Incidence of tuberculosis after bone marrow transplantation in a single center from Turkey

Tuberculosis (TB) is generally seen in immunodeficient states and its incidence would be expected to increase after hematopoietic stem cell transplantation (SCT), particularly in the allogeneic setting. However, recent reports from developed countries did not support this hypothesis. Turkey is one of the countries where the disease is endemic. Over a period of 10 years two cases of TB among 120 allogeneic and 65 autologous bone marrow or peripheral blood SCT were encountered. The first patient was a 42-year-old male with acute nonlymphoblastic leukemia (ANLL) who underwent allogenic SCT from his HLA-identical sister in first remission. His early post transplant period was unremarkable and showed no clinical acute or chronic graft versus host disease (GVHD). His chest X-ray and CT scan revealed alveolar infiltrate of the left apical lobe one year after the procedure and sputum showed acid-fast bacilli, later identified as Mycobacterium tuberculosis. He was put on combination chemotherapy. He is now well and disease-free 30 months after transplant with no complaints of pulmonary TB. The second patient with chronic phase CML underwent allogeneic peripheral SCT from his HLA-identical sister. He suffered from grade II acute and extensive chronic GVHD partially treated with immunosuppressive therapy. He showed pulmonary TB 15 months after transplantation. He is still on combination chemotherapy. Although our numbers are small, the annual incidence of TB after SCT is 1.1% (2/185) which is nearly 30 to 40 times higher than the incidence of TB in the general Turkish population. In other words, an immunosuppressive state after allogenic SCT seems to increase the risk of TB in Turkey. In conclusion, TB should be considered in the differential diagnosis of unexplained infections after SCT, especially in countries, where the disease is endemic.