Chronic Borrelia burgdorferi infection triggers NKT lymphomagenesis

Risk of haematologic cancers among individuals tested for Borrelia burgdorferi antibodies, and Borrelia burgdorferi seropositive individuals: a nationwide population-based matched cohort study

OBJECTIVES

In a nationwide, matched cohort study, we aimed to investigate risks of haematologic cancers among individuals tested for Borrelia burgdorferi (Bb) antibodies, and among serum Bb seropositive individuals.

METHODS

We identified all Bb seropositive individuals in Denmark (1993-2020) (n = 52 200) and constructed two age- and sex-matched comparison cohorts: (a) Bb seronegative controls (n = 104 400) and (b) background population controls (n = 261 000). We calculated short-term OR (aOR) (<1 month of study inclusion), and long-term hazard ratios (aHR) (>1 month after study inclusion) adjusted for age and sex. We stratified seropositive individuals on only Bb-IgM seropositive (n = 26 103), only Bb-IgG seropositive (n = 18 698), and Bb-IgM-and-IgG seropositive (n = 7399).

RESULTS

Compared with the background population, individuals tested for Bb antibodies had increased short-term (aOR: 12.6, 95% CI: 10.1-15.6) and long-term (aHR: 1.3, 95% CI: 1.2-1.4) risk of haematologic cancers. The Bb seropositive individuals had no increased risk of haematologic cancers compared with those who tested negative for Bb, except that Bb-IgM-and-IgG seropositive individuals had increased long-term risk of chronic lymphatic leukaemia (aHR: 2.0, 95% CI: 1.2-3.4).

DISCUSSION

Our results suggest that Bb antibody testing is included in the work-up of unspecific symptoms preceding diagnosis of haematologic cancers. Bb-IgM-and-IgG seropositivity was associated with a two-fold increased long-term risk of chronic lymphatic leukaemia, which warrants further investigation.

Chronic T cell receptor stimulation unmasks NK receptor signaling in peripheral T cell lymphomas via epigenetic reprogramming

Peripheral T cell lymphomas (PTCLs) represent a significant unmet medical need with dismal clinical outcomes. The T cell receptor (TCR) is emerging as a key driver of T lymphocyte transformation. However, the role of chronic TCR activation in lymphomagenesis and in lymphoma cell survival is still poorly understood. Using a mouse model, we report that chronic TCR stimulation drove T cell lymphomagenesis, whereas TCR signaling did not contribute to PTCL survival. The combination of kinome, transcriptome, and epigenome analyses of mouse PTCLs revealed a NK cell-like reprogramming of PTCL cells with expression of NK receptors (NKRs) and downstream signaling molecules such as Tyrobp and SYK. Activating NKRs were functional in PTCLs and dependent on SYK activity. In vivo blockade of NKR signaling prolonged mouse survival, demonstrating the addiction of PTCLs to NKRs and downstream SYK/mTOR activity for their survival. We studied a large collection of human primary samples and identified several PTCLs recapitulating the phenotype described in this model by their expression of SYK and the NKR, suggesting a similar mechanism of lymphomagenesis and establishing a rationale for clinical studies targeting such molecules.

Diagnostic center for primary care patients with nonspecific symptoms and suspected cancer: compliance to workflow and accuracy of tests and examinations

OBJECTIVE

To evaluate compliance to workflow and accuracy of tests in Sweden's first fast-track referral pathway for patients with nonspecific symptoms and suspected cancer (SCAN).

DESIGN

Prospective cohort study with consecutive inclusion of patients referred to the diagnostic center (DC).

SETTING

Patients with nonspecific symptoms were examined in primary care according to a protocol including two test packages and diagnostic imaging. If symptoms were not explained, patients were referred to the DC and a DC-test package was taken. At the DC, further investigations resulted in diagnosis/no diagnosis.

SUBJECTS

A total of 290 patients, median age 69 years (interquartile range [IQR] 59-76), 48% men, participated. A total of 64 (22%) were diagnosed with cancer, 186 (64%) with non-malignant disease and 40 (14%) had no new disease.

MAIN OUTCOME MEASURE

Compliance was estimated by percentage of compulsory tests taken. Test accuracy was assessed by likelihood ratios (LRs) regarding cancer.

RESULTS

A total of 23 (8%) patients had taken both primary care packages, whereas 150 (52%) patients went through entire diagnostic imaging. Abnormal pulmonary X-ray, peak expiratory flow (PEF) and calcium had the highest LRs in primary care (3.5; 3.2; 2.7). A total of 105 (36%) took the complete DC-package, of which bilirubin and cytomegalovirus had the highest LRs (11.5; 10.9). The median number (IQR) of abnormal primary care tests was 5 (3-6) for cancer, 3 (2-6) for other diagnoses and 1 (0-3) for no diagnosis.

CONCLUSIONS

Compliance to test packages in primary care was low, which warrants review of the workflow. Few single tests had high accuracy regarding cancer, but the number of abnormal tests can provide guidance in complicated investigations of suspected malignancies.KEY POINTSFast-track referral pathways for patients with nonspecific serious symptoms have been implemented in several countries and are part of the national cancer strategy in all of Scandinavia.Compliance with compulsory tests in primary care was modest in this study; 8% of the patients had taken the entire compulsory test packages.Few single compulsory tests had high accuracy regarding subsequent cancer, which warrants a review of tests and examinations. However, patients diagnosed with cancer had a higher number of abnormal test results compared to the other groups.

Bacterial infection and non-Hodgkin's lymphoma

One quarter of all cancers are linked to infectious diseases. The link between viral infection and cancer has been widely studied, but few reports have focused on the carcinogenic role of bacterial infection. Nonetheless, Helicobacter pylori, Chlamydia psittaci, Coxiella burnetii, Borrelia burgdorferi and Campylobacter jejuni are bacteria that can be associated with non-Hodgkin's lymphoma (NHL), the most common haematologic malignancy. Here, we review the evidence in favour of a link between these bacterial infections and NHL. Sero-epidemiological observation makes it possible to identify a link between H. pylori, C. burnetii, B. burgdorferi infection and NHL. Helicobacter pylori, Chlamydia psittaci, Coxiella burnetii, Borrelia burgdorferi and Campylobacter jejuni could be identified in NHL tissue samples at the site of chronic inflammation, where B and T lymphocytes are attracted to participate in follicle formation. Lymphoma remissions have been observed under antimicrobial therapies supporting the carcinogenic contribution of bacteria. If the theory of causality is characterized by the lack of universal criteria for establishing a causal link between two diseases, infection and lymphoma, epidemiological, clinical, and histological evidences reported here, should lead clinicians to pay attention to these infectious agents, to detect early lymphoma transformation.