Autoimmune or Inflammatory Diseases in 1,968 Consecutive Patients with Polycythemia Vera and Essential Thrombocythemia: Impact on Disease Outcome and Co-Morbidities

Background

Previous studies have suggested a higher prevalence of autoimmune or inflammatory diseases (AID) in patients with myeloproliferative neoplasms (MPN) (Haematologica 2010; 95:1216); more recent studies have suggested the absence of impact on tumor genetics or disease outcome (Leukemia 2023; 37:1741). In the current study, we conducted a before and after MPN diagnosis survey, in order to examine the prevalence of AID and its impact on overall and transformation-free survival as well as the risk of thrombosis or other co-morbidities, such as cancer.

Methods

The current study was conducted under an institutional review board approved minimum risk protocol. Diagnostic criteria were according to the International Consensus Classification (Blood 2022; 140:1200). AID was operationally classified as occuring before or after diagnosis, with the latter requiring first diagnosis occuring ≥3 months after MPN diagnosis. Non-driver mutations were screened by next-generation sequencing (NGS) and was available for 620 patients. Cox proportional hazard regression model was used for univariate and multivariable analysis. Kaplan-Meier plots were used for time-to-event assessment, using JMP Pro 17.0.0 software SAS Institute, Cary, NC, USA.

Results

The study population included 1,968 consecutive patients with polycythemia vera (PV; N=1,001) or essential thrombocythemia (ET; N=967), seen at the Mayo Clinic between 1970 and 2024. Mutation information was available in 620 patients. AID was diagnosed before or after MPN diagnosis in 157 (8%) patients, including 121 (6%) before and 43 (4%) after. 134 (85%) patients had history of only one AID while 23 (15%) had ≥2 AIDs. The most prevalent diagnoses included organ-specific AID (48 cases before and 21 after MPN diagnosis), inflammatory arthritis (37 before and 6 after), connective tissue diseases (17 before and 7 after) and inflammatory dermatosis (20 before and 4 after). For each one of these four categories, thyroid disorders (21 before and 6 after), rheumatoid arthritis (22 before and 2 after), antiphospholipid syndrome (8 before and 1 after), and psoriasis (11 before and 4 after) were the most frequent, respectively.

Patients with pre-MPN AID history were older (p=0.02) and were more likely to have ET vs. PV and be females (p<0.01); they were also more likely to present with venous (18% vs. 12%, p=0.04) but not arterial (p=0.2) thrombosis. Pre-MPN AID history was significantly associated with pre-MPN cancer history, with the latter including (25% vs 14%, p<0.01) or excluding (18% vs 10%, p<0.01) non melanoma skin cancers (NMSC). Pre-MPN AID history did not correlate with driver or other mutations (including TET2, ASXL1, DNMT3A), leukocyte, neutrophil, monocyte, or lymphocyte counts (p≥0.1 in all instances). Pre-MPN history of AID did not affect overall (p=0.08), myelofibrosis-free (p=0.3), leukemia-free (p=0.3), arterial thrombosis-free (p=0.9), or venous thrombosis-free (p=0.6) survival.

Second cancer-free survival (SC-FS), including (p<0.01) or excluding (p<0.01) NMSC, was negatively affected by pre-MPN history of AID. Multivariate analysis confirmed the independent detrimental effect of a pre-MPN history of AID (HR 1.7, p<0.01) on SC-FS; other independent risk factors for SC-FS were older age (p<0.01), male sex (p<0.01) and pre-MPN history of cancer (p<0.01). The association between pre-MPN history of AID and second cancer was also apparent when the latter was limited to lymphoproliferative neoplasms, although with borderline significance (p=0.08), which was further confirmed by adjusting for age and sex (p=0.09). Median time from MPN diagnosis to post-MPN AID was 9 years (range 1-23), which was similar between PV and ET (p=0.5). Post-MPN development of AID was more likely in females (HR 2.3; p=0.01) and in patients with pre-MPN history of AID (HR 4.8; p<0.01) or hypertension (HR 2.1; p<0.03). These risk factors remained significant during multivariable analysis of post-MPN AID-free survival.

Conclusions

The current study suggests an increased risk of post-MPN AID and second cancers, in patients with pre-MPN history of AID. The study also showed a significant association between pre-MPN history of AID and venous thrombosis at time of MPN diagnosis. These observations reinforce the widely suggested role of tumor-extrinsic inflammation in exacerbating MPN-intrinsic thrombophilia and the development of cancer.