 6, serum amyloid A and haptoglobin as markers of treatment efficacy in pigs experimentally infected with Actinobacillus pleuropneumoniae

The possibility to use acute phase proteins to monitor the elimination of a bacterial infection in pigs would facilitate an objective assessment of treatment with various antimicrobial substances. To examine this possibility, the acute phase response (IL-6, serum amyloid A (SAA), and haptoglobin) elicited by Actinobacillus pleuropneumoniae and its reduction on treatment with various antibiotics was studied in serum from specific pathogen free (SPF) pigs. Pigs were infected intranasally with A. pleuropneumoniae serotype 2, and either left as non-treated control pigs or treated with different antibiotics intramuscularly at onset of respiratory disease (20h post-infection). Pigs responded to the infection with prominent increases in activity and concentrations of IL-6, SAA, and haptoglobin. These responses were to a certain extent overlapping and covered the time span from a few hours after infection until development of detectable levels of specific antibodies (7-10 days post-infection in untreated pigs). The haptoglobin response lasted until the end of the study on day 17 and thereby partly coincided with the antibody response. Treatment with antimicrobials that effectively reduced establishment of the infection with A. pleuropneumoniae also reduced the duration of all three acute phase responses, and reduced the concentration of serum haptoglobin. In contrast, less efficacious treatments did not reduce these acute phase responses. Thus, acute phase reactants can be applied to monitor therapeutic effects of antimicrobial drugs in the pig and measurements of IL-6, SAA and haptoglobin could add valuable information about the stage of infection during a disease outbreak.

Putative biomarkers for evaluating antibiotic treatment: an experimental model of porcine Actinobacillus pleuropneumoniae infection

Biomarkers of infection were screened for their possible role as evaluators of antibiotic treatment in an aerosol infection model of porcine pneumonia caused by Actinobacillus pleuropneumoniae (Ap). Following infection of 12 pigs, clinical signs of pneumonia developed within 20 h, whereafter the animals received a single dose of either danofloxacin (2.5mg/kg) or tiamulin (10 mg/kg). To test the discriminative properties of the biomarkers, the dosage regimens were designed with an expected difference in therapeutic efficacy in favour of danofloxacin. Accordingly, the danofloxacin-treated pigs recovered clinically within 24h after treatment, whereas tiamulin-treated animals remained clinically ill until the end of the study, 48 h after treatment. A similar picture was seen for the biomarkers of infection. During the infection period, plasma C-reactive protein (CRP), interleukin-6 and haptoglobin increased, whereas plasma zinc, ascorbic acid and alpha-tocopherol decreased. In the danofloxacin-treated animals, CRP, interleukin-6, zinc, ascorbic acid and alpha-tocopherol reverted significantly towards normalisation within 24h of treatment. In contrast, signs of normalisation were absent (CRP, zinc and ascorbic acid) or less marked (interleukin-6 and alpha-tocopherol) in the tiamulin-treated animals. Plasma haptoglobin remained elevated throughout the study in both groups. This indicates that CRP, zinc, ascorbic acid and to a lesser extent interleukin-6 and alpha-tocopherol might be used to evaluate antibiotic treatment of acute Ap-infection in pigs. The present model provides a valuable tool in the evaluation of antibiotic treatments, offering the advantage of clinical and pathological examinations combined with the use of biochemical infection markers.

The erythrocyte adhesiveness/aggregation test for the detection of an acute phase response and for the assessment of its intensity

We have developed a simple slide test and image analysis to reveal the state of erythrocyte adhesiveness/aggregation in the peripheral blood of patients with various degrees of the humoral acute phase response. The significant correlation between the results of the erythrocyte adhesiveness/aggregation test (EAAT), the erythrocyte sedimentation rate and fibrinogen concentration support the notion that it is possible to use the EAAT as a marker for the intensity of the acute phase response. Within a group of 860 individuals, we were able to differentiate effectively between groups of patients with a different intensity of humoral acute phase response. The present study confirms previous observations that support the applicability of the EAAT to routine clinical practice.

C-reactive protein and IL-6: new marker proteins for the diagnosis of CJD in plasma?

BACKGROUND

CJD is usually diagnosed by clinical and neuropathological findings. A number of proteins regarded as markers for neuronal damage in plasma or serum have recently been described. Markers typical for tissue damage, although not usually associated with CJD, are another possibility. An evaluation of the relative usefulness of markers of neuronal and tissue damage in identifying CJD could be beneficial.

STUDY DESIGN AND METHODS

Plasma samples were collected from 46 patients with sporadic CJD and from a control group of 42 healthy subjects. The samples were analyzed with tests that were specific for C-reactive protein (CRP), IL-6, neuron-specific enolase (NSE), S-100 proteins, and cellular prion protein (PrP(c)). The results were compared, and a cutoff level for each test used was defined as the 90th percentile from the control group.

RESULTS

The assay specific for NSE identified only 13 percent of the sporadic CJD patients as positive. The identification rate of the other markers was significantly higher: S-100, 76.1 percent; PrP(c), 76.1 percent; CRP, 78.3 percent; and IL-6, 73.3 percent. Only three of the samples were positive in all five tests.

CONCLUSION

The markers for tissue damage, CRP and IL-6, are as useful as the previously described markers for neuronal damage in the diagnosis of CJD in plasma. All the markers tested are, however, of only limited value in the diagnosis of CJD in plasma. A combination of all surrogate markers improves the specificity but still provides no definitive diagnosis of the disease.

Interleukin-6 and C-reactive protein serum levels in sepsis-related fatalities during the early postmortem period

Postmortem interleukin-6 (IL-6) and C-reactive protein (CRP) serum levels were investigated prospectively in sepsis-related fatalities and non-septic fatalities by using a linear regression model. At least three blood samples were collected between 0.3 and 139 h postmortem from sepsis-related fatalities (n=8) and non-septic fatalities (n=16). In addition, one antemortem blood sample was collected shortly before death from the septic patients. Antemortem and postmortem IL-6 and CRP levels were highly elevated in all individuals included in the sepsis group. An excessive postmortem increase of IL-6 serum levels associated with progressive time after death was observed in five out of the eight septic patients. Both, IL-6 and CRP serum concentrations seem to be suitable biochemical postmortem markers of sepsis. The determination of IL-6 serum levels above 1500 pg/ml in peripheral venous blood obtained in the early postmortem interval can be considered as a diagnostic hint towards an underlying septic condition. A more precise postmortem discrimination between sepsis and non-septic underlying causes of death is provided by the postmortem measurement of serum CRP in peripheral venous blood: on condition that at least two postmortem CRP values have been determined at different time points postmortem, the CRP level of a deceased at the time of death can be calculated by using linear regression analysis. When assessing postmortem IL-6 and CRP concentrations as biochemical postmortem markers of sepsis, various clinical conditions, such as a preceding trauma or burn injury going along with elevated IL-6 and/or CRP levels prior to death as a result of the systemic inflammatory response syndrome (SIRS) should be taken into consideration, thus adding relevant information for the practical interpretation of the results.

The acute phase response of haptoglobin and serum amyloid A (SAA) in cattle undergoing experimental infection with bovine respiratory syncytial virus

The ability of a pure virus infection to induce an acute phase protein response is of interest as viral infections are normally considered to be less efficient in inducing an acute phase protein response than bacterial infections. This was studied in a bovine model for infection with bovine respiratory syncytial virus (BRSV), analysing the induction of the two most dominant bovine acute phase proteins haptoglobin and serum amyloid A (SAA). Strong and reproducible acute phase responses were detected for both proteins, peaking at around 7-8 days after inoculation of BRSV, while no response was seen in mock-inoculated control animals. The serum concentrations reached for SAA and haptoglobin during the BRSV-induced acute phase response were generally the same or higher than previously reported for bacterial infections in calves. The magnitude and the duration of the haptoglobin response was found to correlate well with the severity of clinical signs (fever) and with the extent of lung consolidation while SAA responded most rapidly to infection.

Erythrocyte sedimentation rate and C-reactive protein in the evaluation of disease activity and severity in polymyalgia rheumatica: a prospective follow-up study

OBJECTIVE

To determine the frequency and clinical features of patients with polymyalgia rheumatica (PMR) and normal erythrocyte sedimentation rate (ESR) at diagnosis or during relapse/recurrence. To evaluate the usefulness of C-reactive protein (CRP) and ESR in the assessment of PMR activity.

METHODS

A prospective follow-up study on 177 consecutive patients meeting the criteria for PMR diagnosed over a 5-year period was conducted in two Italian secondary referral centers of rheumatology. At diagnosis and during follow-up, ESR (Westergren method) and CRP (nephelometry) were measured in all patients. Phenotypic analysis of lymphocyte subpopulations was performed on 78 PMR patients at diagnosis. A two-color technique using the association of specific monoclonal antibodies was applied. A control group consisting of 18 healthy adults older than 60 years was matched for age and sex with the PMR patients.

RESULTS

Ten of 177 (6%) patients had normal ESR values at diagnosis (< or = 30 mm/h). Patients with normal ESR were predominantly men and had lower CRP levels; systemic signs and symptoms were more frequent in patients with higher ESR. The percentages of circulating CD8+ cells were similar in the two groups. CRP values at diagnosis were normal in only 2 of 177 (1%) patients. CRP values were elevated in 9 of 10 patients with normal ESR at diagnosis. Twenty-five episodes of relapse/recurrence with normal ESR occurred in 17 patients. CRP was high in 62% of these episodes. Results of univariate analysis indicated that the 10th percentile for ESR (40 mm/h) and the 70th percentile for CRP (7.8 mg/dL) values at diagnosis were the best cutoff points that discriminate between patients with and without relapse/recurrence. Cox proportional hazards modeling showed that ESR greater than 40 mm/h and CRP greater than 7.8 mg/dL at diagnosis were the two variables that independently increased the risk of relapse/recurrence. However, the relative risk related to ESR was twice than that related to CRP (4.9 vs 2.1).

CONCLUSION

PMR with a normal ESR at diagnosis was infrequent in our study compared with previous studies. ESR was a superior predictor of relapse than CRP. However, CRP was a more sensitive indicator of current disease activity.

Negative C-reactive protein in children with bacterial infection

PURPOSE

To evaluate the practical value of initial C-reactive protein (CRP) in the diagnosis of bacterial infection in children.

METHODS

The subjects comprised 11 children, six boys and five girls, aged 3 months through to 3 years (median age 16 months), whose initial CRP levels were < 1.0 mg/dL despite bacterial infection. C-reactive protein was quantitated at the first medical examination by nephelometry.

RESULTS

The diagnosis was urinary tract infection (n = 4), bacterial meningitis (n = 2), sepsis (n = 2), pneumonia (n = 2) and arthritis of the hip joint (n = 1). The CRP levels were significantly elevated during the course of infection, ranging from 7.6 to 28.5 mg/dL. The bacterial etiology was non-specific. Eight patients were examined within 12 h of onset, three exhibited negative CRP values despite the duration of the insult over 12 h. Six patients were tentatively diagnosed as having a bacterial infection, but the other five were not. Each patient was treated, leading to a favorable outcome without any serious complications.

CONCLUSIONS

Low levels of CRP do not rule out the possibility of bacterial infection in children. The initial value of CRP may be negative, even in patients with severe bacterial infection or even after 12 h from onset. The data suggest that pediatricians should consistently be aware of the possibility of bacterial infection even if the initial CRP test result is negative and that serial CRP measurements appear to be practical.

A non-competitive chemiluminescence enzyme immunoassay for the equine acute phase protein serum amyloid A (SAA) -- a clinically useful inflammatory marker in the horse

A non-competitive chemiluminescence enzyme immunoassay for measuring serum amyloid A (SAA) in equine serum was developed. A polyclonal anti-equine-amyloid A antiserum specific for equine SAA was utilized, and the assay was standardized using highly purified equine SAA. An acute phase horse serum was calibrated against the purified SAA and was used as standard when running the assay. Serum SAA concentrations in the range of 3-1210 mg/l could be measured. The reference range of SAA in clinically healthy adult horses was <7 mg/l. The clinical validation of the assay comprised the SAA responses after surgery and experimentally induced aseptic arthritis, and those associated with viral and bacterial infections. The SAA response after surgery (castration) was consistent, with peak concentrations on day 2 and a return to normal SAA concentrations within eight days. The aseptic arthritis produced an SAA response with a pattern similar to that seen after surgery, with peak concentrations of SAA 36-48 h after induction. Seven horses showed a biphasic pattern, with a second rise in SAA concentrations on day 4 and 5. All animals had SAA levels <7 mg/l on day 15. All horses with viral and bacterial infections had SAA concentrations above 7 mg/l. The ranges of SAA concentrations following the different types of inflammation overlap, being consistent with the unspecific nature of the SAA response. This study revealed that SAA is a sensitive and unspecific marker for inflammation, and describes the dynamics of the SAA response after standardized and well defined tissue damage.

Cartilage and bone macromolecules in knee joint synovial fluid in rheumatoid arthritis: relation to development of knee or hip joint destruction

OBJECTIVE

To examine the hypothesis that aggrecan, cartilage oligomeric matrix protein (COMP), and bone sialoprotein (BSP) concentrations in synovial fluid could provide information on variations of progression of joint destruction in rheumatoid arthritis.

METHODS

Aggrecan, COMP, and BSP were quantified by enzyme linked immunosorbent assays in longitudinally collected knee joint synovial fluid samples of patients rapidly developing destruction in knees or hips, the "'destructive" group, n = 18, and in patients slowly developing destruction, the "non-destructive" group, n = 25.

RESULTS

The aggrecan concentrations decreased from initially high levels (P < < 0.001), and the BSP concentrations increased (P < < 0.001) over time in the destructive group, whereas levels of both markers were low and did not change in the non-destructive group. The COMP levels did not change in any of the groups. The aggrecan concentrations were initially highest in the group developing destructions (P < < 0.001), whereas no difference between the groups was found regarding levels of COMP or BSP in the first sample.

CONCLUSIONS

A destructive group was characterised by higher initial aggrecan concentrations and rising BSP concentrations in synovial fluid with time. Quantification of cartilage and bone derived macromolecules contributes to the assessment of extent of tissue destruction and may help in the early identification of patients at risk of rapidly progressing destruction.

Evaluation of early rheumatoid arthritis disease activity and outcome

In rheumatoid arthritis nowadays a more aggressive treatment strategy is followed based on early consistent use of second-line agents frequently given in combination. This approach requires an accurate monitoring of the disease activity to follow the course of the disease and to evaluate therapeutic interventions. International consensus is reached over a core set of disease activity variables, including: a 28-joint count for tenderness and swelling, an acute phase reactant, patient's pain and global disease activity, physician's global disease activity, functional disability and radiographs. Guidelines for measurement techniques need to be further specified. Indices of disease activity are developed to improve the unambiguous interpretation of disease activity and comparability of trial results. These measures can be divided in measures for current disease activity and improvement criteria. Further validation will be necessary to adapt finally a uniform measurement technique. The usefulness of self-administered joint counts needs to be studied further.

Diagnostic value of C-reactive protein and transthyretin in bone infections of the lower limb

In a prospective study, white and red blood cell counts, hematocrit, erythrocyte sedimentation rate (ESR), albumin, alpha-1 acid glycoprotein, C-reactive protein (CRP), and transthyretin (TTR) values were determined by serial measurements during 23 days in 80 patients with an open fracture of the lower limb. Postoperative reference profiles were defined in 74 patients without septic complications. In the six remaining patients, serum CRP and TTR concentrations were found efficient for the early diagnosis of postoperative infections: a CRP/TTR mass concentration ratio higher than 0.6 from the 8th day after surgery was sensitive (100%) and specific (93%). Variations of CRP and TTR concentrations often preceded the clinical diagnosis in patients with early infection. ESR was found unreliable with regard to postoperative infection because of its high dependence with respect to red blood cell count.

Long pentraxins: an emerging group of proteins with diverse functions

The earliest described pentraxins, C reactive protein (CRP) and serum amyloid P component (SAP), are cytokine-inducible acute phase proteins implicated in innate immunity whose concentrations in the blood increase dramatically upon infection or trauma. The highly conserved family of pentraxins was thought to consist solely of approximately 25 kDa proteins. Recently, several distinct larger proteins have been identified in which only the C-terminal halves show characteristic features of the pentraxin family. One of the recently described "long" pentraxins (TSG-14/PTX3) is inducible by TNF or IL-1 and is produced during the acute phase response. Other newly identified long pentraxins are constitutively expressed proteins associated with sperm-egg fusion (apexin/p50), may function at the neuronal synapse (neuronal pentraxin I, NPI), or may serve yet other, unknown functions (NPII and XL-PXN1). Evidence obtained by molecular modeling and by direct physicochemical analysis suggests that TSG-14 protein retains some characteristic structural features of the pentraxins, including the formation of pentameric complexes.

beta-Amyloid induces increased release of interleukin-1 beta from lipopolysaccharide-activated human monocytes

Previous reports have demonstrated that IL-1 is elevated in the Alzheimer's disease brain. We propose that beta-amyloid (A beta) in senile plaques triggers microglial interleukin-1(IL-1) release. Since microglia and monocytes have similar lineage and functions, the human monocyte cell line, THP-1, was used to determine whether A beta peptides can stimulate release of IL-1 beta. THP-1 cells were grown in culture with LPS and incubated with various A beta peptides (0.5-10 microM). IL-1 released into the medium was measured using either an IL-1 beta ELISA or an IL-1 bioassay. Treatment of activated THP-1 cells with A beta 25-35, fibrillar A beta 1-40, or A beta 1-42 significantly elevated IL-1 beta release. A beta 25-35 with a scrambled sequence or non-fibrillar A beta 1-40 did not significantly change IL-1 beta release from activated THP-1 cells. The A beta 25-35- and fibrillar A beta 1-40 induced IL-1 beta release was dose-dependent. IL-1 released following treatment with A beta 25-35 and measured using an IL-1 bioassay gave similar results. The present report provides evidence that A beta is capable of elevating release of functional IL-1 beta, a potent pro-inflammatory cytokine, from macrophages/microglia and provides support that a chronic local inflammatory response is an ongoing phenomenon within and surrounding senile plaques.