Spinal IgG4-Related Hypertrophic Pachymeningitis with Spinal Cord Compression: Case Report and Literature Review.

BACKGROUND: Back pain is a leading reason for patients to seek medical attention. Although musculoskeletal causes are common, patients can also present with rarer etiologies. CASE DESCRIPTION: A 50-year-old man presented with 2 months of isolated upper back pain initially suspected to be secondary to overuse muscular strain. During the next 3 months, his pain worsened, and he developed lower extremity dysesthesia and subjective weakness, despite normal neurological examination findings. Nonrevealing laboratory workup included normal muscle enzymes, C-reactive protein, urinalysis, and human leukocyte antigen B27. Magnetic resonance imaging revealed a normal brain but a hypointense C7-T5 epidural mass, prompting a neurosurgical recommendation for laminectomy with evacuation of the suspected hematoma. His symptoms fully and promptly resolved after a 5-day course of prednisone 40 mg. When his symptoms recurred within 2 months, he underwent T4-T5 laminectomy with biopsy of a mass confluent with the dura mater. Initial pathological examination revealed fibrotic tissue of unclear etiology with polyclonal lymphoid infiltrate but no malignant cells, vasculitis, or granulomas. After months of recurrent, steroid-responsive symptoms, he presented to the rheumatology clinic. Repeat spinal magnetic resonance imaging demonstrated progression of epidural thickening with suspected spinal cord compression. Previous biopsy samples were then immunostained for IgG4, revealing focally dense IgG4-positive plasma cells, up to 29 cells per high power field, consistent with spinal IgG4-related hypertrophic pachymeningitis. He began rituximab therapy with a prednisone taper and demonstrated symptomatic and neurologic improvement with successful withdrawal from corticosteroids. CONCLUSIONS: To the best of our knowledge, the present case represents the 12th reported case of spinal IgG4-related hypertrophic pachymeningitis. An early diagnosis and treatment could prevent progression to permanent neurological impairment and functional disability.

Type I interferon and systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease associated with multiple immunologic abnormalities. Prominent among these is upregulation of type I interferon (IFN)?a powerful immune adjuvant. IFN is, in part, produced in SLE in response to autoantigens in the form of self-nucleic acids and their associated nuclear proteins. Sources of these autoantigens include apoptotic and necrotic cells as well as neutrophils undergoing a specific form of cell death called NETosis. Although plasmacytoid dendritic cells are the main producers of IFN-a, other cells are important regulators of this process. Both genetic and environmental risk factors play a role in the development and pathogenesis of SLE. Further highlighting the importance of IFN, candidate gene and genome-wide association studies have identified a number of genes involved in type I IFN pathways associated with SLE. In this review, 3 monogenic deficiencies that result in lupus-like phenotypes and several polygenic variants that have been consistently associated with SLE are highlighted, and the relationship of these genes to IFN-a production is discussed. Clinical associations of the type I IFN pathway and the use of IFN-blocking agents as therapeutic agents in SLE are also reviewed.