[Arthritis and osteomyelitis in childhood and adolescence-Bacterial and nonbacterial]

Bacterial arthritis and osteomyelitis are usually acute diseases, which in this way differ from the often insidious course of nonbacterial osteomyelitis; however, there is often an overlap both in less acute courses of bacterial illnesses and also in nonbacterial osteitis. The overlapping clinical phenomena can be explained by similar pathophysiological processes. In bacteria-related illnesses the identification of the pathogen and empirical or targeted anti-infectious treatment are prioritized, whereas no triggering agent is known for nonbacterial diseases. The diagnostics are based on the exclusion of differential diagnoses, clinical scores and magnetic resonance imaging (MRI). An activity-adapted anti-inflammatory treatment is indicated.

Priorities in Chronic nonbacterial osteomyelitis (CNO) - results from an international survey and roundtable discussions

OBJECTIVE

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disorder that predominantly affects children and young people. The pathophysiology and molecular mechanisms of CNO remain poorly understood, and diagnostic criteria and biomarkers are lacking. As a result, treatment is empiric and follows personal experience, case series and expert consensus plans.

METHODS

A survey was designed to gain insight on clinician and patient experiences of diagnosing and treating CNO and to collate opinions on research priorities. A version containing 24 questions was circulated among international expert clinicians and clinical academics (27 contacted, 21 responses). An equivalent questionnaire containing 20 questions was shared to explore the experience and priorities of CNO patients and family members (93 responses).

RESULTS

Responses were used to select topics for four moderated roundtable discussions at the "International Conference on CNO and autoinflammatory bone disease" (Liverpool, United Kingdom, May 25-26^th, 2022). The group identified deciphering the pathophysiology of CNO to be the highest priority, followed by clinical trials, necessary outcome measures and classification criteria. Surprisingly, mental wellbeing scored behind these items.

CONCLUSIONS

Agreement exists among clinicians, academics, patients and families that deciphering the pathophysiology of CNO is of highest priority to inform clinical trials that will allow for the approval of medications for the treatment of CNO by regulatory agencies.

Gathering expert consensus to inform a proposed trial in chronic nonbacterial osteomyelitis (CNO)

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease that primarily affects children and adolescents. CNO is associated with pain, bone swelling, deformity, and fractures. Its pathophysiology is characterized by increased inflammasome assembly and imbalanced expression of cytokines. Treatment is currently based on personal experience, case series and resulting expert recommendations. Randomized controlled trials (RCTs) have not been initiated because of the rarity of CNO, expired patent protection of some medications, and the absence of agreed outcome measures. An international group of fourteen CNO experts and two patient/parent representatives was assembled to generate consensus to inform and conduct future RCTs. The exercise delivered consensus inclusion and exclusion criteria, patent protected (excludes TNF inhibitors) treatments of immediate interest (biological DMARDs targeting IL-1 and IL-17), primary (improvement of pain; physician global assessment) and secondary endpoints (improved MRI; improved PedCNO score which includes physician and patient global scores) for future RCTs in CNO.

Treatment of type I ROP with intravitreal bevacizumab or laser photocoagulation according to retinal zone

AIMS

To investigate the outcome of intravitreal bevacizumab (IVB) compared with laser photocoagulation in type I retinopathy of prematurity (ROP).

METHODS

Case records of 54 consecutive very low birth weight (VLBW) infants with type I ROP (posterior ROP, n=33; peripheral zone II, n=21) who were treated either with IVB (n=37) or laser photocoagulation (n=17) between 2011 and 2015 were retrospectively evaluated.

RESULTS

Patients with posterior ROP displayed significantly faster regression of active ROP within 12 days (range 9-15 days) if treated with IVB compared with laser photocoagulation, where active ROP regressed within 57 days (range 28-63 days) (p>0.001). No difference was observed in peripheral zone II.Five of seven patients (12%) who developed a recurrence in both eyes after IVB required additional laser photocoagulation within a mean of 12.7 weeks (11.3-15.6 weeks) after the previous treatment. After laser photocoagulation one patient with posterior ROP developed macular dragging and another patient developed a temporary exudative retinal detachment in both eyes. 12 months after treatment the spherical equivalent was not statistically significant different between IVB and laser photocoagulation in posterior ROP patients. However, IVB lead to a significant lower spherical equivalent in infants with posterior ROP (+0.37 dioptres, range -0.5 to +1.88 dioptres) compared with peripheral zone II (+3.0 dioptres range +2.0 to +4.0 dioptres, p<0.001).

CONCLUSIONS

IVB leads to faster regression of active ROP in infants with posterior ROP compared with laser photocoagulation. Spherical equivalent after 12 months was comparable in those treated with IVB and laser photocoagulation, but it was significantly lower in posterior ROP than in peripheral zone II.

Altered expression of IL-10 family cytokines in monocytes from CRMO patients result in enhanced IL-1β expression and release

Chronic recurrent multifocal osteomyelitis (CRMO) is characterized by reduced activation of protein kinases ERK1 and 2 in monocytes resulting in impaired IL-10 expression. IL10 and its homologs IL19 and IL20 are organized in the IL10 cluster on chromosome 1q32. IL-10 and IL-19 are immune-regulatory cytokines, while IL-20 acts in a pro-inflammatory manner. The NLRP3 inflammasome, a multi-protein complex forming in response to innate stimuli, mediates IL-1β cleavage and release. Here, we investigated IL-10-related cytokine expression in CRMO monocytes, underlying molecular events, and effects on inflammatory responses. We observed reduced anti-inflammatory IL-10 and IL-19 expression, and enhanced IL-20 expression in CRMO monocytes. Reduced IL-10 and IL-19 expression was associated with impaired Sp-1 recruitment to regulatory regions, contributing to NLRP3 inflammasome activation, which may induce inflammatory bone-loss. Our findings underscore the importance of balanced receptor-, cell-, and tissue-specific cytokine expression for immune homeostasis, providing additional arguments for cytokine blocking strategies in CRMO.

CD226 (DNAM-1) is associated with susceptibility to juvenile idiopathic arthritis

OBJECTIVES

Juvenile idiopathic arthritis (JIA) is considered a complex genetic autoimmune disease. We investigated the association of genetic variants previously implicated in JIA, autoimmunity and/or immunoregulation, with susceptibility to JIA.

METHODS

A genetic association study was performed in 639 JIA patients and 1613 healthy controls of northwest European descent. Ninety-three single nucleotide polymorphisms (SNP) were genotyped in a candidate gene approach. Results of the entire JIA patient group (all subtypes) were compared with results obtained, alternatively, with a clinically homogeneous patient group including only oligoarticular and rheumatoid factor (RF) negative polyarticular JIA patients (n=493). Meta-analyses were performed for all SNPs that have been typed in other Caucasian JIA cohorts before.

RESULTS

SNPs in or near PTPN22, VTCN1, the IL2-IL21 region, ANKRD55 and TNFA were confirmed to be associated with JIA (p<0.05), strengthening the evidence for involvement of these genes in JIA. In the majority of these replicated SNPs, effect sizes were larger when analysing a homogeneous patient cohort than when analysing all subtypes. We identified two novel associations with oligoarticular and RF-negative polyarticular JIA: CD226 rs763361 (OR 1.30, 95% CI 1.12 to 1.51, p=0.0006) and CD28 rs1980422 (OR 1.29, 95% CI 1.07 to 1.55, p=0.008). Meta-analyses including reported studies confirmed the association of both SNPs with susceptibility to JIA (OR 1.16, p=0.001 and OR 1.18, p=0.001, for rs763361 and rs1980422, respectively).

CONCLUSIONS

The CD226 gene has been identified as novel association with JIA, and a SNP near CD28 as a suggestive association. Both genes are probable candidate risk factors, since they are involved in costimulation of T cells.

Genetic variation in VTCN1 (B7-H4) is associated with course of disease in juvenile idiopathic arthritis

OBJECTIVE

The course of disease in juvenile idiopathic arthritis (JIA) is unpredictable with episodes of activity and remission. In order to identify predictive factors, 93 SNPs, JIA subtype, age at onset and ANA status were studied in relation to disease course.

METHODS

Genetic and clinical parameters were analysed in a cohort of 272 Caucasian patients with persistent oligoarthritis (n=129), extended oligoarthritis (n=57) and rheumatoid factor negative polyarthritis (n=86). Categories of disease course (remitting (n=65), intermediate (n=96) and unremitting (n=111)) were designed based on the cumulative time spent in active disease in the first 2 years.

RESULTS

Univariate analysis revealed association of the course of disease with JIA subtype (p=5.7*10(-5)) and three SNPs; VTCN1 rs10 923 223 (p=4.4*10(-5)), VTCN1 rs12 046 117 (p=0.017) and CDK6 rs42 041 (p=0.038). In a subsequent multivariate ordinal logistic regression analysis, VTCN1 rs10 923 223 (OR 0.41, 95%-CI 0.26 to 0.63) and JIA subtype (OR 3.8, 95%-CI 2.0 to 7.2; OR 2.5, 95%-CI 1.4 to 4.2, for extended oligoarthritis and RF-negative polyarthritis vs persistent oligoarthritis, respectively) were the strongest independent factors for course of disease.

CONCLUSIONS

This study provides evidence that VTCN1, encoding B7-H4, is associated with course of disease in selected subtypes of JIA. VTCN1 might be useful in predicting the course of disease.

Chronic non-bacterial osteomyelitis is associated with impaired Sp1 signaling, reduced IL10 promoter phosphorylation, and reduced myeloid IL-10 expression

Chronic non-bacterial osteomyelitis (CNO) is an auto-inflammatory disorder that affects the skeletal system. Interleukin (IL-)10 is an immune-modulatory cytokine that controls inflammation, and limits inflammatory cytokine responses. Dysregulation of IL-10 expression has been shown to result in autoimmune and infectious diseases. We investigated IL-10 expression by monocytic cells from CNO patients and controls. In response to stimulation with LPS, IL-10 expression from CNO monocytes was reduced (p<0.001). This was independent of IL10 promoter polymorphisms. Thus, we investigated Sp1 recruitment to the IL10 promoter and saw markedly reduced binding in CNO monocytes. This was accompanied with reduced phosphorylation of histone H3 serine 10 (H3S10), an activating epigenetic mark. Impaired recruitment of Sp1 to the IL10 promoter, and reduced H3S10 phosphorylation, may be a reflection of deficient MAPK signaling in CNO monocytes in response to LPS stimulation. Thus, we have discovered a mechanism that may be central in the pathophysiology of CNO.

Reference values for B cell subpopulations from infancy to adulthood

The composition of the peripheral blood lymphocyte compartment underlies developmental changes during ontogeny. Recently, several new B cell populations have been characterized which were suggested to develop in an age-dependent manner. However, age-dependent reference values for distinct B cell populations have rarely been reported. Therefore, we have characterized developmental changes in peripheral B cell populations from infancy to adulthood in order to define age-dependent reference values. Using a flow cytometric approach we analysed the frequencies as well as the absolute counts of naive, switched and non-switched memory B cells, CD27-negative memory B cells, transitional B cells as well as CD21(low) CD38(low) B cells from neonates up to the age of 50 years. Most of the B cell subsets showed age-dependent developmental changes: while the peripheral B cell pool during infancy is characterized predominantly by transitional and naive B cells, the fraction of switched and non-switched memory B cells increases gradually with age. CD21(low) CD38(low) B cells as well as plasmablasts do not exhibit developmental changes. In summary, we could demonstrate particular changes in the peripheral blood B cell compartment during ontogeny. This study provides reference values of different B cell subpopulations offering comparability for studies addressing disturbed peripheral B cell development in immunodeficiency, autoimmunity or B cell reconstitution following cell-depleting therapies.

Clinical course and prognostic value of disease activity in the first two years in different subtypes of juvenile idiopathic arthritis

OBJECTIVE

Juvenile idiopathic arthritis (JIA) is a heterogeneous disease involving chronic arthritis. The clinical course is characterized by a fluctuating pattern of active and inactive disease. We have described in detail the clinical course in different JIA subtypes during the first 2 years after diagnosis and studied its relationship to disease activity in the following years.

METHODS

Detailed clinical data on different parameters describing the disease activity in sequential time periods covering the first 2 years after diagnosis were retrieved from the charts of 311 patients with JIA and compared between subtypes. In a cohort of 146 patients, the relation of these different clinical variables to the course of disease in the following 3 years was evaluated.

RESULTS

The percentage of time with active disease in the first 2 years differed significantly between subtypes. In all subtypes, a broad spectrum of activity was observed. The time with active disease in the first 2 years was the most significant factor associated with the duration of active disease in the following years.

CONCLUSION

Different percentages of time with active disease have been observed between JIA subtypes in the first 2 years. The cumulative duration of activity varied widely within each subtype. Regarding the prognosis of the individual patient, the clinical course in the first 2 years appears to be predictive of the clinical course in the following years. Patients that have less time with active disease in the first 2 years are not likely to develop an unremitting clinical course later on.

Do B cells play a role in the pathogenesis of juvenile idiopathic arthritis?

Juvenile idiopathic arthritis (JIA) is the most common cause of chronic arthritis in childhood and adolescents and encompasses a heterogeneous group of diseases. The role of B cells (BC) in autoimmune diseases has been put in a new perspective due to the promising results of BC depleting therapies in RA. Experiments in mouse models have shed new light on the Ab-independent role of BC in the pathogenesis of autoimmune diseases. We discuss whether BC play a role in the pathogenesis of JIA appraising the question for an immunological basis of BC directed therapy.

Association of the autoimmunity locus 4q27 with juvenile idiopathic arthritis

OBJECTIVE

Juvenile idiopathic arthritis (JIA) is characterized by chronic arthritis and an autoimmune etiology. In several autoimmune diseases, including rheumatoid arthritis (RA), an association with the 4q27 locus has been reported. We undertook this study to investigate the possible role of the 4q27 locus in JIA.

METHODS

A case-control association study was conducted, with a total of 655 Caucasian JIA patients and 791 healthy controls divided into 2 independent sample sets. The rs6822844 marker in the 4q27 locus was genotyped.

RESULTS

In the first and larger sample set, a 5% decrease in T allele frequency was observed in patients compared with controls (allelic odds ratio [OR] 0.72 [95% confidence interval 0.55-0.95], P = 0.019), and in the second set, a 3% decrease was observed (allelic OR 0.81 [95% confidence interval 0.61-1.09], P = 0.169). The combined data set generated an OR of 0.76 (95% confidence interval 0.62-0.93, P = 7.08 x 10(-3)). When the different JIA subtypes were analyzed individually, significant decreases were seen in the subtypes with a polyarticular course of disease (extended oligoarthritis [P = 0.019] and rheumatoid factor-negative polyarthritis [P = 0.038]).

CONCLUSION

Our findings suggest that the 4q27 locus, previously reported to be associated with RA, type 1 diabetes mellitus, celiac disease, and psoriatic arthritis, is also associated with susceptibility to JIA.

Time to treatment as an important factor for the response to methotrexate in juvenile idiopathic arthritis

OBJECTIVE

Methotrexate (MTX) is the most commonly used disease-modifying antirheumatic drug in juvenile idiopathic arthritis (JIA). Currently, individual response to MTX cannot be reliably predicted. Identification of clinical and genetic factors that influence the response to MTX could be helpful in realizing the optimal treatment for individual patients.

METHODS

A cohort of 128 JIA patients treated with MTX were studied retrospectively. Eleven clinical parameters and genotypes of 6 single nucleotide polymorphisms in 5 genes related to the mechanism of action of MTX were compared between MTX responders and nonresponders using a multivariate regression analysis.

RESULTS

The time from diagnosis to start of MTX treatment, physician's global assessment at baseline, and the starting dose were significantly associated with the response to MTX at 6 months after initiation. Patients with a shorter time from diagnosis to start of MTX and a higher disease activity according to the physician but with a lower MTX dose showed an increased response. The effect of the starting dose on MTX response seemed to be mainly due to the influence of the systemic JIA subtype. The time from diagnosis to start of MTX treatment and physician's global assessment at baseline were highly correlated. Therefore, the precise effect size of each independent variable could not be determined.

CONCLUSION

In children with JIA, the time from diagnosis to start of MTX appears to be an important factor for MTX response. Our results suggest that an earlier start of MTX treatment will lead to an increased response.

How can calcium pyrophosphate crystals induce inflammation in hypophosphatasia or chronic inflammatory joint diseases?

Hypophosphatasia (HP) is a rare inborn error of bone and mineral metabolism characterized by a defect in the tissue non-specific alkaline phosphatase (TNSALP) gene. Calcium pyrophosphate dihydrate (CPPD) crystals are known to accumulate as substrates of TNSALP in tissues and joints of patients with HP. In CPPD-induced arthritis these crystals are known to induce an inflammatory response. HP patients do suffer from pain in their lower extremities. However, it is not clear whether CPPD crystals contribute to these musculoskeletal complaints in HP. As long as there is no curative treatment of HP, symptomatic treatment in order to improve clinical features, especially with regard to pain and physical activity, is of major interest to the patients. Knowledge of the mechanisms underlying crystal-induced cell activation, however, is limited. Here we describe recent advances in elucidating the signal transduction pathways activated by CPPD crystals as endogenous "danger signals". Recent investigations provided evidence that Toll/interleukin-1 receptor (TIR) domain containing receptors including Toll-like receptors (TLRs) and interleukin-1 receptor (IL-1R), as well as the triggering receptor expressed on myeloid cells 1 (TREM-1) and the NACHT-leucin rich repeat and pyrin-domain-containing protein (NALP3) containing inflammasome are essentially involved in acute CPPD crystal-induced inflammation. These receptors are considered in part as components of the innate immune system. Further studies are needed to improve our understanding of the pathophysiological mechanisms leading to inflammation and tissue destruction associated with deposition of microcrystals. They might support the development of new therapeutic strategies for crystal-induced inflammation. Eventually, patients with HP might as well profit from such strategies addressing these metabolic disorders secondary to the gene defect.

The TRAF1/C5 region is a risk factor for polyarthritis in juvenile idiopathic arthritis

OBJECTIVE

Juvenile idiopathic arthritis (JIA) is a chronic disorder in which both genetic and environmental factors are involved. Recently, we identified the TRAF1/C5 region (located on chromosome 9q33-34) as a risk factor for rheumatoid arthritis (RA) (p(combined) = 1.4 x 10(-8)). In the present study the association of the TRAF1/C5 region with the susceptibility to JIA was investigated.

METHODS

A case-control association study was performed in 338 Caucasian patients with JIA and 511 healthy individuals. We genotyped the single nucleotide polymorphism rs10818488 as a marker for the TRAF1/C5 region.

RESULTS

The A allele was associated with the susceptibility to rheumatoid factor-negative polyarthritis with an 11% increase in allele frequency (OR 1.54, 95% CI 1.09 to 2.18; p = 0.012). This association was stronger when combining subtypes with a polyarticular phenotype (OR 1.46, 95% CI 1.12 to 1.90; p = 0.004). In addition, we observed a trend towards an increase in A allele frequency in patients with extended oligoarthritis versus persistent oligoarthritis (49%, 38% respectively); p = 0.055.

CONCLUSIONS

Apart from being a well replicated risk factor for RA, TRAF1/C5 also appears to be a risk factor for the rheumatoid factor-negative polyarthritis subtype of JIA and, more generally, seems to be associated with subtypes of JIA characterised by a polyarticular course.

Safety and efficacy of combination of etanercept and methotrexate compared to treatment with etanercept only in patients with juvenile idiopathic arthritis (JIA): preliminary data from the German JIA Registry

Objective:

Etanercept monotherapy has been studied and approved for treatment of polyarticular juvenile idiopathic arthritis (JIA). The following study evaluates the safety and efficacy of combination therapy of etanercept and methotrexate compared to etanercept monotherapy in JIA.

Methods:

We perfomed an open, non-randomised study on patients who had previously failed to respond to at least one disease-modifying antirheumatic drug (DMARD). A total of 722 patients with JIA in whom at least 1 item of follow-up data was recorded were identified; of these, 118 patients treated with further slow acting drugs were excluded. In all, 504 patients were treated with a combination of etanercept and methotrexate. A total of 100 patients treated with etanercept only were in the control group. Efficacy was calculated using the American College of Rheumatology paediatric scores for 30, 50 and 70% improvement (PedACR30/50/70). Adverse events (AEs) and serious adverse events (SAEs) were reported.

Results:

After 12 months 55 patients in the monotherapy group and 376 patients in the etanercept and methotrexate group were available for comparison. For the intention to treat analysis, 65 patients discontinuing treatment prematurely were included. All activity parameters decreased significantly in both treatment groups. After 12 months 81%/74%/62% of patients of the etanercept and methotrexate group and 70%/63%/45% of patients of the etanercept monotherapy group achieved PedACR30/50/70 scores, respectively (p<0.05 for PedACR30, p<0.01 for PedACR70). The likelihood of achieving a PedACR70 increased with combination therapy with an odds ratio of 2.1 (95% CI 1.2 to 3.5). In total, 25 infectious and 23 non-infectious SAEs including 3 malignancies occurred in the etanercept and methotrexate group, and 1 infectious and 3 non-infectious SAEs occurred in the single etanercept group.

Conclusions:

The patients’ disease activity improved during etanercept monotherapy and etanercept and methotrexate combination therapy. Tolerability in both treatment groups was comparable.

Stevens-Johnson syndrome without skin lesions

In childhood, Mycoplasma pneumoniae infections usually present as respiratory tract disease. However, extrapulmonary manifestations can be severe but the association with M. pneumoniae might not be considered. Here two adolescents who presented with severe exudative and ulcerative stomatitis accompanied by conjunctivitis and genital erosions are reported on. The skin was unaffected. The diagnosis of an acute M. pneumoniae infection was confirmed by serology and PCR. There are only few reports about this clinical entity and its nomenclature is inconsistent. The denomination 'incomplete Stevens-Johnson syndrome' has been suggested.

Bacterial triggers and autoimmune rheumatic diseases

Autoimmune rheumatic diseases are generally considered as a multifactorial aetiology, mainly genetic susceptibility combined with environmental triggers of which bacteria are considered one of the most prominent. Among the rheumatic diseases where bacterial agents are more clearly involved as triggers are: reactive arthritis (ReA), rheumatic fever (RF) and Lyme disease. The role of bacterial infections in inducing other seronegative spondyloarthritis and antiphospholipid antibody syndrome has been hypothesized but is still not proven. The classic form of ReA is associated with the presence of HLA-B27 and is triggered by the urethritis or enteritis causing pathogens Chlamydia trachomatis and the enterobacteria Salmonella, Shigella, and Yersinia, respectively. But several other pathogens such as Brucella, Leptospira, Mycobacteria, Neisseria, Staphylococcus and Streptococcus have also been reported to cause ReA. RF is due to an autoimmune reaction triggered by an untreated throat infection by Streptococcus pyogenes in susceptible individuals. Carditis is the most serious manifestation of RF and HLA-DR7 is predominantly observed in the development of valvular lesions. Lyme disease is a tick-transmitted disease caused by the spirochete Borrelia burgdorferi. Knowledge is limited about how this spirochete interacts with human tissues and cells. Some data report that Borrelia burgdorferi can manipulate resident cells towards a pro- but also anti-inflammatory reaction and persist over a long period of time inside the human body or even inside human cells.

The lambda gene immunoglobulin repertoire of human neonatal B cells

The dynamics of immunoglobulin rearrangements and selection, which depend on age, antigen exposure and tolerance functions, are only partly understood. Thus, we analyzed and compared the lambda chain immunoglobulin repertoire of individual IgD+ human neonatal B cells with the adult peripheral B cell VlambdaJlambda repertoire. Some Vlambda genes, 4C, 2A2, 2B2, 5A, 1G and 4B, were overexpressed in the non-productive neonatal repertoire, whereas other Vlambda genes (2E, 2A2, 3H, 2B2, 1C and 1G) were overexpressed in the productive repertoire. The adult B cell repertoire revealed nearly the same predominance of genes in the non-productive and productive repertoire. A comparison of the non-productive and productive repertoire indicated that the genes 3H and 1C were positively selected, whereas the genes 4C, 2A1, 3I, 5A, 9A, 4A and 4B were negatively selected. All four functional Jlambda genes were used in both repertoires. Jlambda2/3 was used mainly. Insertions of non-templated nucleotides at the VlambdaJlambda-junction by the enzyme TdT were less frequent as compared to the adult, but the CDR3 length was the same. Comparison of CD5+IgD+ and CD5-IgD+ B cells revealed no differences between neonatal productive rearrangements. However, the genes 1C and 1G were used more often in the non-productive repertoire of CD5+ B cells, whereas gene 4B was used significantly more frequent in CD5- B cells. These data provide evidence that the primary usage and subsequent selection of Vlambda genes in the neonate are surprisingly comparable with the adult. This suggests that selection into the productive Vlambda repertoire in principal might be driven mainly by autoantigens in the newborn, as well as in adulthood, since newborns have not been exposed to exogenous antigens.

Seronegative Lyme arthritis

We present a 10-year-old girl who had been diagnosed with juvenile idiopathic arthritis 5 years before and who experienced a flare of arthritis affecting one knee while she was off medication for almost 3 years. Seronegative Lyme arthritis had to be diagnosed based on the detection of Borrelia burgdorferi DNA in synovial fluid. No humoral immune response to Borrelia burgdorferi was detectable before, at the time of diagnosis and up to 3 years later.

Linear scleroderma 'en coup de sabre' associated with cerebral and ocular vasculitis

Linear scleroderma 'en coup de sabre' (LSCS) has been reported in association with intracranial abnormalities. We report the case of an 11-year-old boy with LSCS who presented with recurrent headaches. Cranial magnetic resonance imaging (MRI) and angiography were consistent with the diagnosis of a cerebral vasculitis. In addition, retinal examination showed an exudative inflammatory lesion consistent with vasculitis.

Toll-like receptors in Borrelia burgdorferi-induced inflammation

Lyme arthritis, the most common manifestation of late Lyme disease, has been associated with the presence of Borellia burgdorferi in the joint. However, it is still unclear whether the pathogen itself is able to elicit such a sustained inflammatory response, or whether an aberrant immunological reaction of the host is the main driving force. Borrelia antigens, including lipoproteins, flagellin and DNA, are ligands of Toll-like receptors, and can thus elicit a strong stimulation of host cells, such as neutrophils, mononuclear cells and resident tissue cells. Understanding the molecular basis of the signalling events caused by Borrelia lipoproteins will lead to a greater understanding of inflammation in Lyme arthritis and, hopefully, new treatment strategies for chronic antibiotic-resistant disease.

Effective NSAID treatment indicates that hyperprostaglandinism is affecting the clinical severity of childhood hypophosphatasia

Background

Hypophosphatasia (HP) is an inborn error of bone metabolism characterized by a genetic defect in the gene encoding the tissue-nonspecific alkaline phosphatase (TNSALP). There is a lack of knowledge as to how the variability and clinical severity of the HP phenotype (especially pain and walking impairment) are related to metabolic disturbances or impairments, subsequent to the molecular defect.

Methods

We analyzed the changes in clinical symptoms and the prostaglandin (PG) metabolism in response to treatment with non-steroidal anti-inflammatory drugs (NSAIDs) in six children affected by childhood HP. In addition, by exposing HP fibroblasts to pyridoxal phosphate and/or calcium pyrophosphate in vitro, we analyzed whether the alterations in PG levels are sequelae related to the metabolic defect.

Results

Childhood HP patients, who often complain about pain in the lower limbs without evident fractures, have systemic hyperprostaglandinism. Symptomatic anti-inflammatory treatment with NSAIDs significantly improved pain-associated physical impairment. Calcium pyrophosphate, but not pyridoxal phosphate, induced cyclooxygenase-2 (COX-2) gene expression and PG production in HP and normal fibroblasts in vitro.

Conclusion

Clinical features of childhood HP related to pain in the lower legs may be, at least in part, sequelae related to elevated PG levels, secondary to the primary metabolic defect. Consequently, NSAID treatment does improve the clinical features of childhood HP.

Cerebral mass in a 13-year-old girl following long-term sojourn in the Tropics

Cysticercosis of the central nervous system is the main cause of late-onset epilepsy in tropical countries. The case of a 13-year-old German girl with a generalized seizure following long-term sojourns in the Tropics is reported. Cranial imaging showed two cerebral lesions with central calcifications. Serological, molecular and cultural examination of cerebrospinal fluid and blood was negative for various parasites, fungi and bacteria including mycobacteria. Histopathological examination after neurosurgical resection revealed calcareous bodies pathognomonic for platyhelminths, in particular tapeworms. Taken together, the radiological and histopathological findings indicate infection with cysticerci, the larvae of Taenia solium.

Differential expression patterns of recombination-activating genes in individual mature B cells in juvenile idiopathic arthritis

BACKGROUND

Re-expression of the recombination-activating genes (RAG) in peripheral B cells may be relevant in the development of autoreactive antibodies in autoimmune diseases. The presence of antinuclear antibodies (ANA) as a hallmark of oligoarticular juvenile idiopathic arthritis (o-JIA, early-onset type) indicates a breakdown in immunological tolerance.

AIM

To examine the expression of RAG genes in peripheral blood mature B lymphocytes in patients with o-JIA.

METHODS

777 memory B cells from peripheral blood, CD19+ CD27+ CD5+ or CD19+ CD27+ CD5-, isolated from three ANA+ children with o-JIA and three healthy age-matched children, were examined for the expression of RAG1 and RAG2 mRNA. mRNA transcripts of activation-induced cytidine deaminase and immunoglobulin G were searched to further determine their developmental stage.

RESULTS

mRNA was present for any of the two RAG genes in the B cells of children with JIA and controls. However, the predominance of RAG1 or RAG2 was different. A significantly decreased frequency of RAG2-expressing memory B cells in both CD5+ and CD5- populations was noted in children with JIA (p<0.001), whereas the number of RAG1-expressing B cells was slightly increased. The coordinate expression of both the RAG genes was a rare event, similar in the CD5+ populations (1% in controls, 2% in children with JIA), but different among the CD5- compartments (5% v 0%; p<0.01).

CONCLUSION

These results argue for a reduced coordinate RAG expression in the peripheral CD5- memory B cells of patients with o-JIA. Thus, it was hypothesised that impaired receptor revision contributes to autoimmune pathogenesis in JIA.

Analysis of RAG expression by peripheral blood CD5+ and CD5- B cells of patients with childhood systemic lupus erythematosus

BACKGROUND

The assembly of immunoglobulin genes during B cell development in the bone marrow is dependent on the expression of recombination activating genes (RAG) 1 and 2. Recently, RAG expression in peripheral blood IgD+ B cells outside the bone marrow has been demonstrated and is associated with the development of autoimmune diseases.

OBJECTIVE

To investigate RAG expression in the CD5+ or CD5- IgD+ B cell compartment in childhood systemic lupus erythematosus (SLE).

METHODS

Using a combination of flow cytometric cell sorting and reverse transcriptase polymerase chain reaction analysis of cDNA libraries generated from individual cells, the expression of RAG, VpreB, and CD154 mRNA by individual peripheral blood B cells of three paediatric SLE patients was examined in detail.

RESULTS

While only one patient had a significantly increased frequency of RAG+ B cells in the CD5- B cell population, all patients showed higher frequencies of RAG+ B cells in the CD5+IgD+ B cell population. The frequency of RAG+ IgD+CD5+/- B cells was reduced during intravenous cyclophosphamide treatment. In healthy age matched children, RAG expressing IgD+ B cells were hardly detectable. Coexpression of RAG and VpreB or CD154 mRNA could only be found in SLE B cells.

CONCLUSIONS

RAG expression in peripheral blood B cells of SLE patients is particularly increased in the IgD+CD5+ B cell population. CD5+ and CD5- B cells in SLE have the potential to undergo receptor revision leading to the generation of high affinity pathogenic autoantibodies.

Differential expression of chemokines in synovial cells exposed to different Borrelia burgdorferi isolates

OBJECTIVE

Lyme borreliosis is characterized by strong inflammatory reactions probably due to the presence of Borrelia burgdorferi in the joint. It has been suggested that Borrelia induces the immunological mechanisms that either can amplify the inflammatory response or can suppress it. To reveal the underlying mechanisms of chemoattraction and activation of responding leukocytes, we investigated the induction of chemokines in human synoviocytes exposed to two different B. burgdorferi sensu stricto isolates (strain Geho and B31).

METHODS

Synoviocytes were exposed in vitro up to 5 days. Semiquantitative reverse transcription polymerase chain reaction (RT-PCR) was used to assess the relative chemokine mRNA expression of RANTES/CCL5, SDF-1alpha/CXCL12 alpha, SDF-1beta/CXCL12 beta, MCP-1/CCL2, MCP-2/CCL8, IL-8/CXCL8 and MIP-1alpha/CCL3, and enzyme-linked immunosorbant assay (ELISA) was used to assess the protein expression of RANTES, SDF-1, MCP-1, and MIP-1alpha in the culture supernatant.

RESULTS

MCP-1 gene expression was not changed by strain B31 but MCP-1 gene expression along with protein concentration was suppressed by strain Geho. Both strains induced RANTES mRNA and protein concentration. SDF-1 gene expression was suppressed, whereas protein concentrations were unchanged by both strains. IL-8 gene expression was unchanged by using strain Geho but significantly upregulated by strain B31. Both strains induced MCP-2 mRNA expression. MIP-1alpha mRNA expression was induced, but chemokine concentration was suppressed by both strains.

CONCLUSION

This study suggests that the orchestra of chemokines plays an important role in the immunopathogenesis of early Lyme arthritis.

Chronic non-bacterial osteomyelitis in children

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) in children is a chronic non-suppurative inflammation involving multiple sites. Some children affected by chronic non-bacterial osteomyelitis (CNO) do not have multiple lesions or a recurrent course.

OBJECTIVE

To characterise the long term outcome of children with the full spectrum of CNO.

METHODS

30 children diagnosed with CNO were followed up for a mean of 5.6 years and their disease assessed using a clinical score, multiple imaging, and a diagnostic biopsy, including extensive microbial analysis.

RESULTS

9 patients had unifocal non-relapsing disease, 3 unifocal lesions with relapses, 9 multifocal lesions without relapses, and 9 multifocal lesions with relapses (CRMO). Granulocytes were present significantly more often in CRMO than in unifocal and non-recurrent lesions. Pustulosis was more common in multifocal cases regardless of recurrence. Mean duration of treatment in 15 children with a single occurrence was 9.2 months. Naproxen treatment was generally effective. Naproxen treatment in 12 patients with relapses lasted 25 months. However, 7 of these were not effectively treated with naproxen alone. Five were treated with oral glucocorticoids for 27 days in addition to naproxen, which induced remission in four, lasting for at least 1.5 years. Longitudinal growth of affected bones was not altered, except for the development of hyperostosis.

CONCLUSION

CNO is a spectrum of inflammatory conditions, with CRMO being the most severe. Most children with CNO have a favourable outcome of the disease. Oral glucocorticoids may be necessary in severe recurrent cases.

Differential expression of matrix metalloproteinases and cyclooxygenases in synovial cells exposed to Borrelia burgdorferi

OBJECTIVE AND DESIGN

Lyme arthritis is characterized by strong inflammatory reactions probably due to the presence of Borrelia burgdorferi in the joint. It has been suggested that Borrelia adopts different molecular mechanisms that either can amplify the host's inflammatory response or can suppress it. In the present study we analyzed the induction of matrix metalloproteinases (MMPs) and cyclooxygenases (COXs) in human synoviocytes exposed to different B. burgdorferi sensu stricto isolates (Geho and B31).

MATERIALS AND METHODS

Synoviocytes were exposed in vitro for 12 h up to 5 days. Semiquantitative reverse transcription polymerase chain reaction was used to assess the mRNA expression of MMP-1 to 13, COX-1 and COX-2. Prostaglandin E2 (PGE2) production was assessed by ELISA.

RESULTS

MMP-1 was unchanged in synovial cells exposed to strain Geho, whereas it was downregulated by strain B31. MMP-13 was downregulated by both strains. COX-2 was upregulated by strain B31, which resulted in increased PGE2 concentration in the supernatant. In contrast, COX-1 was slightly upregulated and COX-2 tended to be downregulated by Geho resulting in a decreased PGE2 concentration.

CONCLUSIONS

The differential expression of MMPs and COXs suggests that different B. burgdorferi strains influence different molecular mechanisms leading to chronic inflammation. This might be reflected in the clinical variability among Lyme arthritis patients.

Lyme borreliosis: from infection to autoimmunity

Lyme borreliosis in humans is an inflammatory disease affecting multiple organ systems, including the nervous system, cardiovascular system, joints and muscles. The causative agent, the spirochaete Borrelia burgdorferi, is transmitted to the host by a tick bite. The pathogenesis of the disease in its early stages is associated largely with the presence of viable bacteria at the site of inflammation, whereas in the later stages of disease, autoimmune features seem to contribute significantly. In addition, it has been suggested that chronic persistence of B. burgdorferi in affected tissues is of pathogenic relevance. Long-term exposure of the host immune system to spirochaetes and/or borrelial compounds may induce chronic autoimmune disease. The study of bacterium-host interactions has revealed a variety of proinflammatory and also immunomodulatory-immunosuppressive features caused by the pathogen. Therapeutic strategies using antibiotics are generally successful, but chronic disease may require immunosuppressive treatment. Effective and safe vaccines using recombinant outer surface protein A have been developed, but have not been propagated because of fears that autoimmunity might be induced. Nevertheless, new insights into the modes of transmission of B. burgdorferi to the warm-blooded host have been generated by studying the action of these vaccines.

The German etanercept registry for treatment of juvenile idiopathic arthritis

OBJECTIVE

To describe a registry set up to monitor children treated with etanercept in Germany and Austria.

METHODS

Giannini's criteria, duration of morning stiffness, number of swollen, tender and contracted joints, adverse events, and reasons for discontinuation were assessed.

RESULTS

322 patients with juvenile idiopathic arthritis (JIA) and 12 additional patients with non-JIA rheumatic diagnoses were included. Therapeutic efficacy was observed from one month after treatment was started. The number of patients with significant improvement and the degree of improvement increased during the first year. The mean (SD) number of tender and swollen joints decreased from 9 (9) and 8.4 (9) to 3.0 (6.5) and 4.5 (7) after one month, and to 2.2 (5.5) and 3.3 (5.5) after three months; morning stiffness decreased from 45 (65) minutes to 12 (30) and 7 (19) after one and three months (p<0.001 for all). Using Gianinni's criteria of 30%, 50%, and 70% improvement, a therapeutic response in JIA patients was achieved in, respectively, 66%, 54%, and 30% after one month, 78%, 61%, and 38% after three months, and 83%, 72%, and 52% after six months. Therapeutic efficacy was lower in patients with systemic onset arthritis. Overall tolerability was good: in 592 patient treatment-years there were 69 reports of adverse events in 56 patients, including one CNS demyelination. There were no opportunistic infections or lupus-like reactions. Treatment was discontinued in 53 JIA patients, in 25 because of lack of efficacy.

CONCLUSION

Etanercept treatment was safe and led to a significant improvement in most JIA patients resistant to conventional treatment.