Is There any Additional Benefit of Multiple Doses of Tocilizumab in COVID-19 Patients?

Many patients with coronavirus disease 2019 (COVID-19) have a hyperactive immune response (cytokine storm) which has been incriminated in multiorgan dysfunction (MOD). Interleukin-6 (IL-6) and granulocyte-macrophage colony-stimulating factor (GM-CSF) are the key cytokines involved in mediating systemic inflammation and triggering endothelial dysfunction. To limit these effects, IL-6 receptor inhibitors (IL6ri) have been used in COVID-19 patients. The best approach regarding the total number of doses in COVID-19 patients is still unclear. In this single-center retrospective study, we investigated if multiple doses of tocilizumab (TCZ) prevented deterioration of COVID-19 patients. Patients were divided into two cohorts based on the number of TCZ doses; cohort 1 (received one dose) and cohort 2 (received ≥ two doses). In both cohorts, all-cause-mortality was the primary outcome. Of 270 hospitalized patients with COVID-19, 81 patients received TCZ. Fifty patients received one dose of TCZ and 31 received ≥ two doses. All-cause-mortality in cohort 2 remained higher (41.9%) suggesting that there was no additional benefit of multiple doses of TCZ to prevent the primary outcome. In addition, multiple doses of TCZ did not change any other secondary outcome [(ICU admission, acute kidney injury (AKI), acute respiratory distress syndrome (ARDS), acute cardiac injury (ACI), thrombotic events, septic shock, and total hospital stay].

Interferon regulatory factors in human lupus pathogenesis.

Systemic lupus erythematosus (SLE) is a severe multisystem autoimmune disease that results from both genetic predisposition and environmental factors. Many lines of investigation support interferon alpha (IFN-α) as a causal agent in human lupus, and high levels of serum IFN-α are a heritable risk factor for SLE. Interferon regulatory factors (IRFs) are a family of transcription factors involved in host defense, which can induce transcription of IFN-α and other immune response genes after activation. In SLE, circulating immune complexes that contain nucleic acid are prevalent. These complexes are recognized by endosomal Toll-like receptors, resulting in activation of downstream IRF proteins. Genetic variants in the IRF5 and IRF7 genes have been associated with SLE susceptibility, and these same variants are associated with increased serum IFN-α in SLE patients. The increase in serum IFN-α related to IRF5 and 7 genotypes is observed only in patients with particular antibody specificities. This suggests that chronic stimulation of the endosomal Toll-like receptors by autoantibody immune complexes is required for IRF SLE-risk variants to cause elevation of circulating IFN-α and subsequent risk of SLE. Recently, genetic variation in the IRF8 gene has been associated with SLE and multiple sclerosis, and studies support an impact of IRF8 genotype on the IFN-α pathway. In summary, the SLE-associated polymorphisms in the IRF family of proteins seem to be gain-of-function variants, and understanding the impact of these variants on the IFN-α pathway in vivo may guide therapeutic strategies directed at the Toll-like receptor/IRF/IFN-α pathway in SLE.

Interferon alpha in systemic lupus erythematosus.

The pleiotropic cytokine interferon alpha is involved in multiple aspects of lupus etiology and pathogenesis. Interferon alpha is important under normal circumstances for antiviral responses and immune activation. However, heightened levels of serum interferon alpha and expression of interferon response genes are common in lupus patients. Lupus-associated autoantibodies can drive the production of interferon alpha and heightened levels of interferon interfere with immune regulation. Several genes in the pathways leading to interferon production or signaling are associated with risk for lupus. Clinical and cellular manifestations of excess interferon alpha in lupus combined with the genetic risk factors associated with interferon make this cytokine a rare bridge between genetic risk and phenotypic effects. Interferon alpha influences the clinical picture of lupus and may represent a therapeutic target. This paper provides an overview of the cellular, genetic, and clinical aspects of interferon alpha in lupus.

Significant CD4, CD8, and CD19 lymphopenia in peripheral blood of sarcoidosis patients correlates with severe disease manifestations.

BACKGROUND: Sarcoidosis is a poorly understood chronic inflammatory condition. Infiltration of affected organs by lymphocytes is characteristic of sarcoidosis, however previous reports suggest that circulating lymphocyte counts are low in some patients with the disease. The goal of this study was to evaluate lymphocyte subsets in peripheral blood in a cohort of sarcoidosis patients to determine the prevalence, severity, and clinical features associated with lymphopenia in major lymphocyte subsets. METHODOLOGY/PRINCIPAL FINDINGS: Lymphocyte subsets in 28 sarcoid patients were analyzed using flow cytometry to determine the percentage of CD4, CD8, and CD19 positive cells. Greater than 50% of patients had abnormally low CD4, CD8, or CD19 counts (p<4x10(-10)). Lymphopenia was profound in some cases, and five of the patients had absolute CD4 counts below 200. CD4, CD8, and CD19 lymphocyte subset counts were significantly correlated (Spearman's rho 0.57, p = 0.0017), and 10 patients had low counts in all three subsets. Patients with severe organ system involvement including neurologic, cardiac, ocular, and advanced pulmonary disease had lower lymphocyte subset counts as a group than those patients with less severe manifestations (CD4 p = 0.0043, CD8 p = 0.026, CD19 p = 0.033). No significant relationships were observed between various medical therapies and lymphocyte counts, and lymphopenia was present in patients who were not receiving any medical therapy. CONCLUSIONS/SIGNIFICANCE: Significant lymphopenia involving CD4, CD8, and CD19 positive cells was common in sarcoidosis patients and correlated with disease severity. Our findings suggest that lymphopenia relates more to disease pathology than medical treatment.

Genetic variation at the IRF7/PHRF1 locus is associated with autoantibody profile and serum interferon-alpha activity in lupus patients.

OBJECTIVE: Interferon-alpha (IFNalpha) is a heritable risk factor for systemic lupus erythematosus (SLE). Genetic variation near IRF7 is implicated in SLE susceptibility. SLE-associated autoantibodies can stimulate IFNalpha production through the Toll-like receptor/IRF7 pathway. This study was undertaken to determine whether variants of IRF7 act as risk factors for SLE by increasing IFNalpha production and whether autoantibodies are important to this phenomenon. METHODS: We studied 492 patients with SLE (236 African American, 162 European American, and 94 Hispanic American subjects). Serum levels of IFNalpha were measured using a reporter cell assay, and single-nucleotide polymorphisms (SNPs) in the IRF7/PHRF1 locus were genotyped. RESULTS: In a joint analysis of European American and Hispanic American subjects, the rs702966 C allele was associated with the presence of anti-double-stranded DNA (anti-dsDNA) antibodies (odds ratio [OR] 1.83, P = 0.0069). The rs702966 CC genotype was only associated with higher serum levels of IFNalpha in European American and Hispanic American patients with anti-dsDNA antibodies (joint analysis P = 4.1 x 10(-5) in anti-dsDNA-positive patients and P = 0.99 in anti-dsDNA-negative patients). In African American subjects, anti-Sm antibodies were associated with the rs4963128 SNP near IRF7 (OR 1.95, P = 0.0017). The rs4963128 CT and TT genotypes were associated with higher serum levels of IFNalpha only in African American patients with anti-Sm antibodies (P = 0.0012). In African American patients lacking anti-Sm antibodies, an effect of anti-dsDNA-rs702966 C allele interaction on serum levels of IFNalpha was observed, similar to the other patient groups (overall joint analysis P = 1.0 x 10(-6)). In European American and Hispanic American patients, the IRF5 SLE risk haplotype showed an additive effect with the rs702966 C allele on IFNalpha level in anti-dsDNA-positive patients. CONCLUSION: Our findings indicate that IRF7/PHRF1 variants in combination with SLE-associated autoantibodies result in higher serum levels of IFNalpha, providing a biologic relevance for this locus at the protein level in human SLE in vivo.

Ocrelizumab: a step forward in the evolution of B-cell therapy.

Recent advances in our understanding of B-cell dysregulation and its important link to autoimmunity have brought about a radical change in the management of autoimmune diseases. Over the past few years, encouraging data from several clinical trials of rituximab, a chimeric anti-CD20 antibody, have led to its approval for use in rheumatoid arthritis (RA). These data, regarding clinical efficacy, safety, improved patient-reported outcomes and cost-effectiveness with the use of rituximab in patients with RA, have led to the exploration of other agents targeting B-cell functions. Ocrelizumab, a novel humanized anti-CD20 antibody, has shown clinical efficacy and safety in a recently reported trial in patients with RA. Future clinical trials will help evaluate further the role of ocrelizumab in RA and its potential use in other autoimmune diseases. This review describes current understanding of B-cell therapy, the role of rituximab in the treatment of RA and the evolving role of ocrelizumab as a B-cell-targeted therapy.