Diagnosis and treatment of interstitial lung disease related to systemic autoimmune myopathies: a narrative review.

Systemic autoimmune myopathies (SAMs) are rare diseases that lead to muscle inflammation and may be associated with a variety of systemic manifestations. Although there is great heterogeneity in the spectrum of extra-muscular involvement in SAMs, interstitial lung disease (ILD) is the most frequent lung manifestation. SAM-related ILD (SAM-ILD) presents significant variations according to geographic location and temporal trends and is associated with increased morbidity and mortality. Several myositis autoantibodies have been discovered over the last decades, including antibodies targeting aminoacyl-tRNA synthetase enzymes, which are associated with a variable risk of developing ILD and a myriad of other clinical features. In this review, the most relevant topics regarding clinical manifestations, risk factors, diagnostic tests, autoantibodies, treatment, and prognosis of SAM-ILD are highlighted. We searched PubMed for relevant articles published in English, Portuguese, or Spanish from January 2002 to September 2022. The most common SAM-ILD patterns are nonspecific interstitial pneumonia and organizing pneumonia. The combination of clinical, functional, laboratory, and tomographic features is usually sufficient for diagnostic confirmation, without the need for additional invasive methods. Glucocorticoids remain the first-line treatment for SAM-ILD, although other traditional immunosuppressants, such as azathioprine, mycophenolate, and cyclophosphamide have demonstrated some efficacy and, therefore, have an important role as steroid-sparing agents.

COVID-19 as potential aggravating factor for the natural course of new onset-dermatomyositis.

Borges et al. have recently reported the first case of a dermatomyositis onset in close association with established coronavirus disease 2019 (COVID-19). Similarly, we report a patient who, on the contrary, had COVID-19 following early established dermatomyositis. We report prospectively the outcome of her disease.

Brachio-cervical inflammatory myopathy associated with systemic sclerosis. Case series and review of literature.

This study was aimed at describing a case series of brachio-cervical inflammatory myopathy (BCIM) associated with systemic sclerosis (SSc), due to its rarity and limited coverage in published data. Another aim was to provide a literature review. We reported four cases of BCIM-SSc from our tertiary center. In addition, we researched the literature and found six articles featuring 17 patients who fit this phenotype. We pooled all cases and reported their features. Most patients were female and had limited SSc, and the median time of BCIM presentation was three years after SSc diagnosis. Asymmetric muscle involvement, scapular winging, dropped head, axial weakness, camptocormia, dysphagia, and dermatomyositis stigmas were common features. All patients had esophageal involvement. Most had positive antinuclear antibody results, a scleroderma pattern in their capillaroscopy images, elevated serum creatine phosphokinase, myopathic electrophysiology, and muscle involvement in magnetic resonance imaging. Muscle histopathological findings varied widely, but in general all showed the presence of lymphoid infiltrates, muscle atrophy, increased MHC-I expression, MAC deposits, vasculopathy, and muscle fiber necrosis. The response to immunosuppressive therapy was highly irregular. BCIM-SSc is a rare disorder that shares many similar phenotypes among the described cases, but has a highly heterogeneous response to treatment. At present, more data on the physiopathology, clinical features, and treatment is still needed.

Is there an association between upper limb claudication and handgrip strength in Takayasu arteritis?

Limb vascular claudication and hand muscle weakness are common symptoms of Takayasu arteritis (TAK). However, no studies have correlated these two symptoms. Therefore, the aim of the study was to evaluate handgrip strength and its correlation with both upper-limb vascular claudication and imaging of the vessels. This cross-sectional study compared 36 patients with TAK who were matched by age, gender, and body mass index with 36 individuals without TAK (CTR). Hand strength (assessed with handgrip dynamometer), functional capacity (Health Assessment Questionnaire, HAQ), upper-limb vascular claudication symptoms (patients' selfreported form), and disease activity (Indian Takayasu Clinical Activity Score [ITAS] 2010; Physician Global Assessment [PGA], C-reactive protein, and erythrocyte sedimentation rate) were evaluated as well as vessel imaging (e.g., angiotomography or angioresonance) and blood pressure. The median age of the patients was 42.0 years (35.5-51.5 years), whereas the mean disease duration was 13.1±6.8 years. No patient had active disease. Compared to the CTR, the patients with TAK showed reduced strength in the left-hand (22.9±5.9 vs 26.3±5.6 kg; p=0.014) and increased HAQ scores [0.50 (0.12-0.87) vs 0.00 (0.00-0.00); p<0.001]. Both groups had comparable blood pressure. Among patients with TAK, lefthand strength was inversely correlated with HAQ (Spearman correlation: rho=-0.584; p<0.001) and positively correlated with right-hand strength (rho=0.644; p<0.001). Moreover, neither hand's strengths in the patients were correlated with subclavian stenosis imaging, blood pressure or limb vascular claudication. The reduction of strength in the upper left limb is inversely related to the functional capacity (HAQ score) of TAK. This reduction appears unrelated to classical vascular claudication, vessel imaging or blood pressure.

Transcranial direct current stimulation improves myofascial pain syndrome and chronic fatigue.

Not available.

The clinical manifestations at the onset of antisynthetase syndrome: A chameleon with multiple faces.

The antisynthetase syndrome (ASS) is clinically characterized by fever, myositis, interstitial lung disease, joint involvement, mechanic's hands, or Raynaud's phenomenon, and the presence of antisynthetase autoantibodies. These clinical manifestations may not occur simultaneously. Therefore, the aim of this study was to analyze the sequence in which these clinical manifestations can develop at the onset of ASS. This retrospective, single-center cohort study enrolled 55 ASS patients. Their mean age at the onset of ASS symptoms was 42.3±11.8 years. There was a predominance of female patients (75.9%) and white patients (72.7%). At initial presentation, 41.8% of the patients had fever, 43.6% had joint symptoms, 38.2% had myositis, 36.4% had interstitial lung disease, 18.2% had Raynaud's phenomenon, and 16.4% had mechanic's hands. Subsequent clinical symptoms emerged at varying time points. In two out of 55 cases, joint, muscle, and lung manifestations developed simultaneously. The median time between the onset of symptoms and the complete ASS clinical manifestation was 19.9 (4.0-60.2) months; whereas, the timeframe between the onset of symptoms and the ASS diagnosis was 29.0 (11.0-63.0) months. The confounding misdiagnoses interfering with the initial diagnosis were polymyositis (52.7%), dermatomyositis (29.1%), nonspecific interstitial pneumopathy (23.6%), rheumatoid arthritis (18.2%), and others (10.9%). Clinical features at the onset of ASS are highly variable. Consequently, confounding factors can lead to significant delays for the final and definitive diagnosis of ASS. Therefore, ASS should be considered a differential diagnosis in patients with initial symptoms of joint, lung, and/or muscle involvements, as well as fever, mechanic's hands, and/or Raynaud's phenomenon manifestations.

Is there a reliable association between patient-reported limb claudication and vascular imaging methods in Takayasu arteritis?

Vessel imaging in Takayasu arteritis (TAK) is often performed in clinical practice following laboratory test abnormalities or clinical symptoms, such as limb claudication. Conversely, the association between limb claudication and vessel imaging manifestations has not been assessed. This observational, cross-sectional study analyzed 139 adult TAK patients from 2000 to 2018. Their arterial vessel imaging information (especially significant stenosis and occlusion data) was registered and crosschecked with clinical and laboratory data. When vessel imaging was performed, the median age and disease duration of the patients were 38 (27.3-47.0) and 5.0 (1.0-12.0) years, respectively. There was no association between arterial abnormalities and demographic data, constitutional symptoms or laboratory parameters. Limb claudication was reported in 42 patients (30.2%): 17.3% reported it in the upper left limb (ULL), 12.2% reported it in the upper right limb (URL), 12.9% reported it in the lower left limb (LLL), and 12.2% reported it in the lower right limb (LRL). When crossmatched with imaging, both ULL and URL were associated with left vertebral artery stenosis/occlusion, and URL was associated with right iliac artery stenosis/occlusion, but no other association was found. In contrast, both LLL and LRL claudication were associated with infrarenal aortic, left iliac and right iliac artery stenosis/ occlusion (p<0.05). Moreover, the ULL and URL claudication symptoms were significantly associated with each other (p<0.001). Upper limb claudication was associated only with left vertebral artery stenosis/occlusion, whereas the subclavian arteries were not, suggesting that the symptom might not be fully explained by limb ischemia. In contrast, lower limb claudication was associated especially with infrarenal aortic and/or iliac arteries stenosis/occlusion.

High levels of serum hyaluronic acid in adults with dermatomyositis.

UNLABELLED: BACKGROUND / OBJECTIVES: Hyaluronic acid (HA) is rarely described in dermatomyositis (DM). Thus, we determined any clinical association of serum levels of hyaluronic acid (HA) in patients with dermatomyositis (DM). MATERIALS AND METHODS: This cross-sectional single-center analysis 75 DM and 75 healthy individuals, during the period from January 2012 to July 2013. An anti-HA antibody assay was performed using specific ELISA/EIA kits, according to the manufacturer's protocol. RESULTS: The patients with DM and control subjects had comparable demographic distributions (p>0.05). The median time duration between disease diagnosis and initial symptoms was 6.0 [3.0-12.0] months, with a median DM disease duration of 4.0 [1.0-7.0] years. The median level of serum HA was significantly increased in patients with DM compared to the control group [329.0 (80.0-958.0) vs. 133.0 (30.0-262.0) ng/mL, respectively; p<0.001]. Additional analysis involving patients with DM showed that the serum level of HA did not correlate with age, duration between disease diagnosis and initial symptoms, disease duration, disease status, serum muscle enzyme levels or cumulative prednisolone dose (p>0.05). Serum HA also did not correlate with gender, ethnicity, auto-antibodies or drug use (p>0.05), but did correlate with cutaneous features, such as photosensitivity (p=0.001), "shawl" sign (p=0.018), "V-neck" sign (p=0.005) and cuticular hypertrophy (p=0.014). CONCLUSIONS: A high level of serum AH was observed in DM compared to healthy individuals. In DM, HA did not correlate to demographic, auto-antibodies and therapy parameters. However, HA correlated specifically with some cutaneous features, suggesting that this glycosaminoglycan could be involved in modulating cutaneous inflammation in this population. More studies are necessary to understand the correlation between AH and patients with DM.

Serum hyaluronic acid in polymyositis: high serum levels tend to correlate with disease activity.

OBJECTIVE: Polymyositis (PM) is a rare systemic idiopathic inflammatory myopathy. Hyaluronic acid (HA) is closely linked to inflammatory cellular reactions and disease activity. Increased serum levels of HA have been reported in several inflammatory diseases, but currently, there are no studies analysing the HA in PM. Thus, clinical association of HA with PM in patients was determined in the present study. METHODS: The present cross-sectional study was performed at one centre from 2012 to 2013 and included 35 consecutive adult patients with PM (Bohan and Peter criteria, 1975) and 38 adult healthy volunteers. The serum HA was assessed with anti-HA antibody, using the specific ELISA/EIA kits according to the manufacturer's protocol. RESULTS: The average age, distribution of females and ethnicity were comparable in patients with PM and the control group. Regarding disease status, patients with PM had a median patient visual analogue score (VAS) of 2 [0-6], physician VAS of 1 [0-3], MMT-8 of 74 [68-80] and HAQ of 0.48 [0.00-1.14]. The serum levels of HA were also significantly increased in patients with PM (390±412 ng/mL) compared to healthy subjects (129±119 ng/mL), p=0.001. In an additional analysis, the serum levels of HA did not correlate with PM demographic data (gender and ethnicity), current organ involvement or autoantibodies and were not been influenced by the use of prednisolone and/or immunosuppressives by the PM patients. However, there was a positive correlation between serum levels of HA and VAS (patient and physician), and a negative correlation between serum levels of HA and MMT-8. CONCLUSION: High serum levels of HA were observed in patients with PM and tended to correlate with PM disease activity. Additional studies are needed to assess this correlation, as well as to understand the mechanism involved in the pathogenesis of PM by HA.

Clinical and immunological features of 888 Brazilian systemic lupus patients from a monocentric cohort: comparison with other populations.

Epidemiological studies with systemic lupus erythematosus (SLE) patients have been reported worldwide but, until now, a large evaluation had not been performed in Brazil. Therefore, we determined the clinical and immunological features of 888 SLE patients followed at our service from 2008 to 2012. The mean age at SLE onset and the mean disease duration were 29.9 ± 9.5 years old and 14.5 ± 8.4 years, respectively. A predominance of female gender (91.9%) and Caucasian ethnicity (69.9%) were observed. Cumulative mucocutaneous manifestations (90.7%) were most commonly identified (malar rash (83.2%), photosensitivity (76.9%)) followed by articular (87.4%), hematological (44.0%) and renal (36.9%) involvements. Antinuclear antibody was detected in all patients, followed by anti-dsDNA (35.1%), anti-Sm (21.8%) and anti-ribosomal P protein antibodies (19.8%). Additional comparison of clinical and laboratory features between genders revealed that malar rash was observed more in female SLE patients (84.5% vs. 69.4%, p = 0.001). Male lupus patients presented a higher frequency of anti-dsDNA (45.8% vs. 34.2%, p = 0.047) and a trend of more nephritis (47.2% vs. 36.0%, p = 0.059). In conclusion, we identified a high prevalence of mucocutaneous manifestations in this Brazilian SLE cohort compared to other countries, mainly malar rash that was most commonly observed in female patients. Anti-dsDNA and other specific SLE autoantibodies were also identified in a higher frequency, predominantly in the male gender.

Alveolar hemorrhage: distinct features of juvenile and adult onset systemic lupus erythematosus.

We compared outcomes of alveolar hemorrhage (AH) in juvenile (JSLE) and adult onset SLE (ASLE). From 263 JSLE and 1522 ASLE, the AH occurred in 13 (4.9%) and 15 (1.0%) patients, respectively (p < .001). Both groups had comparable disease duration (2.6 ± 3.0 vs. 5.6 ± 7.0 years, p = .151) and median SLEDAI scores [17.5 (2 to 32) vs. 17.5 (3 to 28), p = 1.000]. At AH onset, a higher frequency of JSLE were already on a high prednisone dose ( > 0.5 mg/kg/day) compared to ASLE (54% vs. 15%, p = .042). The mean drop of hemoglobin was significantly lower in JSLE (2.9 ± 0.9 vs. 5.5 ± 2.9 g/dL, p = .006). Although treatments with methylprednisolone, plasmapheresis, intravenous immunoglobulin and cyclophosphamide were similar in both groups (p > .050), regarding outcomes, there was a trend in high frequency of mechanical ventilation use (85% vs. 47%, p = .055) and also significant mortality (69% vs. 13%, p = .006) in JSLE compared to ASLE. The sepsis frequency was comparable in both groups (50% vs. 27%, p = .433). We have identified that AH in JSLE has a worse outcome most likely related to respiratory failure. The AH onset in JSLE already treated with high-dose steroids raises the concern of inadequate response to this treatment and reinforces the recommendation of early aggressive alternative therapies in this group of patients.

Outcomes and organ dysfunctions of critically ill patients with systemic lupus erythematosus and other systemic rheumatic diseases

Our objective was to compare the pattern of organ dysfunctions and outcomes of critically ill patients with systemic lupus erythematosus (SLE) with patients with other systemic rheumatic diseases (SRD). We studied 116 critically ill SRD patients, 59 SLE and 57 other-SRD patients. The SLE group was younger and included more women. Respiratory failure (61 percent) and shock (39 percent) were the most common causes of ICU admission for other-SRD and SLE groups, respectively. ICU length-of-stay was similar for the two groups. The 60-day survival adjusted for the groups’ baseline imbalances was not different (P = 0.792). Total SOFA scores were equal for the two groups at admission and during ICU stay, although respiratory function was worse in the other-SRD group at admission and renal and hematological functions were worse in the SLE group at admission. The incidence of severe respiratory dysfunction (respiratory SOFA >2) at admission was higher in the other-SRD group, whereas severe hematological dysfunction (hematological SOFA >2) during ICU stay was higher in the SLE group. SLE patients were younger and displayed a decreased incidence of respiratory failure compared to patients with other-SRDs. However, the incidences of renal and hematological failure and the presence of shock at admission were higher in the SLE group. The 60-day survival rates were similar.

Outcomes and organ dysfunctions of critically ill patients with systemic lupus erythematosus and other systemic rheumatic diseases.

Our objective was to compare the pattern of organ dysfunctions and outcomes of critically ill patients with systemic lupus erythematosus (SLE) with patients with other systemic rheumatic diseases (SRD). We studied 116 critically ill SRD patients, 59 SLE and 57 other-SRD patients. The SLE group was younger and included more women. Respiratory failure (61%) and shock (39%) were the most common causes of ICU admission for other-SRD and SLE groups, respectively. ICU length-of-stay was similar for the two groups. The 60-day survival adjusted for the groups' baseline imbalances was not different (P = 0.792). Total SOFA scores were equal for the two groups at admission and during ICU stay, although respiratory function was worse in the other-SRD group at admission and renal and hematological functions were worse in the SLE group at admission. The incidence of severe respiratory dysfunction (respiratory SOFA >2) at admission was higher in the other-SRD group, whereas severe hematological dysfunction (hematological SOFA >2) during ICU stay was higher in the SLE group. SLE patients were younger and displayed a decreased incidence of respiratory failure compared to patients with other-SRDs. However, the incidences of renal and hematological failure and the presence of shock at admission were higher in the SLE group. The 60-day survival rates were similar.

Lupus pleuritis: a relevant risk factor for pulmonary tuberculosis.

The objective of the study was to evaluate risk factors for pulmonary tuberculosis in systemic lupus erythematosus (SLE). Clinical/laboratorial features of 1283 SLE patients (ACR criteria) followed at the Lupus Clinic were obtained from the electronic register database from 2001 to 2009. Pulmonary tuberculosis was diagnosed in 20 patients (1.6%) (TB+ group). As control group (TB-), 40 patients without tuberculosis matched for age, gender, ethnicity, age at SLE diagnosis, and disease duration were arbitrarily selected. All 20 patients of the TB+ group presented confirmed pulmonary tuberculosis from 1 to 23 years after SLE diagnosis (7.6 ± 8.1 years). Frequencies of previous SLE involvements (cutaneous, articular, hematological, renal, pericarditis, pneumonitis, and central nervous system) were alike in TB+ and TB- groups (p > 0.05). In contrast, prior pleuritis was more frequent in the TB+ group (40% vs. 5%, p = 0.001). In fact, pulmonary tuberculosis was diagnosed in 8/10 patients with previous pleuritis. Immunosuppressive and corticosteroid therapies at the moment of tuberculosis diagnosis were also similar in both groups (p > 0.05). We have identified pleuritis as a relevant risk factor for pulmonary tuberculosis, suggesting that previous pleural injury is a critical part of the complex interplay between altered immune system, socio-economic conditions, and increased susceptibility to this mycobacterial infection.

Validation of the Spanish, Portuguese and French versions of the Lupus Damage Index questionnaire: data from North and South America, Spain and Portugal.

We have previously developed and validated a self-administered questionnaire, modelled after the Systemic Lupus International Collaborating Clinics Damage Index (SDI), the Lupus Damage Index Questionnaire (LDIQ), which may allow the ascertainment of this construct in systemic lupus erythematosus (SLE) patients followed in the community and thus expand observations made about damage. We have now translated, back-translated and adapted the LDIQ to Spanish, Portuguese and French and applied it to patients followed at academic and non-academic centres in North and South America, Portugal and Spain while their physicians scored the SDI. A total of 887 patients (659 Spanish-speaking, 140 Portuguese-speaking and 80 French-speaking patients) and 40 physicians participated. Overall, patients scored all LDIQ versions higher than their physicians (total score and all domains). Infrequent manifestations had less optimal clinimetric properties but overall agreement was more than 95% for the majority of items. Higher correlations were observed among the Spanish-speaking patients than the Portuguese-speaking and French-speaking patients; further adjustments may be needed before the Portuguese and French versions of the LDIQ are applied in community-based studies. The relationship between the LDIQ and other outcome parameters is currently being investigated in a different patient sample.

Helicobacter pylori seropositivity among 963 Japanese Brazilians according to sex, age, generation, and lifestyle factors.

Seropositivity of anti-Helicobacter pylori antibody (HP + ) was examined among Japanese Brazilians. The study was announced through 18 Japanese community culture associations in São Paulo, Curitiba, Mogi das Cruzes, and Mirandopolis in 2001. Among 969 participants, 963 individuals aged 33 - 69 years were analyzed. The overall HP + % was 48.1% (95% confidence interval, 44.9 - 51.3%). There was no difference in HP + % between 399 males and 564 females (49.6% and 47.0%, respectively). The HP + % increased with age; 35.3% for those aged 33 - 39 years, 46.2% for those aged 40 - 49 years, 46.5% for those aged 50 - 59 years, and 56.9% for those aged 60 - 69 years, but no differences were observed among the generations (Issei, Nisei, and Sansei) for each 10-year age group. Mogi das Cruzes, a rural area, showed a higher HP + %. Length of education was inversely associated with the positivity; the odds ratio (OR) relative to those with eight years or less of schooling was 0.61 (0.42 - 0.89) for those with 12 years or more. The associations with smoking and alcohol drinking were not significant. Fruit intake was associated with the HP + %; the OR relative to everyday intake was 1.38 (1.05 - 1.83) for less frequent intake, while intake frequencies of green tea, miso soup, and pickled vegetables (tsukemono) were not. Multivariate analysis including sex, 10-year age group, residence, education, and fruit intake showed that all factors except sex were significant. This is the largest study of HP infection among Japanese Brazilians, and the results indicated a similar pattern of age-specific infection rate to that for Japanese in Japan.

Development of new heparin-like compounds and other antithrombotic drugs and their interaction with vascular endothelial cells

The anticlotting and antithrombotic activities of heparin, heparan sulfate, low molecular weight heparins, heparin and heparin-like compounds from various sources used in clinical practice or under development are briefly reviewed. Heparin isolated from shrimp mimics the pharmacological activities of low molecular weight heparins. A heparan sulfate from Artemia franciscana and a dermatan sulfate from tuna fish show a potent heparin cofactor II activity. A heparan sulfate derived from bovine pancreas has a potent antithrombotic activity in an arterial and venous thrombosis model with a negligible activity upon the serine proteases of the coagulation cascade. It is suggested that the antithrombotic activity of heparin and other antithrombotic agents is due at least in part to their action on endothelial cells stimulating the synthesis of an antithrombotic heparan sulfate.

Development of new heparin-like compounds and other antithrombotic drugs and their interaction with vascular endothelial cells.

The anticlotting and antithrombotic activities of heparin, heparan sulfate, low molecular weight heparins, heparin and heparin-like compounds from various sources used in clinical practice or under development are briefly reviewed. Heparin isolated from shrimp mimics the pharmacological activities of low molecular weight heparins. A heparan sulfate from Artemia franciscana and a dermatan sulfate from tuna fish show a potent heparin cofactor II activity. A heparan sulfate derived from bovine pancreas has a potent antithrombotic activity in an arterial and venous thrombosis model with a negligible activity upon the serine proteases of the coagulation cascade. It is suggested that the antithrombotic activity of heparin and other antithrombotic agents is due at least in part to their action on endothelial cells stimulating the synthesis of an antithrombotic heparan sulfate.

New insights on the specificity of heparin and heparan sulfate lyases from Flavobacterium heparinum revealed by the use of synthetic derivatives of K5 polysaccharide from E. coli and 2-O-desulfated heparin.

The capsular polysaccharide from E. Coli, strain K5 composed of ...-->4)beta-D-GlcA(1-->4)alpha-D-GlcNAc(1-->4)beta-D-GlcA (1-->..., chemically modified K5 polysaccharides, bearing sulfates at C-2 and C-6 of the hexosamine moiety and at the C-2 of the glucuronic acid residues as well as 2-O desulfated heparin were used as substrates to study the specificity of heparitinases I and II and heparinase from Flavobacterium heparinum. The natural K5 polysaccharide was susceptible only to heparitinase I forming deltaU-GlcNAc. N-deacetylated, N-sulfated K5 became susceptible to both heparitinases I and II producing deltaU-GlcNS. The K5 polysaccharides containing sulfate at the C-2 and C-6 positions of the hexosamine moiety and C-2 position of the glucuronic acid residues were susceptible only to heparitinase II producing deltaU-GlcNS,6S and deltaU,2S-GlcNS,6S respectively. These combined results led to the conclusion that the sulfate at C-6 position of the glucosamine is impeditive for the action of heparitinase I and that heparitinase II requires at least a C-2 or a C-6 sulfate in the glucosamine residues of the substrate for its activity. Iduronic acid-2-O-desulfated heparin was susceptible only to heparitinase II producing deltaU-GlcNS,6S. All the modified K5 polysaccharides as well as the desulfated heparin were not substrates for heparinase. This led to the conclusion that heparitinase II acts upon linkages containing non-sulfated iduronic acid residues and that heparinase requires C-2 sulfated iduronic acid residues for its activity.