To describe a case of IgG4-related disease as a secondary autoimmune manifestation of Alemtuzumab

Alemtuzumab is a recombinant humanised monoclonal antibody used in the management of multiple sclerosis, that binds to CD52 antigen, present on the surface of most B and T lymphocytes. It has been associated with secondary immune-mediated conditions including thyroid disease, immune thrombocytopenia and anti-glomerular basement membrane glomerulonephritis.  Secondary autoimmunity is thought to occur as a result of imbalance in B and T cells during immune reconstitution, including hyper-repopulation of B cells.

IgG4-related disease is an immune-mediated fibro-inflammatory disorder that can affect multiple organs. Clinical presentations include lymphadenopathy, autoimmune pancreatitis, salivary gland involvement and retroperitoneal fibrosis.  The pathogenesis is hypothesized to be caused by CD4 T cell and B cell dysregulation leading to proliferation and tissue deposition of IgG4-positive plasma cells. Management options include steroids and rituximab, further supporting the role of B cells in its pathophysiology.

A 44 year old man with a fifteen year history of multiple sclerosis, who previously received treatment with Alemtuzumab (Lemtrada), presented with a left sided neck lump. His neurological status had been stable for 3 years. CT and PET imaging revealed cervical and axillary lymphadenopathy. Serum IgG subclasses were normal.  Excisional lymph node biopsies of two cervical lymph nodes showed changes consistent with IgG4-related lymphadenopathy. Flow cytometry of lymph node tissue did not detect an aberrant T cell or monoclonal B cell populations. The patient had no other systemic manifestations of IgG4-related disease. He is currently receiving treatment with oral steroids.

We describe a presentation of IgG4-related disease, not previously described to be associated with, but likely to be, the result of secondary autoimmunity following treatment with Alemtuzumab for multiple sclerosis.