Contributions
Abstract: EP1658
Type: Poster Sessions
Abstract Category: Therapy - Risk management for disease modifying treatments
Background: Disease modifying therapies (DMTs) for multiple sclerosis (MS) have diverse effects on the immune system, and several can affect the risk for certain infections such as tuberculosis (TB). Screening for TB is recommended prior to initiation of certain DMTs, but TB testing generally occurs in the setting of ongoing DMT use. Results of the serum Interferon Gamma Release Assay (IGRA) for TB screening may be affected by use of certain DMTs, but this has not been described.
Objectives: To determine the effects of different MS DMTs on serum-based TB screening via IGRA, and to evaluate the degree to which lymphopenia is related to an indeterminate test result.
Methods: We identified all patients with MS at our institution who underwent TB testing via IGRA between January 2016 and December 2017. We recorded the IGRA results, current DMT, and absolute lymphocyte count (ALC). The proportion of patients with indeterminate TB test results was compared across DMTs via Chi-squared testing. Logistic regression will be used to determine whether the odds of indeterminate testing are increased in the setting of lymphopenia.
Results: To date, we have collected overall test information on 955 patients with MS who underwent TB testing via IGRA: 96.3% (n = 920) tested negative, 1.0% (n = 10) tested positive, and 2.6% (n = 25) had indeterminate results. We have analyzed 70 of these records in detail, with collection of DMT and ALC information. 51.4% (n = 36) were on DMTs at the time of testing, including fingolimod, natalizumab, dimethyl fumarate, glatiramer acetate, and interferon beta. There was not a statistically significant difference in IGRA test results across DMT (chi-squared p-value = 0.91). However, at this time, we likely do not have a dataset sufficiently large enough to appropriately examine the association of certain DMTs or lymphopenia with an indeterminate IGRA result.
Conclusions: Overall, abnormal IGRA testing was uncommon in our MS population. Certain DMTs may affect the results and interpretation of serum TB testing via IGRA. Our small database thus far does not demonstrate consistent patterns of indeterminate results within certain DMTs or lymphocyte counts, likely due to its small size. However, based on clinical observation of this phenomenon, we anticipate more informative data as we continue to include more patients in the study. Ongoing analysis will examine the effects of lymphopenia in more detail.
Disclosure: Laura Baldassari has received personal fees for serving on a scientific advisory board for Teva, and receives funding via a Sylvia Lawry Physician Fellowship Grant through the National Multiple Sclerosis Society (#FP-1606-24540).
Mary A Willis serves on the speakers bureau for Genzyme, Biogen, Novartis, and Ipsen.
Abstract: EP1658
Type: Poster Sessions
Abstract Category: Therapy - Risk management for disease modifying treatments
Background: Disease modifying therapies (DMTs) for multiple sclerosis (MS) have diverse effects on the immune system, and several can affect the risk for certain infections such as tuberculosis (TB). Screening for TB is recommended prior to initiation of certain DMTs, but TB testing generally occurs in the setting of ongoing DMT use. Results of the serum Interferon Gamma Release Assay (IGRA) for TB screening may be affected by use of certain DMTs, but this has not been described.
Objectives: To determine the effects of different MS DMTs on serum-based TB screening via IGRA, and to evaluate the degree to which lymphopenia is related to an indeterminate test result.
Methods: We identified all patients with MS at our institution who underwent TB testing via IGRA between January 2016 and December 2017. We recorded the IGRA results, current DMT, and absolute lymphocyte count (ALC). The proportion of patients with indeterminate TB test results was compared across DMTs via Chi-squared testing. Logistic regression will be used to determine whether the odds of indeterminate testing are increased in the setting of lymphopenia.
Results: To date, we have collected overall test information on 955 patients with MS who underwent TB testing via IGRA: 96.3% (n = 920) tested negative, 1.0% (n = 10) tested positive, and 2.6% (n = 25) had indeterminate results. We have analyzed 70 of these records in detail, with collection of DMT and ALC information. 51.4% (n = 36) were on DMTs at the time of testing, including fingolimod, natalizumab, dimethyl fumarate, glatiramer acetate, and interferon beta. There was not a statistically significant difference in IGRA test results across DMT (chi-squared p-value = 0.91). However, at this time, we likely do not have a dataset sufficiently large enough to appropriately examine the association of certain DMTs or lymphopenia with an indeterminate IGRA result.
Conclusions: Overall, abnormal IGRA testing was uncommon in our MS population. Certain DMTs may affect the results and interpretation of serum TB testing via IGRA. Our small database thus far does not demonstrate consistent patterns of indeterminate results within certain DMTs or lymphocyte counts, likely due to its small size. However, based on clinical observation of this phenomenon, we anticipate more informative data as we continue to include more patients in the study. Ongoing analysis will examine the effects of lymphopenia in more detail.
Disclosure: Laura Baldassari has received personal fees for serving on a scientific advisory board for Teva, and receives funding via a Sylvia Lawry Physician Fellowship Grant through the National Multiple Sclerosis Society (#FP-1606-24540).
Mary A Willis serves on the speakers bureau for Genzyme, Biogen, Novartis, and Ipsen.