Mark Yates

Superresolution imaging of the cytoplasmic phosphatase PTPN22 links integrin-mediated T cell adhesion with autoimmunity

The tyrosine phosphatase PTPN22 redistributes from clusters to the leading edge in migrating T cells to inhibit integrin-mediated adhesion. Release the phosphatase! T cells need to move through the circulation, attach to endothelial cells, transmigrate into tissues, and stably interact with target cells. The phosphatase PTPN22 targets phosphorylated tyrosines in Src and Syk family kinases, many of which are phosphorylated and activated in migrating T cells in response to the binding of the integrin LFA-1 to its ligand ICAM-1. Burn et al. used superresolution microscopy to show that PTPN22 formed clusters in nonmigrating T cells, which were dispersed in T cells that migrated on surfaces coated with ICAM-1. Freed from these complexes, PTPN22 interacted with its targets near the front of the migrating T cell, which inhibited LFA-1 signaling. In contrast, clusters containing the PTPN22 R620W mutant, a variant that is associated with autoimmune diseases, failed to disaggregate in migrating T cells, and thus, LFA-1 clustering and signaling were not inhibited. Together, these data suggest how a mutation associated with autoimmunity dysregulates T cell adhesion and migration. Integrins are heterodimeric transmembrane proteins that play a fundamental role in the migration of leukocytes to sites of infection or injury. We found that protein tyrosine phosphatase nonreceptor type 22 (PTPN22) inhibits signaling by the integrin lymphocyte function-associated antigen–1 (LFA-1) in effector T cells. PTPN22 colocalized with its substrates at the leading edge of cells migrating on surfaces coated with the LFA-1 ligand intercellular adhesion molecule–1 (ICAM-1). Knockout or knockdown of PTPN22 or expression of the autoimmune disease–associated PTPN22-R620W variant resulted in the enhanced phosphorylation of signaling molecules downstream of integrins. Superresolution imaging revealed that PTPN22-R620 (wild-type PTPN22) was present as large clusters in unstimulated T cells and that these disaggregated upon stimulation of LFA-1, enabling increased association of PTPN22 with its binding partners at the leading edge. The failure of PTPN22-R620W molecules to be retained at the leading edge led to increased LFA-1 clustering and integrin-mediated cell adhesion. Our data define a previously uncharacterized mechanism for fine-tuning integrin signaling in T cells, as well as a paradigm of autoimmunity in humans in which disease susceptibility is underpinned by inherited phosphatase mutations that perturb integrin function.

SAT0676 (SERONEGATIVE) males show better eular treatment response than females in newly diagnosed rheumatoid arthritis (RA)

Background Gender has been reported to play a role in attainment of RA remission (1), but the data are inconsistent. The impact of gender in early RA therefore warrants further investigation. Objectives To assess the impact of gender on early RA outcomes. Methods An audit, designed as a national prospective longitudinal observational study, was conducted to assess early RA care. All NHS providers in England and Wales were required to participate. Follow up data were captured over 3 months for subjects with a diagnosis of RA. Logistic regression was used to estimate associations between gender and DAS-28 response. Smoking status, baseline disease activity, age, antibody status, symptom duration, referral times, and treatment were considered in multivariate models. Results 136 of 146 eligible trusts submitted data. 11,752 subjects consented, 5,622 were diagnosed with RA. DAS-28 response was available for 2234/5622 (39.7%). Male patients had a similar 3 month improvement in their DAS-28 to females, despite having a lower mean baseline score. Male gender associated with a higher rate of good EULAR response (DAS improvement >1.2, follow up DAS <3.3), with an adjusted odds ratio of 1.42 (CI 1.17–1.72). There were no differences between the genders in their treatment use or in other aspects of care including speed of referral (Table 1). The male excess in good EULAR response was more pronounced in seronegative compared with seropositive RA (1.98 (CI 1.4–2.8) compared to 1.21 (0.96–1.53)).Table 1 Male Female P value N=786 N=1432 Age mean (SD) 61.6 (13.2) 58.1 (15.1) 0* Smoker % 28 21 0** Social deprivation decile mean (SD) 5.4 (2.9) 5.5 (2.9) 0.6** Seropositive % 66 70 0.05** symptom duration days 230 226 0.8* Baseline DAS-28 mean (SD) 5.1 (1.4) 5.3 (1.3) 0.03* FU DAS-28 mean (SD) 3.3 (1.5) 3.6 (1.5) 0.0001* Change in DAS-28 mean (SD) 1.8 (1.7) 1.7 (1.6) 0.08* EULAR good response % 43.4 36.7 0.002** Timely referral % 16 15 0.3** Timely rheumatology assessment % 39 39 0.7** Steroids commenced at baseline % 87 86 0.7** Early DMARD treatment % 28 27 0.9** Any DMARD prescribed within 6 weeks % 70 70 0.9** DMARD choice; Methotrexate monotherapy % 69 68 0.6** DMARD choice; combination therapy % 44 44 0.8** *t-test **chi-squared. Social deprivation decile from deprivation rank calculated via super output area. Conclusions The association of male gender with improved outcomes in early RA has not been shown before in a national cohort of this scope. Previous work suggests seronegative individuals achieve greater clinical response (2), here we present this effect amplified in men. To the authors knowledge this is a new finding. This is likely multifactorial, with biological effect of gender, greater diagnostic uncertainty and higher reporting of global scores in women all potentially playing a role. References Svensson B, Andersson M, Forslind K, Ajeganova S, Hafstrom I. Persistently active disease is common in patients with rheumatoid arthritis, particularly in women: a long-term inception cohort study. Scan rheum. 2016;45(6):448–55. Barra L, Pope JE, Orav JE, et al. Prognosis of seronegative patients in a large prospective cohort of patients with early inflammatory arthritis. Rheum. 2014;41(12):2361–9. Disclosure of Interest None declared

SAT0699 Rapid assessment predicts disease activity improvement in newly diagnosed rheumatoid arthritis (RA)

Background Early intervention in RA is associated with improved outcomes in randomised trials. UK guidelines stipulate that those with suspected RA are assessed by a rheumatologist within 3 weeks of referral. However, there are limited real world data confirming the value of early assessment. Previous work suggests social deprivation predicts severe disease at presentation and a worse clinical course (1). The impact of deprivation in early assessment has yet to be characterised on a national level. Objectives To investigate if rapid assessment in secondary care associates with achieving a good treatment response, and if this is modulated by social deprivation. Methods An audit, designed as a prospective longitudinal observational study, was conducted to assess early RA care. All NHS providers in England and Wales were required to participate. Follow up data were captured over 3 months for subjects with a diagnosis of RA. Rheumatologist assessment within 3 weeks of referral was the predictor variable. The primary outcome was good EULAR DAS response; the secondary outcome was meaningful improvement in RAID score. Logistic regression was used to estimate for associations. Confounders including age, gender, baseline DAS28 and RAID scores were considered in analyses. The index of multiple deprivation (IMD) rank was calculated for each individual based on super-output geographical areas. The IMD rank was then stratified into quintiles and included as a confounder. Results 136 of 146 eligible trusts submitted data. 11,752 subjects consented, 5,622 were diagnosed with RA. 94/5622 (1.7%) had incomplete assessment date data. DAS28 response was available for 2234/5622 (39.7%), and RAID response for 901/5622 (16%). The table shows baseline characteristics and response for subjects with complete data. Assessment within 3 weeks associated with a significantly greater improvement in DAS28 and RAID scores, with an adjusted odds ratio for a good EULAR response 1.38 (1.15–1.66) and meaningful RAID reduction 1.44 (1.03–2.02). Seen within 3 weeks Not seen within 3 weeks P Value N 878 1356 Age (SD) 58.6 (14.8) 59.9 (14.1) 0.046* Female (%) 65.2 64.4 0.24** White British (%) 86 88.9 0.015** Current smoker (%) 21.1 25.4 0.009** IMD quintile mean 3 3 DAS28 EULAR good response (%) 43.7 35.8 0.001** DAS28 EULAR moderate response (%) 31.2 35 DAS28 EULAR no response (%) 25.1 29.1 Achieved MCID† RAID (%) 48 40.7 0.026* *t-test; **chi-squared. †Minimal clinically important difference (reduction by 50% or absolute reduction >3). Conclusions These real world data confirm rapid assessment significantly predicts treatment response, in terms of clinical disease activity and patient reported outcomes. Amongst those who were assessed within 3 weeks of referral, an additional 8% achieved a good EULAR response. The association with RAID response was strengthened when social deprivation was included as a confounder. The relationship between IMD and RAID response appears to be non-linear and requires further study. References ERAS Study Group. Socioeconomic deprivation and rheumatoid disease:What lessons for the health service? Ann rheum dis. 2000;59(10):794–9. Disclosure of Interest None declared