High prevalence of Pneumocystis jirovecii colonization among patients with autoimmune inflammatory diseases and corticosteroid therapy.

BACKGROUND: Patients with autoimmune inflammatory diseases (AID) account for 13-36% of Pneumocystis pneumonia (PCP) cases in human immunodeficiency virus (HIV)-negative patients. Up to 88% of PCP cases in HIV-negative patients are associated with prior steroid treatment. Pulmonary colonization with Pneumocystis in HIV-negative patients is associated with corticosteroid therapy in up to 75% of cases. The aim of this study was to detect the prevalence and risk factors of pulmonary colonization with Pneumocystis jirovecii in patients with AID receiving corticosteroid therapy in comparison with healthy control persons. METHODS: We investigated induced sputa of 102 patients with AID on current corticosteroid treatment and of 117 healthy controls for the presence of P. jirovecii using polymerase chain reaction (PCR). RESULTS: Twenty-nine patients (28.5%) with AID were colonized with P. jirovecii compared to three healthy controls (2.6%) [p < 0.001, odds ratio (OR) 15.10, 95% confidence interval (CI) 4.43-51.38]. In patients with AID, age over 60 years was significantly associated with colonization (p = 0.015, OR 3.19, 95% CI 1.27-7.94). Multivariate analysis showed age to be independently associated with the colonization of P. jirovecii (95% CI 1.002-1.092). Neither duration nor dose of corticosteroid therapy nor immunosuppressive co-medication had a significant influence on P. jirovecii colonization. CONCLUSION: Patients with AID, especially those over 60 years of age, display a high prevalence of colonization with P. jirovecii. Clinicians should be aware of this and ensure that they consider the possibility of PCP when pulmonary symptoms arise in these patients.

Autoantibodies in autoimmune diseases.

The occurrence of autoantibodies is a common feature of autoimmune diseases. This review is intended to give an overview of the most important autoantibodies and their role in diagnosis, disease activity and prognosis in rheumatoid arthritis (RA), systemic lupus erythematodes (SLE) and multiple sclerosis (MS). Whereas in RA and SLE these antibodies are meaningful for diagnosis and partially for the prognosis of the disease, the situation is quite different in the case of MS. Up to date, no specific antibody is known to be exclusively present in the serum or cerebrospinal fluid (CSF) of MS-patients compared to the respective fluids of healthy individuals. Nevertheless, there are some antigens that are reported to be bound significantly more often by MS-patients' serum or CSF than by comparable samples of healthy volunteers. In addition to the importance of several autoantibodies for diagnosis of the respective disease, the serum concentration of certain antibodies in RA and SLE is associated with therapy response. Since therapy with biologicals (e. g. TNF-alpha blockade, B-cell depletion) is expensive, monitoring these autoantibodies seems to be an additional useful tool for early identification of therapy responders or non-responders.

IgG1 and IgG4 are the predominant subclasses among auto-antibodies against two citrullinated antigens in RA.

OBJECTIVE: Antibody subclasses reflect specific immunological processes and may be indicative of the underlying pathological pattern in an autoimmune disease like RA. We therefore quantified anti-cyclic citrullinated peptides (CCP) and anti- citrullinated vimentin (MCV) IgG subclass titres in RA patients and compared them with the respective titres of antibodies directed against the varicella zoster virus (VZV) and to total serum titres. METHODS: Sera of 77 patients fulfilling the ACR criteria for RA were collected. An IgG subclass-specific ELISA system was then established and combined with commercially available MCV, CCP and VZV pre-coated microtitre plates. RESULTS: Even though IgG1 is the predominant subclass among antibodies against CCP and MCV in RA patients, IgG4 is second with respect to titres and frequencies. This increase in IgG4 among RA-specific antibodies is independent of disease duration and does not reflect a general skewing of the immune response in these patients as overall serum titres and antibodies directed against VZV show a normal distribution of IgG1, IgG2, IgG3 and IgG4. CONCLUSION: Elevated IgG4 titres are specific for auto-antibodies against citrullinated antigens in RA and are indicative of a Th2-biased environment during the generation of auto-reactive plasma cells. We discuss here an indirect role for IgG4 auto-antibodies in hindering the elimination of auto-reactive B and plasma cells and thus driving the autoimmune process.

Spots, blots, peaks and chips: proteomic approaches in autoimmune diseases.

During the past five years, investigations employing a variety of proteomic technologies have yielded a wealth of information on a number of autoimmune disorders. Animal models of autoimmune disease have been examined and have provided clues that can be useful in elucidating molecular pathways and mechanisms that play a role in autoimmune disorders. Human sera and body fluids have been analyzed and have resulted in the identification of autoantibodies that can be used as diagnostic markers in specific autoimmune diseases, and proteomic fingerprints of tissues and body fluids have resulted in the identification of individual proteins or patterns of protein expression that are deregulated in autoimmune diseases. The information provided by these proteomic studies are of diagnostic and therapeutic potential. This review provides an overview of the approaches used in the proteomic analyses of autoimmune disease.

Efficacy and tolerability of intravenous tropisetron in the treatment of fibromyalgia.

OBJECTIVE: To determine the efficacy of a serotonin receptor (5-HT(3)) antagonist in the treatment of fibromyalgia (FM) in a prospective, randomized, double-blind, placebo-controlled, multicentre trial. METHODS: Twenty-one female patients (age 21-63 years) with FM according to the American College of Rheumatology classification criteria for FM were assigned randomly to either a placebo group or to receive a daily intravenous bolus injection of 5 mg tropisetron for 5 days. RESULTS: In patients receiving tropisetron, the visual analogue scale (VAS) score for pain decreased by 28.9 compared with a decrease of 6.8 in the placebo group [probability (p)=0.063; effect size: 0.794]. Similar results were obtained using a body diagram pain score as a secondary efficacy parameter: mean pain reduction was 27.2 in the tropisetron group, versus 2.8 in the placebo group (p=0.038; effect size: 0.902). CONCLUSION: 5-HT(3) receptor antagonists provide significant pain relief for a group of FM patients.

A new approach to studying angiogenesis in rheumatoid arthritis by means of power Doppler ultrasonography and measurement of serum vascular endothelial growth factor.

OBJECTIVE: To evaluate angiogenesis as an essential component of pannus formation and cartilage destruction in rheumatoid arthritis (RA) using power Doppler ultrasonography (PDUS) and serum vascular endothelial growth factor (VEGF) measurement. METHODS: Twenty-one RA patients with a painful and swollen wrist and 12 healthy controls were examined with ultrasound. By means of standard scans, vascularity near and inside the joint capsule was visualized with PDUS. Two trained investigators performed sonography. Representative video clips were stored and read by two independent investigators, under blinded conditions, with regard to the microvascular Doppler flow being either inside or outside the joint capsule and with respect to a qualitative estimate of the intensity of blood flow, according to a grading from 1 to 3. Serum levels of VEGF were measured with a standard quantitative sandwich ELISA. RESULTS: The power Doppler mode identified increased synovial microvascular blood flow inside the joint capsule in 17 of 21 RA patients (81%) vs one of the healthy controls. We found large variation in serum VEGF levels in RA patients and in healthy controls. The degree of synovial vascularity determined by PDUS showed no correlation with the immediate serum VEGF level in the same patient. CONCLUSION: The high correlation between intra-articular microvascular power Doppler flow and clinical synovitis in RA patients (P<0.0001) indicates that PDUS may be helpful in studying the role of synovial blood vessels in rheumatoid inflammation.

[The expert assessment of fibromyalgia]. / Zur Begutachtung der Fibromyalgie.

Research on fibromyalgia over the last ten years has focused on the broad variety of pathogenetic aspects of a pain amplification syndrome. This emphasizes pain as the leading symptom. The sociomedical implications are obvious and considerable, and therefore fibromyalgia has increasingly become the subject of expert assessments. The expert assessment should not discuss the existence or non-existence of fibromyalgia, but evaluate the individual impairments, disabilities and handicaps which may lead to an individual degree of dysfunctioning.

[Essential cryoglobulinemic vasculitis with severe peripheral neuropathy and neurogenic muscular atrophy -- inducing remission by cascade filtration]. / Essentielle kryoglobulinämische Vaskulitis mit hochgradiger peripherer Neuropathie und neurogener Muskelatrophie -- Remissionsinduktion mittels Differenzialfiltrationsapherese.

We report on a 60 year old patient with peripheral neuropathy, neurogenic muscular atrophy, skin ulcers, arthritis and weakness. Detection of cryoglobulins in association with typical clinical symptoms, exclusion of hepatitis C and any other disease led to a rare diagnosis: essential cryoglobulinemic vasculitis. The case demonstrates not only the difficult diagnostic process but also the problems of an adequate and effective therapy. Since the usual immunosuppressive treatments such as methotrexate, high dose corticosteroid and intermittent intravenous pulse cyclophosphamide therapy (Austin's scheme) failed, we performed plasmapheresis (cascade filtration), which brought about an immediate and long-term remission. Besides discussing various types of plasmapheresis procedures and potential pathophysiological mechanisms, we point out that this therapy could find an early use in severe essential cryoglobulinemic vasculitis because of its excellent risk/benefit ratio.

[Structural quality of acute internal medicine rheumatology clinics--Project Group of the Association of Rheumatologic Acute Clinics]. / Strukturqualität akut-internistischer rheumatologischer Kliniken--Projektgruppenarbeit des VRA.

A study group representing the VRA (Association of Rheumatology Clinics in Germany) has worked out the structural quality paper presented here. Five guidelines for structural quality have been established by the VRA and are laid out in this paper. Required space and personnel for implementing these guidelines are considered. A highly competent, multi-disciplinary team must be available to ensure the long-term quality of in-patient treatment of rheumatic patients, the majority of whom are chronically ill and are suffering from chronic pain of varying intensity which restricts their daily activities. The necessity for such in-patient treatment is reflected in a 6-point-questionnaire (draft) adapted to the Appropriateness Evaluation Protocol. Considering the introduction of a flat-rate fee system (DRG-system) the structural quality paper describes the implementation of a specified electronic data processing documentation which is linked to a central hospital information system. According to the concept of benchmarking, the paper takes into account future developments of the German health system. It will be adjusted continuously to changing political guidelines for health services.

[Neuroendocrine-immunologic mechanisms in rheumatic diseases--a congress report]. / Neuroendokrine-immunologische Mechanismen bei rheumatischen Erkrankungen--Ein Kongressbericht.

Neuro-endocrine immune mechanisms play an important immunomodulatory role for rheumatic diseases as evidenced by long-recognized effects of glucocorticoids, gender, pregnancy, hemiparalysis, and stress on various clinical and epidemiological aspects. Recently, some regulatory pathways have been identified between the neuroendocrine and immune systems which seem to be altered in these diseases. Cooperation between the autonomic nervous system and the hypothalamic pituitary adrenal axis (HPA axis) is important to dampen the reaction of the immune system. In chronic inflammatory diseases such as rheumatic diseases these systems have become deficient. Moreover, hyperexcitability of sensory nerves due to peripheral and central neuronal sensitization can support the local inflammatory process.

Short-term treatment of primary fibromyalgia with the 5-HT3-receptor antagonist tropisetron. Results of a randomized, double-blind, placebo-controlled multicenter trial in 418 patients.

We investigated the efficacy and tolerability of short-term treatment with tropisetron, a selective, competitive 5-HT3-receptor antagonist in fibromyalgia. The trial was designed as a prospective, multicenter, double-blind, parallel-group, dose-finding study. We randomly assigned 418 patients suffering from primary fibromyalgia to receive either placebo, 5 mg, 10 mg or 15 mg tropisetron once daily for 10 days. Clinical response was measured by changes in pain score, visual analog scale, tender point count and ancillary symptoms. Responders were prospectively defined as patients showing a 35% or higher reduction in pain score. Treatment with 5 mg tropisetron resulted in a significantly higher response rate (39.2%) than placebo (26.2%) (p < 0.05). In the visual analog scale, the group administered 5 mg tropisetron showed a significant improvement (p < 0.05) and the group administered 10 mg tropisetron showed a nonsignificant clinical benefit. The number of painful tender points was significantly reduced (p = 0.002) in the 5 mg tropisetron group. Regarding ancillary symptoms, the 5 mg tropisetron group showed a significant improvement (p < 0.05) in sleep and dizziness. The patients' overall assessment of efficacy was significantly higher for 5 mg (p = 0.016) and 10 mg (p = 0.002) tropisetron than for placebo. The safety and tolerability of tropisetron was good; gastrointestinal tract symptoms were the most frequently reported adverse events. Short-term treatment of fibromyalgia patients with 5 mg tropisetron for 10 days proved to be efficacious and well tolerated. In this study a bell-shaped dose-response curve was seen.

Nociception, pain, and antinociception: current concepts.

The physiology of nociception involves a complex interaction of peripheral and central nervous system (CNS) structures, extending from the skin, the viscera and the musculoskeletal tissues to the cerebral cortex. The pathophysiology of chronic pain shows alterations of normal physiological pathways, giving rise to hyperalgesia or allodynia. After integration in the spinal cord, nociceptive information is transferred to thalamic structures before it reaches the somatosensory cortex. Each of these levels of the CNS contain modulatory mechanisms. The two most important systems in modulating nociception and antinociception, the N-methyl-D-aspartate (NMDA) and opioid receptor system, show a close distribution pattern in nearly all CNS regions, and activation of NMDA receptors has been found to contribute to the hyperalgesia associated with nerve injury or inflammation. Apart from substance P (SP), the major facilitatory effect in nociception is exerted by glutamate as the natural activator of NMDA receptors. Stimulation of ionotropic NMDA receptors causes intraneuronal elevation of Ca2+ which stimulates nitric oxide synthase (NOS) and the production of nitric oxide (NO). NO as a gaseous molecule diffuses out from the neuron and by action on guanylyl cyclase, NO stimulates in neighboring neurons the formation of cGMP. Depending on the expression of cGMP-controlled ion channels in target neurons, NO may act excitatory or inhibitory. NO has been implicated in the development of hyperexcitability, resulting in hyperalgesia or allodynia, by increasing nociceptive transmitters at their central terminals. Among the three subtypes of opioid receptors, mu- and delta-receptors either inhibit or potentiate NMDA receptor-mediated events, while kappa opioids antagonize NMDA receptor-mediated activity. Recently, CRH has been found to act at all levels of the neuraxis to produce analgesia. Modulation of nociception occurs at all levels of the neuraxis, thus, eliciting the multidimensional experience of pain involving sensory-discriminative, affective-motivational, cognitive and locomotor components.

Relationship between disease activity and serum levels of vitamin D metabolites and parathyroid hormone in ankylosing spondylitis.

Vertebral fractures due to osteoporosis are a common but frequently unrecognized complication of ankylosing spondylitis (AS) and various factors may contribute to the development of osteoporosis in AS. It is known that inflammatory activity in rheumatic disease (i.e., proinflammatory cytokines) itself plays a possible role in the pathophysiology of bone loss. 1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) seems to be another possible candidate for mediatory function in regulating both the inflammatory process and bone turnover. The aim of this study was to evaluate the relation between disease activity, bone turnover and calciotropic hormones. In 70 patients with established AS and an age- and sex-matched control group, the relation between disease activity (erythrocyte sedimentation rate, C-reactive protein, Bath Ankylosing Spondylitis Disease Activity Index), and serum levels of vitamin D metabolites, parathyroid hormone (PTH), bone alkaline phosphatase (bAP) and urinary pyridinium cross-links were determined. Serum levels of 1,25(OH)2D3 (p<0.01) and PTH (p<0.01) were negatively correlated with disease activity, the excretion of urinary pyridinium crosslinks showed a positive correlation with disease activity (p<0.01), and 1,25(OH)2D3 and PTH were positively correlated with bAP (p<0.01). These results indicate that high disease activity in AS is associated with an alteration in vitamin D metabolism and increased bone resorption. Furthermore, the decreased levels of 1,25(OH)2D3 may contribute to a negative calcium balance and inhibition of bone formation. Our results suggest further research is necessary to determine whether low levels of 1,25(OH)2D3 as an endogenous immune modulator suppressing activated T cells and cell proliferation may accelerate the inflammation process in AS.

Neuroendocrine perturbations in fibromyalgia and chronic fatigue syndrome.

A large body of data from a number of different laboratories worldwide has demonstrated a general tendency for reduced adrenocortical responsiveness in CFS. It is still not clear if this is secondary to CNS abnormalities leading to decreased activity of CRH- or AVP-producing hypothalamic neurons. Primary hypofunction of the CRH neurons has been described on the basis of genetic and environmental influences. Other pathways could secondarily influence HPA axis activity, however. For example, serotonergic and noradrenergic input acts to stimulate HPA axis activity. Deficient serotonergic activity in CFS has been suggested by some of the studies as reviewed here. In addition, hypofunction of sympathetic nervous system function has been described and could contribute to abnormalities of central components of the HPA axis. One could interpret the clinical trial of glucocorticoid replacement in patients with CFS as confirmation of adrenal insufficiency if one were convinced of a positive therapeutic effect. If patient symptoms were related to impaired activation of central components of the axis, replacing glucocorticoids would merely exacerbate symptoms caused by enhanced negative feedback. Further study of specific components of the HPA axis should ultimately clarify the reproducible abnormalities associated with a clinical picture of CFS. In contrast to CFS, the results of the different hormonal axes in FMS support the assumption that the distortion of the hormonal pattern observed can be attributed to hyperactivity of CRH neurons. This hyperactivity may be driven and sustained by stress exerted by chronic pain originating in the musculoskeletal system or by an alteration of the CNS mechanism of nociception. The elevated activity of CRH neurons also seems to cause alteration of the set point of other hormonal axes. In addition to its control of the adrenal hormones, CRH stimulates somatostatin secretion at the hypothalamic level, which, in turn, causes inhibition of growth hormone and thyroid-stimulating hormone at the pituitary level. The suppression of gonadal function may also be attributed to elevated CRH because of its ability to inhibit hypothalamic luteinizing hormone-releasing hormone release; however, a remote effect on the ovary by the inhibition of follicle-stimulating hormone-stimulated estrogen production must also be considered. Serotonin (5-HT) precursors such as tryptophan (5-HTP), drugs that release 5-HT, or drugs that act directly on 5-HT receptors stimulate the HPA axis, indicating a stimulatory effect of serotonergic input on HPA axis function. Hyperfunction of the HPA axis could also reflect an elevated serotonergic tonus in the CNS of FMS patients. The authors conclude that the observed pattern of hormonal deviations in patients with FMS is a CNS adjustment to chronic pain and stress, constitutes a specific entity of FMS, and is primarily evoked by activated CRH neurons.

Neuroendocrine and hormonal perturbations and relations to the serotonergic system in fibromyalgia patients.

The symptomatology of the fibromyalgia syndrome (FMS) often resembles an alteration in central nervous set points at least in three systems. The patients suffer under chronic pain in the region of the locomotor system, presumably reflecting a disturbed central processing of pain. Anxiety and depression often characterizes the clinical picture. Almost all of the hormonal feedback mechanisms controlled by the hypothalamus are altered. Characteristic for FMS patients are the elevated basal values of ACTH, follicle-stimulating hormone (FSH), and cortisol as well as lowered basal values of insulin-like growth factor 1 (IGF-1, somatomedin C), free triiodothyronine (FT3), and oestrogen. In FMS patients, the systemic administration of the relevant releasing hormones of corticotropin-releasing hormone (CRH), growth hormone-releasing hormone (GHRH), thyreotropin-releasing hormone (TRH), and luteinizing hormone-releasing hormone (LHRH) leads to increased secretion of ACTH and prolactin, whereas the degree to which TSH can be stimulated is reduced. The stimulation of the hypophysis with LHRH in female FMS patients during their follicular phase results in a significantly reduced LH response. All in all, the typical alterations in set points of hormonal regulation that are typical for FMS patients can be explained as a primary stress activation of hypothalamic CRH neurons caused by the chronic pain. In addition to the stimulation of pituitary ACTH secretion, CRH activates somatostatin on the hypothalamic level, which in turn inhibits the release of GH and TSH on the hypophyseal level. The lowered oestrogen levels could be accounted for both via an inhibitory effect of the CRH on the hypothalamic release of LHRH or via a direct CRH-mediated inhibition of the FSH-stimulated oestrogen production in the ovary. Serotonin (5HT), precursors like tryptophan (5HTP), drugs which release 5HT or act directly on 5HT receptors stimulate HPA axis, indicating a stimulatory serotonergic influence on HPA axis function. Therefore activation of the HPA axis may reflect an elevated serotonergic tonus in the central nervous system of FMS patients.

Efficacy and tolerability of tropisetron in primary fibromyalgia--a highly selective and competitive 5-HT3 receptor antagonist. German Fibromyalgia Study Group.

OBJECTIVE: Based on a potential role for serotonin receptors in fibromyalgia, we investigated the efficacy and tolerability of treatment with tropisetron, a highly selective, competitive inhibitor of the 5-HT3 receptor. METHODS: In this prospective, multicenter, double-blind, parallel-group, dose-finding study, 418 patients suffering from primary fibromyalgia (ACR criteria) were randomly assigned to receive either placebo, 5 mg, 10 mg or 15 mg tropisetron once daily, respectively. The duration of treatment was 10 days. The clinical response was measured by changes in pain-score, visual analog scale (VAS), and the number of painful tender-points. RESULTS: Treatment with 5 mg tropisetron resulted in a significantly higher response rate (39.2%) when compared with placebo (26.2%) (p=0.033). The absolute reduction in pain-score was -13.5% for 5 mg tropisetron, -13.0% for 10 mg tropisetron, and -6.3% for placebo (p<0.05). The effects of 15 mg tropisetron were similar to placebo, thus suggesting a bell-shaped dose-response curve. Compared with placebo, treatment with 5 mg tropisetron led to a significant improvement (p<0.05) in VAS, while a clear trend in terms of clinical benefit was seen with 10 mg tropisetron. The number of painful tender-points was also reduced significantly (p=0.002) in the 5 mg tropisetron group. Of interest, during the 12-month follow-up period, pain intensity of responders on 5 mg and 10 mg tropisetron was still markedly below baseline. The treatment was well tolerated, with gastro-intestinal complaints being the most frequently reported side effects, in keeping with the known safety profile for 5-HT3 receptor antagonists. CONCLUSIONS: This study demonstrates the efficacy of short-term treatment with 5 mg tropisetron once daily in primary fibromyalgia. Treatment was well tolerated and prolonged clinical benefits were seen.

Ultrasonography of the glenohumeral joints--a helpful instrument in differentiation in elderly onset rheumatoid arthritis and polymyalgia rheumatica.

In a prospective study, the glenohumeral joints of 51 patients (aged 60 or above) were examined, using ultrasonography. Twenty-two patients were suffering from characteristic polymyalgia rheumatica (PMR) symptoms. In contrast, 29 other patients initially had similar complaints, but were diagnosed as having elderly onset rheumatoid arthritis (EORA, rheumatoid factor negative) upon development of typical symptoms. Ultrasound examination revealed glenohumeral joint inflammation in 40.9% (9/22) of the patients with PMR and 65.5% (19/29) of the patients with EORA. A discrete symmetrical biceps tendon sheath effusion was found in only three patients and unilateral in six patients with PMR. In contrast, 12 patients with EORA presented a massive effusion of the biceps tendon sheath, in some cases combined with a bilateral subdeltoid bursitis, and an intraarticular (i.a.) effusion/synovitis. To summarize our results: an i.a. effusion/synovitis, subdeltoid bursitis and biceps tendon sheath effusion were more frequent in patients with EORA, with a predominate symmetry and signs for massive inflammation. The typical ultrasonographic result in patients with PMR was a unilateral inflammation of the glenohumeral joint with predominate discrete biceps tendon sheath effusion and, in comparison with the EORA group, with signs of a low grade inflammation. We conclude that the results of our prospective study might be helpful in the differentiation of PMR and a rheumatoid factor negative subgroup of EORA at the first time of manifestation where clinical overlaps can be observed. However, ultrasonography of the glenohumeral joints might be a good and helpful instrument of differentiation in both diseases.

Serum amyloid A--an indicator of inflammation in ankylosing spondylitis.

Biological markers of inflammation are useful for the diagnosis and monitoring of inflammatory rheumatic diseases. The present study tested, whether serum amyloid A (SAA) could be used as a marker of inflammatory disease activity in ankylosing spondylitis (AS). In 72 patients with AS, the two valuable surrogate markers of disease activity, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), and an established clinical activity score (Bath Ankylosing Spondylitis Disease Activity Index, BASDAI) were correlated to the serum levels of SAA. It was found that SAA correlates well with ESR, CRP, and BASDAI. Because of its strong correlation, SAA seems to be an additional very useful disease activity marker. When used in diagnosis, and especially in monitoring of inflammation, further studies are required. Another interesting point of view is the described role of plasma SAA as a precursor of Amyloid A (AA) protein in secondary amyloidosis, a known complication in AS. In all probability, high circulating SAA levels are a predisposing indicator of disease activity.