Outpatient healthcare utilization among incident cases of systemic sclerosis: results from a population-based US cohort (1988-2016)

OBJECTIVE

Systemic sclerosis (SSc) is a complex, heterogeneous connective tissue disease with multiorgan dysfunction. This study aimed to compare healthcare utilization among incident cases of SSc versus age- and gender-matched comparators.

METHOD

A population-based cohort of physician-diagnosed patients with SSc in Olmsted County, MN, USA, from 1 January 1988 to 31 December 2016 was assembled. A 2:1 cohort of age- and gender-matched non-SSc subjects was randomly selected for comparison. Patients were followed until death, migration from Olmsted County, or 31 December 2017. Outpatient utilization data were obtained beginning 12 months before the SSc incidence/index date and compared using negative binomial and multinomial models. Services were summarized as visit-days to avoid overestimation of services provided.

RESULTS

The study included 69 incident SSc cases and 138 non-SSc comparators (mean ± sd age 57 ± 16 years at diagnosis/index, 90% female). Patients with SSc had higher utilization of outpatient physician, laboratory, and combined radiology visit-days annually for the year before and for each of the first 5 years after diagnosis than comparators. Among patients with SSc, healthcare utilization was highest during the year of SSc diagnosis. Rate ratios comparing utilization in patients with and without SSc ranged from 1.8 to 3.0 for all comparisons.

CONCLUSION

Higher utilization of outpatient physician, laboratory, and radiology visit-days was observed among patients with SSc compared to non-SSc subjects throughout 5 years of disease duration, indicating high and continued care needs in this patient population. The highest utilization of services among SSc patients occurred during the year of SSc diagnosis.

POS0836 CONDUCTION AND RHYTHM DISORDERS AMONG PATIENTS WITH SYSTEMIC SCLEROSIS: A US POPULATION BASED STUDY

Background:

Systemic sclerosis (SSc) can impact multiple areas of the heart through fibrotic and vascular processes; leading to variable cardiac involvement including electrocardiogram (ECG) abnormalities. Conduction and rhythm disorders are associated with worse prognosis in patients with SSc. (1, 2)

Objectives:

To study the incidence, risk factors and outcomes of conduction and rhythm disorders in a US population-based cohort of patients with SSc and non-SSc comparators from the same geographic area.

Methods:

A previously identified incident cohort of SSc patients (1980-2016) in a well-defined geographic area was compared to a randomly selected 2:1 cohort of age- and sex-matched non-SSc subjects from the same population base. Demographics, disease characteristics, cardiovascular risk factors and laboratory tests were abstracted by manual record review. ECGs and Holter ECGs were reviewed to determine the occurrence of any conduction or rhythm abnormalities. The need for cardiac interventions was also abstracted.

Results:

78 incident SSc cases and 156 non-SSc comparators were identified [age 56 years± 15.7, 91% female]. Prevalence of any conduction disorders before SSc diagnosis compared to non-SSc comparators was 15% vs. 7% (p=0.06), and any rhythm disorder was 18% vs. 13% (p=0.33). During a median follow up of 10.5 years in patients with SSc and 13.0 years in non-SSc comparators, conduction disorders developed in 25 SSc patients with a cumulative incidence (ci) of 20.5% (95% CI: 12.4-34.1%) compared to 28 non-SSc patients with ci of 10.4% (95% CI: 6.2-17.4%) (HR: 2.57; 95% CI: 1.48-4.45), while rhythm disorders developed in 27 SSc patients with ci of 27.3% (95% CI: 17.9-41.6%) vs 43 non-SSc patients with ci of 18.0% (95% CI: 12.3-26.4%) (HR: 1.62; 95% CI: 1.00-2.64). (Figure 1).

Conduction disorders in patients with SSc during follow up included: 1st-degree atrioventricular block (AVB) (n=12), 2nd-degree AVB (n=1), 3rd-degree AVB (n=1), right bundle branch block (n=10), left bundle branch block (n=4), bifascicular block (n=6), and prolonged-QT (n=13). Rhythm disorders included: atrial fibrillation (n=10), atrial flutter (n=4), supraventricular tachycardia (n=4), ventricular tachycardia (n=1), and premature ventricular contractions (n=16).

Pulmonary hypertension (PHT) was the only significant risk factor identified for development of both conduction and rhythm disorders (HR=8.38, 95% CI: 1.32-53.40 and HR=8.07, 95% CI: 1.60-40.74, respectively). Current smoking significantly increased the risk for development of rhythm disorders (HR=2.91, 95% CI: 1.19-7.12). Conduction and rhythm disorders were associated with increased mortality among patients with SSc (HR=7.60, 95% CI: 3.49-16.55 and HR=4.87, 95% CI: 2.28-10.42, respectively, after adjusting for age, sex and calendar year of diagnosis).

Conclusion:

Patients with SSc have a significantly higher prevalence of conduction disorders at disease onset than non-SSc comparators. During the course of their disease, their risk of developing conduction disorders is 2.6-fold, and risk of rhythm disorders is 1.6-fold increased, compared to non-SSc subjects.

PHT was significantly associated with increased risk of developing conduction and rhythm disorders among patients with SSc, a finding that should warrant increased vigilance and screening for ECG abnormalities in this population.

References:

[1]Tyndall A.J. et al. Ann Rheum Dis, 2010. 69(10): p. 1809-15.

[2]Desai C.S. et al. Curr Opin Rheumatol, 2011. 23(6): p. 545-54.

Figure 1.

Cumulative incidence of any conduction or any rhythm disorder in SSc (solid line) vs non-SSc comparators (dashed line).

Disclosure of Interests:

None declared

Incidence of systemic lupus erythematosus in a population-based cohort using revised 1997 American College of Rheumatology and the 2012 Systemic Lupus International Collaborating Clinics classification criteria

In 2012, the Systemic Lupus International Collaborating Clinics (SLICC) group published a new set of classification criteria for systemic lupus erythematosus (SLE). Studies applying these criteria to real-life scenarios have found either equal or greater sensitivity and equal or lower specificity to the 1997 ACR classification criteria (ACR 97). Nonetheless, there are no studies that have used the SLICC 12 criteria to investigate the incidence of lupus. We used the resource of the Rochester Epidemiology Project to identify incident SLE patients in Olmsted County, Minnesota, from 1993 to 2005, who fulfilled the ACR 97 or SLICC 12 criteria. A total of 58 patients met criteria by SLICC 12 and 44 patients met criteria by ACR 97. The adjusted incidence of 4.9 per 100,000 person-years by SLICC 12 was higher than that by ACR 97 (3.7 per 100,000 person-years, p = 0.04). The median duration from the appearance of first criterion to fulfillment of the criteria was shorter for the SLICC 12 than for ACR 97 (3.9 months vs 8.1 months). The higher incidence by SLICC 12 criteria came primarily from the ability to classify patients with renal-limited disease, the expansion of the immunologic criteria and the expansion of neurologic criteria.

Effect of treatment with methotrexate, hydroxychloroquine, and prednisone on lymphocyte polyamine levels in rheumatoid arthritis: correlation with the clinical response and rheumatoid factor synthesis

OBJECTIVE

Polyamines are increased in activated lymphocytes, including peripheral blood lymphocytes (PBL) from patients with rheumatoid arthritis (RA), and are important in modulating immune-mediated cellular responses. In vitro studies have suggested that methotrexate (MTX) interferes with polyamine synthesis. This study evaluated the in vivo polyamine response to MTX compared to other anti-arthritic agents, and correlated it with the clinical and immunological response.

METHODS

The polyamine content of PBL was determined in 14 RA patients at initiation of treatment with MTX (n = 8), hydroxychloroquine (HCQ) (n = 3), or prednisone (n = 3), and then monthly for four months. IgM rheumatoid factor (RF) synthesis by PBL in vitro was assessed and tender joints were counted monthly.

RESULTS

Polyamines (spermine and spermidine) decreased by 55% at three months in the MTX group compared to 4% and 9% in the HCQ and prednisone groups, respectively (p < 0.01). However, group differences in the clinical and immunological response were not significant. In the MTX group there was a positive correlation between polyamine levels and the joint count. Such a correlation was not observed in the other groups.

CONCLUSION

These data suggest that MTX interference with the polyamine pathway is not shared by prednisone and HCQ, and is associated with its beneficial effect in RA.

In vitro effects of methotrexate on polyamine levels in lymphocytes from rheumatoid arthritis patients

OBJECTIVE

Several studies have documented increased levels of polyamines in rheumatoid arthritis (RA). We have suggested that one of the mechanisms of action of methotrexate (MTX) involves the inhibition of polyamine synthesis in lymphocytes. In this study, we sought to establish the inhibitory effect of MTX on polyamine synthesis and its specificity.

METHODS

Polyamine levels were determined in stimulated RA lymphocytes incubated in vitro with MTX and compared to levels in lymphocytes incubated with hydrocortisone, D-penicillamine, or medium alone. Lymphocyte polyamine levels were correlated with IgM-rheumatoid factor (RF) synthesis.

RESULTS

Incubation with MTX resulted in concentration-dependent decreased intracellular levels of spermidine and spermine, while putrescine levels were not affected. Addition of folinic acid or S-adenosyl-methionine (SAM) prevented this MTX-induced inhibition. Incubation with D-penicillamine or hydrocortisone had no significant effect on polyamine levels. There was a positive correlation between intracellular polyamine levels and the inhibition of IgM-RF synthesis by MTX.

CONCLUSION

These data suggest that MTX inhibits the synthesis of spermidine and spermine in stimulated RA lymphocytes through inhibition of the SAM-dependent pathway. This inhibition may be related to the immune-modulating properties of MTX.

Effects of systemic onset juvenile rheumatoid arthritis on facial morphology and temporomandibular joint form and function

OBJECTIVE

Twenty-four patients with systemic onset juvenile rheumatoid arthritis (JRA) were evaluated to determine its effects on facial morphology and temporomandibular joint (TMJ) form and function.

METHODS

Patients were evaluated with medical and dental histories, facial photographs, intraoral examination, TMJ examination, lateral tomograms or panoramic radiographs, cephalograms, and impressions for study models. The craniomandibular index (CMI) was used to quantitate mandibular movement, tenderness, and TMJ noise. Symptoms were measured by symptom severity index (SSI). CMI data from the patients with JRA were compared to a group of 24 children without JRA with similar mean age and sex distribution.

RESULTS

Our study indicates the facial morphology of patients with systemic onset JRA is similar to that of healthy children except for a mild convex facial profile and backward rotation of the mandible. Changes in facial form were associated with radiographic condylar abnormalities. CMI scores and SSI scores of systemic onset patients were significantly greater than controls, and radiographic condylar changes were noted in 29.2% of the patients with systemic onset JRA.

CONCLUSION

Our study suggests that systemic onset JRA significantly affects TMJ form and function. Facial form was only affected in the few patients with significant radiographic condylar changes.

Effects of polyarticular and pauciarticular onset juvenile rheumatoid arthritis on facial and mandibular growth

OBJECTIVE

To characterize the functional and morphologic effects of polyarticular and pauciarticular onset juvenile rheumatoid arthritis (JRA) on the temporomandibular joint (TMJ).

METHODS

Medical and dental histories, intraoral, lateral cephalometric, and panoramic radiographs, facial photographs, and dental study models were obtained for each of 30 patients with JRA (17 pauciarticular and 13 polyarticular onset). Measures of TMJ dysfunction were gathered during the clinical examination, and an index of condylar morphology was inferred from the panoramic radiographs. The lateral cephalograms were traced, and data from 34 linear and angular measures used to compare the facial morphology of the 2 JRA onset types, both to normative standards and to each other (Student's t test). The Kruskal-Wallis test was used to evaluate the significance of between-group differences for the various ordinal indices.

RESULTS

As indicated by the higher TMJ dysfunction and condylar index scores, polyarticular onset JRA affects the form and function of the TMJ more frequently and severely than does pauciarticular onset. Moreover, compared to normative cephalometric standards, the patients with polyarticular onset had small, short faces with underdeveloped mandibles.

CONCLUSION

Both polyarticular and pauciarticular onset JRA have a negative effect on the form, function, and esthetics of the face and mandible; however, the effects are more pronounced with polyarticular JRA than pauciarticular onset.

Immune complexes from sera of patients with juvenile rheumatoid arthritis reveal novel 40 and 60 kd bands

OBJECTIVE

Immune complexes (IC) have been detected in the majority of sera of patients with juvenile rheumatoid arthritis (JRA). Our aim was to determine the possible constituents of these IC.

METHODS

One hundred and four sera from patients with JRA were separated on a Sepharose 4B column to which were bound F(ab')2 fragments of goat anti-human IgM antibody to separate IgM-containing IC. The column was sequentially eluted with 1 M ammonia and 0.1 M glycine-HCl buffer, pH 3. The eluted material was treated with sodium dodecyl sulfate (SDS) and simultaneously reduced with 2-mercaptoethanol. Individual components were then separated by SDS-gradient polyaclylamide gel electrophoresis and were transferred to nitrocellulose by Western blotting. The nitrocellulose strips were overlaid with the patient's own serum and developed with specific antiserum to human IgM and IgG.

RESULTS

Four bands were noted in the majority of JRA patients, including a band in the 70-80 kD area to the IgM heavy chain and in the 50 kD area to the IgG heavy chain. Additional bands specific for JRA patients' sera were noted in the 40 kD and 60 kD areas. Overall, 61 of 104 sera demonstrated all four bands; 78 showed the 40 kD band and 73 the 60 kD band.

CONCLUSION

These IC were previously shown to contain IgM rheumatoid factor (RF), IgG-RF, and IgG in addition to the 40 and/or 60 kD constituents present in the isolates. Preliminary studies on these constituents suggest the possibility of the 60 kD band being the human 60 kD mitochondrial heat shock protein. Further investigations of these immune complex components may aid in the understanding of the pathophysiology of JRA.

Parvovirus infection mimicking systemic lupus erythematosus

There are striking similarities between human parvovirus B19 (HPV-B19) infection and systemic lupus erythematosus (SLE): both may present with malar rash, fever, arthropathy, myalgia, cytopenia, hypocomplementemia, anti-DNA, and antinuclear antibodies (ANA). Therefore, it is difficult at times to differentiate HPV-B19 infection from SLE presentation or exacerbation. We report 4 cases of HPV-B19 infection mimicking SLE and review 10 other reported cases, all of whom were women. The similarity to a typical SLE presentation was indeed striking: most patients presented with rash, arthropathy, myalgia, fever, and positive ANA. In some cases, HPV-B19 infection seemed to exacerbate SLE rather then resemble it, and differentiation was difficult. Nearly all patients improved within several weeks. However, a few patients had symptoms and laboratory abnormalities lasting more than 6 months. The possibility of HPV-B19 infection should be entertained in patients presenting with SLE-like features.

Effect of dietary protein and estradiol-17 beta on growth and insulin-like growth factor I in cattle during realimentation

Forty-eight medium-framed, crossbred steers (average BW = 268 +/- 20 kg) were limit-fed a 35% concentrate diet to gain approximately .10 kg/d during a 66-d restriction (REST) period. This was followed by a 98-d realimentation (REAL) period in which steers were allotted to a 3 x 2 factorial arrangement of treatments. Treatments were 80% concentrate diets containing 9, 12, or 15% CP, and implantation of one-half of the steers with 24 mg/steer of estradiol-17 beta (E2; Compudose). The allotted steers were distributed across four pens (12 steers/pen) with each pen containing two replicates of each treatment combination. Individual feed intakes were monitored using a Calan gate system. Each steer had ad libitum access to its respective diet. Longissimus muscle area and fat thickness at the 12th rib were measured using real-time ultrasound. Dry matter intake was not affected by CP or E2 through d 56. Steers fed 9% CP weighed less (quadratic, P < .05) after d 14 than steers fed 12 or 15% CP due to slower (quadratic, P < .05) gains during this initial period. Implantation increased (P < .05) ADG from d 15 to 56 resulting in heavier BW (P < .05) on d 56 and 98. Increasing concentrations of dietary CP resulted in linear (P < .05) increases in longissimus muscle area on d 28 and 56, and fat thickness on d 98. Serum IGF-I concentrations were lowest on d -21 of REST and highest on d 28 of REAL (quadratic, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokine levels in serum and synovial fluid of patients with juvenile rheumatoid arthritis

OBJECTIVE

Cytokines play an important role in mediating inflammation and in regulating the immune response of many rheumatological diseases. In patients with juvenile rheumatoid arthritis (JRA), levels of 6 cytokines, interleukin 1 alpha (IL-1 alpha), IL-1 beta (IL-1 beta), IL-2, IL-2 receptor (IL-2R), IL-6, and tumor necrosis factor alpha (TNF-alpha) were measured in serum and synovial fluid (SF) in an effort to evaluate their significance.

METHODS

Serum concentrations of the 6 cytokines were measured in 62 patients with JRA including 22 pauciarticular onset, 26 polyarticular onset, and 14 systemic onset patients, and 29 disease and healthy controls using enzyme-linked immunoabsorbent assays (ELISA). Seventeen SF from patients with JRA were examined for cytokine levels.

RESULTS

Elevated serum levels of IL-2R were found in patients with systemic onset and elevated IL-2 levels in pauciarticular and polyarticular onset JRA as compared to controls. Pauciarticular and polyarticular onset patients also had elevated IL-1 alpha and IL-6 levels. There were no statistical differences found between the groups for TNF-alpha and IL-1 beta. SF revealed elevated levels of IL-1 beta, IL-2R, and IL-6; however, correlation was noted between serum and SF levels only for IL-1 alpha, not for the other cytokines. Mean serum levels of IL-2R in all onset types with active disease and IL-6 levels in active polyarticular and pauciarticular onset were elevated when compared with mean inactive levels.

CONCLUSION

Our studies indicate that (1) IL-1 alpha, IL-2, IL-2R, and IL-6 levels are increased in serum of patients with JRA with different onset types; (2) elevated levels of IL-1 beta, IL-2R, and IL-6 are found in their SF compared to serum levels; (3) a correlation exists between serum and SF levels only for IL-1 alpha; (4) mean IL-2R levels are elevated with active disease in all onset types and mean IL-6 levels with active polyarticular and pauciarticular onset disease are elevated compared to mean levels of inactive patients; and (5) cytokines may thus play a role as inflammatory mediators in JRA.

Thrombotic microangiographic hemolytic anemia in systemic lupus erythematosus

Thrombotic microangiopathic hemolytic anemia (TMHA) is characterized by thrombocytopenia, microangiopathic hemolytic anemia, fever, neurological symptoms, and kidney involvement. It presents as thrombotic thrombocytopenic purpura (TTP) or hemolytic uremic syndrome (HUS). TMHA has been considered to occur only rarely in systemic lupus erythematosus (SLE). However, there has been an increase in the reporting of this association in recent years, and autopsy studies have suggested that TMHA may be underdiagnosed in SLE because of the similarity in symptoms. We report four patients with SLE-related TMHA and describe 24 more patients from a literature review. All patients were women, 50% had active SLE, 89% presented as TTP, and 11% presented as HUS. Those patients with active SLE had low complement levels. Antiphospholipid antibodies or lupus anticoagulant were positive in 5 of 8 cases. Patients treated with plasma infusions or plasmapheresis had a lower mortality rate at 25% compared with 57% mortality in patients who were not treated with plasma infusions or plasmapheresis. It is suggested that TMHA should be considered in any SLE patient presenting with neurological symptoms or renal failure associated with fever, hemolytic anemia, and thrombocytopenia. Early recognition and appropriate therapy with plasmapheresis may improve prognosis.

Adult respiratory distress syndrome associated with antiphospholipid antibody syndrome

Antiphospholipid antibody syndrome (APS) has been shown to be associated with arterial and venous thromboses, recurrent miscarriages, and thrombocytopenia. We describe 3 cases of adult respiratory distress syndrome (ARDS) in patients with primary APS. The autopsy in one patient revealed no evidence of vasculitis, but extensive small vessel thrombosis of multiple organs including the lungs was seen. No infectious process, connective tissue diseases, or pulmonary edema could be documented and there was no clinical or laboratory evidence of vasculitis in the other 2 patients. The 2 patients who survived responded dramatically to intravenous steroids.

Arthropathies of cystic fibrosis: case reports and review of the literature

Patients with cystic fibrosis (CF) have demonstrated more arthritides with their longer life expectancy. The most common presentations have been that of an episodic arthritis or a hypertrophic osteoarthropathy. However, other arthropathies have been associated with CF. We now describe 3 new patients with CF and arthritis, and review the types of arthritis that may be found in patients with CF. This report is to increase awareness of the arthropathies that may be found in patients with CF so that proper evaluation, classification, and treatment may be facilitated.

Serum antiocular antibodies in patients with juvenile rheumatoid arthritis

Although the uveitis associated with juvenile rheumatoid arthritis (JRA) is presumed to have an autoimmune etiology, its pathogenesis is unknown. We utilized immunohistochemical techniques to detect the presence of serum antibodies directed against ocular tissues in these patients. The staining patterns of serum from patients with JRA, with and without uveitis, were compared with normal controls. Antibodies directed against epitopes in iris and ciliary body basement membranes, lens epithelium and fibers, Bruch's membrane, and iris and retinal blood vessels were observed in the sera of several individuals. These staining patterns were statistically more frequent among the pauciarticular and polyarticular JRA patients, with and without uveitis, than either the systemic JRA or normal populations. These results demonstrate the presence of antiocular antibodies in the sera of JRA patients, with and without uveitis. Whether those nonuveitic JRA patients with antiocular antibodies will develop uveitis is unknown at this time.

Autoantibody studies in juvenile rheumatoid arthritis

Early studies showed few immunologic abnormalities in juvenile rheumatoid arthritis (JRA) patients. There were no specific laboratory markers useful for diagnosis and assessment of the course of disease in JRA. Previous work showed an association of antinuclear antibodies (ANA) with early-onset pauciarticular disease and iridocyclitis. Similarly, the presence of 19S immunoglobulin (Ig) M rheumatoid factors (RF) was associated with late-onset polyarticular disease in girls. More recent studies have detected many unique autoantibodies. Newer assays show 19S IgM RF in up to 35% of JRA patients, although still mainly in girls with late-onset polyarticular disease. Hidden 19S IgM RF can be shown in up to 75% of JRA patients using different procedures, primarily in those with active polyarticular-or pauciarticular-onset disease. Immune complexes have been detected in JRA patients by means of different techniques; their presence usually correlates with active disease. Studies on a specific ANA in JRA have shown no common extractable nuclear antigen, but antihistone antibodies have been found in up to 75% of cases, again mainly in those with pauciarticular onset and iritis. Finally, a variety of unusual immunologic proteins have also been detected, including anti-ocular, anti-cellular, anti-cardiolipin, anti-perinuclear factor, and anti-collagen antibodies. This review evaluates the significance of these antibodies that can now be found in JRA.

Quantification of ventricular remodeling in the tight-skin mouse cardiomyopathy with acoustic microscopy

To determine the role of ultrasonic tissue characterization for the detection of changes in myocardial architecture associated with cardiomyopathy, acoustic microscopy was performed on the hearts of 4- to 6-month-old tight-skin mice [TSK/+, C57-B10.D2 (58B)/SN strain], a model of cardiomyopathy characterized by diffuse interstitial fibrosis. Ultrasonic backscatter was measured from excised segments of left ventricular free walls of five TSK mice and five sex- and age-matched normal controls with a 50 MHz broad band focused piezoelectric transducer operated in a saline-filled water tank at room temperature. Forty-nine radio frequency (RF) lines were digitized from each specimen at 2 ns/sample. Power spectral analysis of RF data was performed and mean integrated backscatter (IB) computed. The TSK group demonstrated greater IB (-53.6 +/- 0.6 dB, n = 5) than did the control group (-56.6 +/- 0.7 dB, n = 5; p < 0.02). Myocardial collagen content determined by hydroxyproline assay increased by 11% in the TSK group (2.54 +/- 0.08 microgram/mg dry wt, n = 5) over that in controls (2.28 +/- 0.07 microgram/mg dry wt, n = 5; p < 0.05). A significant linear relationship was observed between myocardial hydroxyproline concentration and IB (r = 0.74; p < 0.02). Thus, ultrasonic tissue characterization permits sensitive detection of modest changes in the extent of interstitial fibrosis that accompany tissue remodeling in the early stages of cardiomyopathy.

Effect of consuming fungus-infected and fungus-free tall fescue and ergotamine tartrate on selected physiological variables of cattle in environmentally controlled conditions

Two experiments were conducted to determine the physiological responses of consuming a fungus-free (FF) or fungus-infected (INF) tall fescue diet (Exp. 1) or the FF diet plus ergotamine tartrate at 30 ppm (FF/ET, Exp. 2) in a thermoneutral (21 degrees C) or heat-stressed environment (32 degrees C, dry bulb; 10 degrees C dew point). Treatment periods lasted 28 d after a 10-d adaptation period. Experiment 1 was replicated three times, and Exp. 2 was replicated twice, with eight Holstein steers in each replicate (mean BW = 185 kg). Feed intake (FI), rectal temperature (RT), and respiration rate (RR) were recorded daily, and heart rate (HR) and infrared temperatures at the ear canal (ECT), ear tip (ETT), pastern (PT), coronary band (CBT), and tail tip (TTT) were recorded weekly. Consumption of INF and FF/ET compared with FF diets decreased (P less than .10) FI, HR, ECT, PT, CBT, and TTT and elevated (P less than .10) RT and RR by 2.8, 2.77 kg/d; 17, 23 beats/min; .8, 1.1 degrees C; .9, 1.1 degrees C; .8, .9 degrees C; 1.1, 2.6 degrees C; .3, .5 degrees C; and 8, 8 breaths/min; respectively. Ear-tip temperature was reduced (P less than .10) 1.6 degrees C by consumption of INF but not by consumption of FF/ET. Reduction of peripheral temperatures is indicative of reduced blood flow to peripheral areas as a result of vasoconstriction.(ABSTRACT TRUNCATED AT 250 WORDS)

Antiperinuclear factor in juvenile rheumatoid arthritis

The serological diagnosis of juvenile rheumatoid arthritis (JRA) is difficult, with only 7-10% of patients 19S IgM rheumatoid factor positive. About 60-70% of patients are positive for hidden 19S IgM rheumatoid factor, but this test requires serum separation and is not available in most laboratories. Antiperinuclear factor has been described in both seropositive and seronegative adult patients with rheumatoid arthritis, but has not been thoroughly evaluated in children with JRA. This study determined the diagnostic sensitivity and specificity of antiperinuclear factor in patients with JRA. Serum samples from 64 children with JRA, 24 with systemic lupus erythematosus (SLE), and 24 control subjects were tested for the presence of antiperinuclear factor. A total of 10 (83%) of seropositive, polyarticular onset and six (37%) of seronegative, polyarticular onset patients with JRA were positive for antiperinuclear factor. The occurrence of antiperinuclear factor in five (19%) with pauciarticular onset and one (10%) with systemic onset (JRA) as well as in four (17%) with SLE was not increased compared with the control subjects (1/24 (4%)). These data show an overall diagnostic sensitivity and specificity of 34 and 90% respectively in this group of patients. Although less sensitive than the hidden rheumatoid factor assay, the antiperinuclear factor assay is easier to perform and may contribute to the serological diagnosis of JRA.

Correlation of antiperinuclear factor with antibodies to streptococcal cell-wall peptidoglycan-polysaccharide polymers and rheumatoid factor

Antiperinuclear factor (APF) has been noted in most seropositive rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA) patients. The nature of the antigen is unknown; however, there are some suggestions that it might be a glycoprotein or proteoglycan. We studied the correlation of APF with antiproteoglycan antibodies and the reactivity of IgM-rheumatoid factor (RF) with the perinuclear antigen. Ten serum samples were separated to IgG, IgM, and IgM-RF enriched fractions. In seven samples, APF was found in the IgG fraction. Only 4 had APF in their IgM rheumatoid factor (RF)-containing fraction. In two of these, APF activity was present solely in the IgM RF fraction and was inhibited by pre-incubation with IgG. Fifty-five JRA patients' sera were also tested for the presence of antibodies to Streptococcal cell wall peptidoglycan-polysaccharide polymers (PG-PSP). 76% of the APF-positive sera were anti-PG-PSP positive and 59% of the APF-negative sera were also anti-PG-PSP negative. Furthermore, 75% of the APF-positive sera lost their APF activity following adsorption to Streptococcal cell wall PG-PSP. Our results show that in JRA sera APF are polyclonal antibodies of both the IgG and IgM classes. Although the presence of APF correlates with RF positivity, and they sometimes may cross-react, many IgM RF-containing fractions do not show APF activity. However, the presence of APF does correlate with anti-PG-PSP positivity and the data suggest cross-reactivity between these two antibodies. This implies antigenic similarity between Streptococcal cell wall PG-PSP and the perinuclear antigen.

Production of IgM rheumatoid factor by normal lymphocytes after stimulation with preparations containing IgM rheumatoid factor from patients with juvenile arthritis

Preparations containing IgM rheumatoid factor (RF) and hidden IgM RF were isolated from the serum samples of nine patients with juvenile rheumatoid arthritis. Six of these preparations stimulated lymphocytes from normal donors to produce IgG and IgM, of which up to 11% had IgM RF activity. In contrast, the polyclonal activator pokeweed mitogen also stimulated IgM production, but only 1% had IgM RF activity. A relation between the activator and IgM RF or hidden IgM RF is suggested. This is based on the positive correlation between IgM RF concentration in these preparations and their ability to stimulate lymphocytes to produce IgG, IgM, and IgM RF. These data indicate that preparations from patients with juvenile rheumatoid arthritis containing IgM RF and hidden IgM RF are potent stimulants of lymphocytes from normal donors, with specific production of IgM RF.

Heart disease in systemic sclerosis

Primary cardiovascular manifestations of SSc include pericardial disease, myocardial disease, conduction abnormalities, and cardiac arrhythmias. Significant cardiac abnormalities are present in more than half of SSc patients at autopsy. As the frequency of subclinical cardiac involvement is now appreciated and noninvasive cardiac diagnostic modalities continue to improve, the ability to detect early asymptomatic involvement in SSc has improved. Two-dimensional echocardiography, radionucleotide imaging, and ambulatory ECG allow recurrent serial testing with virtually no morbidity. The current treatment of cardiac involvement in SSc is emperic and primarily directed at symptomatology. Large prospective randomized trials are needed to determine if preventive therapy is effective. With the advent of new immunological and cardiotropic agents and a better understanding of the primary disease process, our ability to alter the pathogenesis and final outcome of cardiac involvement in SSc should improve.

Diflunisal versus naproxen in the management of rheumatoid arthritis

Diflunisal (500 mg orally, twice daily) and naproxen (375 mg orally, twice daily) were compared for efficacy and tolerability in a 12-week open-label study in 33 patients with active rheumatoid arthritis (RA). Both drugs resulted in marked reduction in the number of swollen, tender, and painful joints and comparable improvement in patients' assessment of disease activity and pain. There were no significant differences between the two medications in the measured indices of disease activity. No adverse experiences were reported by patients in either treatment group. The results indicate that both diflunisal and naproxen were equally effective and that both agents are generally well tolerated in this group of patients with RA.

Antibodies to iris and retina detected in sera from patients with juvenile rheumatoid arthritis with iridocyclitis by indirect immunofluorescence studies on human eye tissue

Sera from 12 patients with juvenile rheumatoid arthritis (JRA) with active iridocyclitis were incubated with frozen, sectioned, whole human eye tissue. Antibodies were detected using fluorescein conjugated goat F(ab')2 antibody to human IgG by immunofluorescent microscopy. Immunofluorescence was determined on tissue from the iris, retina, and 3 portions of the ciliary body. Sera of patients with JRA with iridocyclitis were compared to sera from patients with JRA with and without antinuclear antibodies (ANA) and healthy children. An increased frequency of antibody to the human iris was seen with sera of patients with JRA with iridocyclitis compared to healthy children's sera. A higher frequency of antibody was also noted to human retina in sera of patients with JRA with iridocyclitis compared to patients without ANA and healthy children. No increased frequency of antibody was detected to ciliary body. Sera of 7 patients with JRA with iridocyclitis were also compared during a time of inactive eye disease to a time of active disease. No difference in binding to eye tissue was detected at times of inactive disease compared to controls. Our results demonstrate the presence of antibody to iris and retina by immunofluorescence in the sera of patients with JRA with iridocyclitis.

Antinuclear antibody in juvenile rheumatoid arthritis sera reacts with 50-40 kDa antigen(s) found in HeLa nuclear extracts

To identify whether sera containing antinuclear antibody (ANA) from patients with juvenile rheumatoid arthritis (JRA) recognize a common antigen, extracts of HeLa nuclei were prepared by incubating the nuclei with buffers of sequentially increasing salt concentrations (0.1 M, 0.3 M, and 0.5 M NaCl). Western blot analysis using sera from 82 patients with JRA revealed that 63% of ANA positive JRA sera reacted with 2 bands (50-40 kDa) in the 0.3 M extract whereas only 14% of ANA negative JRA sera had antibody to these bands. Antibody to the 50-40 kDa antigen(s) strongly correlated with the presence of ANA by immunofluorescence and was found in 70% of patients with iritis; however, it did not correlate with disease subgroup or disease activity.

Cross-reactive antiidiotypic antibodies against human rheumatoid factors from patients with juvenile rheumatoid arthritis

We prepared antiidiotypic (anti-Id) antibody to 2 polyclonal IgM rheumatoid factors (IgM-RF) and 2 polyclonal "hidden" IgM-RF. The anti-Id antibodies were isolated by chromatography on Sepharose 4B, to which was bound rabbit anti-human IgG Fc fragments. F(ab')2 fragments from the anti-Id antibodies were generated by pepsin digestion and isolated by gel filtration. The anti-Id antibodies directed against RF from 4 patients with juvenile rheumatoid arthritis (JRA) were tested by an inhibition hemolytic assay for cross-reactivity with IgM-RF from 4 adult patients with rheumatoid arthritis, 6 patients with JRA, and 13 JRA patients with hidden RF. The 4 anti-Id antibodies had variable cross-reactivity with the isolated adult RA RF, JRA RF, and JRA hidden RF. Similar results were obtained by a direct-binding enzyme-linked immunosorbent assay for the anti-Id antibodies. The broad pattern of cross-reactivity was apparently unrelated to a particular amino acid sequence, but was associated with the antigen-binding site of IgM-RF. These results suggest the possibility that the anti-Id antibodies prepared against isolated RF obtained from JRA patients bear the "internal image" of antigen; that is, the Fc region of human IgG. These anti-Id antibodies may be generated in JRA patients and may possess specific immunomodulatory properties.

Clostridium difficile associated reactive arthritis in an HLA-B27 positive female: report and literature review

A case of Clostridium difficile associated reactive arthritis in an HLA-B27 positive female is reported and compared to 9 other cases. The clinical course of C. difficile associated reactive arthritis is similar to that caused by other enteric pathogens. Therefore, C. difficile should be considered in the differential diagnosis of the reactive arthritides.

Endomyocardial biopsy in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) has numerous cardiovascular manifestations. Myocarditis is present in more than 50% of patients with SLE at autopsy, but it may be silent clinically during life. Percutaneous endomyocardial biopsy performed in 4 patients with SLE was found helpful in establishing the diagnosis and in determining the extent of the inflammatory myocarditis. The findings aided the regulation of therapy, particularly the administration of immunosuppressive drugs.

Complement fixing immune complexes containing antinuclear antibodies in patients with systemic lupus erythematosus

Immune complexes (IC) in the sera of patients with systemic lupus erythematosus (SLE) were isolated using goat antihuman C3 and rabbit antihuman Clq immunoabsorbent columns. The sera from 12 patients with SLE were sequentially eluted from the columns with veronal buffer, 0.02 M EDTA, 0.5 M NaCl, and 1 M propionic acid. The isolated IC were analyzed for antinuclear antibodies (ANA) with an HEp-2 cell substrate. ANA were detected in 6 patients' eluates from the EDTA fractions and 2 patients' propionic acid fraction by the antihuman Clq column method. ANA were noted in 7 patients' isolates from antihuman C3 column, 6 EDTA fractions, and 2 patients' propionic acid fractions. The ANA showed speckled patterns in 6 patients and a diffuse pattern in 1. Our studies demonstrate complement fixing IC containing ANA can be detected in the sera of patients with SLE by isolation with the antihuman Clq and antihuman C3 columns.

Enzyme linked (ELISA) immunoabsorbent assay for the detection of hidden 19S IgM rheumatoid factors in juvenile rheumatoid arthritis

Determination of hidden IgM rheumatoid factors (RF) in juvenile rheumatoid arthritis (JRA) offers advantages for diagnosis and in following disease activity. Sera from 30 patients with JRA were assayed for RF by latex fixation test (LFT), sensitized sheep cell agglutination test (SCAT), nephelometry, and by ELISA. IgM containing fractions were prepared by chromatography and assayed for hidden RF by the hemolytic method and ELISA. Ten patients were seropositive by LFT. All of them gave positive tests on the serum for RF with the SCAT, nephelometry, and ELISA, and on the IgM containing fractions by the hemolytic assay and ELISA. Seventeen patients seronegative by LFT were positive for hidden RF by the hemolytic test and ELISA on the IgM containing fraction. When unfractionated serum was used, 15 were positive by ELISA. Three patients were seronegative and also negative for hidden RF by the hemolytic assay and ELISA. Thus, only 2 of 30 patients had discordant results between the hemolytic assay on the IgM containing fraction and the ELISA on the serum. Our results indicate the ELISA on the serum in conjunction with the LFT offers a simple, rapid, alternative test for hidden 19S IgM RF in JRA patients.

Collagenous abnormalities in the heart of the tight-skin mouse

The tight-skin (TSK) mouse, a possible animal model for scleroderma, has multiple abnormalities including increased dermal thickness, cardiomegaly, emphysematous lungs, and an enlarged skeleton. Previous investigations have demonstrated an increased collagen and glycosaminoglycan (GAG) content in the skin and lungs of these mice. The present correlative investigation of the biochemical and ultrastructural properties of the heart in the TSK mouse also revealed an increased presence of collagen. Analysis of collagen types in the TSK heart showed there was a shift in the ratio of type I: type III: type V from the normal values. Over 90% of the collagen was type I, while both types III and V were decreased in this organ. The ultrastructural examination of the left ventricle demonstrated extensive accumulations of perivascular and intercellular edema fluid, foci of myocytolysis, and areas of moderately increased collagen deposits within interstitial sites. These findings suggest that an increased collagen deposition (type 1) may be a contributing factor to cardiac enlargement in the TSK mouse.

Glycosaminoglycan composition of tight skin and control mouse skins

Tight skin (TSK) mouse skin has previously been shown to contain increased amounts of collagen and glycosaminoglycans (GAG). We now report on the GAG composition of TSK mouse skin. Using an electrophoretic and an enzymatic HPLC method, skin from 99 TSK and control mice (newborn, 1 month-old, and 6 months-old) were analyzed for GAG composition. There was no significant difference between TSK and control GAG.

19S IgM rheumatoid factor-7S IgG rheumatoid factor immune complexes isolated in sera of patients with juvenile rheumatoid arthritis

19S IgM rheumatoid factors (RF) and hidden 19S IgM RF have been associated with increased disease activity in juvenile rheumatoid arthritis (JRA). Recently, immune complexes (IC) were isolated from JRA sera by several methods which demonstrated the presence of 19S IgM RF. The present study evaluates 25 JRA patients' sera by separation on a Sepharose 4B column to which were bound F(ab')2 fragments of goat IgG antihuman IgM antibody to separate IgM-containing IC. The columns were sequentially eluted with 1 M ammonia and 0.1 M glycine-HCl buffer, pH 3.0. The isolated fractions were assayed for 19S IgM RF and 7S IgM RF by ELISA, IgG levels by immunodiffusion, and by preparative isoelectric focusing. The ammonia eluate from the alpha HIgM column revealed IgG, 19S IgM RF in six patients, and IgM RF in four patients. All were polyarticular-onset JRA patients. In the glycine-HCl eluate of sera, 19S IgM RF and IgG were also detected in 15 patients, all six seropositive, polyarticular-onset, six seronegative, polyarticular-onset, and three pauciarticular-onset patients. Significant 7S IgG RF titers were demonstrated in the glycine-HCl eluates of six patients, five seropositive, polyarticular-onset patients, and one seronegative, polyarticular-onset patient. Analysis by preparative isoelectric focusing of the IgM RF and IgG RF positive ammonia and glycine-HCl eluates showed IgM RF throughout the pH range (4-10), but the highest amount of IgM RF was in the pH range 4.0-5.5. Significant IgG RF titers were detected only in this restricted spectrotypic area of pH 4.0-5.5.(ABSTRACT TRUNCATED AT 250 WORDS)

Hidden 19S IgM rheumatoid factor in adults with juvenile rheumatoid arthritis onset

Forty-eight adult patients with juvenile rheumatoid arthritis (JRA) (onset before age 16 years) were evaluated at the age of 17 years or more for the presence of hidden 19S IgM rheumatoid factors (RF), i.e., 19S IgM RF that can be detected by the complement-dependent haemolytic assay in the IgM-containing fraction after separation of the serum by acid gel filtration. The average age of the patients was 25.3 years. The mean duration of disease was 16.5 years. Thirty-two of 48 patients (67%) showed the presence of hidden 19S IgM RF in their serum. Disease activity correlated with hidden RF titres in 62% (55/88) of the evaluations. The results indicate that patients with seronegative JRA onset continue to have significant titres of hidden 19S IgM RF in their sera into early adulthood.

Use of the HEp-2 cell substrate in the detection of antinuclear antibodies in juvenile rheumatoid arthritis

Presence and titer of antinuclear antibodies (ANA) were determined in 217 juvenile rheumatoid arthritis (JRA) patients, by indirect immunofluorescence using HEp-2 cells as substrate. Positive ANA titers (greater than or equal to 1:40) were present in 131 (60%) of the JRA patients. All 3 JRA onset types demonstrated increased percentages of ANA positivity compared with healthy children. Sixty-seven percent of the patients in the polyarticular onset group had positive titers; titers were positive in 62% of the pauciarticular onset group and in 32% of the systemic onset group. ANA were also found in 45% of control patients with other connective tissue diseases. In JRA patients, the speckled pattern occurred most commonly (72%). Fourteen patients (8 with pauciarticular onset and 6 with polyarticular onset) had iridocyclitis; all of them had high titers (greater than or equal to 1:80) of ANA. The use of HEp-2 cells provided a sensitive substrate for detecting ANA in JRA. It proved to be of value in differentiating JRA patients from healthy controls, but not from patients with other connective tissue diseases.

Glycosaminoglycan content in the lung of the tight-skin mouse

Morphologic and physiologic pulmonary changes have been described in the tight-skin (TSK) mouse, but no biochemical studies have been done. We performed qualitative and quantitative analyses of glycosaminoglycans (GAG) on lungs of the TSK mouse. Total GAG were determined by cetylpyridinium chloride precipitation in whole lung specimens from TSK mice and normal (N) mice of different age groups: 1, 6, and 12 months old. There was no significant difference in total GAG, GAG concentration, or dry lung weight between TSK and N mice in any of the 3 age groups. In addition, fractionation of the GAG by electrophoresis revealed similar amounts of individual GAG (predominantly dermatan sulfate and heparin) in TSK and N mice within each age group. Therefore, structural abnormalities in the TSK mouse lung were not demonstrated to be due to qualitative or quantitative changes in GAG.

Autoantibodies in juvenile arthritis

Sera from 104 children with JA with different onset-types of disease were evaluated for 19S IgM RF by the LFT , hidden 19S IgM RF by the hemolytic assay, ANA by HEp-2 cell substrate, and levels of IC by the C1qSPA . Their relationship to active disease was determined. Classical 19S IgM RF were detected by the LFT in only seven patients. All were late-onset polyarticular females. Hidden 19S IgM RF were detected by the hemolytic assay in the separated IgM-containing fraction in 55 patients of all onset-types. Clinical activity correlated with the presence of hidden 19S IgM RF in 82% of cases. ANA, using the HEp-2 cell substrate, were found in 61 patients, the majority showing a speckled, immunofluorescent pattern. ANA were noted in all RF positive patients and in nine of 10 patients with iridocyclitis. IC were found in 39 patients, and correlation with clinical activity occurred in 54% of cases. A search for positive associations among the four parameters showed no statistically significant correlations except for the concordance of ANA positivity in all seven RF positive patients. The presence of hidden RF correlated more closely with disease activity (P less than 0.001) than did that of ANA or IC. The significance of these data and previous studies remains to be determined. We have demonstrated that in the average JA population 7% have 19S IgM RF and about 60% have hidden RF, ANA, or elevated levels of IC. The present findings of 98 of 104 patients with at least one of the abnormal immunoproteins , the association of ANA in patients with iridocyclitis or with RF positivity, of hidden RF with disease activity, and the presence of 19S IgM RF in isolated IC suggest a possible immunologic etiology for JA.

HLA antigens in black and white patients with juvenile arthritis: associations with rheumatoid factor, hidden rheumatoid factor, antinuclear antibodies, and immune complex levels

HLA typing for -A, -B, -C, -DR, and -MT antigens and simultaneous studies for the presence of 19S IgM rheumatoid factor (RF), hidden 19S IgM RF, antinuclear antibodies (ANA), and immune complexes (IC) were performed on 24 black and 80 white patients with juvenile arthritis (JA) of different onset types. HLA-DRW6 (p less than 0.05) was associated with pauciarticular onset and early onset pauciarticular black patients. HLA-DR4 was found in both blacks and whites with chronic disease (p less than 0.01) and with the presence of RF (p less than 0.05) and hidden RF (p less than 0.05). In the whites, HLA-DR5 (p less than 0.05) and DRW8 (p less than 0.001) were associated with pauciarticular onset and early onset pauciarticular patients. HLA- DRW8 was also associated with white JA patients with iridocyclitis (p less than 0.001) and black (p less than 0.01) and white patients (p less than 0.001) with the presence of ANA. HLA-MT2 was demonstrated in all 24 black patients (p less than 0.001) and in 54/80 white patients (p less than 0.001). HLA-MT2 was associated with black (p less than 0.01) and white (p less than 0.001) patients with early onset pauciarticular disease and the presence of iridocyclitis in white patients (p less than 0.001). The association of HLA antigens in black JA patients has not been reported before.

Review of auranofin, an oral chrysotherapeutic agent

The chemistry, pharmacology, pharmacokinetics, clinical use and efficacy, adverse effects, and dosage of auranofin, an oral chrysotherapeutic agent used in treatment of rheumatoid arthritis, are reviewed. Auranofin is lipid-soluble and is monomeric in solution. It has a modulatory effect on both the humoral and cellular immune systems. Auranofin may be a condition-dependent immunoregulating agent rather than an immunosuppressive agent. It inhibits (1) monocyte-mediated antibody-dependent cellular toxicity, (2) release of enzymes from polymorphonuclear leukocytes that may contribute to the pathogenesis of rheumatoid arthritis, and (3) neutrophil activity. In patients with rheumatoid arthritis, 15-33% of an oral dose of auranofin 6 mg is absorbed. Peak plasma gold concentrations are achieved in one to two hours. Gold is highly protein bound. Elimination occurs through the feces and urine; 73-100% of auranofin gold is excreted. Plasma half-life is three weeks. Patients receiving auranofin 3 mg twice daily for rheumatoid arthritis reported improvement after five weeks of therapy; improvement has also been reported with lower doses. Diarrhea, rashes, and pruritus were the most common adverse effects. Auranofin is safe and effective for short- and long-term treatment of patients with rheumatoid arthritis. Its relative safety and potency compared with injectable gold salts and other drugs need further study.

The tight-skin mouse: physical and biochemical properties of the skin

The tight-skin (TSK) mouse has unusual structural skin properties. These include increased thickness of the dermis, increased tensile strength, and increased adherence to subcutaneous tissues. We have investigated several physical and biochemical characteristics of skin from the TSK mouse and compared them to the normal mouse. An increase in thickness, wet weight, and hydroxyproline content was found in the skin of the TSK mouse. In addition, there was an increase in the ratio of soluble to insoluble collagen in the TSK mouse when compared to the normal mouse. These findings in the skin of the TSK mouse are similar to the changes found in the skin of patients with progressive systemic sclerosis.

Glycosaminoglycan content in skin of the tight-skin mouse

The tight-skin (TSK) mouse has cutaneous changes similar to those found in the skin of patients with progressive systemic sclerosis (PSS). Previous studies have shown that both have common abnormalities in skin thickness, dry weight, and hydroxyproline content. In this study, glycosaminoglycans (GAGs), major components of the ground substance, were quantitated in skins from TSK mice and compared with age-matched normal mice. Biochemical studies included determinations of hexosamines, uronic acids, and total GAGs by cetylpyridinium chloride precipitation. Dry weights and water-fat content of skin biopsy specimens from TSK mice were also compared with those of normal mice. Hexosamine, uronic acid, total GAGs, and dry weight were increased in TSK mouse skin when compared with normal mouse skin. The water-fat content did not differ significantly. These findings were similar to those known to occur in PSS skin, further suggesting that the TSK mouse might serve as an animal model for the skin changes found in PSS patients.

Longitudinal study of the presence of hidden 19S IgM rheumatoid factor in juvenile rheumatoid arthritis

Complement-fixing hidden 19S IgM rheumatoid factor (RF), i.e., 19S IgM RF that can be detected in the IgM-containing fraction by the hemolytic assay after separation of the serum by acid gel filtration, was evaluated serially (3 or more evaluations) over a 4-year period in 26 children with juvenile rheumatoid arthritis (JRA) correlating its presence with disease activity. Six children with continually active disease had consistently elevated hidden RF titers (26 evaluations), and the titers of 4 children with inactive disease remained insignificant (12 evaluations). Sixteen children had disease with variable activity over this period. Of these, 11 (43 evaluations) demonstrated positive correlation between disease activity and hidden RF titers. Five patients (8/20 evaluations) did not show correlation of disease activity with hidden RF titers. Thus, the presence of hidden RF correlated with disease activity in 93 of 101 evaluations. When hidden RF titers and the erythrocyte sedimentation rate were determined simultaneously on 40 occasions, the presence of hidden 19S IgM RF correlated significantly better (p less than 0.001) with disease activity.