Thrombocytosis of active rheumatoid disease

Clinical prediction rule for bacterial arthritis: Chi-squared automatic interaction detector decision tree analysis model

Objectives:

Differences in demographic factors, symptoms, and laboratory data between bacterial and non-bacterial arthritis have not been defined. We aimed to identify predictors of bacterial arthritis, excluding synovial testing.

Methods:

This retrospective cross-sectional survey was performed at a university hospital. All patients included received arthrocentesis from January 1, 2010, to December 31, 2020. Clinical information was gathered from medical charts from the time of synovial fluid sample collection. Factors potentially predictive of bacterial arthritis were analyzed using the Student’s t-test or chi-squared test, and the chi-squared automatic interaction detector decision tree analysis. The resulting subgroups were divided into three groups according to the risk of bacterial arthritis: low-risk, intermediate-risk, or high-risk groups.

Results:

A total of 460 patients (male/female = 229/231; mean ± standard deviation age, 70.26 ± 17.66 years) were included, of whom 68 patients (14.8%) had bacterial arthritis. The chi-squared automatic interaction detector decision tree analysis revealed that patients with C-reactive protein > 21.09 mg/dL (incidence of septic arthritis: 48.7%) and C-reactive protein ⩽ 21.09 mg/dL plus 27.70 < platelet count ⩽ 30.70 × 10⁴/μL (incidence: 36.1%) were high-risk groups.

Conclusions:

Our results emphasize that patients categorized as high risk of bacterial arthritis, and appropriate treatment could be initiated as soon as possible.

Genetic variants associated with platelet count are predictive of human disease and physiological markers

Platelets play an important role in hemostasis and other aspects of vascular biology. We conducted a meta-analysis of platelet count GWAS using data on 536,974 Europeans and identified 577 independent associations. To search for mechanisms through which these variants affect platelets, we applied cis-expression quantitative trait locus, DEPICT and IPA analyses and assessed genetic sharing between platelet count and various traits using polygenic risk scoring. We found genetic sharing between platelet count and counts of other blood cells (except red blood cells), in addition to several other quantitative traits, including markers of cardiovascular, liver and kidney functions, height, and weight. Platelet count polygenic risk score was predictive of myeloproliferative neoplasms, rheumatoid arthritis, ankylosing spondylitis, hypertension, and benign prostate hyperplasia. Taken together, these results advance understanding of diverse aspects of platelet biology and how they affect biological processes in health and disease.

Evgenia Mikaelsdottir et al. report a study of variants associated with platelet count among European individuals where they identify 577 associations. They also report a genetic overlap between platelet count and human diseases, including myeloproliferative neoplasms, rheumatoid arthritis, and hypertension, as well as a genetic overlap between platelet count and various physiological markers.

Risk of venous thromboembolism in immune-mediated inflammatory diseases: a UK matched cohort study

Objectives

To describe the risk of venous thromboembolism (VTE), and risk factors for VTE, in people with immune-mediated inflammatory diseases (IMID) (ulcerative colitis, Crohn’s disease (CD), rheumatoid arthritis (RA) and psoriatic arthritis (PsA)), compared with a matched control population.

Methods

A total of 53 378 people with an IMID were identified over 1999–2019 in the UK Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) primary care database and were matched to 213 512 people without an IMID. The association between the presence of any IMID, and each IMID separately, and risk of VTE was estimated using unadjusted and multivariable-adjusted Cox proportional hazards models. The prevalence of VTE risk factors, and associations between VTE risk factors and risk of VTE, were estimated in people with and without an IMID.

Results

People with an IMID were at increased risk of VTE (adjusted HR [aHR] 1.46, 95% CI 1.36,1.56), compared with matched controls. When assessing individual diseases, risk was increased for CD (aHR 1.74, 95% CI 1.45 to 2.08), ulcerative colitis (aHR 1.27, 95% CI 1.10 to 1.45) and RA (aHR 1.54, 95% CI 1.40 to 1.70) but there was no evidence of an association for PsA (aHR 1.21, 95% CI 0.96 to 1.52). In people with an IMID, independent risk factors for VTE included male sex, overweight/obese body mass index, current smoking, history of fracture, and, across study follow-up, abnormal platelet count.

Conclusions

VTE risk is increased in people with IMIDs. Routinely available clinical information may be helpful to identify individuals with an IMID at increased future risk of VTE.

Observational study registration number

Clinicaltrials.gov (NCT03835780).

Prognosis of pneumonia in patients with rheumatoid arthritis: the role of medication and disease activity prior to admission a population-based cohort study

Objective

Patients with rheumatoid arthritis (RA) experience an increased risk of infections, but the prognosis of infections is unclear. We examined if patients with RA have worse outcomes from pneumonia than non-RA individuals.

Methods

In a population-based cohort study, we computed 90-day mortality rates and crude and adjusted HRs comparing pneumonia patients with and without RA. Among patients with RA, we evaluated prognostic effects of RA medications including prednisolone and disease activity as assessed by C reactive protein (CRP) or platelet levels measured 30–180 days before admission to avoid any influence from the subsequent infection.

Results

Among 52 577 patients hospitalised for the first time with pneumonia, 1220 (2.3%) had RA. The 90-day mortality was 19.9% for patients with RA and 18.9% for non-RA patients (adjusted 90-day HR of 1.05 (95% CI 0.92 to 1.19)). Compared with CRP levels <8 mg/L, CRP levels ≥20 mg/L predicted increased mortality in patients with RA with adjusted 90-day HRs of 4.98 (95% CI 2.19 to 11.36). Compared with methotrexate monotherapy, both prednisolone (HR 1.43 (95% CI 0.91 to 2.22)) and no RA therapy (HR 1.35 (95% CI 0.85 to 2.14)) tended to increase 90-day mortality. Compared with patients who used prednisolone and had low CRP levels, high CRP predicted increased mortality both in patients who used prednisolone (HR 3.09, 95% CI 1.25 to 7.65) and those who did not (HR 2.35, 95% CI 0.94 to 5.87).

Conclusions

Overall, RA does not increase mortality following hospitalisation for pneumonia. However, high RA disease activity prior to admission predicts increased pneumonia mortality in patients regardless of prednisolone use.

Defective cholesterol metabolism in haematopoietic stem cells promotes monocyte-driven atherosclerosis in rheumatoid arthritis

Aim

Rheumatoid arthritis (RA) is associated with an approximately two-fold elevated risk of cardiovascular (CV)-related mortality. Patients with RA present with systemic inflammation including raised circulating myeloid cells, but fail to display traditional CV risk-factors, particularly dyslipidaemia. We aimed to explore if increased circulating myeloid cells is associated with impaired atherosclerotic lesion regression or altered progression in RA.

Methods and results

Using flow cytometry, we noted prominent monocytosis, neutrophilia, and thrombocytosis in two mouse models of RA. This was due to enhanced proliferation of the haematopoietic stem and progenitor cells (HSPCs) in the bone marrow and the spleen. HSPCs expansion was associated with an increase in the cholesterol content, due to a down-regulation of cholesterol efflux genes, Apoe, Abca1, and Abcg1. The HSPCs also had enhanced expression of key myeloid promoting growth factor receptors. Systemic inflammation was found to cause defective cellular cholesterol metabolism. Increased myeloid cells in mice with RA were associated with a significant impairment in lesion regression, even though cholesterol levels were equivalent to non-arthritic mice. Lesions from arthritic mice exhibited a less stable phenotype as demonstrated by increased immune cell infiltration, lipid accumulation, and decreased collagen formation. In a progression model, we noted monocytosis, enhanced monocytes recruitment to lesions, and increased plaque macrophages. This was reversed with administration of reconstituted high-density lipoprotein (rHDL). Furthermore, RA patients have expanded CD16+ monocyte subsets and a down-regulation of ABCA1 and ABCG1.

Conclusion

Rheumatoid arthritis impairs atherosclerotic regression and alters progression, which is associated with an expansion of myeloid cells and disturbed cellular cholesterol handling, independent of plasma cholesterol levels. Infusion of rHDL prevented enhanced myelopoiesis and monocyte entry into lesions. Targeting cellular cholesterol defects in people with RA, even if plasma cholesterol is within the normal range, may limit vascular disease.

Is thrombocytosis always an indicator of autosplenectomy in patients with systemic lupus erythematosus?

In systemic lupus erythematosus (SLE), the most commonly encountered finding related to platelets is thrombocytopenia whereas thrombocytosis is rarely reported. Our aim here was to reveal the type and the frequency of thrombocytosis in SLE patients along with its causes. Data of patients were evaluated retrospectively. Patients who had a platelet count of > 450,000/mm³ (> 450 × 10⁹/L) in at least two subsequent counts and lasting more than 6 months during the follow-up were considered to have "persistent thrombocytosis". Peripheral smear results of patients with thrombocytosis were analyzed, and spleen imaging was performed for autosplenectomy/hyposplenism to patients with persistent thrombocytosis. A total of 205 patients with SLE were included in the study [196 (95.6%) female, mean age 41.5 years]. Out of 12 patients (5.9%) with thrombocytosis, 9 (4.3%) had transient thrombocytosis and 3 patients (1.4%) had persistent thrombocytosis. Of those with transient thrombocytosis, 5 were associated with iron deficiency anemia (IDA), 2 to polyarthritis, and the remaining 2 to digital ischemia and/or cutaneous vasculitis. Of three patients with persistent thrombocytosis, one was identified to have had splenectomy due to resistant immune thrombocytopenic purpura, and the other two (0.9%) patients had autosplenectomy. The only independent risk factor for the development of thrombocytosis was the presence of cutaneous vasculitis (OR 10.79 (95% CI 2.14-54.47), p = 0.0004). During the course of SLE, frequency of thrombocytosis is similar to that of the general population and the most common cause is reactive thrombocytosis. If the thrombocytosis was persistent, rheumatologist must consider that the patient may have autosplenectomy/asplenia/hyposplenism.

A Study on Association between Common Haematological Parameters and Disease Activity in Rheumatoid Arthritis

INTRODUCTION

Rheumatoid Arthritis (RA) is a chronic systemic inflammatory disease where assessment of disease activity is essential for management of patient. Currently, many composite scoring systems are used for evaluation of disease activity but they are mainly clinical-based. As several haematological parameters are altered due to systemic inflammatory process in RA, this study was intended to evaluate role of common haematological parameters to assess disease activity in RA.

AIM

To find out the association of disease activity of Rheumatoid Arthritis (RA) with platelet count, Mean Platelet Volume (MPV) and Haemoglobin (Hb) level so that these cost-effective haematological parameters can be used as additional factors to assess disease activity.

MATERIALS AND METHODS

This hospital based cross-sectional study was done on newly diagnosed patients of RA along with age and sex matched healthy control population. Patients suffering from malignancies, renal failure, diabetes mellitus or RA patients on drug therapy were excluded. Clinically, disease activity of RA was measured using DAS 28-3 Score (Modified Disease Activity Score using three variables- tender joint count, swollen joint count and ESR). Haematological parameters were measured by automated cell counter.

RESULTS

Total 80 cases were selected (60 female and 20 male). 48 patients with high disease activity (DAS 28-3>5.1) were labelled as Group-A and 32 with low to moderate disease activity (DAS 28-3 ≤5.1) as Group- B. Mean platelet count of patients of group A and group B were 4.53 lac/cmm and 2.17 lac/cmm respectively (p <0.001). MPV mean in group A and B were 11.86 fl and 10.19 fl respectively (p <0.001). Mean Hb (g/dl) was 10.05 and 12.25 for group A and B respectively (p=0.001) for male patients while in females it was 10.12 and 11.91 for group A and B, respectively (p=0.003). Mean platelet count and MPV in control population were 2.07 lac/cmm and 9.4 fl, respectively while mean Hb (g/dl) was 13.31 (male) and 12.01 (female).

CONCLUSION

In our study it was observed that Hb is significantly lower in patients with high disease activity whereas platelet count and MPV are significantly higher with high disease activity compared to patients with low to moderate disease activity.

Clinical features and pathological joint changes in dogs with erosive immune-mediated polyarthritis: 13 cases (2004-2012)

OBJECTIVE To evaluate the clinical features and pathological joint changes in dogs with erosive immune-mediated polyarthritis (IMPA). DESIGN Retrospective case series. ANIMALS 13 dogs with erosive IMPA and 66 dogs with nonerosive IMPA. PROCEDURES The medical record database of a veterinary teaching hospital was reviewed to identify dogs with IMPA that were examined between October 2004 and December 2012. For each IMPA-affected dog, information extracted from the medical record included signalment, diagnostic test results, radiographic findings, and treatments administered. Dogs were classified as having erosive IMPA if review of radiographs revealed the presence of bone lysis in multiple joints, and descriptive data were generated for those dogs. All available direct smears of synovial fluid samples underwent cytologic evaluation. The synovial fluid total nucleated cell count and WBC differential count were estimated and compared between dogs with erosive IMPA and dogs with nonerosive IMPA. RESULTS 13 of 79 (16%) dogs had erosive IMPA. Dogs with erosive IMPA had a mean ± SD age of 7.1 ± 2.4 years and body weight of 8.3 ± 3.4 kg (18.3 ± 7.5 lb). All 13 dogs had erosive lesions in their carpal joints. The estimated median synovial fluid lymphocyte count for dogs with erosive IMPA was significantly greater than that for dogs with nonerosive IMPA. All dogs received immunosuppressive therapy with leflunomide (n = 9), prednisone (3), or prednisone-azathioprine (1). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated erosive IMPA most commonly affected the carpal joints of middle-aged small-breed dogs. Further genetic analyses and analysis of lymphocyte-subsets are warranted for dogs with erosive IMPA.

Marked Thrombocytosis in Chronic Eosinophilic Pneumonia and Analysis of Cytokine Mechanism

A 47-year-old woman with marked thrombocytosis of 1,650 × 10(9)/L was diagnosed with chronic eosinophilic pneumonia (CEP) based on imaging of the lung and abundant eosinophils in bronchoalveolar lavage fluid. Known gene abnormalities that cause eosinophilia were not detected in bone marrow cells. Treatment with oral prednisolone at 20 mg/day relieved the CEP and resolved the laboratory abnormalities, including eosinophilia and thrombocytosis. Serum concentrations of interleukin (IL)-5 and IL-6 were elevated to 9.6 and 14.0 pg/mL, respectively. The megakaryocyte-potentiating activity of IL-6 and possibly, that of IL-1β, which is known to be secreted by activated eosinophils, may have caused the marked thrombocytosis in this patient.

Early recognition of intraventricular hemorrhage in the setting of thrombocytosis in the emergency department

Thrombocytosis is frequently encountered as an incidental laboratory finding since isolated thrombocytosis is often asymptomatic. Even though thrombocytosis is benign and self-limiting in most cases, it can at times result in thrombosis or hemorrhage. The most common type of thrombocytosis is reactive (secondary) thrombocytosis and can be due to infections, trauma, surgery, or occult malignancy. Since thrombocytosis is a known risk factor for thrombosis, it is commonly a concern for ischemic stroke and myocardial infarction. Much less common are hemorrhagic events associated with thrombocytosis. Studies have shown that when hemorrhage is present in patients with thrombocytosis, it is most often seen in the setting of chronic myelogenous leukemia and essential thrombocythemia. In essential thrombocythemia, the overall risk of bleeding and thrombosis is 0.33% per patient-year and 6.6% per patient-year, respectively. In the general population, the risk of bleeding and thrombosis is 0% and 1.2%, respectively. The present study is a case report of an 83-year-old man who presented to the emergency department with hypertension and headache, who was then found to have significant thrombocytosis (platelets >1,000×10(9)/L) and acute right intraventricular hemorrhage without any signs of neurological deficits, or evidence of vascular malformations or mass. We present this case report for review and discussion of some of the challenges and considerations associated with the management of such patients.

A novel role for thrombopoietin in regulating osteoclast development in humans and mice

Emerging data suggest that megakaryocytes (MKs) play a significant role in skeletal homeostasis. Indeed, osteosclerosis observed in several MK-related disorders may be a result of increased numbers of MKs. In support of this idea, we have previously demonstrated that MKs increase osteoblast (OB) proliferation by a direct cell-cell contact mechanism and that MKs also inhibit osteoclast (OC) formation. As MKs and OCs are derived from the same hematopoietic precursor, in these osteoclastogenesis studies we examined the role of the main MK growth factor, thrombopoietin (TPO) on OC formation and bone resorption. Here we show that TPO directly increases OC formation and differentiation in vitro. Specifically, we demonstrate the TPO receptor (c-mpl or CD110) is expressed on cells of the OC lineage, c-mpl is required for TPO to enhance OC formation in vitro, and TPO activates the mitogen-activated protein kinases, Janus kinase/signal transducer and activator of transcription, and nuclear factor-kappaB signaling pathways, but does not activate the PI3K/AKT pathway. Further, we found TPO enhances OC resorption in CD14+CD110+ human OC progenitors derived from peripheral blood mononuclear cells, and further separating OC progenitors based on CD110 expression enriches for mature OC development. The regulation of OCs by TPO highlights a novel therapeutic target for bone loss diseases and may be important to consider in the numerous hematologic disorders associated with alterations in TPO/c-mpl signaling as well as in patients suffering from bone disorders.

Coagulation Status in Hidradenitis Suppurativa: A Danish Population- and Hospital-Based Cross-Sectional Study

BACKGROUND

Chronic inflammatory diseases other than hidradenitis suppurativa (HS) have been associated with prothrombotic/hypercoagulable status.

OBJECTIVE

To investigate a possible association between the chronic inflammatory skin disease HS and prothrombotic/hypercoagulable state.

METHODS

We performed a hospital- and population-based cross-sectional study investigating the coagulation status (thrombocytes, mean platelet volume [MPV], international normalized ratio [INR] and activated partial thromboplastin time [APTT]).

RESULTS

32 hospital HS subjects, 430 population HS subjects and 20,780 population non-HS control subjects were identified. The adjusted analyses showed no differences in the levels of thrombocytes, MPV, INR or APTT between the HS groups (hospital HS group, population HS group) when compared to controls (p = 0.089, p = 0.3078; p = 0.5499, p = 0.0659; p = 0.0932; p = 0.3432).

CONCLUSION

We did not find an association between HS and prothrombotic/hypercoagulable status. Thus, thrombocytes may not be activated in HS. Furthermore, INR may not be affected in HS, suggesting that intrinsic and vitamin K-dependent coagulation factors appear unaffected.

Platelet and red blood cell interactions and their role in rheumatoid arthritis

Cytokines, lymphocytes, platelets and several biomolecules have long been implicated in the pathology of rheumatoid arthritis (RA), and the influences of antibody production and tagging, and cytokine, chemokine and enzyme production at specific rheumatoid joints were thought to be exclusive to the advancement of disease parameters. Another role player in RA is red blood cells (RBCs) which, of late, have been found to be involved in RA pathobiology, as there is a positive correlation between RBC counts and joint pathology, as well as with inflammatory biomarkers in the disease. There is also an association between RBC distribution width and the incidence of myocardial infarction amongst RA patients, and there is a change in the lipid distribution within RBC membranes. Of late, certain RBC-associated factors with previously obscure roles and cell-derived particles thought to be inconsequential to the other constituents of plasma were found to be active biomolecular players. Several of these have been discovered to be present in or originating from RBCs. Their influences have been shown to involve in membrane dynamics that cause structural and functional changes in both platelets and RBCs. RBC-derived microparticles are emerging entities found to play direct roles in immunomodulation via interactions with other plasma cells. These correlations highlight the direct influences of RBCs on exacerbating RA pathology. This review will attempt to shed more light on how RBCs, in the true inflammatory milieu of RA, are playing an even greater role than previously assumed.

Chronic arthritis and cardiovascular disease: altered blood parameters give rise to a prothrombotic propensity

OBJECTIVE

Rheumatoid arthritis, and to a lesser extent ankylosing spondylitis and psoriatic arthritis, associates with increased morbidity and mortality due to cardiovascular complications. We hypothesized that the increased risk of cardiovascular disease is reflected by changes in blood parameters that are compatible with a prothrombotic propensity. To substantiate this notion, we performed an extensive literature search identifying such parameters.

METHODS

A search through PubMed (1970-2013) was done to find primary articles with the following search terms: rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis or synovial fluid. These were combined with keywords reflecting processes of atherothrombosis: atherosclerosis, cardiovascular disease, coagulation, endothelial, fibrinolysis, mean platelet volume, microparticle, platelet, platelet count and mass, thrombosis, and thrombus.

RESULTS

The published studies point to a multitude of blood-related processes that can contribute to a prothrombotic propensity in chronic inflammatory diseases. These include an increase in platelet mass; low-level platelet activation, enforced by interaction with leukocytes and the formation of proinflammatory cytokines; a locally activated endothelium; and an increased coagulant activity. Patient treatment with methotrexate or TNF-α blockers appears to result in normalization of several of these prothrombotic parameters.

CONCLUSION

This analysis provides a first identification of the mechanisms by which inflammatory arthritis can aggravate cardiovascular disease.

Response to traditional disease-modifying anti-rheumatic drugs in indigent South Africans with early rheumatoid arthritis

The clinical response to traditional disease-modifying anti-rheumatic drugs (DMARDs) in indigent South Africans with early rheumatoid arthritis was investigated. A cohort of patients with early (≤2 years) RA who were DMARD-naïve at inception were prospectively assessed for response to DMARDs using the Simplified Disease Activity Index (SDAI) over a 12-month period. Patients with low disease activity (LDA) at 12 months were compared to those with moderate and high disease activity with respect to demographic, clinical, autoantibody and radiographic features. The 171 patients (140 females) had a mean (SD) age of 47.1 (12.4) years, symptom duration of 11.7 (7.1) months and baseline SDAI of 39.4 (16.2). There was a significant overall improvement in the SDAI and its components in the 134 (78.4%) patients who completed the 12 months visit, but only 28.4% of them achieved LDA. The majority of patients (91%) were treated with methotrexate as monotherapy or in combination with chloroquine and/or sulphasalazine. Baseline features that independently predicted a LDA state at 12 months were lower Health Assessment Questionnaire Disability Index (p = 0.023) and a higher haemoglobin level (p = 0.048). Receiver operating characteristic curve analysis showed that the 6-month SDAI was better than the baseline SDAI in predicting the 12-month SDAI (area under the curve of 0.69 vs. 0.52, respectively, p = 0.008). In conclusion, less than a third of the patients achieved a low disease activity at 12 months on traditional DMARDs. Patients who have an inadequate response to traditional DMARDs at 6 months are unlikely to show further improvement on traditional DMARDs at 12 months. These findings underscore the need for better disease control by an aggressive tight control strategy, including intense patient education and biologic therapy.

Platelet function in rheumatoid arthritis: arthritic and cardiovascular implications

Patients with rheumatoid arthritis (RA) are at high risk of cardiovascular events. Platelet biomarkers are involved in inflammation, atherosclerosis and thrombosis. Cardiovascular and RA-associated factors can alter the structure and function of platelets, starting from megakaryocytopoiesis. Reactive megakaryocytopoiesis increases circulating platelets count and triggers hyperactivity. Hyperactive platelets target synovial membranes with subsequent local rheumatoid inflammation. Hyperactive platelets interact with other cells, and target the vascular wall. Accumulating evidence suggests that disease modifying anti-rheumatic drugs (DMARD) decrease platelet activity.

Platelet function in rheumatoid arthritis: arthritic and cardiovascular implications

Patients with rheumatoid arthritis (RA) are at high risk of cardiovascular events. Platelet biomarkers are involved in inflammation, atherosclerosis and thrombosis. Cardiovascular and RA-associated factors can alter the structure and function of platelets, starting from megakaryocytopoiesis. Reactive megakaryocytopoiesis increases circulating platelets count and triggers hyperactivity. Hyperactive platelets target synovial membranes with subsequent local rheumatoid inflammation. Hyperactive platelets interact with other cells, and target the vascular wall. Accumulating evidence suggests that disease modifying anti-rheumatic drugs (DMARD) decrease platelet activity.

The effect of desmopressin on blood loss in patients with rheumatoid arthritis undergoing hip arthroplasty

BACKGROUND

Blood loss is an important issue for patients with rheumatoid arthritis undergoing hip surgery. We hypothesised that intraoperative desmopressin treatment would result in a reduction in blood loss in rheumatoid patients undergoing total hip arthroplasty.

METHODS

Seventy-five patients scheduled for elective total hip arthroplasty were randomised to three groups to receive 0.4 microg/kg desmopressin (D 0.4), 0.2 microg/kg desmopressin (D 0.2) or placebo intraoperatively in a double-blind fashion. Blood transfusions were based on calculated safe allowable blood loss and haemoglobin measurements (trigger 90 g/l, 5.59 mmol/l). The primary endpoint was the total blood loss measured till the end of the fourth post-operative day. Secondary endpoints included red cell transfusion requirements and haemoglobin.

RESULTS

Total blood loss during the study period was not significantly different between the groups (D 0.4 1829 +/- 1068; D 0.2 2240 +/- 843 and placebo 2254 +/- 1040 ml; P= 0.50). The total amount of red cell transfusions was fewer in group D 0.4 (3.6 +/- 1.6 U) when compared with D 0.2 (4.4 +/- 1.7 U; P=0.009) and placebo (4.5 +/- 2.0 U; P= 0.011) groups. Haemoglobin concentration was lower in the placebo group in the first (5.42 +/- 1.16 vs. 5.98 +/- 0.47 mmol/l; P=0.033) and the second (6.28 +/- 0.66 vs. 6.69 +/- 0.47 mmol/l; P=0.033) post-operative mornings compared with group D 0.4.

CONCLUSION

Despite a lack of difference in the primary outcome, total blood loss, intraoperative administration of 0.4 microg/kg desmopressin resulted in fewer total red cell transfusion requirements in rheumatoid patients undergoing total hip arthroplasty when compared with 0.2 microg/kg treatment and placebo.

Platelets amplify inflammation in arthritis via collagen-dependent microparticle production

In addition to their pivotal role in thrombosis and wound repair, platelets participate in inflammatory responses. We investigated the role of platelets in the autoimmune disease rheumatoid arthritis. We identified platelet microparticles--submicrometer vesicles elaborated by activated platelets--in joint fluid from patients with rheumatoid arthritis and other forms of inflammatory arthritis, but not in joint fluid from patients with osteoarthritis. Platelet microparticles were proinflammatory, eliciting cytokine responses from synovial fibroblasts via interleukin-1. Consistent with these findings, depletion of platelets attenuated murine inflammatory arthritis. Using both pharmacologic and genetic approaches, we identified the collagen receptor glycoprotein VI as a key trigger for platelet microparticle generation in arthritis pathophysiology. Thus, these findings demonstrate a previously unappreciated role for platelets and their activation-induced microparticles in inflammatory joint diseases.

Leukocytapheresis (LCAP) decreases the level of platelet-derived microparticles (MPs) and increases the level of granulocytes-derived MPs: a possible connection with the effect of LCAP on rheumatoid arthritis

Microparticles (MPs) are believed to play an important role in inflammatory diseases such as rheumatoid arthritis (RA). Leukocytapheresis (LCAP) is one of the options available for the treatment of RA. We analyzed the levels of MPs in RA, by flow cytometry, especially in relation to the effect of LCAP. Twenty female patients with RA were recruited into this study. Six of the 20 patients with RA further received LCAP. Plasma levels of platelet-derived MPs were high in patients with RA and are correlated with disease activity. LCAP significantly improved RA in all six patients. The numbers of platelet-derived MPs significantly decreased after the first session of LCAP, which was probably due to direct removal by LCAP. Mean numbers of platelet-derived MPs after four sessions of LCAP markedly decreased. The numbers of granulocyte-derived MPs, which are suggested to have an anti-inflammatory effect, were markedly increased after the first session of LCAP. These data suggest that removal of platelet-derived MPs and increase of granulocyte-derived MPs are novel mechanisms of LCAP as effective treatment in RA.

The role of megakaryocytes in skeletal homeostasis and rheumatoid arthritis

PURPOSE OF REVIEW

This review provides an update on the role of megakaryocytes in skeletal homeostasis, and discusses these findings in the context of rheumatoid arthritis.

RECENT FINDINGS

Thrombocytosis is a common complication of rheumatoid arthritis, and is presumably caused by an up-regulation in megakaryocytopoiesis. In general, patients with rheumatoid arthritis exhibit localized joint bone erosion with systemic bone loss, and rheumatoid arthritis patients with thrombocytosis tend to have more severe disease. Interestingly, in addition to their role in rheumatoid arthritis with thrombocytosis, it has been demonstrated recently that megakaryocytes play a dual role in regulating skeletal mass by inhibiting bone resorption while simultaneously stimulating bone formation. This seeming contradiction in the putative role of megakaryocytes in skeletal regulation and rheumatoid arthritis is the focus of this review.

SUMMARY

In rheumatoid arthritis there are substantial increases in the levels of several pro-inflammatory pleiotropic cytokines. As would be expected, in addition to their role in inflammation, these cytokines play a critical role in the megakaryocytopoiesis seen in patients who develop reactive thrombocytosis, and these cytokines also are known to regulate osteoclastogenesis. Thus, it appears that in rheumatoid arthritis with reactive thrombocytosis, the ability of the cytokines to enhance osteoclastogenesis outweighs the ability of megakaryocytes to inhibit osteoclastogenesis.

Investigation of platelet glycoprotein IIIa polymorphism using flow cytometry in patients with rheumatoid arthritis

OBJECTIVES

Previous work has shown that the human platelet antigen (HPA) 1b polymorphism of platelet glycoprotein IIIa (GPIIIa) is implicated in the development of ischaemic vascular disease. HPA1b positive platelets have a lower threshold for activation and may exert a greater thrombotic tendency than those without the 1b allele. However, platelets heterozygous for the polymorphism are also more sensitive to aspirin than those homozygous for the 1b allele, which have a similar sensitivity to those without the 1b allele. A flow cytometric method has become available to identify this polymorphism. The aim of our study was to evaluate the use of this assay in patients with rheumatoid arthritis (RA) and to determine the incidence of the 1b allele in these patients. We also compared platelet aggregation and platelet/white blood cell interaction in patients with or without this polymorphism.

METHODS

We enrolled 99 patients and measured platelet aggregation in whole blood and platelet-rich plasma (prp), platelet/white blood cell interaction and C-reactive protein (CRP).

RESULTS

Thirty-four of the 99 patients were unsuitable for analysis because their baseline expression of GPIIIa was outwith the normal range, making the results outwith the limits of the flow cytometric method. The incidence of the 1b allele in the patients was 29%, with incidence being higher in females, although this failed to reach statistical significance. The number of circulating platelet aggregates and adenosine diphosphate (ADP)-induced aggregation in prp was significantly higher in those patients with the 1b allele.

CONCLUSIONS

This method may be of use as an initial screening test.

Relationships between platelets and inflammatory markers in rheumatoid arthritis

AIM OF THE STUDY

To investigate platelets and different inflammatory markers in conjunction with a substantial inflammatory reaction. We used individuals with active rheumatoid arthritis (RA) as an experimental cohort.

METHODS

We selected 16 patients with active RA having at least one affected joint. On day 1, platelet and neutrophil counts together with C-reactive protein (CRP) were determined. We further analysed platelet volume (MPV) and plasma levels of thrombopoietin (TPO), P-selectin, myeloperoxidase and interleukin 6 (IL-6). After 2 years when all patients failed to show any swollen joints all analyses were repeated.

RESULTS AND CONCLUSIONS

As expected platelet count, CRP and IL-6 were elevated in active RA. The measures correlated with each other thus reflecting the same characteristic of the inflammatory response. The neutrophil count, MPV and myeloperoxidase also mirror disease activity. They failed to correlate with other activity markers thus providing unique information. MPV and myeloperoxidase on day 1 correlated with recovery values. Therefore, they could be suitable to use when following the inflammatory reaction over a long period of time.

High proteinase 3-anti-neutrophil cytoplasmic antibody (ANCA) level measured by the capture enzyme-linked immunosorbent assay method is associated with decreased patient survival in ANCA-associated vasculitis with renal involvement

Wegener granulomatosis (WG) and microscopic polyangiitis (MP), diseases associated with antineutrophil cytoplasmic antibodies (ANCA), had an extremely poor prognosis before the introduction of cyclophosphamide and corticosteroids for their treatment. However, there is still reduced patient survival, and some studies have documented severe side effects of the immunosuppressants used. This 10-yr follow-up study assessed 117 consecutive patients with WG or MP with biopsy-confirmed renal involvement. The cumulative relative patient survival was lower: 0.664 for women and 0.648 for men. The causes of death (n = 64) were in most cases registered as associated with the vasculitic disease. Analysis of possible predictive factors for patient survival by multiple Cox regression analysis revealed that a very high level of proteinase 3 (PR3)-ANCA measured by the capture ELISA method, a diagnosis of MP, and older age were factors predicting poorer patient survival. High levels of B-thrombocytes at time of diagnosis were associated with a better prognosis. For patients surviving the first year, remission-sustaining therapy with azathioprine for longer than 12 mo was associated with improved patient survival. Thirty-nine patients developed end-stage renal failure. Elevated serum creatinine at time of diagnosis and a very high level of PR3-ANCA by capture ELISA were factors predicting a higher risk for renal failure during follow-up. The epitope on PR3 assessed by capture ELISA needs to be further analyzed and explored: it seemed to implicate poorer patient and renal survival in WG or MP with renal involvement.

Pathologic thrombopoiesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is frequently complicated by thrombocytosis correlated with disease activity. The exact pathogenetic mechanism(s) that cause increased platelet counts in RA are still unknown. Recent investigations indicate that proinflammatory pleiotropic cytokines of RA also have megakaryocytopoietic/thrombopoietic properties. Moreover, several lineage-dominant hematopoietic cytokines can also act as acute phase responders and contribute to the inflammation. This review focuses on the current literature and our experience regarding the dual relationships of the pathologic thrombopoiesis of RA. Growth factors contributing to it, namely interleukin (IL)-6, IL-11, stem cell factor, leukemia inhibitory factor, granulocyte colony stimulating factor, thrombopoietin (TPO), and the regulation of megakaryocytopoiesis during the inflammatory cascade are reviewed. Some data indicate that thrombopoietin could contribute to the reactive thrombocytosis of RA. In the non-lineage-specific gp130 cytokine family, IL-6 appears to predominate for the induction of megakaryopoiesis. However, other cytokines and growth factors may also contribute to the pathologic megakaryocytopoiesis of RA. Those pleiotropic mediators seem to act in concert to regulate this enigmatic process. Clarification of the pathobiologic basis of thrombopoiesis in RA may improve understanding of the disease pathogenesis and management of the inflammatory thrombocytosis.

Elevated levels of platelet microparticles are associated with disease activity in rheumatoid arthritis

OBJECTIVE

Platelets are involved in various thrombotic events, often by means of platelet-derived microparticles (PMPs). It is likely that platelets are also involved in inflammation. Because inflammatory processes play a central role in rheumatoid arthritis (RA), we sought to determine whether PMPs are present in this disease.

METHODS

This descriptive, cross-sectional study included 19 RA patients and 10 healthy controls. Nine of the patients had active RA (erythrocyte sedimentation rate [ESR] > or =28 mm/hour and/or C-reactive protein [CRP] level > or =28 mg/liter, > or =9 painful joints, and > or =6 swollen joints), and 10 had inactive disease (ESR < or =27 mm/hour, CRP < or =27 mg/liter, no tender joints, and no swollen joints). Platelet counts and PMP numbers were determined using cell counter and flow cytometry, respectively.

RESULTS

Platelet counts in the 3 groups were similar. However, levels of PMPs in RA patients were significantly higher than those in healthy controls (median 616 versus 118 x 10(6)/liter; P = 0.005). PMP levels were higher in patients with active RA than in those with inactive RA (median 2,104 versus 504 x 10(6)/liter; P > 0.05). Moreover, PMP levels correlated with disease activity (r = 0.67, P = 0.05).

CONCLUSION

PMPs are associated with RA, and PMP levels are correlated with disease activity. Thus, platelets probably play a part in the inflammatory process of RA by means of PMPs. Given the importance of PMPs in cardiovascular diseases, this may be one reason for the enhanced cardiovascular morbidity and mortality in RA.

Inhibition of platelet activation by 5-aminosalicylic acid in inflammatory bowel disease

BACKGROUND

Platelets play an important role in inflammation and are activated in inflammatory bowel disease. Micro-vascular thrombosis in the gut wall leading to intestinal micro-infarction may be a pathogenic feature of Crohn's disease. 5-Aminosalicylic acid is an effective treatment for patients with inflammatory bowel disease.

AIMS

To assess the effects of 5-aminosalicylic acid on platelet activation, when taken orally and in vitro by patients with inflammatory bowel disease.

METHODS

Spontaneous and thrombin-induced platelet activation were studied using fluorescent antibodies to the activated platelet surface glycoprotein P-selectin and flow cytometry.

RESULTS

Baseline platelet activation in inflammatory bowel disease was significantly greater than that in controls (P=0.0003). Independent of diagnosis or disease activity, spontaneous ex-vivo platelet activation was 50% lower in patients with inflammatory bowel disease taking 5-aminosalicylic acid orally than in those not on such treatment (P < 0.05). In vitro, 5-aminosalicylic acid significantly reduced both spontaneous (P < 0. 03 for >/=1 microM 5-aminosalicylic acid) and thrombin-induced platelet activation (P < 0.02 for >/= 1 microM 5-aminosalicylic acid).

CONCLUSIONS

5-Aminosalicylic acid given either orally or in vitro inhibits platelet activation. If this effect reflects an in vivo action in the gut, it could contribute to the beneficial actions of 5-aminosalicylic acid in inflammatory bowel disease.

Aetiology and clinical significance of thrombocytosis: analysis of 732 patients with an elevated platelet count

OBJECTIVE

To determine the aetiology and clinical significance of an elevated platelet count (thrombocytosis) in a large cohort of patients.

DESIGN

A retrospective review of the medical records was performed on all patients, who had at least one platelet count > or = 500 x 10(9) L-1.

SETTING

Departments of Medicine and Surgery, University of Ulm, Germany.

SUBJECTS

A total of 732 patients with thrombocytosis.

MAIN OUTCOME MEASURES

Classification of thrombocytosis and thromboembolic complications, and evaluation of laboratory parameters distinguishing between primary and secondary thrombocytosis.

RESULTS

Of the total of 732 patients, 89 (12.3%) had primary and 643 (87.7%) had secondary thrombocytosis. Essential thrombocythaemia was observed in 40 of 89 patients (45%) with primary thrombocytosis. The most frequent causes of secondary thrombocytosis were tissue damage (42%), infection (24%), malignancy (13%) and chronic inflammation (10%). Primary thrombocytosis was significantly associated with a higher platelet count and an increased incidence of both arterial and venous thromboembolic complications. In secondary thrombocytosis, thromboembolic events were restricted to the venous system and occurred only in the presence of other risk factors. Mean values of leucocyte count, haematocrit, erythrocyte sedimentation rate, fibrinogen, serum potassium and lactate dehydrogenase were significantly different in primary and secondary thrombocytosis.

CONCLUSIONS

The finding of an elevated platelet count on routine blood examination has diagnostic, prognostic and therapeutic implications. It is of clinical importance to distinguish between primary and secondary thrombocytosis, as thrombotic complications occur more frequently in primary thrombocytosis. Unless additional risk factors are present, secondary thrombocytosis is not associated with a significant risk for thromboembolic events.

Effect of experimental diabetes mellitus and arthritis on the pharmacokinetics of hydroxychloroquine enantiomers in rats

PURPOSE

To study the effect of experimental diabetes and arthritis on the pharmacokinetics of hydroxychloroquine (HCQ) enantiomers in rats.

METHODS

The pharmacokinetic studies were carried out following administration of 40 mg/kg of racemic HCQ to diabetic, insulin-treated diabetic, adjuvant arthritic and control rats.

RESULTS

Renal (70% and 62% for R- and S-HCQ, respectively) and non-renal clearance (100% and 145% for R- and S-HCQ, respectively) of HCQ enantiomers were significantly increased in diabetic rats. Diabetes-induced alterations in the disposition of HCQ were reversed by insulin treatment. In arthritic rats, systemic clearance (CL) of HCQ enantiomers was significantly reduced (1.05 +/- 0.15 and 1.3 +/- 0.19 l/h/kg for R- and S-HCQ, respectively) compared to controls (1.69 +/- 0.32 and 1.93 +/- 0.34 l/h/kg for R- and S-HCQ, respectively). The fraction unbound of the R- and S-HCQ were 49.4% and 50.5% lower in platelet rich plasma of arthritic rats compared to healthy rats. Increased blood concentrations of HCQ enantiomers in arthritic rats were significantly related to the degree of inflammation.

CONCLUSIONS

Diabetes significantly increased the CL of both R- and S-HCQ by increasing renal and non-renal clearance. Arthritis caused a significant decrease in CL of HCQ enantiomers through increased binding and a decreased intrinsic clearance. The effect of the diseases on the pharmacokinetics of HCQ, however, was not stereoselective.

Thrombocytosis. Etiologic analysis of 663 patients

Six hundred sixty-three children aged 1 to 16 years with thrombocytosis (defined as a platelet count of more than 500 x 10(9)/L) seen in a university hospital over a 1-year period were studied prospectively for etiology. The causes of thrombocytosis were infection (30.6%), hemolytic anemia (19.3%), tissue damage (15.2%), rebound thrombocytosis (14.8%), chronic inflammation (4.1%), renal disorders (4.1%), and malignancy (2%). Thrombocytosis associated with multiple, simultaneous causative factors was seen in 3.3% of cases. Among all patients with infections, osteomyelitis and septic arthritis were associated with higher platelet counts than other infections (P < .0001). Thrombocytosis secondary to infections was significantly more common in children under 5 years of age, whereas chronic inflammation, malignancy, and renal disorders were more common causes of thrombocytosis in children over 5 years of age. Thrombocytosis of 1 million or more platelets was seen in 13 (2%) children. No thrombocytosis-related complications were seen in any children, and none required any specific treatment. Thrombocytosis is a frequent finding in children. It is due to a variety of etiologic factors and is of little clinical discriminatory value. It is often due to an acute-phase phenomenon in response to infection, tissue damage, blood loss, or anemia, and is rarely due to malignancy.

Activated human platelets in plasma excite nociceptors in rat skin, in vitro

Extravascular activation of thrombocytes may contribute to nociceptor excitation and pain, since platelets store and, upon stimulation, release potential algogenic substances such as serotonin, histamine and precursor molecules of bradykinin. To test this hypothesis, a skin-nerve preparation of rat hairy skin, in vitro, was used that allows to record and characterize single afferent nerve fibers. In a first protocol, receptive fields of nociceptive C-fibers, at the corium side of the skin patch, were exposed to adenosine diphosphate (ADP), to heparinized human platelet-rich plasma (PRP) and to PRP activated by ADP. Such activated platelets excited 9/11 units characterized as mechano-heat responsive C-nociceptors (CMH); peak discharges of more than 10 spikes/s were observed. After application of activated PRP, 4/5 high threshold mechanosensitive C-units and 4/5 mechano-cold sensitive C-units became responsive to heat stimulation but only few of these fibers were excited (1/5 in each group). In a second series of experiments the exposure to native PRP was prolonged to test for the effect of spontaneous platelet activation resulting from cutaneous collagen. Prolonged exposure did, but not significantly, enhance fiber discharge. During subsequent exposure to activated PRP, the discharge commenced, on average, after a significant delay of about three minutes. With this protocol 5/7 CMH units were driven by activated platelets. Following both protocols, mechanical (v.Frey) and thermal thresholds of the CMH units were not significantly altered. The findings demonstrate that nociceptors can indeed be driven and sensitized by activated platelets. This pain inducing mechanism may be relevant to certain clinical conditions, and it appears promising to scrutinize the chemical factors involved.

Marked thrombocytosis with chromosomal abnormalities in a patient with rheumatoid arthritis

An 80 year-old Japanese woman with rheumatoid arthritis (RA), complicated with thrombocytosis is described. Mild to moderate thrombocytosis is commonly observed in patients with RA, but she had marked thrombocytosis of over 1000 x 10(3)/mm3 and monosomy 22 with marker chromosome. This case suggests that thrombocytosis unusual with disease activity of RA might occur, and that careful evaluation of the thrombocytosis is required.

Connective tissue activation. XXXV. Detection of connective tissue activating peptide-III isoforms in synovium from osteoarthritis and rheumatoid arthritis patients: patterns of interaction with other synovial cytokines in cell culture

OBJECTIVE

To determine whether extracts of unincubated osteoarthritis (OA) and rheumatoid arthritis (RA) synovial tissue contain connective tissue activating peptide-III (CTAP-III) isoforms and prostaglandin E2 (PGE2), and whether such extracts have growth-promoting activity, and to determine whether binary combinations of CTAP-III with other cytokines reported to be present in synovial tissue lead to synergistic, additive, or inhibitory effects on growth.

METHODS

Acid-ethanol extracts of human synovium were examined for growth-promoting activity by measuring formation of 14C-glycosaminoglycan (14C-GAG) and 3H-DNA in synovial cell cultures; PGE2 was measured by enzyme immunoassay, and CTAP-III isoforms were identified by Western blotting of extracted proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Growth-promoting activity of CTAP-III and other cytokines was tested in synovial cultures treated with the agonists singly and in binary combination, by measuring changes in synthesis of 14C-GAG and 3H-DNA.

RESULTS

Platelet-derived CTAP-III and a cleavage isoform with the electrophoretic mobility of CTAP-III-des 1-15/neutrophil-activating peptide-2 (NAP-2) and PGE2 were found in biologically active extracts of synovial samples from patients with RA and OA. Five growth factors (recombinant epidermal growth factor [rEGF], recombinant interleukin-1 beta [rIL-1 beta], basic fibroblast growth factor [bFGF], PGE1, and PGE2) in binary combination with CTAP-III showed synergism in stimulating GAG synthesis; two (recombinant platelet-derived growth factor type BB [rPDGE-BB] and recombinant transforming growth factor beta [rTGF beta]) had an additive effect. In combination with CTAP-III, rEGF and rPDGF-BB had a synergistic effect in promoting DNA synthesis, rTGF beta and rbFGF had an additive effect, and rIL-1 beta, PGE1, and PGE2 were antagonistic.

CONCLUSIONS

The results suggest that, in addition to endogenous factors, CTAP-III and other platelet-derived cytokines may play roles in regulating synovial cell metabolism in RA and OA, and that combinations of growth factors may be more significant than single agents in amplification or suppression of important cell functions.

Mechanisms of thrombocytopenia in the acute phase of antigen-induced arthritis in rabbits

Arthritis induced in hyperimmune rabbits by the intra-articular injection of the specific antigen was associated with a fall in circulating platelet number that lasted up to 60 days. Pretreatment of the animals with indomethacin and econazol at doses that significantly decreased thromboxane levels in the synovial fluids reduced the arthritis-related thrombocytopenia in the acute phase of arthritis. A similar inhibition was seen when L-655,240, a specific Thromboxane A2 antagonist, and BN 52021, a Platelet Activating Factor antagonist were used. The results suggest that both thromboxane and PAF are involved in the mechanisms leading to thrombocytopenia in this experimental model of arthritis.

Thrombocytosis in adults: analysis of 777 patients

A total of 777 patients with thrombocytosis, defined as a platelet count of greater than 500 x 10(9)l-1, seen in a University hospital over a 1-year period, were studied prospectively for aetiology. The most frequent causes of thrombocytosis were infection (21.9%), rebound thrombocytosis (19.4%), tissue damage (17.9%), chronic inflammatory disorders (13.1%) and malignancy (5.9%). Thrombocytosis associated with multiple causative factors, occurring simultaneously, was seen in 6.1% of cases. Thrombocytosis of greater than or equal to 1 million x 10(9)l-1 was found most frequently in patients with multiple aetiological factors occurring at the same time, in myeloproliferative disorders, or in postsplenectomy patients.

Thrombocytosis in active rheumatoid arthritis. Relation to other parameters of inflammatory activity and confounding effect of automated cell counting

The magnitude of thrombocytosis and the possible confounding effect of platelet clumping, an in vitro artifact resulting in spuriously low platelet counts, in active rheumatoid arthritis (RA) was evaluated by a prospective survey of 57 consecutive patients, 60% of whom had thrombocytosis. Five cases (9%) of platelet clumping, assessed by H6000 pictures, were found. A low-grade platelet loss in many of the samples anticoagulated by EDTA was suggested by comparison with platelet counts obtained in parallel blood samples anticoagulated by citrate. Thus, the possibility of spuriously low platelet counts due to laboratory artifacts must always be taken into consideration in RA patients. The relation between thrombocytosis and other estimates of disease activity was also studied. The platelet count in citrated blood in active RA was significantly correlated with ESR, acute phase plasma proteins, and neutrophil, basophil and monocyte counts. In a multivariate regression model, however, only the correlation with haptoglobin (p = 0.06) approached significance.

Lymphocytes, polymorphonuclear leukocytes, macrophages and platelets in synovium involved by rheumatoid arthritis. A study with monoclonal antibodies

The inflammatory cell infiltrate involving synovial tissues from joints affected by rheumatoid arthritis (RA)++ has been contrasted with that present in synovium removed from joints involved by previous trauma (T) or osteoarthritis (OA). Cell deployment has been mapped by immunohistochemistry using monoclonal antibodies which recognise epitopes characterising T and B cells, polymorphonuclear leukocytes, mononuclear phagocytes and platelets. Mononuclear phagocytes were the most consistent feature of the rheumatoid inflammatory cell exudate and were present, particularly in the synovial layer, in all OA/T samples. The synovial cells lacked the C3b complement receptor, CR1, but expressed CR3, the receptor for C3bi. In rheumatoid synovium, interdigitating cells were difficult to identify but cells of dendritic morphology bore at least one macrophage epitope. T cells far out-numbered B cells and generally lacked the IL-2 receptor which is an indicator of T cell activation. Care is required in the estimation of the T helper/inducer (TH) T suppressor/cytotoxic (Ts) ratio. Polymorphonuclear leukocytes were demonstrated around vessels and near the synovial intimal cell layer suggesting rapid tissue transit. Extravascular platelets were sparse. Follicular dendritic cells were defined by their central location in lymphoid follicles and strong expression of CR1 receptors. HLA-DR expression was widespread except on endothelial cells.

Multifactorial pathogenesis: ought we to classify disease or treat the individual's causes of disease?

Added to the uniqueness of most of us imparted by HLA, our individual differences in the expression of other genetic traits, foetal period steroid imprints on brain and other functions, and regulators shared by body and mind indicate that each one of us (except most monozygotic twins) is born as a unique individual whole (I). Mechanisms suspected to be contributing ones in classified synovitides appear to correspond to individually exaggerated or depressed modes of response by physiological mechanisms linked to our unique individual wholes (II). If we upgrade the importance of influences of combinations of 'contributing' mechanisms, the importance of the alleged unknown fundamental causes of these diseases diminishes (III). This broad interpretation of 'multifactorial pathogenesis' can probably be applied to many common types of disease (IV), implying that disease classifications may poorly reflect the individual's causes of disease (V). There is reason to challenge modern concepts about disease (VI).

Does sulphasalazine cause folate deficiency in rheumatoid arthritis?

Sulphasalazine impairs folic acid absorption and metabolism but rarely leads to folate deficiency in inflammatory bowel disease (IBD). In rheumatoid arthritis (RA), however, serum and red cell folate concentrations are often low and sulphasalazine might stress folate metabolism. In a prospective study, 2 g sulphasalazine was compared with 500 mg penicillamine daily in 30 patients over 24 weeks. Pre-treatment serum and red cell folate concentrations were low-normal. Improvements in disease activity and haemoglobin occurred in both treatment groups, but MCV increased only in patients taking sulphasalazine. Serum and red cell folate concentrations did not change in either group. Increased MCV with sulphasalazine might therefore reflect reticulocytosis secondary to drug-induced haemolysis. The mechanisms by which sulphasalazine antagonizes folate metabolism are dose-dependent and, consequently, higher doses might precipitate folate deficiency.

Long-term low dose ticlopidine treatment in rheumatoid arthritis: effects on serum sulphydryl levels, technetium index, erythrocyte sedimentation rate, and clinical disease activity

In 22 patients with rheumatoid arthritis oral ticlopidine 250 mg/day for 18 months induced clinical improvement, confirmed by a significant decrease in the counts of involved joint. A significant decrease was observed in the technetium index (Tc-index) and the erythrocyte sedimentation rate (ESR), and a significant increase occurred in the serum sulphydryl (SH) levels. The long-term changes in serum SH and Tc-index produced by ticlopidine may represent a specific antirheumatic activity of this platelet-inhibiting drug.

The long term effects of sulphasalazine in the treatment of rheumatoid arthritis and a comparative study with penicillamine

The long term efficacy and tolerability of sulphasalazine (SASP) in the treatment of 21 patients with active classical or definite rheumatoid arthritis (RA) were examined and compared with the effects of penicillamine in a similarly active group of RA patients. Nineteen of the 21 patients treated with SASP improved during the first 6 months as shown by significant changes in the clinical and laboratory variables. Clinical improvement was maintained for the remainder of the year. Improvement in laboratory variables was maintained at 9 months but showed some deterioration at 1 year. Six patients went into remission by the ARA criteria, and 16 were able to continue the drug at the end of 1 year. In addition SASP had a steroid-sparing effect in 4 of the patients on systemic steroids. No potentially dangerous side effects were encountered by the end of the first year, although 5 patients were withdrawn. Dyspepsia, nausea and abdominal discomfort were the most common side-effects, although rashes (3) and macrocytosis (2) also occurred. Eighteen of the 21 patients treated with penicillamine improved during 9 months, although there was some deterioration at 1 year. Eight patients were withdrawn because of side-effects - thrombocytopenia (5), nephrotic syndrome (1) and proteinuria (2). This study suggests that SASP has a disease modifying action maintained over a year and associated with low toxicity. It is a useful addition to the small number of second-line drugs with a possibly different mode of action.