Cell Death and Apoptosis in Ostearthritic Cartilage

Osteoarthritis (OA) is the most common chronic joint disease in the elderly population, causing significant pain and disability. Because the cardinal feature of OA is a progressive loss of articular cartilage, a great portion of the research endeavour into the pathogenesis of OA has been focused on the regulation of matrix synthesis and degradation. The phenotypic stability and survival of the chondrocytes are essential for the maintenance of a proper cartilage matrix. This has lead to the long-standing assumption that cell death is a central feature in OA cartilage degeneration. The important role of apoptosis in OA has been demonstrated in in vitro and in vivo models. However, it should be noted that the relative contribution of apoptotic cell death in the pathogenesis of OA is still difficult to assess because of the chronic nature of the disease process. Therefore, the apoptosis of chondrocytes seems to be a potential target for therapeutic interventions in OA. The death receptor, mitochondrial and endoplasmic reticulum pathways are the major cellular pathways of apoptosis. Of all these elements involved in the apoptosis of chondrocytes, caspase inhibition has been studied with the most detail. Other molecules with the capacity to modulate mitochondria function, phosphatase (PP-1A/B) activity and pro-apoptosis stimuli (NO, prostaglandins, cytokines, ROS) could be excellent targets to block apoptosis of chondrocytes. Finally, the regulation of the natural inhibitors of apoptosis (c-FLIP, BAR, ARC and HC-gp39) could complement the other strategies to reduce cartilage degradation.

The prevalence and risk factors associated with isolated untreated systolic hypertension in Korea: the Korean National Health and Nutrition Survey 2001

Although isolated systolic hypertension (ISH) increases the risk of coronary heart disease and stroke, more than any other hypertension subtype, the prevalence and risk factors associated with ISH in the Korean population are not known. The 2001 Korean National Health and Nutrition Survey was a cross-sectional and nationally representative survey conducted in 2001. The prevalence of ISH by age and body mass index (BMI) was examined in 6601 Korean adults over 20 years of age. After adjusting for age, 4.32+/-0.32% of Korean adults had ISH, 5.28+/-0.37% had isolated diastolic hypertension and 5.82+/-0.36% had systolic/diastolic hypertension. The overall prevalence of ISH was found to increase directly with advancing age and increasing BMI. Although the ISH was found to be more common in men overall (4.81+/-0.50% in men, 4.12+/-0.37% in women), it was more common in women over 70 years of age. Independent variables associated with risk for ISH included advanced age, BMI, triglyceride (TG) levels, monthly income and alcohol intake. However, gender, fasting blood glucose, total cholesterol and high-density lipoprotein cholesterol levels, residential area, education level and smoking were found not to be significantly associated with ISH risk. The findings of the present study demonstrate that the prevalence of untreated ISH in Korea was lower than in Western countries. Age, BMI, TG levels, monthly income and alcohol intake were associated with ISH.

Comparative effect of seeds of Rhynchosia volubilis and soybean on MG-63 human osteoblastic cell proliferation and estrogenicity

The seeds of Rhynchosia volubilis (SRV) (Leguminosae) and soybean have been used in oriental folk medicine to prevent postmenopausal osteoporosis. Their beneficial effects are caused by a high content of isoflavone, which function as partial agonists or antagonists of estrogen. To compare the estrogenic effects of SRV and soybean on the MG-63 osteoblastic cell proliferation, 70% methanol extracts of SRV or soybean were treated on MG-63 cells. Although biphasic over a concentration range of 0.001 mg/ml-0.1 mg/ml, both SRV and soybean extracts increased MG-63 cell proliferation. However SRV was more effective at increasing the cell proliferation that paralleled with the greater estrogenic effects as determined by estrogen receptor alpha (ERalpha) expression, an estrogenic response element (ERE)-luciferase activity and the selective expression of insulin-like growth factor-I (IGF-I). SRV-induced IGF-I expression resulted from increases in the mRNA levels. Despite the increased expression of ERbeta, ERE activity and IGF-I expression by soybean were lower than those by SRV. Furthermore, the comparable estrogenic effects between SRV and the combined treatment of genistein and daidzein standards at 0.5 x 10(-8) M, which is a concentration of these two isoflavones similar to that of SRV at 0.001 mg/ml, demonstrate that the greater estrogenicity of SRV for MG-63 cell proliferation is mediated by the synergism of low levels of isoflavones for the selective expression of IGF-I.

Arthritis information on the Web and its influence on patients and physicians: a Korean study

OBJECTIVES

This study was conducted to assess the contents of Web-sourced arthritis information and to determine its influence on arthritis patients and medical practice in Korea.

METHODS

An electronic search was conducted using the word "arthritis". Web sites found in the Korean language were critically assessed according to authorship, the type of publication, contents, financial interests, and the type of financial interest. Questionnaire surveys of arthritis patients and rheumatologists were performed to appraise the impact of the arthritis information on the Web.

RESULTS

Among 138 web sites retrieved, 18.8% were classified as advertisement and 44.9% as having financial interests, such as the promotion of products or services. Among 257 arthritis patients surveyed, 28% reported that they searched for arthritis information on the web, and the parameters significantly associated with Internet searching were a younger age, being employed, and having a higher income and a higher education. While the difference in ratings regarding the accuracy of Web-sourced arthritis information between physicians and patients was not significant, only 16.1% of physicians responded that their patients understand the Internet content accurately. Physicians also tended to reply more negatively about the contents and the influence of Web-sourced arthritis information than patients.

CONCLUSION

Analysis of Korean arthritis web sites revealed many sites with financial interests. There was also a discrepancy found between patients and physicians regarding the impact of Web-sourced arthritis information on the doctor-patient relationship. Because the impact of the Internet on health care is expected to increase, physicians need to be prepared to help patients benefit from information obtained from the Internet.

Effects of hwangryunjihwang-tang on in vitro ertilization and ovulation in mice fed a high-fat diet

It has been generally accepted that hwangryunjihwang-tang (h-tang) is a useful prescription for treating polydipsia and to prevent obesity induced by a high-fat diet. The aim of this study was to clarify whether h-tang improved reproductive dysfunction caused by obesity in mice. Mice were fed a high density protein and lipid diet for 4 weeks, followed by administration of h-tang at 480 mg/kg body weight per day for 4 days. Thereafter, changes of body weight, ovulation rate, in vitro and in vivo fertilization, embryonic development and implantation rate were measured. H-tang markedly reduced the body weight of obese mice fed a high-fat diet, but not mice fed a normal diet. H-tang significantly improved ovulation rates, in vitro and in vivo fertilization rates and embryonic development. These results indicate pharmacological reversal of reproductive dysfunction caused by obesity, perhaps by adjusting internal secretions and metabolic functions.

Relationship between chondrocyte apoptosis and matrix depletion in human articular cartilage

OBJECTIVE

Chondrocyte apoptosis has been described in studies of the pathogenesis of various arthritides. Since matrix degradation is important in the pathology of arthritis, we investigated the effect of matrix depletion on chondrocyte apoptosis.

METHODS

Consecutive 1 mm sections of child's rib cartilage were cultured under 4 sets of conditions: (1) control; and treatment with (2) hyaluronidase, (3) collagenase, (4) hyaluronidase/collagenase alternately. Sections were harvested on Days 5, 8, and 11, and the proportion of apoptotic cells was measured by propidium iodide staining and flow cytometry. Changes of Fas and Fas ligand expression were verified by immunohistochemistry and Western blot.

RESULTS

Collagenase treatment led to an increase of apoptosis, which began on Day 8, whereas hyaluronidase treatment had no effect on chondrocyte viability up to Day 11. Alternating hyaluronidase and collagenase treatment induced chondrocyte death earlier, but the difference in apoptotic rate was not significant on Days 8 or 11 compared to collagenase treatment alone. Immunohistochemistry showed the expression of Fas ligand in all enzymatically treated specimens. Expression of Fas receptor was ubiquitous in both control and treated specimens.

CONCLUSION

The collagen framework is important in the maintenance of chondrocyte survival in human cartilage. Upregulation of Fas ligand in matrix depleted specimens suggested that the Fas pathway may have a role in apoptosis induced by matrix depletion.

Schwann cell proliferative responses to cAMP and Nf1 are mediated by cyclin D1

In most mammalian cells, the cAMP-dependent protein kinase A pathway promotes growth arrest and cell differentiation. However in Schwann cells, the reverse is true. Elevated levels of cAMP function as the cofactor to a broad range of mitogenic cues in culture and in animals. Previous studies have suggested that cAMP acts at an early point in the Schwann cell mitogenic response, perhaps by stimulating the expression of growth factor receptors. We show here that cAMP acts downstream rather than upstream of growth factor receptor expression. The essential function(s) of cAMP is exerted as Schwann cells progress through the G(1) phase of the cell cycle. Ectopic expression studies using an inducible retroviral vector show that the G(1) phase requirement for cAMP can be alleviated by a single protein, cyclin D1. We show, in addition, that at least one function of the Nf1 tumor suppressor is to antagonize the accumulation of cAMP and the expression of cyclin D1 in Schwann cells. Thus a G(1) phase-specific protein, cyclin D1, accounts for two salient features of Schwann cell growth control: the promitotic response to cAMP and the antimitotic response to the Nf1 tumor suppressor.

Identification of IgE-binding components of citrus red mite in sera of patients with citrus red mite-induced asthma

BACKGROUND

Our previous investigations demonstrated that citrus red mite (CRM) antigen could cause IgE-mediated bronchoconstriction in exposed farmers working on citrus farms.

OBJECTIVE

This study was performed to confirm IgE-binding components and major allergens within the CRM antigens.

METHODS

Ten subjects who had been diagnosed as having CRM-induced asthma were enrolled. Serum-specific IgE antibodies to CRM antigens were measured by using an ELISA. To identify IgE-binding components and major allergens, SDS-PAGE, 2-dimensional PAGE, IgE-immunoblot analysis, and amino acid sequencing of major allergens were performed.

RESULTS

All the asthmatic subjects had high specific IgE antibodies to CRMs. Twelve percent SDS-PAGE analysis showed more than 10 protein bands ranging from 6 to 64 kd. SDS-PAGE and IgE-immunoblot analysis with each individual serum showed 5 IgE-binding components (11, 24, 35, 40, and 64 kd), with 2 (24 and 35 kd) of them bound in more than 50% of the study subjects. Two-dimensional PAGE and IgE-immunoblot analysis demonstrated that the major allergen at 24 kd had 2 bands with different isoelectric points of 4.75 and 5.1. Thirty-five kilodaltons had one band with an isoelectric point of 4.75. All amino acid sequencing of the 2 major allergens was performed, which was not homologous with any previously characterized allergens.

CONCLUSION

Five IgE-binding components and 2 major allergens (24 and 35 kd) were identified within the CRM antigen. The N-terminal amino acid sequence of the 2 major allergens (24 and 35 kd) was determined.

Type III procollagen N-terminal propeptide, soluble interleukin-2 receptor, and von Willebrand factor in systemic sclerosis

OBJECTIVE

To evaluate the blood concentration of type III procollagen N-terminal propeptide (PIIINP), soluble interleukin-2 receptor (sIL-2R), and von Willebrand factor (vWF) in systemic sclerosis (SSc) patients.

METHODS

PIIINP, sIL-2R, and vWF were measured in the sera and plasma of 29 SSc patients and 29 sex- and age-matched healthy controls. Serum PIIINP was determined by radioimmunoassay. Both serum sIL-2R and plasma vWF were measured by enzyme-linked immunosorbent assay (ELISA). Associations between concentrations and clinical and laboratory features were evaluated.

RESULTS

Serum levels of PIIINP and sIL-2R were significantly higher in the SSc group than in the control group (p < 0.01 for both). No differences in serum PIIINP and sIL-2R levels were found between the limited and diffuse cutaneous subsets. However, PIIINP concentrations were significantly higher in anti-Scl-70 positive SSc patients compared with those of anti-Scl-70 negative patients (p = 0.01). Serum PIIINP levels were significantly higher in SSc patients with restrictive pulmonary function (FVC < 80%) than in patients with normal pulmonary function (p < 0.05). The correlation between PIIINP levels and FVC (p < 0.05) was negative, but the correlation between PIIINP levels and modified Rodnan skin scores (p < 0.05) was positive. sIL-2R levels were not correlated with skin and pulmonary involvement of SSc. There was no difference in vWF levels between those of the SSc patients and those of the control groups.

CONCLUSION

These results suggest that serum PIIINP serves as a biologic marker for the extent of skin and pulmonary involvement in systemic sclerosis. Increased serum levels of sIL-2R in SSc patients support a role for T lymphocyte activation in the pathogenesis of systemic sclerosis.

Spondylitis is the most common pattern of psoriatic arthritis in Korea

We assessed the prevalence and clinical features of psoriatic arthritis (PsA) in Korean patients with psoriasis. The prevalence of PsA in patients with psoriasis was 9%. Patients with PsA were older and had a longer duration of skin disease than those with psoriasis alone (median age, 40 vs 35 years, P = 0.03, and 15.3 vs 11.7 years, P = 0.04, respectively). Spondylitis was the most common pattern of PsA (50%). Nail change, dactylitis, and enthesopathy were observed in 36%, 15.4%, and 15.6% of patients with PsA, respectively. Increased erythrocyte sedimentation rate (ESR), antinuclear antibody, and radiological sacroiliitis were more frequent in patients with PsA than in those with uncomplicated psoriasis (25.8% vs 10.3%, P = 0.04; 37.9% vs 16.7%, P = 0.02; and 37.8% vs 1.1%, P < 0.01, respectively). The onset ages of psoriasis and arthritis in the spondylitis group were significantly lower than those in the non-spondylitis group (median age, 21.5 vs 31 years, P = 0.03, and 28.5 vs 43.5 years, P = 0.01, respectively). HLA-B27 was prevalent in 8% of patients with PsA.

A developmentally regulated switch directs regenerative growth of Schwann cells through cyclin D1

Sciatic nerve axons in cyclin D1 knockout mice develop normally, become properly ensheathed by Schwann cells, and appear to function normally. However, in the Wallerian degeneration model of nerve injury, the mitotic response of Schwann cells is completely inhibited. The mitotic block is Schwann cell autonomous and developmentally regulated. Rescue analysis (by "knockin" of cyclin E) indicates that D1 protein, rather than regulatory elements of the D1 gene, provides the essential Schwann cell function. Genetic inhibition of the Schwann cell cycle shows that neuronal responses to nerve injury are surprisingly independent of Schwann cell mitotic responses. Even axonal regrowth into the distal zone of a nerve crush injury is not markedly impaired in cyclin D1-/- mice.

Apoptotic chondrocyte death in human osteoarthritis

OBJECTIVE

To define apoptotic chondrocyte death and the expression of Bcl-2, Bax, and Fas in human osteoarthritis (OA) cartilage.

METHODS

Cartilage samples were obtained from patients with knee OA at the time of joint replacement surgery and from normal autopsy cases. In OA, sections were obtained both from the lesional area, usually within 1 cm of bony exposure, and from the non-lesional area, which had macroscopically normal appearance or only mild surface irregularities. Apoptosis was verified by microscopic examination of hematoxylin and eosin stained specimens, TUNEL staining, electron microscopy, and DNA ladder analysis by electrophoresis. Immunohistochemistry was done to study the expression of Bcl-2, Bax, and Fas. Apoptotic cells and Bcl-2, Bax, and Fas positive cells were counted within defined microscopic fields. Expression of Bcl-2 and Bax was verified by Western blot.

RESULTS

The percentage of apoptotic cells in the lesional area was significantly higher than in the non-lesional area in cartilage from the same patient with OA, while apoptotic cells were rarely seen in normal cartilage. This result was confirmed by TUNEL stain. Many chondrocytes with chromatin condensation were verified in electron microscopy, and DNA from OA lesional cartilage revealed a DNA ladder on electrophoresis. Bcl-2 and Fas expressions were significantly higher in the OA lesional area than in the non-lesional area. On the other hand, Bcl-2 expression in normal cartilage was significantly higher than in OA cartilage. There was no significant difference in Bax expression among normal, OA lesional, and OA non-lesional cartilage.

CONCLUSION

These results show that apoptotic chondrocyte death occurs more frequently in OA compared to normal cartilage and in OA lesional compared to OA non-lesional cartilage. The different expression patterns of Bcl-2 and Fas in OA lesional and non-lesional cartilage suggest that they might be involved in the pathogenesis of OA.

Altered serum cytokine and immunoglobulin levels in the workers exposed to antimony

1 Antimony (Sb), an industrial and environmental toxicant, is known to cause dermatitis and pulmonary inflammations, but the immunomodulatory effects of environmental or occupational exposure to Sb have not been reported. To initiate investigation of Sb-induced alterations of the immune system, the concentrations of the IgG subclasses, IgE, interleukin-2, interferon-gamma, and interleukin-4 in sera obtained from workers exposed to Sb through antimony trioxide manufacture were determined and compared with those of control subjects. 2 The serum levels of IgG1, an immunoglobulin involved in host defense against many microbial infections, were significantly lower in the sera of Sb-exposed individuals than the controls. The serum concentrations of IgE, an immunoglobulin mediating allergic hypersensitivity, also were lower in the Sb-exposed workers than the controls. In addition, the levels of interleukin-2 and interferon-gamma, multifunctional cytokines for T-cell mediated immunity, were lowered in the factory workers. 3 A significant positive correlation between IgG4 and urine Sb levels was found among the Sb-exposed workers, indicating a possible role of IgG4 in Sb-mediated pulmonary or skin pathogenesis. 4 The present study provides the first report on immune alterations induced by occupational exposure to Sb and suggests that Sb exposure disturbs immunohomeostasis in humans observed as a function of aberrant serum cytokine and immunoglobulin levels, which could influence health.

Neurofibromin, the neurofibromatosis type 1 Ras-GAP, is required for appropriate P0 expression and myelination

The neurofibromatosis type 1 (NF1) gene product, neurofibromin, regulates activation of the Ras intracellular signaling pathway in Schwann cells. Schwann cells purified from mouse embryos with null mutations in the Nf1 gene increase expression of the major myelin glycoprotein P0. v-Ras expression in cultured Schwann cells partially mimics loss of Nf1, suggesting a role for Ras in upregulation of P0 expression in Nf1-deficient cells. We tested whether loss of Nf1 alters the ability of Schwann cells to form myelin. No significant changes in myelin formation resulted when Nf1-deficient or v-Ras-expressing Schwann cells were cultured with normal neurons. Yet, in organotypic cultures of neurons, Schwann cells, and fibroblasts without neurofibromin, myelination was dramatically reduced. We suggest that Nf1-dependent signaling cascades in neurons and/or fibroblasts, as well as Schwann cells, are required for normal myelination.

Apoptotic chondrocyte death in rheumatoid arthritis

OBJECTIVE

Recently, chondrocytes were shown to undergo apoptosis by the addition of nitric oxide and by coupling of Fas/Fas ligand in vitro, suggesting the possibility that chondrocytes have an inherent programmed cell death pathway that operates in adult cartilage. Chondrocyte apoptosis was verified in situ in articular cartilage samples from humans with osteoarthritis (OA) and from an animal model of OA. The present study investigates apoptotic chondrocyte death and the expression of Bcl-2 and Fas in rheumatoid arthritis (RA) cartilage.

METHODS

Cartilage samples were obtained from 13 RA patients at the time of joint replacement surgery and from 8 normal subjects at autopsy. Apoptotic chondrocytes were observed and counted in hematoxylin and eosin-stained cartilage specimens. Apoptosis was verified by TUNEL, electron microscopy, and DNA ladder assay. Bcl-2 and Fas expression were evaluated by immunohistochemistry.

RESULTS

Apoptotic cells were frequently observed in RA cartilage, whereas normal cartilage rarely showed apoptotic cells (3.01% versus 0.15%, respectively), a finding that was further confirmed by TUNEL staining. On electron microscopy, numerous apoptotic cells with typical chromatin condensation were observed in RA cartilage. DNA from RA cartilage also revealed 180-basepair nucleosome ladders on electrophoresis. Bcl-2 expression was significantly lower in RA cartilage than in normal cartilage (23.3% versus 43.1%, respectively), whereas Fas expression was not statistically different.

CONCLUSION

Apoptotic chondrocyte death and decreased Bcl-2 expression were verified in RA cartilage. They might provide a novel model system for the research of cartilage breakdown and joint destruction in RA.

Genetic risk and protective factors for idiopathic inflammatory myopathy in Koreans and American whites: a tale of two loci

OBJECTIVE

To better understand genetic contributions to autoimmunity, immunogenetic markers were studied in two racially discrete and geographically isolated populations of patients with idiopathic inflammatory myopathy (IIM).

METHODS

Clinical characteristics, as well as clinical and autoantibody subsets, were defined in 151 American white patients and 50 Korean patients with IIM. HLA-DRB1 and DQA1 genotyping was performed on patients and racially matched controls by standard molecular techniques. Gm allotypes and phenotypes were determined by the hemagglutination-inhibition method.

RESULTS

HLA-DRB1*0301, the linked allele DQA1*0501, and DRB1 alleles sharing the first hypervariable region motif 9EYSTS13 were major genetic risk factors for the development of myositis in whites (corrected P [Pcorr] < 0.0004, odds ratio [OR] 11.2, 4.5, and 3.1, respectively, for each factor versus controls). Although both the white and Korean patients had a similar distribution of clinical characteristics, autoantibody profiles, and clinical groups, no HLA-DRB1 nor DQA1 allele or motif was found to be a risk factor for IIM in the Korean patients. However, DRB1*14 was a protective factor in Korean patients without myositis-specific autoantibodies (Pcorr = 0.004, OR 0.046). In addition, although no Gm phenotype or allotype was identified as a risk factor in whites, Gm 21 was a protective factor for the development of IIM in Koreans (Pcorr = 0.024, OR 0.3).

CONCLUSION

Although myositis patients in the US and Korea share similar clinical and serologic features, the immune response genes predisposing to and protecting from myositis in each of these ethnic groups differ at two chromosomal loci. These data suggest that multiple genetic loci should be studied to identify risk and protective factors for some autoimmune diseases in various ethnic populations.

Theoretical and treatment issues of personality disorders in individualistic and collectivistic societies

The author will attempt to equate so-called personality disorders with what used to be called psychoneurosis. Some suggestions for theoretical and technical modifications to apply psychoanalysis and psychotherapy on selective cases within the current managed care environment have been offered. In order to develop a comprehensive and effective psychotherapy system, a collaboration of psychotherapists both in collectivistic and individualistic societies is highly desirable. Furthermore, the differences of personality disorder and neurosis in both social structure are either minimal or insignificant from a psychotherapeutic point of view.

Paclitaxel reduces anti-dsDNA antibody titer and BUN, prolonging survival in murine lupus

We evaluated the effect of paclitaxel on the severity of autoimmunity in the murine model of systemic lupus erythematosus (SLE), NZB x NZW F1 mice. Fifteen 20 week old (NZB x NZW) F1 female mice were given a dose of 10 mg/kg paclitaxel by the intraperitoneal route on three alternate days followed by 7.5 mg/kg on three additional alternate days. This pattern of treatment was repeated every 4 weeks for a period of 28 weeks. 20 control mice were injected intraperitoneally with an equal volume of the vehicle used. Serum anti-double stranded DNA (dsDNA) antibody titers and the blood urea nitrogen (BUN) were significantly diminished in the paclitaxel treated group compared to the vehicle treated group. While the onset of proteinuria appeared to be delayed in the experimental group, the difference was not significant. Survival rate improved significantly in paclitaxel treated group (p = 0.04 by log-rank test). These results suggest that paclitaxel is beneficial in the suppression of autoimmunity in this strain of mice by reducing the anti-dsDNA antibody titer and the BUN, prolonging survival.

Molecular and genetic characterization of two anti-DNA antibodies derived from patients with systemic lupus erythematosus

Anti-double stranded(ds) DNA antibody is one of markers of systemic lupus erythematosus (SLE). Two human monoclonal anti-DNA antibody-producing cell lines were established from two SLE patients. One cell line secreted IgG isotype antibody (KSUG) and the other secreted IgM isotype antibody (KSUN). The light chains of the two immunoglobulins were lambda chains. The nucleotide sequences for the immunoglobulin variable region genes of the two antibodies were determined and compared to germline sequences. The heavy and lambda light chains of KSUG were VH3 family and V lambda IIIb, respectively. The heavy and lambda light chains of KSUN were VH4 family and V lambda IX, respectively. Antibody KSUG, IgG isotype, showed somatic mutations, whereas KSUN, IgM isotype, used the germline gene without mutation. These findings reconfirm the current paradigms that IgM anti-DNA antibodies are produced by utilizing germline genes whereas IgG anti-DNA antibodies are produced by somatic mutations.

Mycobacterium tuberculosis infection in a corticosteroid-treated rheumatic disease patient population

OBJECTIVE

To investigate the incidence and risk factors of Mycobacterium tuberculosis infection in longterm corticosteroid treated rheumatic disease patients.

METHODS

We assessed retrospectively the incidence of active tuberculosis and its risk factors in 269 rheumatic disease patients treated with moderate to high doses of corticosteroid for an evaluation period representing 1,035 corticosteroid years of therapy.

RESULTS

The mean daily dose of steroid was 18.7 mg prednisolone and the mean daily dose during the first year of treatment was 20.4 mg prednisolone. 21 of these patients developed active tuberculosis resulting in an incidence rate of 20/1,000 patient-years. Cumulative and mean daily steroid doses during the follow-up period and during the first year of treatment, and a history of steroid pulse therapy were significantly correlated with the development of tuberculosis. A past history of tuberculosis, initial chest P-A abnormality, the starting dose of steroid, a history of more than 30 mg/day of prednisolone for more than one month, and a history of cytotoxic therapy were not related to the development of tuberculosis.

CONCLUSION

The incidence of active tuberculosis is increased in rheumatic patients on moderate-to-high dose steroid treatment. Its risk factors are the cumulative and mean daily steroid doses during the follow-up period and during the first year of steroid treatment, and a history of steroid pulse therapy.