Clinicogenomic factors of biotherapy immunogenicity in autoimmune disease: A prospective multicohort study of the ABIRISK consortium.

BACKGROUND: Biopharmaceutical products (BPs) are widely used to treat autoimmune diseases, but immunogenicity limits their efficacy for an important proportion of patients. Our knowledge of patient-related factors influencing the occurrence of antidrug antibodies (ADAs) is still limited. METHODS AND FINDINGS: The European consortium ABIRISK (Anti-Biopharmaceutical Immunization: prediction and analysis of clinical relevance to minimize the RISK) conducted a clinical and genomic multicohort prospective study of 560 patients with multiple sclerosis (MS, n = 147), rheumatoid arthritis (RA, n = 229), Crohn's disease (n = 148), or ulcerative colitis (n = 36) treated with 8 different biopharmaceuticals (etanercept, n = 84; infliximab, n = 101; adalimumab, n = 153; interferon [IFN]-beta-1a intramuscularly [IM], n = 38; IFN-beta-1a subcutaneously [SC], n = 68; IFN-beta-1b SC, n = 41; rituximab, n = 31; tocilizumab, n = 44) and followed during the first 12 months of therapy for time to ADA development. From the bioclinical data collected, we explored the relationships between patient-related factors and the occurrence of ADAs. Both baseline and time-dependent factors such as concomitant medications were analyzed using Cox proportional hazard regression models. Mean age and disease duration were 35.1 and 0.85 years, respectively, for MS; 54.2 and 3.17 years for RA; and 36.9 and 3.69 years for inflammatory bowel diseases (IBDs). In a multivariate Cox regression model including each of the clinical and genetic factors mentioned hereafter, among the clinical factors, immunosuppressants (adjusted hazard ratio [aHR] = 0.408 [95% confidence interval (CI) 0.253-0.657], p < 0.001) and antibiotics (aHR = 0.121 [0.0437-0.333], p < 0.0001) were independently negatively associated with time to ADA development, whereas infections during the study (aHR = 2.757 [1.616-4.704], p < 0.001) and tobacco smoking (aHR = 2.150 [1.319-3.503], p < 0.01) were positively associated. 351,824 Single-Nucleotide Polymorphisms (SNPs) and 38 imputed Human Leukocyte Antigen (HLA) alleles were analyzed through a genome-wide association study. We found that the HLA-DQA1*05 allele significantly increased the rate of immunogenicity (aHR = 3.9 [1.923-5.976], p < 0.0001 for the homozygotes). Among the 6 genetic variants selected at a 20% false discovery rate (FDR) threshold, the minor allele of rs10508884, which is situated in an intron of the CXCL12 gene, increased the rate of immunogenicity (aHR = 3.804 [2.139-6.764], p < 1 × 10-5 for patients homozygous for the minor allele) and was chosen for validation through a CXCL12 protein enzyme-linked immunosorbent assay (ELISA) on patient serum at baseline before therapy start. CXCL12 protein levels were higher for patients homozygous for the minor allele carrying higher ADA risk (mean: 2,693 pg/ml) than for the other genotypes (mean: 2,317 pg/ml; p = 0.014), and patients with CXCL12 levels above the median in serum were more prone to develop ADAs (aHR = 2.329 [1.106-4.90], p = 0.026). A limitation of the study is the lack of replication; therefore, other studies are required to confirm our findings. CONCLUSION: In our study, we found that immunosuppressants and antibiotics were associated with decreased risk of ADA development, whereas tobacco smoking and infections during the study were associated with increased risk. We found that the HLA-DQA1*05 allele was associated with an increased rate of immunogenicity. Moreover, our results suggest a relationship between CXCL12 production and ADA development independent of the disease, which is consistent with its known function in affinity maturation of antibodies and plasma cell survival. Our findings may help physicians in the management of patients receiving biotherapies.

New and enlarging white matter lesions adjacent to the ventricle system and thalamic atrophy are independently associated with lateral ventricular enlargement in multiple sclerosis.

OBJECTIVE: To investigate the association between new or enlarging T2-weighted (w) white matter (WM) lesions adjacent to the ventricle wall, deep grey matter (DGM) atrophy and lateral ventricular enlargement in multiple sclerosis (MS). METHODS: Patients derived from the Genetic Multiple Sclerosis Associations study. Lateral ventricles and DGM were segmented fully automated at baseline and 5 years follow-up using Automatic Lateral Ventricle delineation (ALVIN) and Multiple Automatically Generated Templates brain segmentation algorithm (MAgeT), respectively. T2w and T1w lesions were manually segmented. To investigate the association between lesion distance to the ventricle wall and the lateral ventricle volume, we parcellated the WM into concentric periventricular bands using FMRIB Software Library. Associations between clinical and MRI parameters were assessed in generalized linear models using generalized estimating equations for repeated measures. RESULTS: We studied 127 MS patients. Lateral ventricles enlarged on average by 2.4%/year. Patients with new/enlarging T2w WM lesions between baseline and follow-up at 5 years had accelerated lateral ventricular enlargement compared with patients without (p = 0.004). This was true in a multivariable analysis adjusted for age, gender, and whole brain atrophy. When looking at the T2w lesions in different periventricular bands, we found the strongest association between new/enlarging T2w lesions and lateral ventricle enlargement for WM lesions adjacent to the ventricle system (p < 0.001). Moreover, and indepedent of new/enlarging WM lesions, DGM atrophy was associated with ventricular enlargement. In a multivariable analysis, this was driven by thalamic atrophy (p < 0.001). CONCLUSION: New/enlarging T2w lesions adjacent to the ventricle system and thalamic atrophy are independently associated with lateral ventricular enlargement in MS.