The incidence of tuberculosis infection in hematopoietic stem cell transplantation recipients: A retrospective cohort study from a center in Turkey.

Background: Immune-compromised patients with latent TB infection (LTBI) are at risk for TB reactivation and should receive prophylaxis. Whereas the tuberculin skin test (TST) has limitations particularly in immune-compromised patients.

Aims: This retrospective study was conducted to determine the incidence of TB infection in adult HSCT recipients whose preventive therapy for LTBI was determined according to the guidance of targeted TST.

Patients And Methods: Five hundred and fifty-eight consecutive HSCT recipients (287 autologous and 271 allogeneic) who survived ≥100 days post-transplantation were included in this analysis.

Results: Tuberculin skin test results were available in 493 of 558 transplants (88.3%). The incidence of negative TST was 54.5% (269 of 493 patients). One multiple myeloma patient with a history of TB and negative TST result and was not on INH prophylaxis developed reactivation of TB infection. None of the recipients under INH prophylaxis (151 of 558 transplants; 27.1%) and none of the 224 patients with TST ≥5 mm developed TB infection.

Discussion: Despite the limitations of being a retrospective analysis and variable prophylaxis thresholds of TST, there are some remarkable results of this analysis. We had no TB infection in the allogeneic HSCT recipients. The high incidence of negative TST results may be attributed to the underlying immune-deficiency. TST may not be a reliable guide for predicting TB reactivation risk in hematology patients.

Conclusion: Tuberculin skin test may have a high rate of false-negative and false-positive results in HSCT recipients. The general guidelines for targeted TST to guide treatment of LTBI may not apply to all regions and situations. More reliable methods are required to predict and treat LTBI in these specific conditions.