ABSTRACT
BACKGROUND: Patients with a compromised immune system are at risk for converting from latent tuberculosis infection (LTBI) to active tuberculosis (TB) infection. Multiple sclerosis (MS) therapies may put individuals with LTBI at higher risk of TB. METHODS: Patients at the Beth Israel Deaconess Medical Center MS Clinic were screened for TB as part of routine testing with the QuantiFERON-TB Gold In-Tube (QFT-GIT) assay (Cellestis Ltd) from 2013 to 2017. Patients were tested either before or during immunomodulatory therapy. RESULTS: Four of 222 patients (1.8%; 95% CI, 0.1%-3.6%) had positive QFT-GIT results; three patients had risk factors for TB, having emigrated from TB-endemic countries or worked in the health care industry. Twenty-eight of 222 patients (12.6%) had an indeterminate assay result, and 75.0% of these occurred in patients taking dimethyl fumarate. Fingolimod, natalizumab, or anti-CD20 treatments showed 0% to 7.7% indeterminate results. CONCLUSIONS: The prevalence of LTBI was 1.8% in the Beth Israel Deaconess Medical Center MS Clinic. Not all LTBI cases were associated with known risk factors for TB. Screening for LTBI before starting immunosuppressive agents for MS could help prevent activation of TB. Dimethyl fumarate use is associated with indeterminate QFT-GIT results, possibly due to functional effects on lymphocytes and levels of cytokines, such as interferon gamma. In contrast, fingolimod use was rarely associated with indeterminate QFT-GIT results despite a high rate of lymphopenia in virtually all patients.
ABSTRACT
Rituximab, a monoclonal antibody to CD20, is an effective treatment for relapsing remitting multiple sclerosis (MS) reducing relapse rate by at least 50% over time. Although the mechanism for this clinical benefit is unclear, rituximab depletes circulating B cells, which can perform antigen presentation and stimulation of T cells. Another anti-CD20 drug, ocrelizumab, has recently been FDA approved to treat both relapsing remitting and progressive forms of MS. While long-term effects of ocrelizumab use are essentially unknown, long-term use of rituximab has been associated with the development of progressive multifocal leukoencephalopathy (PML) at an incidence of approximately 1/25,000 in non-MS conditions. Serostatus for JC virus (JCV), the causative agent for PML, is an important risk stratification tool for natalizumab, but its utility in other MS treatments is uncertain. We found that rituximab use was associated with a reduction in JCV antibody index values in MS patients. Reductions in immunoglobulins, IgM in particular, are seen in concert with JCV antibody reductions. Physicians should exercise caution when using JCV antibody indices to assess any risk of PML for patients on rituximab.
