Presence and Immunoreactivity of Aggregatibacter actinomycetemcomitans in Rheumatoid Arthritis

The presence of periodontal pathogens is associated with an increased prevalence of rheumatoid arthritis (RA). The systemic antibody response to epitopes of these bacteria is often used as a proxy to study correlations between bacteria and RA. The primary aim of the present study is to examine the correlation between the presence of Aggregatibacter actinomycetemcomitans (Aa) in the oral cavity and serum antibodies against the leukotoxin (LtxA) produced by this bacterium. The salivary presence of Aa was analyzed with quantitative PCR and serum LtxA ab in a cell culture-based neutralization assay. The analyses were performed on samples from a well-characterized RA cohort (n = 189) and a reference population of blood donors (n = 101). Salivary Aa was present in 15% of the RA patients and 6% of the blood donors. LtxA ab were detected in 19% of RA-sera and in 16% of sera from blood donors. The correlation between salivary Aa and serum LtxA ab was surprisingly low (rho = 0.55 [95% CI: 0.40, 0.68]). The presence of salivary Aa showed no significant association with any of the RA-associated parameters documented in the cohort. A limitation of the present study is the relatively low number of individuals with detectable concentrations of Aa in saliva. Moreover, in the comparison of detectable Aa prevalence between RA patients and blood donors, we assumed that the two groups were equivalent in other Aa prognostic factors. These limitations must be taken into consideration when the result from the study is interpreted. We conclude that a systemic immune response to Aa LtxA does not fully reflect the prevalence of Aa in saliva. In addition, the association between RA-associated parameters and the presence of Aa was negligible in the present RA cohort.

Exhaled Nitric Oxide Reflects the Immune Reactions of the Airways in Early Rheumatoid Arthritis

Patients with rheumatoid arthritis (RA) have altered levels of exhaled nitric oxide (NO) compared with healthy controls. Here, we investigated whether the clinical features of and immunological factors in RA pathogenesis could be linked to the NO lung dynamics in early disease. A total of 44 patients with early RA and anti-citrullinated peptide antibodies (ACPAs), specified as cyclic citrullinated peptide 2 (CCP2), were included. Their exhaled NO levels were measured, and the alveolar concentration, the airway compartment diffusing capacity and the airway wall concentration of NO were estimated using the Högman-Meriläinen algorithm. The disease activity was measured using the Disease Activity Score for 28 joints. Serum samples were analysed for anti-CCP2, rheumatoid factor, free secretory component, secretory component containing ACPAs, antibodies against Porphyromonas gingivalis (Rgp) and total levels of IgA, IgA1 and IgA2. Significant negative correlations were found between the airway wall concentration of NO and the number of swollen joints (Rho -0.48, p = 0.004), between the airway wall concentration of NO and IgA rheumatoid factor (Rho -0.41, p = 0.017), between the alveolar concentration and free secretory component (Rho -0.35, p = 0.023) and between the alveolar concentration and C-reactive protein (Rho -0.36, p = 0.016), but none were found for anti-CCP2, IgM rheumatoid factor or the anti-Rgp levels. In conclusion, altered NO levels, particularly its production in the airway walls, may have a role in the pathogenesis of ACPA-positive RA.

Prognostic value of serum protein electrophoresis constituents for arthritis development in anti-citrullinated protein antibody-positive patients with musculoskeletal pain

OBJECTIVE

Predictors of arthritis development in patients with anti-citrullinated protein antibodies (ACPAs) and musculoskeletal symptoms are needed for risk stratification and to improve clinical outcomes. The aim of this study was to assess the relationship between serum protein electrophoresis (SPE) constituents and the development of clinical arthritis in ACPA-positive patients with musculoskeletal pain.

METHOD

We prospectively followed 82 ACPA-positive patients with musculoskeletal pain but no baseline arthritis during a median of 72 months (interquartile range 57-81 months). The primary outcome was arthritis development, as judged by clinical examination. SPE constituents were evaluated in baseline sera by immunoturbidimetric methods. Serum levels of the analysed proteins (albumin, orosomucoid, α1-anti-trypsin, haptoglobin, and immunoglobulins IgA, IgG, and IgM) were related to arthritis development by Cox regression analyses.

RESULTS

During the follow-up period, 39/82 patients (48%) progressed to arthritis. Median baseline levels of orosomucoid and α1-anti-trypsin were higher in patients who developed arthritis than in those who did not (p = 0.04), while median albumin levels were significantly lower (p = 0.03). Immunoglobulin levels did not differ between the groups. Univariable analysis demonstrated a significantly increased risk of arthritis with elevated baseline haptoglobin [hazard ratio (HR) 2.53, 95% confidence interval (CI) 1.32-4.85, p = 0.005] and orosomucoid levels (HR 2.63, 95% CI 1.09-6.31, p = 0.03). However, neither remained significant in multivariable analysis adjusting for elevated C-reactive protein (CRP) levels.

CONCLUSION

SPE does not add prognostic value for arthritis development in ACPA-positive patients with musculoskeletal pain.

Elevated Serum Levels of Zonulin Family Peptides in Anticitrullinated Protein Antibody-Positive At-Risk Individuals Without Arthritis

OBJECTIVE

Recent advances imply that early events triggering rheumatoid arthritis (RA) occur at mucosal surfaces. We aimed to evaluate whether intestinal permeability is altered in patients at increased risk of RA, and/or predicts the development of clinical arthritis, by measuring serum zonulin family peptides (ZFP) levels, which are shown to reflect intestinal barrier integrity.

METHODS

Two independent prospective observational cohorts were studied, including subjects with musculoskeletal symptoms and anticitrullinated protein antibodies (ACPA), but without clinical arthritis at baseline. In Sweden, 82 such at-risk patients were compared to 100 age-matched healthy blood donors. In the UK, 307 at-risk patients were compared to 100 ACPA-negative symptomatic controls. ZFP was measured in baseline sera by enzyme-linked immunoassays.

RESULTS

In the Swedish at-risk cohort, ZFP levels were significantly increased in patients compared to controls (mean 41.4 vs 33.6 ng/mL, P < 0.001) and Cox regression analysis showed prognostic value of ZFP for arthritis development (hazard ratio [HZ] 1.04 per ng/mL ZFP increase, 95% CI 1.01-1.07, P = 0.02). Elevated ZFP levels among ACPA-positive at-risk patients compared to symptomatic ACPA-negative controls were confirmed in the UK at-risk cohort (mean 69.7 vs 36.0 ng/mL, P < 0.001), but baseline ZFP were not associated with arthritis development (HR 1.00 per ng/mL ZFP increase, 95% CI 1.00-1.01, P = 0.30).

CONCLUSION

Serum ZFP levels are elevated in ACPA-positive at-risk patients when compared to both healthy blood donors and symptomatic ACPA-negative controls. Thus, gut barrier function may be of importance in RA-associated autoimmunity. A possible prognostic value of serum ZFP merits further investigation, preferably in larger prospective cohorts.

Antibodies to leukotoxin A from the periodontal pathogen Aggregatibacter actinomycetemcomitans in patients at an increased risk of rheumatoid arthritis

Objectives

Periodontitis and underlying bacteria have been linked to the development of rheumatoid arthritis (RA). One suggested pathogen is Aggregatibacter actinomycetemcomitans (A.a.), which expresses leukotoxin A (LtxA) that can citrullinate human proteins, providing a possible trigger for the production of anti-citrullinated protein antibodies (ACPA). In this study, we seek to determine the presence of antibodies toward LtxA in patients at risk of developing RA.

Methods

Two prospective observational patient cohorts (one Swedish and one British) with symptomatic at-risk patients were studied. Anti-LtxA antibodies were analyzed by a cell-based neutralization assay in baseline serum and compared to 100 Swedish blood donors that served as controls.

Results

Serum anti-LtxA levels or positivity did not differ between patients and blood donors. In the British cohort, anti-LtxA was more prevalent among ACPA-positive arthralgia patients compared with ACPA-negative arthralgia cases (24% vs. 13%, p < 0.0001). In the Swedish at-risk cohort, anti-LtxA positive patients were at increased risk of progression to arthritis (hazard ratio (HR) 2.10, 95% CI 1.04-4.20), but this was not confirmed in the UK at-risk cohort (HR 0.99, CI 0.60-1.65).

Conclusion

Serum anti-LtxA is not elevated before RA diagnosis, and associations with disease progression and ACPA levels differ between populations. Other features of the oral microbiome should be explored in upcoming periodontitis-related RA research.

Conformational state of C-reactive protein is critical for reducing immune complex-triggered type I interferon response: Implications for pathogenic mechanisms in autoimmune diseases imprinted by type I interferon gene dysregulation

Presence of autoantibodies targeting nuclear constituents, i.e., double-stranded DNA and small nuclear ribonucleoproteins (snRNPs), remain a cornerstone in systemic lupus erythematosus (SLE). Fcγ receptor IIa (FcγRIIa) dependent uptake of nucleic acid containing immune complexes (ICs) by plasmacytoid dendritic cells (PDCs) can activate toll-like receptors (TLRs) such as TLR7 and TLR9 resulting in type I interferon (IFN) production. Previously, the classical liver-derived acute-phase reactant C-reactive protein (CRP) has been suggested to reduce IC-induced type I IFN production, whereas monomeric (mCRP) vs. pentameric (pCRP) mediated effects have not yet been unraveled. Herein, peripheral blood mononuclear cells (PBMCs) or enriched blood DCs from healthy volunteers were stimulated with SLE sera, snRNP-IgG (ICs), or TLR ligands with or without pCRP, mCRP, or anti-FcγRIIa antibody. Type I IFNs and cytokine responses were investigated using quantitative PCR, ELISA, and flow cytometry. pCRP inhibited IFN gene expression in PBMCs and enriched DCs after incubation with ICs, compared to ICs alone, whereas mCRP had significantly less inhibitory effect. The effect was independent on the order in which IC or CRP was added to the cells. In addition, pCRP inhibited IFN induced by other TLR stimulators, implicating broader inhibitory effects induced by pCRP. We demonstrate pronounced immunoregulatory functions of CRP whereas the inhibitory properties were evidently dependent on CRP's intact conformational state. The inhibition of type I IFNs was not due to competition of FcγRs, or binding of CRP to the ICs. Our findings have implications for autoimmune IC-mediated conditions imprinted by type I IFN gene dysregulation.

Serum serotonin levels are elevated in patients with increased risk of rheumatoid arthritis

Background

Even though serotonin (5-HT) has been ascribed immunomodulatory features, very little is known about its role in chronic inflammatory diseases. Serotonin is implicated in inflammation and increased levels have been associated with progression of bone erosions in RA.

Objective

To investigate serum serotonin levels in patients with increased risk of rheumatoid arthritis (RA) and patients with recent-onset disease. Moreover, we aimed to determine the prognostic value of serotonin for arthritis development and the disease course.

Methods

Two prospective observational patient cohorts were studied; anti-citrullinated protein antibody (ACPA) -positive patients with musculoskeletal pain without clinical arthritis (n = 82) and patients with early RA (n = 412). Serotonin levels were measured by enzyme-linked immunosorbent assay (ELISA) in baseline serum samples from both cohorts, and longitudinally in at-risk individuals.

Results

Compared to healthy controls (median 65 ng/ml), serotonin levels were significantly higher in both at-risk individuals (median 111 ng/ml, p < 0.0001) and patients with early RA (median 135 ng/ml, p < 0.0001). No significant differences were found between at-risk individuals and patients with early RA. At-risk individuals progressing to arthritis had similar levels as those not progressing, and no significant differences were seen over time. Baseline levels in early RA did not associate with mean 28-joint disease activity scores during 3 years follow-up.

Conclusion

Serum serotonin levels are elevated both at, and prior to, onset of RA. However, increased serotonin is not prognostic for arthritis development or disease course.

Extramucosal Formation and Prognostic Value of Secretory Antibodies in Rheumatoid Arthritis

OBJECTIVE

To investigate levels and possible extramucosal formation of secretory Ig, including anti-citrullinated protein antibodies (ACPAs), in rheumatoid arthritis (RA).

METHODS

Three patient groups were studied: 1) ACPA-positive patients with musculoskeletal pain without clinical arthritis, 2) patients with recent-onset RA, and 3) patients with established RA. In baseline serum samples (groups 1 and 2) and paired synovial fluid samples (group 3), we analyzed total secretory IgA, total secretory IgM, free secretory component (SC), and SC-containing ACPA. Extramucosal formation of SC-containing ACPA was investigated by preincubating RA sera and affinity-purified ACPA with recombinant free SC.

RESULTS

Compared to healthy controls, serum levels of total secretory IgA and total secretory IgM were increased both in patients with early RA and at-risk patients (P < 0.05). Patients with early RA with elevated total secretory Ig had significantly higher disease activity during the 3-year follow-up period compared to those without increased levels. At-risk patients who developed arthritis during follow-up (39 of 82) had higher baseline total secretory IgA levels compared to those who did not (P = 0.041). In established RA, total secretory IgA and total secretory IgM levels were higher in serum than in synovial fluid (P < 0.0001), but SC-containing ACPAs adjusted for total secretory Ig concentration were higher in synovial fluid (P < 0.0001). Preincubation with recombinant free SC yielded increased SC-containing ACPA reactivity in sera as well as in affinity-purified IgA and IgM ACPA preparations.

CONCLUSION

Circulating secretory Ig are elevated before and at RA onset. In the presence of free SC, secretory Ig may form outside the mucosa, and SC-containing ACPAs are enriched in RA joints. These findings shed important new light on the mucosal connection in RA development.

Circulating anti-citrullinated protein antibodies containing secretory component are prognostic for arthritis onset in at-risk patients

Autoantibodies related to rheumatoid arthritis (RA), such as anti‐citrullinated protein antibodies (ACPA), are often detectable in the preclinical period years before arthritis onset. However, events triggering arthritis development remain incompletely known. We aimed to determine whether ACPA isotype levels are prognostic for arthritis development in patients presenting with immunoglobulin (Ig)G ACPA and musculoskeletal pain. Study participants (n = 82) had musculoskeletal pain of any sort and duration and a positive IgG ACPA test. None of the patients had arthritis upon clinical examination at baseline, but during follow‐up (mean = 6 years), 48% developed at least one arthritic joint. IgG, IgA, IgM and secretory component (SC)‐containing ACPA was measured in longitudinally collected serum samples. Cox regression analysis was performed to test the prognostic value of baseline antibody levels and changes over time. All analysed ACPA isotype levels were associated with arthritis development in univariable Cox regression analysis. In multivariable analysis, baseline SC ACPA levels were independently prognostic for arthritis development in multivariable analysis [hazard ratio (HR) = 1·006, 95% confidence interval (CI) = 1·001–1·010, P = 0·012]. There were no significant changes in ACPA isotype levels over time, and no significant association between changes over time and arthritis development. In this prospective longitudinal study, baseline serum SC ACPA levels, but neither IgG, IgA nor IgM ACPA are prognostic for future arthritis development. Repeated measurement of ACPA isotypes do not bring additional prognostic value. The results reinforce a mucosal connection in RA development and encourage further exploration of the mechanisms underlying secretory ACPA formation as a trigger for arthritis development.

Bone Erosions Detected by Ultrasound Are Prognostic for Clinical Arthritis Development in Patients With ACPA and Musculoskeletal Pain

Anti-citrullinated protein antibodies (ACPA) often precede onset of rheumatoid arthritis (RA) by years, and there is an urgent clinical need for predictors of arthritis development among such at-risk patients. This study assesses the prognostic value of ultrasound for arthritis development among ACPA-positive patients with musculoskeletal pain. We prospectively followed 82 ACPA-positive patients without clinical signs of arthritis at baseline. Ultrasound at baseline assessed synovial hypertrophy, inflammatory activity by power Doppler, and erosions in small joints of hands and feet. We applied Cox regression analyses to examine associations with clinical arthritis development during follow-up (median, 69 months; range, 24–90 months). We also compared the ultrasound findings among the patients to a control group of 100 blood donors without musculoskeletal pain. Clinical arthritis developed in 39/82 patients (48%) after a median of 6 months (range, 1–71 months). One or more ultrasound erosions occurred in 13/82 patients (16%), with none in control subjects (p < 0.001). Clinical arthritis development was more common among patients with baseline ultrasound erosions than those without (77 vs. 42%, p = 0.032), and remained significant in a multivariable Cox regression analysis that included previously described prognostic factors (HR 3.9, 95% CI 1.6–9.4, p = 0.003). Ultrasound-detected tenosynovitis was more frequent among the patients and associated with clinical arthritis development in a univariable analysis (HR 2.5, 95% CI 1.1–5.7, p = 0.031), but did not remain statistically significant in multivariable analysis. Thus, bone erosions detected by ultrasound are independent predictors of clinical arthritis development in an ACPA-positive at-risk population.

Trial Registration: Regional Ethics Committee in Linköping, Sweden, Dnr M220-09. Registered 16 December 2009, https://etikprovningsmyndigheten.se/.

Pregnant under the pressure of a pandemic: a large-scale longitudinal survey before and during the COVID-19 outbreak

BACKGROUND

One of the groups that is most vulnerable to the COVID-19 pandemic is pregnant women. They cannot choose to refrain from care; they and their children are at risk of severe complications related to the virus; and they lose comfort and support as clinics prohibit their partners and as societal restrictions demand isolation from friends and relatives. It is urgent to study how this group is faring during the pandemic and we focus here on their health-related worries.

METHODS

A longitudinal survey at a Swedish hospital starting 6 months before (16 September 2019) and continuing during the COVID-19 outbreak (until 25 August 2020). A total of 6941 pregnant women and partners of diverse social backgrounds were recruited. Ninety-six percent of birth-giving women in the city take early ultrasounds where recruitment took place. Sixty-two percent of the women with an appointment and fifty-one percent of all partners gave consent to participate.

RESULTS

Pregnant women experienced dramatically increased worries for their own health, as well as for their partner's and their child's health in the beginning of the pandemic. The worries remained at higher than usual levels throughout the pandemic. Similar, but less dramatic changes were seen among partners.

CONCLUSIONS

There is a need for heightened awareness of pregnant women's and partners' health-related worries as a consequence of the COVID-19 pandemic. Related feelings, such as anxiety, have been linked to adverse pregnancy outcome and might have long-term effects. The healthcare system needs to prepare for follow-up visits with these families.

Autoantibodies are major predictors of arthritis development in patients with anti-citrullinated protein antibodies and musculoskeletal pain

Objectives: Predictors of arthritis development are highly warranted among patients with anti-citrullinated protein antibodies (ACPAs) and musculoskeletal symptoms to optimize clinical management. We aimed to identify clinical and laboratory predictors of arthritis development, including biochemically assessed alcohol consumption, among ACPA-positive patients with musculoskeletal pain.Method: 82 ACPA-positive individuals with musculoskeletal pain but no clinical arthritis were followed for a median of 72 months (interquartile range 57-81 months). We evaluated the prognostic value of baseline clinical and laboratory factors including smoking, symptom duration, age, gender, shared epitope, rheumatoid factor (RF), anti-carbamylated protein antibodies, ACPA levels, erythrocyte sedimentation rate, C-reactive protein levels, tender joint count, patient-reported general well-being, 28-joint Disease Activity Score, and alcohol consumption as measured by phosphatidyl ethanol (PEth) levels in whole blood.Results: During follow-up, 48% developed at least one arthritis. Multivariable analysis revealed an increased risk of arthritis development with RF positivity [hazard ratio (HR) = 2.3, 95% confidence interval (CI) 1.1-4.8, p = 0.028] and higher ACPA levels (HR = 1.0, 95% CI 1.000-1.001, p = 0.002). High levels of RF (HR = 4.4, 95% CI 1.7-11) entailed the highest HR in this ACPA-positive population. Neither clinical characteristics nor alcohol consumption measured by PEth conferred significant prognostic value.Conclusions: ACPA levels and concurrent presence of RF are independent predictors of arthritis development among ACPA-positive patients with musculoskeletal pain. The results are compatible with a dose-response relationship between RA-related autoantibodies and risk of arthritis development.

Presence of salivary IgA anti-citrullinated protein antibodies associate with higher disease activity in patients with rheumatoid arthritis

Background

Circulating IgA anti-citrullinated protein antibodies (ACPA) associate with more active disease, but a previous study implied that salivary IgA ACPA is related to a less severe disease. Therefore, we aimed to characterize the IgA ACPA response in the saliva and serum in relation to clinical picture and risk factors among patients with rheumatoid arthritis (RA).

Methods

RA patients (n = 196) and healthy blood donors (n = 101), included in the cross-sectional study “Secretory ACPA in Rheumatoid Arthritis” (SARA), were analyzed for ACPA of IgA isotype, and for subclasses IgA1 and IgA2 ACPA in paired saliva and serum samples using modified enzyme-linked immunosorbent assays (ELISA) targeting reactivity to a cyclic citrullinated peptide (anti-CCP). Cutoff levels for positive tests were set at the 99th percentile for blood donors. Antibody levels were related to clinical characteristics, radiographic damage, smoking habits, and carriage of HLA-DRB1/shared epitope (SE).

Results

IgA ACPA in the saliva was found in 12% of RA patients, IgA1 occurred in 10%, and IgA2 in 9%. In serum, IgA ACPA was found in 45% of the patients, IgA1 in 44%, and IgA2 in 39%. Levels of IgA ACPA in the saliva correlated significantly with serum levels of IgA (r = 0.455). The presence of salivary IgA ACPA was associated with a higher erythrocyte sedimentation rate (ESR), 28-joint disease activity score, tender joint count, and patient global assessment at the time of sampling. None of the antibodies was associated with smoking, SE, or radiographic damage.

Conclusion

Salivary IgA ACPAs were detected in a subset of RA patients in association with higher disease activity. This suggests that mucosal ACPA responses in the oral cavity may contribute to disease-promoting processes in RA.

Elevated free secretory component in early rheumatoid arthritis and prior to arthritis development in patients at increased risk

Objectives

Considering growing evidence of mucosal involvement in RA induction, this study investigated circulating free secretory component (SC) in patients with either recent-onset RA or with ACPA and musculoskeletal pain.

Methods

Two prospective cohorts were studied: TIRA-2 comprising 452 recent-onset RA patients with 3 years of clinical and radiological follow-up, and TIRx patients (n = 104) with ACPA IgG and musculoskeletal pain followed for 290 weeks (median). Blood donors and three different chronic inflammatory diseases served as controls. Free SC was analysed by sandwich ELISA.

Results

Serum levels of free SC were significantly higher in TIRA-2 patients compared with TIRx and all control groups (P < 0.01). Among TIRx patients who subsequently developed arthritis, free SC levels were higher compared with all control groups (P < 0.05) except ankylosing spondylitis (P = 0.74). In TIRA-2, patients with ACPA had higher baseline levels of free SC compared with ACPA negative patients (P < 0.001). Free SC status at baseline did not predict radiographic joint damage or disease activity over time. In TIRx, elevated free SC at baseline trendwise associated with arthritis development during follow-up (P = 0.066) but this disappeared when adjusting for confounders (P = 0.72). Cigarette smoking was associated with higher levels of free SC in both cohorts.

Conclusion

Serum free SC levels are increased in recent-onset RA compared with other inflammatory diseases, and associate with ACPA and smoking. Free SC is elevated before arthritis development among ACPA positive patients with musculoskeletal pain, but does not predict arthritis development. These findings support mucosal engagement in RA development.

Anti-cyclic citrullinated peptide antibodies are associated with radiographic damage but not disease activity in early rheumatoid arthritis diagnosed in 2006-2011

Objective: The discovery of anti-citrullinated protein antibodies (ACPAs) and the introduction of new therapeutic options have had profound impacts on early rheumatoid arthritis (RA) care. Since ACPA status, most widely assessed as reactivity to cyclic citrullinated peptides (CCPs), influences treatment decisions in early RA, we aimed to determine whether anti-CCP remains a predictor of disease activity and radiographic joint damage in more recent 'real-world' early RA. Method: Two observational early RA cohorts from Sweden enrolled patients in 1996-1999 (TIRA-1, n = 239) and 2006-2009 (TIRA-2, n = 444). Clinical and radiographic data and ongoing treatment were prospectively collected up to 3 years. Two other cohorts served as confirmation cohorts (TRAM-1, with enrolment 1996-2000, n = 249; and TRAM-2, 2006-2011, n = 528). Baseline anti-CCP status was related to disease activity, pharmacotherapy, and radiographic joint damage according to Larsen score. Results: In the TIRA-1 cohort, anti-CCP-positive patients had significantly higher 28-joint Disease Activity Score, swollen joint count, C-reactive protein level, and erythrocyte sedimentation rate during follow-up compared with anti-CCP-negative patients. In TIRA-2, no such differences were found, but baseline anti-CCP positivity was associated with higher 3 year Larsen score (5.4 vs 3.5, p = 0.039). In TRAM-2, anti-CCP also predicted radiographic damage (8.9 vs 6.7, p = 0.027), with no significant differences in disease activity. Conclusion: In the early RA cohorts recruiting patients in 2006-2011, baseline anti-CCP positivity was not associated with disease activity over time, but was associated with increased radiographic damage at follow-up. Hence, close radiographic monitoring is warranted in early anti-CCP-positive RA regardless of disease activity.

Secretory antibodies to citrullinated peptides in plasma and saliva from rheumatoid arthritis patients and their unaffected first-degree relatives

The aim of this study was to evaluate secretory antibodies to citrullinated proteins (ACPA) in plasma and immunoglobulin (Ig)A ACPA in saliva from patients with rheumatoid arthritis (RA) and their unaffected first‐degree relatives (FDRs). Patients with RA (n = 194) and first‐degree relatives unaffected by RA (n = 191) were recruited for analysis of secretory antibodies to second‐generation cyclic citrullinated peptides (anti‐CCP) in plasma. From a subpopulation (25 RA patients, 21 first‐degree relatives and 11 controls), saliva samples were obtained for IgA anti‐CCP analysis. The presence of secretory ACPA was compared between subject categories, and related to genetic and environmental risk factors. Secretory ACPA occurred in 37 (19%) plasma samples from patients with RA, but only in two (1%) of FDRs. IgA ACPA in saliva was found in three of 25 (12%) patients with RA, but not in any of the 21 FDRs (< 5%). No significant associations were seen between the presence of secretory ACPA and SE or smoking, either among RA patients or among FDRs. Despite occurring in 19% of RA plasma, secretory ACPA was rare in both saliva and plasma among FDRs, even among those positive for conventional ACPA of non‐mucosal origin. Longitudinal studies are warranted to determine whether circulating secretory ACPA occurs before or in parallel with the development of clinical arthritis.

Changes in anti-citrullinated protein antibody isotype levels in relation to disease activity and response to treatment in early rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease where serum analysis of anti-citrullinated peptide/protein antibodies (ACPA) is an important diagnostic/prognostic tool. Levels and changes of ACPA in RA patients have been studied previously in relation to disease course and therapy response, but less is known regarding ACPA isotype changes in early RA. Hence, recent-onset RA patients (n = 231) were subjected to a 3-year clinical and radiological follow-up. Serum samples were serially collected and ACPA isotypes were analysed using the second-generation cyclic citrullinated peptide (CCP) as capture antigen. Changes in ACPA isotype levels and status were related to disease course and pharmacotherapy. At inclusion, 74% of the patients tested positive for ACPA IgG; 55% for immunoglobulin (Ig)A, 37% for secretory IgA (SIgA) and 35% for IgM. The proportion of positive patients decreased significantly at follow-up regarding ACPA SIgA, IgM and IgA. During the initial 3 months, reduction of the 28-joint disease activity score (DAS28) correlated with reduced levels of ACPA IgG (Rho = 0·242, P = 0·003), IgA (Rho = 0·260, P = 0·008), IgM (Rho = 0·457, P < 0·001) and SIgA (Rho = 0·402, P < 0·001). Levels of ACPA SIgA (P = 0·008) and IgM (P = 0·021) decreased significantly among patients with good response to treatment, which was not seen regarding ACPA IgA or IgG. Changes in ACPA isotype levels were not associated with radiographic damage. In conclusion, ACPA SIgA and IgM declined rapidly upon anti-rheumatic therapy and correlated with decreased disease activity in recent-onset RA. This may indicate that down-regulation of mucosal immunity to citrullinated proteins/peptides and recruitment of new B cells are key features of therapy responses in early RA.

HLA-DR7 and HLA-DQ2: Transgenic mouse strains tested as a model system for ximelagatran hepatotoxicity

The oral thrombin inhibitor ximelagatran was withdrawn in the late clinical trial phase because it adversely affected the liver. In approximately 8% of treated patients, drug-induced liver injury (DILI) was expressed as transient alanine transaminase (ALT) elevations. No evidence of DILI had been revealed in the pre-clinical in vivo studies. A whole genome scan study performed on the clinical study material identified a strong genetic association between the major histocompatibility complex alleles for human leucocyte antigens (HLA) (HLA-DR7 and HLA-DQ2) and elevated ALT levels in treated patients. An immune-mediated pathogenesis was suggested. Here, we evaluated whether HLA transgenic mice models could be used to investigate whether the expression of relevant HLA molecules was enough to reproduce the DILI effects in humans. In silico modelling performed in this study revealed association of both ximelagatran (pro-drug) and melagatran (active drug) to the antigen-presenting groove of the homology modelled HLA-DR7 molecule suggesting “altered repertoire” as a key initiating event driving development of DILI in humans. Transgenic mouse strains (tgms) expressing HLA of serotype HLA-DR7 (HLA-DRB1*0701, -DRA*0102), and HLA-DQ2 (HLA-DQB1*0202,–DQA1*0201) were created. These two lines were crossed with a human (h)CD4 transgenic line, generating the two tgms DR7xhCD4 and DQ2xhCD4. To investigate whether the DILI effects observed in humans could be reproduced in tgms, the mice were treated for 28 days with ximelagatran. Results revealed no signs of DILI when biomarkers for liver toxicity were measured and histopathology was evaluated. In the ximelagatran case, presence of relevant HLA-expression in a pre-clinical model did not fulfil the prerequisite for reproducing DILI observed in patients. Nonetheless, for the first time an HLA-transgenic mouse model has been investigated for use in HLA-associated DILI induced by a low molecular weight compound. This study shows that mimicking of genetic susceptibility, expressed as DILI-associated HLA-types in mice, is not sufficient for reproducing the complex pathogenesis leading to DILI in man.

Immunoglobulin (Ig)G1 and IgG4 anti-cyclic citrullinated peptide (CCP) associate with shared epitope, whereas IgG2 anti-CCP associates with smoking in patients with recent-onset rheumatoid arthritis (the Swedish TIRA project)

Given the possible importance of anti-citrullinated peptide/protein antibodies (ACPA) for initiation and progression of rheumatoid arthritis (RA), extended knowledge about the different isotypes and subclasses is important. In the present study, we analysed the immunoglobulin (Ig)G subclasses regarding reactivity against cyclic citrullinated peptides (anti-CCP) among 504 clinically well-characterized patients with recent-onset RA in relation to smoking habits, shared epitope (SE) status and IgA and pan-IgG anti-CCP antibodies. All patients, regardless of pan-IgG anti-CCP status, were analysed for IgG1-4 CCP reactivity. Sixty-nine per cent were positive in any IgG anti-CCP subclass, and of these 67% tested positive regarding IgG1, 35% IgG2, 32% IgG3, and 59% IgG4 anti-CCP. Among ever-smokers the percentages of IgG2 anti-CCP (P = 0·01) and IgA anti-CCP (P = 0·002)-positive cases were significantly higher compared to never-smokers. A positive IgG anti-CCP subclass -negative cases. Combining SE and smoking data revealed that IgG1 and IgG4 anti-CCP were the IgG anti-CCP isotypes associated with expression of SE, although the lower number of patients positive for IgG2 or IgG3 anti-CCP could, however, have influenced the results. High levels of IgG2 anti-CCP were shown to correlate with expression of the 'non-SE' allele human leucocyte antigen (HLA)-DRB1*15. In conclusion, in this study we describe different risk factor characteristics across the IgG anti-CCP subclasses, where IgG2 appears similar to IgA anti-CCP regarding the predominant association with smoking, while IgG1 and IgG4 related more distinctly to the carriage of SE genes.

Circulating secretory IgA antibodies against cyclic citrullinated peptides in early rheumatoid arthritis associate with inflammatory activity and smoking

Background

A possible association between mucosal immunization and inflammation, as well as the initiation and propagation of rheumatoid arthritis (RA), is attracting renewed interest. The aim of this study was to evaluate the possible occurrence and clinical correlations of circulating secretory immunoglobulin A (SIgA) antibodies against the second-generation cyclic citrullinated peptides (CCP) among patients with recent-onset RA followed prospectively over 3 years.

Methods

Baseline serum samples from 636 patients with recent-onset RA were analyzed for SIgA anti-CCP antibodies by using an enzyme-linked immunosorbent assay with a secondary antibody directed against secretory component. SIgA anti-CCP status at baseline was analyzed in relation to smoking, HLA-DRB1/shared epitope (SE), and the disease course over 3 years. Significant findings were evaluated in regression analysis that included age, sex, smoking, and SE.

Results

Seventeen percent of the patients tested positive for circulating SIgA anti-CCP, and the occurrence was confirmed by detection of secretory component in an affinity-purified IgA anti-CCP fraction. SIgA anti-CCP positivity at baseline was associated with slightly higher baseline erythrocyte sedimentation rate (ESR) (mean 38 vs. 31 mm/first hour, p = 0.004) and C-reactive protein (CRP) (mean 30 vs. 23 mg/L, p = 0.047). During follow-up, SIgA anti-CCP-positive patients had a higher mean AUC regarding ESR (adjusted p = 0.003), although there were no significant differences regarding CRP, tender and swollen joint counts, or radiological joint damage (median Larsen progression 1.0 vs. 1.0, p = 0.22). SIgA anti-CCP was associated significantly with smoking (79 % ever smokers among SIgA anti-CCP-positive patients vs. 59 % in SIgA anti-CCP-negative patients, adjusted OR 2.19, 95 % CI 1.01–4.37, p = 0.027) but not with carriage of the SE (80 % vs. 73 %, p = 0.62).

Conclusions

Circulating SIgA anti-CCP, which is present in a subgroup of patients with early RA, is not related to SE, but it is environmentally linked to cigarette smoking. This finding strengthens the hypothesis that immunization against citrullinated peptides and/or proteins may occur at mucosal surfaces of the airways. Analysis of SIgA antibodies in serum may be a convenient and more versatile means to investigate the “mucosal connection” in RA compared with analyses in mucosal fluid samples.

Soluble urokinase plasminogen activator receptor levels are associated with severity of fibrosis in nonalcoholic fatty liver disease

The identification of individuals with severe liver fibrosis among patients with chronic liver disease is of major importance when evaluating prognosis, potential risk for complications, and when deciding treatment strategies. Although percutaneous liver biopsy is still considered a "gold standard" for staging of liver fibrosis, attempts to find reliable noninvasive markers of liver fibrosis are frequent. Inflammation is essential for the progression of fibrosis. The urokinase plasminogen activator and its receptor have been associated with hepatic inflammation and fibrosis in mice. High serum concentrations of soluble urokinase plasminogen activator receptor (suPAR) are suggested to be involved in inflammation, tissue remodeling, and cancer metastasis. Here, we evaluated serum suPAR as a noninvasive test to detect liver fibrosis in 82 well-characterized patients with nonalcoholic fatty liver disease (NAFLD), and in 38 untreated patients with chronic hepatitis C virus (HCV) infection at the time of their first liver biopsy. suPAR levels were increased in chronic liver disease compared with blood donors (P < 0.001). Patients with HCV had higher suPAR concentrations than patients with NAFLD (P < 0.002). suPAR levels were associated with the severity of fibrosis, particularly in NAFLD, but did not correlate with inflammation. Regarding the performance in predicting severity of fibrosis, suPAR was essentially as good as other commonly used noninvasive fibrosis scoring systems. The results in HCV confirm previous observations. However, this is the first study to investigate suPAR as a biomarker in NAFLD, and the results indicate that suPAR may constitute a severity marker related to fibrosis and prognosis rather than reflecting inflammation.

Effects of Temperature during Moist Heat Treatment on Ruminal Degradability and Intestinal Digestibility of Protein and Amino Acids in Hempseed Cake

The objective of this study was to evaluate ruminal degradability and intestinal digestibility of crude protein (CP) and amino acids (AA) in hempseed cake (HC) that were moist heat treated at different temperatures. Samples of cold-pressed HC were autoclaved for 30 min at 110, 120 or 130°C, and a sample of untreated HC was used as the control. Ruminal degradability of CP was estimated, using the in situ Dacron bag technique; intestinal CP digestibility was estimated for the 16 h in situ residue using a three-step in vitro procedure. AA content was determined for the HC samples (heat treated and untreated) of the intact feed, the 16 h in situ residue and the residue after the three-step procedure. There was a linear increase in RUP (p = 0.001) and intestinal digestibility of RUP (p = 0.003) with increasing temperature during heat treatment. The 130°C treatment increased RUP from 259 to 629 g/kg CP, while intestinal digestibility increased from 176 to 730 g/kg RUP, compared to the control. Hence, the intestinal available dietary CP increased more than eight times. Increasing temperatures during heat treatment resulted in linear decreases in ruminal degradability of total AA (p = 0.006) and individual AA (p<0.05) and an increase in intestinal digestibility that could be explained both by a linear and a quadratic model for total AA and most individual AA (p<0.05). The 130°C treatment decreased ruminal degradability of total AA from 837 to 471 g/kg, while intestinal digestibility increased from 267 to 813 g/kg of rumen undegradable AA, compared with the control. There were differences between ruminal AA degradability and between intestinal AA digestibility within all individual HC treatments (p<0.001). It is concluded that moist heat treatment at 130°C did not overprotect the CP of HC and could be used to shift the site of CP and AA digestion from the rumen to the small intestine. This may increase the value of HC as a protein supplement for ruminants.

A triple-transgenic immunotolerant mouse model

Avoiding unwanted immunogenicity is of key importance in the development of therapeutic drug proteins. Animal models are of less predictive value because most of the drug proteins are recognized as foreign proteins. However, different methods have been developed to obtain immunotolerant animal models. So far, the immunotolerant animal models have been developed to assess one protein at a time and are not suitable for the assessment of combination products. Our aim was to develop an animal model for evaluating the impact of manufacturing and formulation changes on immunogenicity, suitable for both single protein and combination products. We constructed two lines of transgenic mice expressing the three human coagulation factors, II, VII, and X, by inserting a single vector containing the three coagulation factors encoding sequences separated by insulator sequences derived from the chicken beta-globin locus into the mouse genome. Immunization of transgenic mice from the two lines and their wild-type littermates showed that transgenic mice from both lines were immunotolerant to the expressed human coagulation factors. We conclude that transgenic mice immunotolerant to multiple proteins can be obtained, and that these mice are potentially useful as animal models in the assessment of immunogenicity in response to manufacturing changes. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:1116–1124, 2013

Effects of feeding dairy cows different legume-grass silages on milk phytoestrogen concentration

Phytoestrogens are hormone-like substances in plants that can substantially influence human health (positively or negatively), and when fed to dairy cows are partly transferred to their milk. The aim of this study was to investigate the effects of varying the botanical composition and regrowth interval of legume-grass silage on phytoestrogen intake and milk phytoestrogen concentrations. In one experiment, 15 Swedish Red dairy cows were fed 2- or 3-cut red clover-grass silage, or 2-cut birdsfoot trefoil-grass silage. In a second experiment, 16 Norwegian Red dairy cows were fed short-term ley silage with red clover or long-term ley silage with white clover, and the effects of supplementation with α-tocopherol were also tested. High concentrations of formononetin and biochanin A were found in all silage mixtures with red clover. The milk concentration of equol was highest for cows on the 2-cut red clover-grass silage diet (1,494 μg/kg of milk). Because of the metabolism of biochanin A, genistein, and prunetin, their concentrations in milk and the apparent recovery were low. Coumestrol was detected in only short-term and long-term ley silage mixtures, and its milk concentration was low. Concentrations of secoisolariciresinol and matairesinol were higher in 2-cut birdsfoot trefoil-grass and long-term ley silage mixtures, those with legume species other than red clover, and the highest grass proportions. The 2-cut birdsfoot trefoil-grass silage diet also resulted in higher enterolactone concentration than the other diets (226 μg/kg of milk). Lengthening the regrowth interval increased the intake of secoisolariciresinol and decreased the recovery of lignans. Feeding long-term ley silage resulted in higher milk lignan concentrations but lower milk isoflavone concentrations than feeding short-term ley silage. The apparent recovery of all phytoestrogens except prunetin was highest on the 2-cut birdsfoot trefoil-grass silage diet. No effect of α-tocopherol supplementation was observed on milk concentrations of any of the measured phytoestrogens. Variations were observed in milk concentrations of phytoestrogens, especially of equol, among cows, which could not be explained by variations in diet composition or phytoestrogen intake. The results show that milk phytoestrogen concentration is strongly influenced by silage botanical composition, but questions regarding phytoestrogen metabolism remain to be answered.

Dietary influence on the m. longissimus dorsi fatty acid composition of lambs in relation to protein source

Dietary lipid effect, as a consequence of protein supplement, on lamb m. longissimus dorsi fatty acid composition was investigated, with emphasis on biohydrogenation intermediates. Crossbred lambs (White Swedish Landrace × Texel) were fed a barley-based diet without (CON) or with protein supplements including peas (PEA), rapeseed cake (RC) or hempseed cake (HC). The HC diet resulted in the highest muscle 22:6n-3 proportion, with the RC diet being similar (P<0.05). Protein supplement did not affect the c9,t11 conjugated linoleic acid (CLA) proportion, however the HC diet increased some minor CLA isomers, including t10,c12 CLA (P<0.05). The t10-18:1 and total trans-18:1 were lowest for the RC diet (P<0.05), likely relating to rumen conditions and precursor availability. The saturated, monounsaturated and branched-chain fatty acids were largely unaffected by protein supplement. In conclusion, feeding the RC diet lowered the t10-18:1 and total trans-18:1 in meat, and modestly increased 22:6n-3 content. The direction of these changes would be beneficial, making the RC diet the preferred protein supplement; however the magnitude of the changes in the present experiment may not be sufficient to have an impact on human health.

In silico analysis of HLA associations with drug-induced liver injury: use of a HLA-genotyped DNA archive from healthy volunteers

Background

Drug-induced liver injury (DILI) is one of the most common adverse reactions leading to product withdrawal post-marketing. Recently, genome-wide association studies have identified a number of human leukocyte antigen (HLA) alleles associated with DILI; however, the cellular and chemical mechanisms are not fully understood.

Methods

To study these mechanisms, we established an HLA-typed cell archive from 400 healthy volunteers. In addition, we utilized HLA genotype data from more than four million individuals from publicly accessible repositories such as the Allele Frequency Net Database, Major Histocompatibility Complex Database and Immune Epitope Database to study the HLA alleles associated with DILI. We utilized novel in silico strategies to examine HLA haplotype relationships among the alleles associated with DILI by using bioinformatics tools such as NetMHCpan, PyPop, GraphViz, PHYLIP and TreeView.

Results

We demonstrated that many of the alleles that have been associated with liver injury induced by structurally diverse drugs (flucloxacillin, co-amoxiclav, ximelagatran, lapatinib, lumiracoxib) reside on common HLA haplotypes, which were present in populations of diverse ethnicity.

Conclusions

Our bioinformatic analysis indicates that there may be a connection between the different HLA alleles associated with DILI caused by therapeutically and structurally different drugs, possibly through peptide binding of one of the HLA alleles that defines the causal haplotype. Further functional work, together with next-generation sequencing techniques, will be needed to define the causal alleles associated with DILI.

The development of in vitro culture methods to characterize primary T-cell responses to drugs

Adverse drug reactions represent a major stumbling block to drug development and those with an immune etiology are the most difficult to predict. We have developed an in vitro T-cell priming culture method using peripheral blood from healthy volunteers to assess the allergenic potential of drugs. The drug metabolite nitroso sulfamethoxazole (SMX-NO) was used as a model drug allergen to establish optimum assay conditions. Naive T cells were cocultured with monocyte-derived dendritic cells at a ratio of 25:1 in the presence of the drug for a period of 8 days, to expand the number of drug-responsive T cells. The T cells were then incubated with fresh dendritic cells, and drug and their antigen responsiveness analyzed using readouts for proliferation, cytokine secretion, and cell phenotype. All five volunteers showed dose-dependent proliferation as measured by 5-(and 6)-carboxyfluorescein diacetate succinimidyl ester content and by (3)H-thymidine uptake. CD4 T cells that had divided in the presence of SMX-NO had changed from a naive phenotype (CD45RA+) to a memory phenotype (CD45RO+). These memory T cells expressed the chemokine receptors CCR2, CCR4, and CXCR3 suggesting a mixture of T(H)1 and T(H)2 cells in the responding population, with a propensity for homing to the skin. Drug stimulation was also associated with the secretion of a mixture of T(H)1 cytokines (interferon γ) and T(H)2 cytokines (interleukin [IL]-5 and IL-13) as detected by ELISpot. We are currently developing this approach to investigate the allergenic potential of other drugs, including those where an association between specific human leucocyte antigen alleles and susceptibility to an immunological reaction has been established.

The effect of activating and inhibiting Fc-receptors on murine mercury-induced autoimmunity

Fc-receptors for IgG (FcgammaR) link cellular and humoral immune responses, controlling the balance between activating and inhibitory immune responses, and are involved in autoimmune diseases. Mercury (Hg) induces an autoimmune condition in genetically (H-2(s,q,f)) susceptible mice characterized by lymphoproliferation, hypergammaglobulinemia and IgG antinucleolar antibodies (ANoA). Here we investigate the role of activating (FcgammaRI, FcgammaRIII) and inhibitory (FcgammaRIIb) Fc-receptors on mercury-induced autoimmunity (HgIA) using DBA/1 mice (H-2(q)) with targeted FcgammaR mutations and wild type (wt) mice. Mice deficient for the FcRgamma-chain or FcgammaRIII and treated with 15 mg/L HgCl(2) showed a delayed and attenuated IgG1, IgG2a and IgG2b ANoA response compared to wt mice. Female Hg-treated FcgammaRIIB(-/-) mice showed a significant increased of IgG2b ANoA development compared to wt mice. The total serum IgG1 response due to Hg was attenuated in FcRgamma(-/-) and FcgammaRIII(-/-) mice compared to wt mice. Hg-treated FcgammaRIIB(-/-) mice showed an increase of both serum IgG1 and IgE compared to wt mice. We conclude that FcgammaRIII is of importance for the rapidity and final strength of the ANoA response and the increase in serum IgG1 in HgIA, while lack of FcgammaRIIb increases the IgG2b ANoA response and the serum IgG1 and IgE response.

Udder health at a Swedish research farm with both organic and conventional dairy cow management

Our aim was to compare udder health in groups of organically and conventionally managed cows, using data from a longitudinal study in a Swedish dairy-research farm. Management of the groups was identical except for feed composition and the feeding regimen. Our dataset included all lactating cows calving from 1 September 1990 to 31 August 2001 (145 organically and 151 conventionally managed cows). Udder health was assessed by the geometric average somatic-cell count (SCC) within 150 days after calving, by the number of monthly SCC tests >200,000 cells/ml within 150 days after calving and by presence of lactations with veterinary-treated cases of clinical mastitis. The effect of animal group was analysed by multivariable linear, Poisson and logistic-regression models, controlling for factors such as lactation number, breed, year, season and milk yield. The groups did not differ in any measure of udder health. We had power to rule out differences of at least 33,000 cells/ml in the geometric average somatic-cell count, an incidence rate ratio of 0.65 in the incidence of high-SCC milk-testing occasions, and an odds ratio of 0.43 in veterinary treated cases of mastitis.

The role of Fc-receptors in murine mercury-induced systemic autoimmunity

Inorganic mercury (Hg) in genetically susceptible mouse strains induces a T cell-dependent, systemic autoimmune condition (HgIA) characterized by immunostimulation, anti-nuclear antibodies (ANA) and systemic immune-complex (IC) deposits. The exact phenotypic expression of HgIA in different strains depends on H-2 and non-H-2 genes. Fc receptors (FcRs) are important in the development of many autoimmune diseases. In this study, the effect of targeted mutations for activating and inhibiting FcRs in the BALB/c model of HgIA was examined. Hg-treated BALB/c mice without mutation (wild-type, wt) showed heavy IC deposits in the renal glomerular mesangium, as well as in renal and splenic vessel walls. The renal mesangial IC deposits were severely reduced in Hg-treated BALB/c mice without the gamma-chain (lack of the activating receptors FcgammaRI, FcgammaRIII and FcinRI), but unchanged in mice lacking the inhibitory FcgammaRIIB. The Hg-induced vessel wall IC deposits present in wt mice were abolished and reduced in the FcRgamma and FcgammaRIIB strains, respectively. Hg-treated BALB/c wt mice and mice without the gamma-chain showed an increase in serum IgE, while the increase in IgG1 was attenuated in the latter strain. In contrast, absence of the inhibiting FcgammaRIIB augmented the Hg-induced increase of both serum IgG1 and IgE. In conclusion, FcRs are important mainly for the induction of systmeic IC deposits in the HgIA model, but also affects serum IgG1 and IgE levels.

Concentrations of antisecretory factor in eggs and in chicken blood plasma

1. In the present study, the concentration of antisecretory factor (ASF), a lectin with hormone-like properties, and with the capacity to regulate water and electrolyte transport in the small intestine, was higher in hen's egg yolk than in egg white (1.20 v. 0.46 units/ml). 2. The blood plasma concentrations of ASF activity were higher in d-old chicks (1.03 units/ml) than in 7-d-old (0.42 units/ml) or 21-d-old birds (0.18 units/ml); the contents were found to be high again in 35-d-old chickens, but to have decreased by 60 to 90% after transport to slaughter 1 day later. 3. The amount of ASF activity was lower in two groups of chickens manifesting patent loose droppings at slaughter (0.15 units/ml in one group, and 0.08 units/ml in the other), than in two groups with normal faecal consistency (0.65 units/ml in one group, and 0.72 units/ml in the other). 4. The results demonstrate the presence of ASF in eggs, and a variation of ASF activity in chickens blood plasma in relation to age, stress and faecal consistency. The interpretation of these data suggests a regulatory influence of ASF on chicken intestinal transport of water.

Feed-induced lectins in piglets. Feed-induced lectins and their effect on post-weaning diarrhoea, daily weight gain and mortality

The effect on various biological variables of a special weaner feed (FD) with the capacity to induce endogenous synthesis of feed induced lectins (FIL), and a commonly used commercial diet (CD) was evaluated in 891 piglets in four different experiments. The FD diet was found to induce a high activity of FIL (FIL = 0.94 +/- 0.03 units/ml. blood), as compared to CD (FIL < 0.20 units/ml. blood). The FIL values did not decrease after weaning. The incidence of diarrhoea in piglets fed FD 0-14 days post-weaning was 12 +/- 5 per cent, as compared to 41 +/- 9 per cent in the CD group, the difference being significant. Daily weight gain 0-35 days after weaning was 67 +/- 15 grams greater in the FD group than among those fed CD. The consumption of FD was double that of CD in the period before weaning (at 5 weeks), and some 40 per cent more in the postweaning period up to 9 weeks of age.

Plasma level of antisecretory factor (ASF) and its relation to post-weaning diarrhoea in piglets

Antisecretory factor (ASF) is a regulatory peptide which counteracts diarrhoea in the pig; ASF is rapidly absorbed from the pig intestine, and significantly reduces the incidence of neonatal diarrhoea in the suckling offspring. ASF is synthesized in the central nervous system, and released to the blood stream via the pituitary gland. In two different experiments (n = 8 and n = 4), the blood concentration of ASF was followed in 5-weeks old piglets from day 7 before weaning up to day 12 days after weaning. In both experiments ASF concentrations were significantly (p < 0.01) lower on day three post-weaning, than either before weaning or on days 7 and 12 post-weaning. In another experiment, where plasma ASF activity was determined in relation to clinical signs of diarrhoea seven days post-weaning, it was found to be 0.87 +/- 0.08 units/ml (mean +/- SEM) in healthy weaners (n = 15), but only 0.22 +/- 0.05 units/ml in piglets suffering from diarrhoea (n = 15), the difference being significant. The faecal flora both of healthy weaners and of their matched controls suffering from diarrhoea were subjected to bacteriological examination before and after weaning, and found to be similar in both groups, namely a mixture of aerobic and anaerobic Gram negative rods, Campylobacter jejuni, Staphylococcus aureus/epidermidis, and Enterococcus faecalis. No particular pathogen was predominant in any of the diseased animals.

Observations on the action of amperozide: are there social influences on sow-litter productivity?

The effects of amperozide on sow performance when administered as a single intramuscular injection of 1 mg kg-1 at the time of either farrowing or weaning, or on both occasions were evaluated. Treatments were given during the rearing of two consecutive litters with each individual sow remaining on the same treatment throughout the trial. In total, 64 sows, 16 per treatment group, were used to investigate the effects on weight loss during lactation, mastitis-metritis agalactia (MMA) and duration of the reproductive cycle. Untreated control sows lost more weight (2 to 3 kg) during lactation than sows treated with amperozide at farrowing. No clinical outbreak of MMA was recorded in the amperozide groups dosed at the time of farrowing. The number of empty days was decreased (about three days) in sows treated with amperozide at weaning. Furthermore, pre-weaning mortality decreased (8 per cent) and piglet growth rate improved (6 per cent) when sows were treated with amperozide at farrowing. The results suggest that amperozide improves the health status and productivity of sows by reducing their emotional responses to novel or threatening situations.

Thin sow syndrome (TSS): the effect of amperozide

Sixty sows suffering from typical post-weaning TSS were divided into three groups: (1) 20 as negative controls (NC); (2) 20 as positive controls (PC) treated with vitamins, trace elements and antibiotics; and (3) 20 injected with amperozide (2 mg/kg body weight), a new neuroleptic compound with antistress and anxiolytic properties. Amperozide treated sows fully recovered (P less than 0.05) and 80% became pregnant, while figures for the PC and NC groups were only 15% and 10% respectively. Mortality was up to 50% in the NC, 40% in the PC and only 15% in the amperozide treated group (P less than 0.05). These field results warrant further studies in unravelling the aetiology and prevention of this condition.

Effects of amperozide on biting behavior and performance in restricted-fed pigs following regrouping

Eight experiments were conducted to determine the effect of a single administration of amperozide on agonistic behavior and growth performance in newly mixed, restricted-fed pigs. Two hundred 12-wk-old pigs were used in a 4-wk trial (Exp. 1) to investigate the effect of amperozide on agonistic behavior and performance. The pigs were assigned to each pen on the basis of body weight and sex, ensuring that pigs in each pen were unacquainted. Each pig was weighed individually on d 3, 7 and 28. Agonistic behavior was quantified by counting bite and slash marks on each pig at 8, 26 and 48 h after penning. An i.m. injection of amperozide immediately before mixing the pigs reduced the physical damage (P less than .001) at each time point. There was no evidence of amperozide causing either sedation or motor disturbances. On the average, amperozide treatment improved (P less than .001) daily gain in the 4-wk study period by 70 g (17%). In Exp. 2 to 8, 1,648 pigs growing from approximately 20 to 100 kg body weight were used to determine the effect of amperozide on weight gain. Pigs were penned in groups of 9 to 11, randomly assigned to each pen on the basis of sex. Each pig was weighed individually after penning, on d 35 and at slaughter. Untreated control pigs had a poorer growth performance than did amperozide-treated pigs. During the first 5 wk postpenning average daily gain was improved (P less than .001) by 90 g (26%) in pigs receiving a single oral administration of amperozide at penning.(ABSTRACT TRUNCATED AT 250 WORDS)