Presence of active MRI lesions in patients suspected of non-radiographic axial spondyloarthritis with high disease activity and chance at conversion after a 6-month follow-up period.

OBJECTIVES: The primary aim is to evaluate signs of inflammation on MRI of sacroiliac joints (SIJ)/spine in inflammatory back pain (IBP) patients suspected of nr-axSpA with high disease activity. Secondary aims are to describe the onset of new inflammatory lesions at MRI after 6 months and to evaluate gender differences in the presence of inflammation. METHOD: Consecutively, patients with IBP with at least two spondyloarthritis features, high disease activity (BASDAI ≥ 4), and who were TNFi naïve, had a MRI of SIJ and spine. In the absence of active lesions, MRI was repeated after 6 months. MRI images were scored according to the Spondyloarthritis Research Consortium of Canada method. RESULTS: Sixty-nine patients were included (53% female), of whom 39% showed signs of inflammation at the first MRI: 30.9% of the SIJ, 19.1% of the spine and 2.4% at both sites, irrespective of the CRP levels. Males more often showed inflammatory signs at the MRI of the SIJ and spine compared with females (45.5% vs. 33.3%). Consistently, the median SPARCC score was higher in males: for SIJ 14.0 (IQR 2.3-25.0) and for spine 11.5 (IQR 8.5-25.6). Only one patient (4.7%) without baseline inflammatory signs showed active lesions of SIJ after 6 months. CONCLUSIONS: Almost 40% of the IBP patients suspected of nr-axSpA, with high disease activity, showed inflammatory lesions on MRI of SIJ and/or spine, which occurred more often in males compared with females. In the majority (95.3%), an MRI without inflammatory lesions remained negative after 6 months despite high disease activity.Key Points• Forty percent of inflammatory back pain patients with high disease activity showed inflammatory signs on MRI of the SIJ and/or spine.• Only 4% of baseline MRIs without inflammatory signs at baseline conversed to an MRI with inflammatory signs after 6 months.• Male inflammatory back pain patients with high disease activity showed more often inflammatory signs on MRI compared with females.

The role of human leukocyte antigens as predisposing and/or protective factors in patients with idiopathic thrombotic thrombocytopenic purpura.

Fifty-four adult German patients suffering from idiopathic thrombotic thrombocytopenic purpura (TTP) have been examined for HLA class II. All patients presented autoantibodies against ADAMTS13 and ADAMTS13 activity levels <5%. Blood samples have been analyzed for HLA-DRB1 and DQB1 alleles using sequence-specific primer PCR and sequence-specific oligonucleotide PCR. Reference data of German bone marrow and blood donors were obtained from www.allelefrequencies.net. The results were evaluated employing two-sided binomial tests, and p values were corrected using the Benjamini-Hochberg procedure. A significant accumulation for DQB1*02:02 (p < 0.001) and DRB1*11 (p = 0.003) was found within the patient group. Twenty percent (DQB1*02:02) or 48.1% (DRB1*11) of TTP patients were tested positive for the particular HLA antigen compared to 1.2% (DQB1*02:02) or 23.5% (DRB1*11) in the control group. A tendency for a reduced occurrence of HLA-DRB1*04 was revealed (7.4% in patients compared to 24.6% in controls). An association between the HLA antigens DQB1*02:02 and DRB1*11 and disease susceptibility for idiopathic TTP has been found. A higher risk for disease outbreak within persons carrying the mentioned alleles can be assumed. The reduced occurrence of HLA-DRB1*04 in TTP patients indicates a possible protective effect of this HLA allele in disease development.