Nutritional deficiencies and blunted erythropoietin response as causes of the anemia of critical illness

PURPOSE

The purpose of this article was to determine the prevalence of iron, vitamin B12, and folate deficiency and to evaluate the erythropoietin (EPO) response to anemia in a cohort of long-term intensive care unit (ICU) patients.

MATERIALS AND METHODS

All patients admitted to three academic medical center multidisciplinary ICUs were screened for eligibility into a randomized trial of EPO for the treatment of ICU anemia. On their second or third ICU day, patients enrolled in this trial had EPO levels drawn and were screened for iron, B12, and folate deficiency. Weekly EPO levels were obtained throughout patients' ICU stay.

RESULTS

A total of 184 patients were screened for iron, B12, and folate deficiency. Sixteen patients (9%) were iron deficient by study criteria, 4 (2%) were B12 deficient, and 4 (2%) were folate deficient. Mean hemoglobin and reticulocyte percents of the remaining 160 patients were 10.3 +/- 1.2 g/dL and 1.66 +/- 1.09%, respectively. In most patients, serum iron and total iron binding capacity levels were very low, whereas ferritin levels were very high. Mean and median day 2 EPO levels were 35.2 +/- 35.6 mIU/mL and 22.7 mIU/mL, respectively (normal = 4.2-27.8). Serial EPO levels in most persistently anemic patients remained within the normal range.

CONCLUSIONS

In this cohort, screening for iron, B12, and folate deficiency identified potentially correctable abnormalities in more than 13% of patients and should be considered in those who are anticipated to have long ICU stays. Even at an early point of critical illness, most patients had iron studies consistent with anemia of chronic disease (ACD), as well as a blunted EPO response that may contribute to this ACD-like anemia of critical illness.

Routine measurement of pleural fluid amylase is not indicated

BACKGROUND

The routine measurement of pleural fluid amylase is frequently recommended, but the cost-effectiveness of this procedure is unknown.

METHODS

To assess the utility of routine measurement of pleural fluid amylase in evaluating pleural effusions, we measured amylase, glucose, lactate dehydrogenase, and protein levels and blood cell counts in 379 patients undergoing thoracentesis during a 22-month period from 1997 to 1999. Of these, 199 had effusions after cardiac surgery; 61, malignant; 48, transudative; 28, parapneumonic; 2, chylous; 2, rheumatoid; 1, tuberculous; and 1, from chronic pleuritis. There were 37 exudates of unknown origin.

RESULTS

Measurement of pleural fluid amylase levels did not assist in determining the origin of the effusion in any of the patients. Amylase levels greater than 100 U/L (normal serum level in our laboratory is 30-110 U/L) were found in 5 (1.3%) of 379 patients: 1 patient with congestive heart failure (amylase, 173 U/L), 2 with post-cardiac surgery effusions (144 U/L and 130 U/L), 1 with pneumonia (109 U/L), and 1 with lung cancer (105 U/L).

CONCLUSIONS

The routine measurement of pleural fluid amylase levels is neither clinically indicated nor cost-effective. We suggest that pleural fluid serum amylase levels be measured only if there is a pretest suspicion of acute pancreatitis, chronic pancreatic disease, or esophageal rupture.

Vascular endothelial growth factor level correlates with transforming growth factor-beta isoform levels in pleural effusions

BACKGROUND

Recent studies have demonstrated high levels of vascular endothelial growth factor (VEGF) in exudative pleural effusions and a possible etiologic role. The factors regulating VEGF accumulation in the pleural space are unknown. Transforming growth factor (TGF)-beta is a potent stimulator of VEGF expression in vitro. We hypothesized that TGF-beta induces VEGF production in pleural tissues, and, hence, the pleural fluid VEGF levels should correlate with the levels of TGF-beta in pleural fluid of different etiologies.

METHODS

Seventy pleural fluid samples were analyzed. These included 20 malignant, 13 post-coronary artery bypass grafting (CABG), 8 parapneumonic, 11 miscellaneous exudative, and 18 congestive heart failure (CHF) pleural effusions.

RESULTS

Pleural fluid VEGF levels showed good correlation with those of TGF-beta(1) (r = 0.58; p < 0. 0001), TGF-beta(2) (r = 0.43; p < 0.001), and lactate dehydrogenase (r = 0.65; p < 0.001). The levels of TGF-beta(1) and TGF-beta(2) also were correlated (r = 0.60; p < 0.0001). The median levels of TGF-beta(1) (2,480 pg/mL) and TGF-beta(2) (266 pg/mL) in the CHF group were significantly lower than those in the malignant (TGF-beta(1), 4,902 pg/mL; TGF-beta(2), 428 pg/mL), post-CABG (TGF-beta(1), 5,456 pg/mL; TGF-beta(2), 377 pg/mL), parapneumonic (TGF-beta(1), 5,024 pg/mL; TGF-beta(2), 464 pg/mL), and miscellaneous exudate groups (TGF-beta(1), 7,690 pg/mL; TGF-beta(2), 369 pg/mL). There was no significant difference in TGF-beta(1) and TGF-beta(2) levels among the four exudate groups.

CONCLUSIONS

VEGF levels in pleural effusions are significantly correlated with the levels of TGF-beta(1) and beta(2) isoforms. VEGF, TGF-beta(1), and TGF-beta(2) levels were all higher in exudative effusions than in effusions secondary to CHF.

Dipyridamole and exercise SPET provide different estimates of myocardial ischaemic areas: role of the severity of coronary stenoses and of the increase in heart rate during exercise

In patients unable to perform a maximal exercise test, dipyridamole single-photon emission tomography (SPET) has a higher capacity than exercise SPET to detect coronary artery disease (CAD). However, in patients with myocardial ischaemia who are able to perform a maximal exercise test, it is not known whether these two tests may be equally used to assess the areas of myocardial ischaemia. This study was aimed at comparing the results provided by dipyridamole and exercise SPET in CAD patients with documented exercise myocardial ischaemia. Forty CAD patients who had undergone exercise thallium-201 SPET and who had myocardial ischaemia documented by an unequivocally positive exercise test underwent an additional 201Tl SPET study after dipyridamole infusion and low-level (40 W) exercise. The extent of defects was compared between the two tests and predictors of discrepant results were sought among data from exercise testing and coronary angiography. The extent of SPET defects was equivalent between the two tests in only 11 patients (28%), larger defects being observed with exercise in 18 [average difference: 12%+/-5% of left ventricle (LV)] and with dipyridamole in 11 (average difference: 15%+/-11% of LV). The best independent predictors of discrepancies between the two tests were: (1) increase in heart rate at exercise SPET, with defects being smaller at exercise than after dipyridamole in none of the patients with an increase >60 bpm (0/14), but in 42% of the others (11/26; P=0.004); and (2) an ischaemic territory related to a <70% coronary stenosis, for which SPET defects were always induced at exercise (10/10) but in only 30% (3/10) with dipyridamole (P=0.0004). Exercise and dipyridamole SPET provide different estimates of myocardial ischaemic areas. Dipyridamole allows the unmasking of perfusion abnormalities in patients who have low increases in heart rate at exercise SPET. However, dipyridamole is also much less efficient at inducing perfusion abnormalities in the ischaemic areas supplied by coronary stenoses of intermediate severity at rest angiography.

Long-term outcome in patients treated by intracoronary stenting with ticlopidine and aspirin, and deleterious prognostic role of unstable angina pectoris

Compared with stable clinical conditions, unstable angina carries an increased risk of immediate and delayed cardiac adverse events after balloon coronary angioplasty. The influence of stent use in reducing these differences remains unknown. We analyzed the early (30 days) and late outcome of a cohort of 459 consecutive patients who underwent stent placement with ticlopidine and aspirin as antithrombotic regimen according to the presence (group 1, n = 151) or absence (group 2, n = 308) of unstable angina at rest (Braunwald classes II and III). Group 1 patients were older and more likely to be current or former smokers. In group 2, prior myocardial infarction was more frequent. Procedural, in-hospital results, and early outcome were similar in the 2 groups. However, over the long term, the incidence of myocardial infarction (11% vs 6%, p <0.04), target lesion revascularization (19% vs 13%, p <0.04), or any revascularization (30% vs 20%, p <0.01) was significantly higher in group 1. Kaplan-Meier probabilities of survival without myocardial infarction (85% vs 91%, p <0.05), survival without revascularization of the target lesion (73% vs 83%, p <0.01), survival without any revascularization (65% vs 77%, p <0.006), and survival without any events (61% vs 73%, p <0.009) were significantly worse in group 1. In addition, Cox multivariate analysis showed that unstable angina at rest was an independent predictor of target lesion revascularization, of survival without any revascularization, and without any events. Thus, unstable angina at rest remains an adverse prognostic indicator in patients treated with intracoronary stents, particularly with regard to subsequent requirement of revascularization procedures and event-free survival.

Cardiac output measurement with an esophageal doppler in critically ill Emergency Department patients

Cardiac output (CO) is a principal determinant of perfusion in many critically ill patients. The objectives of this study were to determine whether physicians' estimates of CO, or cardiac index (CI), are accurate compared with CO/CI measured by esophageal doppler, and to estimate the physician time necessary for Emergency Department (ED) CO/CI measurement. We prospectively evaluated a convenience sample of critically ill, adult ED patients. Based on all available clinical information, residents and emergency medicine attendings estimated patients' CI as being high, normal, or low. A blinded investigator measured CO/CI using an esophageal doppler probe. Times to achieve optimal doppler signal were recorded. Agreement between physician CI estimates and measured CI values was assessed using the weighted kappa statistic. Thirty-three patients were evaluated. There was no agreement beyond chance between physicians' estimates of CI and measured CI. The mean time for optimal doppler signal was 5.7+/-4.3 min. Physicians' estimates of CI were inaccurate compared with measured CI. Esophageal doppler measurement of CO/CI appears to be practical from a physician time standpoint.

A randomized comparison of indwelling pleural catheter and doxycycline pleurodesis in the management of malignant pleural effusions

BACKGROUND

The purpose of this study was to compare the effectiveness and safety of a chronic indwelling pleural catheter with doxycycline pleurodesis via tube thoracostomy in the treatment of patients with recurrent symptomatic malignant pleural effusions (MPE).

METHODS

In this multi-institutional study conducted between March 1994 and February 1997, 144 patients (61 men and 83 women) were randomized in a 2:1 distribution to either an indwelling pleural catheter or doxycycline pleurodesis. Patients receiving the indwelling catheter drained their effusions via vacuum bottles every other day or as needed for relief of dyspnea.

RESULTS

The median hospitalization time was 1.0 day for the catheter group and 6.5 days for the doxycycline group. The degree of symptomatic improvement in dyspnea and the quality of life was comparable in each group. Six of 28 patients who received doxycycline (21%) had a late recurrence of pleural effusion, whereas 12 of 91 patients who had an indwelling catheter (13%) had a late recurrence of their effusions or a blockage of their catheter after the initially successful treatment (P = 0.446). Of the 91 patients sent home with the pleural catheter, 42 (46%) achieved spontaneous pleurodesis at a median of 26.5 days.

CONCLUSIONS

A chronic indwelling pleural catheter is an effective treatment for the management of patients with symptomatic, recurrent, malignant pleural effusions. When compared with doxycycline pleurodesis via tube thoracostomy, the pleural catheter requires a shorter hospitalization and can be placed and managed on an outpatient basis.

[Angioplasty in chronic coronary occlusion]

In the last few years, coronary angioplasty has been the object of real progress in the treatment of total chronic coronary occlusion; The primary success rate of the procedure regularly exceeds 70% with the use of improved equipment; however, these procedures are not without risk with a reported complication rate close to that of angioplasty of non-occlusive stenosis. The use of stents has significantly reduced the restenosis rate, mainly by decreasing the risk of reocclusion. The indications of angioplasty for chronic occlusion remain controversial: the procedure is justified in patients with angina; in asymptomatic patients, angioplasty may improve global and regional left ventricular function in those with documented myocardial viability and limit ventricular remodelling but the results of a randomised trial of systematic angioplasty versus medical treatment in this type of indication are not yet available.

Efficacy of recombinant human erythropoietin in the critically ill patient: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

To determine whether the administration of recombinant human erythropoietin (rHuEPO) to critically ill patients in the intensive care unit (ICU) would reduce the number of red blood cell (RBC) transfusions required.

DESIGN

A prospective, randomized, double-blind, placebo-controlled, multicenter trial.

SETTING

ICUs at three academic tertiary care medical centers.

PATIENTS

A total of 160 patients who were admitted to the ICU and met the eligibility criteria were enrolled in the study (80 into the rHuEPO group; 80 into the placebo group).

INTERVENTIONS

Patients were randomized to receive either rHuEPO or placebo. The study drug (300 units/kg of rHuEPO or placebo) was administered by subcutaneous injection beginning ICU day 3 and continuing daily for a total of 5 days (until ICU day 7). The subsequent dosing schedule was every other day to achieve a hematocrit (Hct) concentration of >38%. The study drug was given for a minimum of 2 wks or until ICU discharge (for subjects with ICU lengths of stay >2 wks) up to a total of 6 wks (42 days) postrandomization.

MEASUREMENTS AND MAIN RESULTS

The cumulative number of units of RBCs transfused was significantly less in the rHuEPO group than in the placebo group (p<.002, Kolmogorov-Smirnov test). The rHuEPO group was transfused with a total of 166 units of RBCs vs. 305 units of RBCs transfused in the placebo group. The final Hct concentration of the rHuEPO patients was significantly greater than the final Hct concentration of placebo patients (35.1+/-5.6 vs. 31.6+/-4.1; p<.01, respectively). A total of 45% of patients in the rHuEPO group received a blood transfusion between days 8 and 42 or died before study day 42 compared with 55% of patients in the placebo group (relative risk, 0.8; 95% confidence interval, 0.6, 1.1). There were no significant differences between the two groups either in mortality or in the frequency of adverse events.

CONCLUSIONS

The administration of rHuEPO to critically ill patients is effective in raising their Hct concentrations and in reducing the total number of units of RBCs they require.

Vascular endothelial growth factor in pleural fluid

STUDY OBJECTIVES

The purpose of this study was to analyze the relationship of the pleural fluid vascular endothelial growth factor (VEGF) level with the diagnostic category and with the pleural fluid characteristics in a group of 70 patients.

DESIGN

The VEGF levels of consecutive patients undergoing therapeutic thoracentesis were determined with an enzyme-linked immunosorbent assay.

SETTING

University-affiliated tertiary care center.

RESULTS

The median level of pleural fluid VEGF in the patients with congestive heart failure (150 pg/mL) was significantly (p < 0.05) lower than the median level in the patients with coronary artery bypass grafting (357 pg/mL), which in turn was significantly lower (p < 0.05) than the median levels in the patients with malignancy (1,097 pg/mL). The overlap between groups, however, limits the diagnostic usefulness of pleural fluid VEGF levels. The VEGF level was most closely correlated with the lactate dehydrogenase level (r = 0.42, p < 0.001) and was also significantly correlated with the total pleural fluid protein level. The median VEGF levels in the pleural fluid of patients with breast cancer were significantly lower (p = 0.017) than in those with lung cancer. The VEGF level was very high (3,294 pg/mL) in the one patient with pulmonary embolism.

CONCLUSIONS

We conclude that the VEGF levels in pleural fluid differ significantly from one diagnostic category to another with the highest median levels occurring in patients with malignant pleural effusions. We speculate that VEGF may be responsible for the pleural fluid accumulation in at least some situations.

Large pleural effusions occurring after coronary artery bypass grafting. Cardiovascular Surgery Associates, PC

BACKGROUND

Large pleural effusions sometimes occur after coronary artery bypass grafting (CABG), but their characteristics and clinical course are largely unknown.

OBJECTIVE

To describe the clinical course and pleural fluid findings in patients with large pleural effusions occurring after CABG.

DESIGN

Retrospective case series.

SETTING

Tertiary care, university-affiliated, nonprofit teaching hospital.

PATIENTS

3707 patients who had CABG between 1 February 1996 and 1 August 1997.

MEASUREMENTS

Chest radiographs were reviewed, and information on pleural fluid findings, pleural effusion treatment, and cardiac surgery was obtained from medical records and a cardiac surgery database.

RESULTS

Pleural effusions that occupied more than 25% of the hemithorax were found in 29 patients (0.78%). Seven of the effusions were attributed to congestive heart failure, 2 were attributed to pericarditis, and 1 was attributed to pulmonary embolism. The explanation for the remaining 19 effusions was unclear. All but 2 effusions were predominantly left-sided. Of these 19 effusions, 8 were bloody and 11 were nonbloody. Bloody effusions usually occurred earlier, contained higher lactic acid dehydrogenase levels, and were frequently eosinophilic. Nonbloody effusions tended to be more difficult to manage.

CONCLUSIONS

Large pleural effusions may develop in a small proportion of patients after CABG. The cause of many of these effusions is unclear. Most bloody effusions can be managed with one to three therapeutic thoracenteses. Resolution of nonbloody effusions may require anti-inflammatory agents, tube thoracostomy, or intrapleural injection of sclerosing agents.

Comparison of pleural fluid pH values obtained using blood gas machine, pH meter, and pH indicator strip

STUDY PURPOSE

The purpose of this study was to compare the pleural fluid pH values obtained with a blood gas machine (pHbg), with a pH meter (pHmet), and with a pH indicator strip (pHstrip), to determine if the pleural fluid pH measured by a pH meter or a pH indicator strip was sufficiently accurate for clinical decisions.

METHODS

The pleural fluid pH was determined, within 20 min after being collected anaerobically, by a blood gas machine (CIBA-Corning model 288), pH meter (Corning pH meter 610A), and pH indicator strip (Baxter Diagnostic) following routine laboratory procedures in 50 pleural fluids. Pleural fluid pH was determined in seven additional samples with the blood gas machine and a pH meter at 25 and 37 degrees C respectively, initially, and after 30 min.

RESULTS

The mean pHbg (7.42+/-0.01) was significantly less than the mean pHmet (7.58+/-0.02) or the mean pHstrip (8.23+/-0.06). There were significant differences between the pHbg and the pHmet (p < 0.001), and between the pHbg and the pHstrip (p < 0.001). Analysis of the additional seven samples demonstrated that when the blood gas machine was set at 25 degrees C, the pHbg (pHbg = 7.54+/-0.02) and the pHmet (7.53+/-0.01) were almost identical.

CONCLUSION

When the pleural fluid pH is going to be used for decision making, only the pH values provided by the blood gas machine are sufficiently accurate.

Management of parapneumonic effusions

When a patient with a parapneumonic pleural effusion is first evaluated, a therapeutic thoracentesis should be performed if more than a minimal amount of pleural fluid is present. Fluid obtained at the therapeutic thoracentesis should be gram-stained and cultured and analyzed for glucose, pH, LDH, white blood cells, and differential cell count. If the fluid cannot be drained because of loculations, a chest tube should be inserted and thrombolytic agents administered. If the pleural fluid recurs after the initial therapeutic thoracentesis but the patient is doing well clinically and the initial pleural fluid glucose was greater than 60 mg/dL; the pH, greater than 7.2; the LDH, less than three times the upper normal limit for serum and the cultures are negative; he or she can be observed. If one or more of the aforementioned criteria are not met, a second therapeutic thoracentesis should be performed, with repeat diagnostic evaluations of the pleural fluid. If the fluid recurs a second time, a small chest tube should be placed if the pleural fluid glucose and pH were lower and the LDH higher on the second thoracentesis than on the first thoracentesis. Patients with loculated-parapneumonic effusions should be treated with tube thoracostomy and thrombolytic agents. If drainage is incomplete, thoracoscopy, with breakdown of adhesions and debridement of the pleural space, is indicated. If thoracoscopy is unsuccessful, then thoracotomy, with decortication, is indicated unless the patient is too debilitated.

Prediction of poor outcome of intensive care unit patients admitted from the emergency department

OBJECTIVE

To assess whether physicians can identify very low likelihood of survival and very low likelihood of favorable functional outcome in adult nontrauma patients before admission to the intensive care unit (ICU) from the emergency department (ED).

DESIGN

Prospective survey.

SETTING

University hospital ED and ICU.

PARTICIPANTS AND PATIENTS

Critical care fellows and ED physicians and all adult nontrauma patients admitted to the ICU from the ED over 1 yr.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The survey compared predictions of poor outcome from three sources: critical care fellows, ED physicians, and the admission Mortality Probability Model (MPM0). All patients were followed until hospital death or hospital discharge. Six-month follow-up data were obtained for patients predicted to have a < 2% chance of surviving with favorable functional outcome. In the ED, critical care fellows and ED physicians predicted likelihood of patient survival and likelihood of favorable functional outcome. MPM0 estimates of mortality were determined. The sensitivities, specificities, and positive predictive values were calculated for the predictions of < 2% survival and the predictions of < 2% chance of favorable functional outcome made by each prediction group. Complete data were obtained on 236 (96%) of 243 eligible patients. With regard to hospital mortality rate, fellows' predictions had a sensitivity of 27%, a specificity of 99%, and a positive predictive value of 88%; ED physicians' predictions had a sensitivity of 24%, a specificity of 98%, and a positive predictive value of 81%; and MPM0 predictions had a sensitivity of 2%, a specificity of 100%, and a positive predictive value of 100%. With regard to mortality rate combined with poor functional outcome, fellows' predictions had a sensitivity of 35%, a specificity of 99%, and a positive predictive value of 96%; ED physicians' predictions had a sensitivity of 37%, a specificity of 99%, and a positive predictive value of 96%.

CONCLUSIONS

If a cutoff point of < 2% predicted survival is used in the triage of patients away from the ICU, the MPM0 has too low a sensitivity to be used as an effective screen. The low sensitivities and relatively low positive predictive values with wide confidence intervals of physician predictions of < 2% survival also preclude their use in triage. The addition of functional outcome as an end point improves the sensitivity, specificity, and positive predictive value of subjective predictions, making triage of patients away from the ICU at the time of ED evaluation a realistic possibility.

Need and desire for preventive care measures in emergency department patients

STUDY OBJECTIVE

To determine the need and desire for selected preventive care measures in an adult emergency department population, comparing patients with and without primary physicians.

DESIGN

Written survey.

SETTING

Urban university ED.

PARTICIPANTS

English-speaking patients 18 years of age or older who did not arrive by ambulance, did not have a critical illness, and did not have a psychiatric complaint.

RESULTS

The main outcome measures were past preventive care and desire to initiate preventive care measures as part of ED care. Nine hundred fifty-three surveys were distributed; 647 were completed and returned. Twenty-seven percent of patients knew their cholesterol level. Forty-three percent of men aged 40 years or older reported having had a prostate examination in the past year, and 39% of men aged 50 years or older reported having had an examination of stool for blood in the past year. Twenty-one percent of women reported taking calcium, and 67% of women aged 40 years or older had had a mammogram in the past 2 years. Sixty-three percent of patients had a primary physician; these patients were more likely to have received each of the preventive care measures studied (P < .025). Fifty-three percent of women not taking calcium requested information about osteoporosis prevention, and 30% requested prescriptions for calcium supplements. Sixty-two percent of women who did not have a current mammogram requested mammography information, and 60% requested referrals for mammography. Fifty-four percent of patients requested cholesterol and diet information. Patients requesting information, referrals, and prescriptions were given them.

CONCLUSION

In a selected ED population, there was both need and desire for preventive health care measures to be initiated or provided as part of ED care, especially among patients who did not have primary physicians.

Emergency department immunization of the elderly with pneumococcal and influenza vaccines

STUDY OBJECTIVE

To determine the feasibility of immunizing unvaccinated elderly patients with influenza and pneumococcal vaccines in the emergency department.

PARTICIPANTS AND SETTING

A convenience sample of elderly patients presenting to an urban university-affiliated ED.

DESIGN AND INTERVENTIONS

Elderly ED patients were asked about prior influenza and pneumococcal immunization. Nonimmunized patients were given information sheets, were informed of the changes for vaccination, and were asked if they desired immunization as part of their ED care. Those desiring immunization who lacked contraindications were immunized.

RESULTS

One hundred thirty-three patients were enrolled. Eighty-two percent had not been immunized with pneumococcal vaccine; 62% of these nonimmunized patients stated they desired pneumococcal vaccination, and 58% were immunized. Sixty-three percent of the 133 patients had not received current influenza vaccine; 54% of these nonimmunized patients stated they desired influenza vaccine, and 50% were immunized.

CONCLUSION

The majority of elderly ED patients are not immunized adequately with influenza and pneumococcal vaccines as recommended by the Centers for Disease Control and Prevention. Most elderly patients will accept immunization with these vaccines as part of their ED care. These vaccines can be delivered effectively to elderly patients in the ED.

T lymphocyte adhesion to fibronectin (FN): a possible mechanism for T cell accumulation in the rheumatoid joint

The accumulation of T cells within the joint is responsible for the perpetuation of synovitis. This process is partly regulated by selective binding to endothelium. However, adhesion to extra-cellular matrix proteins, like FN, may also be important. FN binding is mediated by certain members of the VLA (beta 1 integrin) family of proteins. To investigate the role of Tc-FN interactions in synovitis the binding of synovial fluid (SF) and peripheral blood (PB) T cells to FN-coated wells, and the expression of cell surface VLA molecules on these cells by double label immunofluorescence, were studied. SF T cells bound better to FN than PB T cells. VLA alpha 4 and VLA beta 1 but not VLA alpha 5 were up-regulated on SF compared with PB T cells. Anti-VLA alpha 4, VLA beta 1 and VLA alpha 5 MoAbs inhibited the binding of SF T cells to FN. The increased binding of SF T cells to FN could have been related to activation and/or to their predominantly memory phenotype. Purified resting memory or naive T cells bound poorly to FN. In contrast, compared with SF T cells, concanavalin A-activated T cells showed a very similar level of binding to FN, comparable expression of VLA molecules and the same pattern of inhibition of binding to FN by MoAbs. Thus, VLA molecules may play an important role in the retention of T cells in the joint and since T cells can be activated via VLA-FN interactions, this mechanism may perpetuate chronic inflammation.