Subtyping of juvenile idiopathic arthritis using latent class analysis. British Paediatric Rheumatology Group

OBJECTIVE: To use statistical techniques to identify underlying subtypes of juvenile idiopathic arthritis (JIA) that best explain the observed relationships of clinical and laboratory variables, and to compare the statistically derived subtypes with those defined by the International League of Associations for Rheumatology (ILAR) criteria and examine them for HLA associations. METHODS: Information on 572 patients diagnosed as having JIA was summarized by 10 clinical and laboratory categorical variables (age at onset, large joint involvement, small joint involvement, polyarthritis, symmetric arthritis, spinal pain, fever, psoriasis, antinuclear antibodies [ANA], and rheumatoid factor). Latent class analysis (LCA) was used to identify underlying ("latent") classes that explained the relationships among the observed variables. Statistical models incorporating 5-8 latent classes were applied to the data. RESULTS: The 7-class model was the most appropriate. Patterns of joint involvement and the presence of ANA were influential in determining latent classes. There was some correspondence between the latent classes and the ILAR categories, but they did not coincide completely. Significant differences between the latent classes were seen for 3 HLA haplotypes (DRB1*04-DQA1*03-DQB1*03, DRB1*13-DQA1*01-DQB1*06, and DRB1*08-DQA1*0401-DQB1*0402). CONCLUSION: LCA provides a novel approach to the task of identifying homogeneous subtypes within the umbrella of JIA. In further work, the identified latent classes will be examined for associations with other candidate genes and for differences in outcome.     

Cells expressing dendritic cell markers are present in the rheumatoid nodule

OBJECTIVE: To determine if dendritic antigen-presenting cells (DC) are present in rheumatoid nodules, as has been reported in the synovial lesions of rheumatoid arthritis. METHODS: Nodules (n = 14) were examined with monoclonal antibodies (Mab) recognizing the DC differentiation/activation markers CD83, CMRF44, and CMRF56 and an antibody recognizing the CD1a antigen present on epithelial tissue associated DC. Results. Cells expressing CMRF44 were common in rheumatoid nodules, comprising 22% of nucleated cells versus 13% in synovial membranes (n = 10). Cells positive for CD1a (5%) and CD83 (2%) were less common. A majority (86%) of CMRF44 positive cells were also positive for the macrophage marker CD14. This left a significant minority of putative DC that were single stained with CMRF44. CONCLUSION: Cells bearing DC markers are as frequent in the rheumatoid nodule as in the synovial lesions. A majority are "indeterminate" cells that are CD14 positive but a proportion are single stained putative DC. The lack of lymphoid collections containing DC and T and B lymphocytes in the nodule suggests that local presentation of antigen may not occur in the rheumatoid nodule, as is thought to be the case in synovial membranes containing lymphoid follicles. This difference could potentially be explained by different states of activation, and differentiation of DC within the 2 lesions.     

Plasma free captopril concentrations during short and long term treatment with oral captopril for heart failure

Plasma free captopril concentrations and haemodynamic response to captopril were studied in 20 patients with severe chronic heart failure. A 25 mg oral dose of captopril produced a 36% reduction in systemic vascular resistance, with individual responses varying from 13% to 64%. Mean systemic pressure fell by 20% and cardiac output rose 28%. The absorption of captopril was rapid. Peak plasma free captopril concentration occurred at 45 minutes after the dose and was followed by a smaller second peak. Peak plasma free captopril concentrations varied more than 20-fold but did not correlate with the maximal reduction in systemic vascular resistance. Elimination half life was seven hours. Fourteen patients were restudied after 1-2 months of captopril treatment and 12 showed symptomatic benefit. There was a sustained improvement in haemodynamic state and in non-invasive indices of myocardial function. During long term treatment the predose plasma free captopril concentration correlated well with dosage, but steady state captopril concentrations did not show a significant relation with haemodynamic response. On a dosage regimen of 25-50 mg three times daily the morning predose plasma free captopril concentration and plasma renin activity were relatively low and suggested that maximal inhibition of the renin-angiotensin system was not maintained throughout the dosage interval.     

Endoluminal gastroplication in children with significant gastro-oesophageal reflux disease

AIMS: To describe paediatric experience, and to assess complications and therapeutic effectiveness of the use of endoluminal gastroplication in children with gastro-oesophageal reflux disease (GORD) refractory to, or dependent on, proton pump inhibitors. METHODS: Seventeen (five male) consecutive children/adolescents (median (range) age 12.4 (6.1-15.9) years, median (range) weight 46.0 (16.5-87.5) kg) with GORD either dependent for more than 12 months on proton pump inhibitors or non-responsive to medical treatment underwent endoscopic gastroplication using a flexible endoscopic sewing device (EndoCinch). Three plications were placed in gastric tissue below the lower oesophageal sphincter. Drug dose requirement, pH measurements, daily symptom severity and frequency, and validated reflux (QOLRAD) and general gastrointestinal (GSRS) quality of life scores were compared before and after endoscopic gastroplication. RESULTS: All patients showed post-treatment improvement in symptom severity, frequency, and quality of life scores (p<0.0001). Three patients with recurrent symptomatic GORD had a repeat procedure within six weeks and did well subsequently. At up to 33 months of follow up (median 23), 14/17 patients remained off all antireflux medications, and 14/17 had maintained their symptomatic improvement. All pH parameters improved and had returned to normal values in 14/16 patients post-treatment and in 6/9 after one year of follow-up: in particular the reflux index had decreased from a median of 16.6% (0.9-67%) to 2.5% (0.7-15.7%) (p<0.0001) six weeks and 4.3% (2.2-20.6) (p<0.02) 12 months post-procedure. The only complication observed was gastric bleeding in one patient due to previously undiagnosed coagulopathy, which spontaneously resolved. CONCLUSIONS: Endoluminal gastroplication is an effective and safe procedure in children/adolescents with significant GORD refractory to, or dependent on, medical anti-GORD therapy.     

Effects of trimethoprim and sulphonamide preparations on the pituitary-thyroid axis of rodents

The effects on pituitary-thyroid function of the commonly prescribed anti-bacterial preparations co-trimoxazole and co-trifamole, and their component drugs, have been studied in the rat and compared to the changes caused by propylthiouracil. Co-trimoxazole and co-trifamole, in doses 20-fold in excess of a pharmacological dose administered for 10 days, produced marked changes in hormone levels consistent with blocking of hyperplastic goitre formation, were also demonstrated. Propylthiouracil produced less marked changes of thyroid hormone levels but higher levels of thyroid-stimulating hormone. Pharmacological doses of co-trimoxazole and co-trifamole and sulphamoxole, the sulphonamide component of co-trifamole, caused significant changes in thyroid hormone levels consistent with anti-thyroidal activity. In contrast, there was no evidence that trimethoprim, which is common to both preparations, or sulphamethoxazole, the sulphonamide component of co-trimoxazole, had an anti-thyroidal action, indeed, serum thyroxine levels were significantly increased at pharmacological dosage. We have concluded that the new commonly prescribed combination preparations retain the goitrogenic properties of the earlier sulphonamides.     

The effect of lithium therapy on parameters thought to be involved in the development of autoimmune thyroid disease

This study has considered the effects of primary affective disorders and lithium therapy on a number of factors thought to be important in the development of autoimmune thyroid disease. These factors were examined in (a) controls with no history of any such disorders; (b) patients with primary affective disorders treated with drugs other than lithium and (c) patients with primary affective disorders treated with lithium alone. Eight of 40 patients who were receiving lithium therapy were found to be positive for thyroid microsomal and/or thyroglobulin antibodies, compared to only 3/40 patients who were receiving some other form of treatment for their depression. Peripheral blood mononuclear cells from patients receiving lithium were found to have significantly reduced numbers of suppressor/cytotoxic T cells (P less than 0.05). In addition, suppressor T cells from these patients showed a significantly reduced response to stimulation with concanavalin A (P less than 0.01). These effects were greatest in patients found to be antibody positive. Increased B cell activity, as measured by increased IgG and IgM release following mitogen stimulation, was seen in patients receiving lithium and in those patients receiving other forms of treatment for their depression. This would suggest that the increase is a feature of primary affective disorders and is not due specifically to lithium treatment. It would appear from this study that lithium therapy induces antibody formation in susceptible individuals and this may ultimately lead to the development of thyroid disease.     

A functional promoter haplotype of macrophage migration inhibitory factor is linked and associated with juvenile idiopathic arthritis

OBJECTIVE: To establish linkage and replicate the association of macrophage migration inhibitory factor (MIF) with juvenile idiopathic arthritis (JIA). METHODS: Three hundred twenty-one Caucasian simplex families from the UK were genotyped for polymorphisms of MIF using SNaPshot ddNTP primer extension, or by a fluorescently labeled primer method, and capillary gel electrophoresis. The functional significance of the promoter polymorphisms was studied using luciferase-based reporter gene assays in human T lymphoblast and epithelial cell lines. RESULTS: MIF was linked and associated with JIA (P = 0.0016). Specifically, a 2-point promoter haplotype, CATT(7)-MIF-173*C, was found to be transmitted in excess (38 transmitted: 21 not transmitted) in the JIA patients. Conditional extended transmission disequilibrium test and pairwise extended transmission disequilibrium test predicted functional interaction between the 2 polymorphic positions. The interaction of the CATT repeat with MIF-173*G/C was found to be specific to the cell type. CONCLUSION: Replication of an association and linkage of MIF with JIA has been established. Functional interaction between the polymorphic positions on the linked haplotype has also been shown. The molecular mechanism of this interaction is currently being investigated.     

Lymphoid follicular proctitis

A heterogeneous group is formed by patients presenting with clinical features suggestive of inflammatory bowel disease limited to the rectum and whose rectal biopsies show lymphoid follicular hyperplasia of the mucosa. All these cases are traditionally considered as one variant of chronic ulcerative colitis, so-called ulcerative proctitis. Twenty such cases were critically assessed on clinical, endoscopic, and histologic grounds, as well as on response to treatment and follow-up data. While 11 patients showed clinicopathologic features consistent with typical chronic ulcerative colitis, the other nine patients appeared to form a different group, for which the term lymphoid follicular proctitis seemed justified. Lymphoid follicular proctitis was, overall, characterized by rectal bleeding, a congested and granular mucosa without ulceration, abnormal and coalescing hyperplastic lymphoid follicle s without acute inflammation, and failure to respond to local steroid therapy. The nature of lymphoid follicular proctitis is uncertain at present but seems unrelated to chronic ulcerative colitis.