Tom Pettersson

Germline Mutations in the Extracellular Domains of the 55 kDa TNF Receptor, TNFR1, Define a Family of Dominantly Inherited Autoinflammatory Syndromes

Autosomal dominant periodic fever syndromes are characterized by unexplained episodes of fever and severe localized inflammation. In seven affected families, we found six different missense mutations of the 55 kDa tumor necrosis factor receptor (TNFR1), five of which disrupt conserved extracellular disulfide bonds. Soluble plasma TNFR1 levels in patients were approximately half normal. Leukocytes bearing a C52F mutation showed increased membrane TNFR1 and reduced receptor cleavage following stimulation. We propose that the autoinflammatory phenotype results from impaired downregulation of membrane TNFR1 and diminished shedding of potentially antagonistic soluble receptor. TNFR1-associated periodic syndromes (TRAPS) establish an important class of mutations in TNF receptors. Detailed analysis of one such mutation suggests impaired cytokine receptor clearance as a novel mechanism of disease.

Beneficial Effect of Interleukin 1 Inhibition with Anakinra in Adult-onset Still's Disease. An Open, Randomized, Multicenter Study

Objective. To study the efficacy of anakinra versus disease-modifying antirheumatic drugs (DMARD) in refractory adult-onset Still’s disease (AOSD). Methods. In a 24-week study, 22 patients with AOSD taking prednisolone ≥ 10 mg/day received anakinra (n = 12) or DMARD (n = 10). The primary endpoint was achievement of remission. Results. At 8 and 24 weeks, 7/12 and 6/12 receiving anakinra and 5/10 and 2/10 receiving DMARD achieved remission. Anakinra induced greater improvement in physical health measured by Medical Outcomes Study Short-Form 36 (SF-36; p < 0.011). During an open-label extension (OLE) of 28 weeks, 7/14 patients taking anakinra and 2/3 taking DMARD were in remission. Conclusion. Anakinra induced more beneficial responses than DMARD in patients with AOSD and was favored in the OLE phase. (ClinicalTrials.gov Protocol Registration NCT01033656).

Abnormal tumor necrosis factor receptor I cell surface expression and NF‐κB activation in tumor necrosis factor receptor–associated periodic syndrome

OBJECTIVE Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) is an autosomal-dominant autoinflammatory condition caused by mutations in the TNFRSF1A gene. The cellular mechanisms by which mutations in this gene trigger inflammation are currently unclear. Because NF-kappaB is the major intracellular signaling component inducing secretion of proinflammatory cytokines, we sought to determine whether differences in the clinical phenotype of patients with TRAPS may be attributable to variable effects of TNFRSF1A mutations on TNFRI expression, localization, or NF-kappaB activity. METHODS Peripheral blood mononuclear cells were obtained from patients (following informed consent), and cellular nuclear and cytosolic fractions were generated by subcellular fractionation. Localization of IkappaBalpha and NF-kappaB was determined by Western blotting of the resultant fractions. NF-kappaB subunit activity was determined by enzyme-linked immunosorbent assay analysis and confirmed by electrophoretic mobility shift assay. Subcellular localization of TNFRI was determined by immunofluorescence confocal microscopy or by immunoblotting following affinity isolation of plasma membrane by subcellular fractionation. RESULTS Cells from patients with the fully penetrant C73R mutation had marked activation of the proinflammatory p65 subunit of NF-kappaB. In contrast, cells from patients with the low-penetrant R92Q mutation displayed high levels of DNA binding by the p50 subunit, an interaction previously linked to repression of inflammation. Interestingly, although cells from patients with the C73R mutation have no TNFRI shedding defect, there was nonetheless an unusually high concentration of functional TNFRI at the plasma membrane. CONCLUSION High levels of TNFRI at the cell surface in patients with the C73R mutation hypersensitizes cells to stimulation by TNF, leading to increased NF-kappaB p65 subunit activation and an exaggerated proinflammatory response.

Proteinuria in cubilin-deficient patients with selective vitamin B12 malabsorption

Abstract.Selective vitamin B12 malabsorption or Gräsbeck-Imerslund disease (megaloblastic anemia 1) is frequently accompanied by proteinuria. The malabsorption-proteinuric syndrome of Finnish patients is caused by a defect in the multiligand receptor cubilin. We studied the urinary proteins of control subjects and 13 adult patients with three defined cubilin mutations (FM1, FM2, FM3), all diagnosed during childhood and subsequently observed. The overall kidney function was unimpaired and did not deteriorate with time. The excretion of total protein and albumin, and to lesser extent of transferrin, immunoglobulin light chains, and α1- and β2-microglobulins, was clearly elevated in 3 patients, mildly elevated in 3, and hardly or not at all increased in the rest. The urinary cobalamin-intrinsic factor receptor was low in 5 patients studied and lowest in the group with clear-cut proteinuria. The proteinuria was not of the classical glomerular or tubular type, but apparently due to the lack of cubilin function needed for tubular reabsorption of some, but not all, proteins of the primary urine.

Allelic variants in genes associated with hereditary periodic fever syndromes as susceptibility factors for reactive systemic AA amyloidosis.

We investigated the hypothesis that low-penetrance mutations in genes (TNFRSF1A, MEFV and NALP3/CIAS1) associated with hereditary periodic fever syndromes (HPFs) might be risk factors for AA amyloidosis among patients with chronic inflammatory disorders, including rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), Crohns disease, undiagnosed recurrent fevers and HPFs themselves. Four of 67 patients with RA plus amyloidosis had MEFV variants compared with none of 34 RA patients without amyloid (P value=0.03). The E148Q variant of MEFV was present in two of the three patients with TNF receptor-associated periodic syndrome (TRAPS) complicated by amyloid in two separate multiplex TRAPS families containing 5 and 16 affected members respectively, and the single patient with Muckle–Wells syndrome who had amyloidosis was homozygous for this variant. The R92Q variant of TNFRSF1A was present in two of 61 JIA patients with amyloidosis, and none of 31 nonamyloidotic JIA patients. No HPF gene mutations were found in 130 healthy control subjects. Although allelic variants in HPFs genes are not major susceptibility factors for AA amyloidosis in chronic inflammatory disease, low-penetrance variants of MEFV and TNFRSF1A may have clinically significant proinflammatory effects.

Diagnostic value of cerebrospinal fluid adenosine deaminase determination

We measured the activity of adenosine deaminase (ADA) in the cerebrospinal fluid of 3 patients with tuberculous meningitis, 38 with viral meningitis, 15 with bacterial meningitis, 5 with malignant lymphoma, 11 with cerebrovascular diseases and 13 with miscellaneous neurological disorders. The highest ADA activities were observed in patients with tuberculous meningitis (median 21.3 U/l, range 20.0-23.0) and lymphoma (13.0 U/l, range 4.0-25.0). The sensitivity of the test for diagnosing tuberculous meningitis was 100% and the specificity 99% when a cut-off value of 20.0 U/l was used. We conclude that determination of ADA in cerebrospinal fluid is useful for the diagnosis of tuberculous meningitis, but that high activity also can be seen in some other CNS disorders, e.g. lymphoma with meningeal involvement.

Injection-site reactions upon Kineret (anakinra) administration: experiences and explanations

Anakinra (Kineret), a recombinant form of human interleukin-1 (IL-1) receptor antagonist, is approved for the treatment of rheumatoid arthritis (RA) in combination with methotrexate. Kineret is self-administered by daily subcutaneous injections in patients with active RA. The mechanism of action of anakinra is to competitively inhibit the local inflammatory effects of IL-1. Kineret is generally safe and well tolerated and the only major treatment-related side effects that appear are skin reactions at the injection site. Due to the relatively short half-life of anakinra, daily injection of the drug is required. This, in combination with the comparably high rates of injection-site reactions (ISRs) associated with the drug, can become a problem for the patient. The present review summarises published data concerning ISRs associated with Kineret and provides some explanations as to their cause. The objective is also to present some clinical experiences of how the ISRs can be managed.

A marked decline in the incidence of renal replacement therapy for amyloidosis associated with inflammatory rheumatic diseases - data from nationwide registries in Finland.

Risk for amyloidosis in rheumatic diseases is associated with a long-lasting inflammation. To assess possible changes in the incidence of terminal uraemia due to amyloidosis associated with rheumatic diseases on a nationwide basis, we scrutinised the files of the Finnish Registry for Kidney Diseases for patients suffering from amyloidosis associated with rheumatoid arthritis (RA), ankylosing spondylitis (AS) or juvenile idiopathic arthritis (JIA) over the period 1995–2008. The registry has an estimated 97–99% coverage of all patients accepted for renal replacement therapy (RRT) in the country. Data on the consumption of antirheumatic drugs were collected from two sources: the Social Insurance Institutions Drug Reimbursement Register, and the Sales Register of the National Agency for Medicines from the above period. Altogether 264 cases were identified. Two hundred twenty-nine of them had RA, 15 AS and 20 JIA. When the total annual number of new admissions to RRT varied between 20 and 37 at the end of 1990s, it was under half of that from 2002 onwards. Over this period, the number of users of low-dose methotrexate (MTX) has increased 3.6-fold, the drug being the most frequently used disease modifying anti-rheumatic drug in Finland. The present nationwide series is the first to show that the incidence of end-stage renal disease due to amyloidosis associated with rheumatic diseases is decreasing. An obvious reason for this is intensive anti-rheumatic drug therapy.

Clinicopathological Characterization and Genomic Aberrations in Subcutaneous Panniculitis-Like T-Cell Lymphoma

Subcutaneous panniculitis-like T-cell lymphomas (SPTLs) represent a rare, difficult-to-diagnose, and poorly characterized subtype of cutaneous T-cell lymphomas (CTCLs) affecting younger people more than the other CTCL forms. We performed a thorough clinical, immunohistological, and molecular analysis of nine Finnish SPTL patients. Specifically, we performed single-cell comparative genomic hybridization (CGH) from laser microdissected, morphologically malignant SPTL cells, as well as loss of heterozygosity (LOH) and fluorescence in situ hybridization (FISH) analysis for the NAV3 (neuron navigator 3) gene. CGH revealed large numbers of DNA copy number changes, the most common of which were losses of chromosomes 1pter, 2pter, 10qter, 11qter, 12qter, 16, 19, 20, and 22 and gains of chromosomes 2q and 4q. Some of the DNA copy number aberrations in SPTL, such as loss of 10q, 17p, and chromosome 19, overlap with those characteristic of common forms of CTCL (mycosis fungoides (MF) and Sezary syndrome (SS)), whereas 5q and 13q gains characterize SPTL. Allelic NAV3 aberrations (LOH or deletion by FISH), previously found in MF and SS, were identified in 44% of the SPTL samples. This study demonstrates that SPTL is also moleculocytogenetically a uniform entity of CTCL and supports the current World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) classification defining SPTL as a subgroup of its own.

High pleural fluid hyaluronan concentrations in rheumatoid arthritis

Previous studies have shown that high pleural fluid (Pf) hyaluronan (HYA) concentrations may be due not only to malignant mesothelioma but also to inflammatory diseases. The objective of this study was to evaluate Pf-HYA in various nonmalignant inflammatory pleural disorders. A radiometric assay was used to determine HYA in Pf and serum (S) of 126 patients, 12 of whom had rheumatoid arthritis (RA), 22 tuberculosis, 22 pneumonia, 41 lung cancer, 10 malignant mesothelioma and 19 congestive heart failure. Pf-HYA values were correlated with values for Pf-tumour necrosis factor (TNF)-alpha and Pf-interleukin (IL)-1beta, as determined by radioimmunoassay. The highest median Pf-HYA (125.6 mg x L(-1), range 0.04-386.5 mg x L(-1)) occurred in patients with malignant mesothelioma. Among patients with nonmalignant inflammatory diseases, significantly higher median Pf-HYA were observed in those with rheumatoid arthritis (64.2 mg x L(-1), range 25.8-106.9 mg x L(-1)) than in those with tuberculosis (25.5 mg x L(-1), range 14.9-57.1 mg x L(-1), p<0.0005) or pneumonia (20.9 mg x L(-1), range 9.5-129.4 mg x L(-1), p<0.005). There was no correlation between Pf-HYA and S-HYA. Pf-HYA correlated positively with Pf-TNF-alpha (r=0.62) and Pf-IL-1beta (r=0.52). High pleural fluid hyaluronan occurs not only in malignant mesothelioma, but also in certain nonmalignant inflammatory diseases, especially rheumatoid arthritis. One explanation for the increase in pleural fluid hyaluronan may be local production of proinflammatory cytokines, such as tumour necrosis factor-alpha and interleukin-1beta.