Clinical Research On Hematological Malignancies Complicated With Active Tuberculosis:A Single Center Experience In China

Large sample clinical retrospective studies about infection caused by Mycobacterium tuberculosis (TB) among the patients with hematological malignancies(HM) have rarely been investigated. The aim of this study was to analyze the clinical features and treatment of the HM patients complicated with active TB.

HM patients complicated with active TB in our single center between January 2006 and December 2012 were retrospectively studied.

Up to 4712 HM patients have been diagnosed and treated, sixty-six patients of which were confirmed with active TB, as a result, the prevalence of active TB in HM patients was 1.40%（pulmonary TB 1.10%, extra-pulmonary TB 0.30%）. The prevalence of various subgroups of HM patients were as following: AML 2.02%、ALL 1.22%、CML and CLL 1.38%、MDS 1.85%、Lymphoma 0.58%、MM 1.15%、SAA 1.66%. In addition, the patients with AML had a significantly higher incidence of TB disease than other subtypes of HM (2.02% vs 1.13%, P=0.017).

Most of the patients were male patients, with a male：female ratio of 2.67：1, median age 41 years old (range 14 to 78). Among them, the median age of extra-pulmonary TB group was younger than the pulmonary TB group (38 vs 44.5 years), so did the neutropenia group when compared with the non-neutropenic group (38 vs 48years). Fifty-two cases（80.3%）were pulmonary TB, 14 cases were（21.2%）extra-pulmonary TB and other 8 cases（12.1%）presented as both pulmonary and extra-pulmonary TB. In addition, atypical clinical manifestations, such as high fever, cough, malnutrition, pleural effusion were the main clinical manifestations in our patients.

Twenty-nine patients(43.9%) were diagnosed with definitely etiological evidence while other 37 patients（56.1%）were diagnosed clinically.  The extra-pulmonary TB group had a higher PPD test positive rate than that of the pulmonary TB group（85.7% vs 46.2%，P=0.014）; The main characteristics of chest CT were as follows：mediastinal or hilar lymphadenopathy, nodules, fibrous cord shadow, pleural effusion. The specificity and sensitivity of T-SPOT.TB test were 100% and 83.3% when 14 patients were checked by this test, which was a helpful tool for diagnosis. In addition, finding more ways to put the lesions under pathological examination was beneficial to the diagnosis of extra-pulmonary TB.

The efficacy of first-line anti-tuberculosis chemotherapy was 87.3%, but the extra-pulmonary TB group presented a lower response rate than the pulmonary one (64.3% vs 90.4%, P=0.01).Patients with fever needed a median 8–day（3～26 days）anti-tuberculosis chemotherapy before their temperature dropped to normal range ,meanwhile the patients who had suffered from lymphnode TB needed 12 days（7～28 days）to get their enlarged lymphnode shrink. The total course in order to cure TB was around 12 months. Six cases were dead due to TB with a 9.1% attributable mortality, moreover, the rate was especially higher in the extra-pulmonary TB group（28.6% vs 3.8%，P=0.016）.

Our study demonstrated that the potential risk factors of HM patients complicated with active TB were as follows: age less than 50 years old, male patients, three months within the diagnosis of HM, intravenous use of immunosuppressive drugs. In addition, age less than 50 years old was the only risk factor of extra-pulmonary TB.

The prevalence of HM patients complicated with active tuberculosis is higher than the general population. Definitely etiological evidence was not easy to collect, which made it difficult for the diagnosis and differential diagnosis of TB. A few characteristics such as age less than 50 years old, male patients, three months within the diagnosis of HM, intravenous use of immunosuppressive drugs were the potential risk factors of HM patients with TB. It was clearly showed that these patients demonstrated good overall responses to the first-line anti-tuberculosis chemotherapy, with relatively lower attributable mortality and good outcome.

No relevant conflicts of interest to declare.