A new study based in Sweden suggests that myeloproliferative neoplasms (MPNs) may be associated with an enhanced risk of infection. The study was published in the journal Leukemia.

Although hematologic malignancies are often associated with a greater risk of infection, infection risk with MPNs has been less characterized, according to the study investigators.

The study was a matched cohort study evaluating infection rates in 8363 patients with MPN in comparison with those of 32,405 population-based controls (n=32,405). Patients with MPN were identified from the Swedish Cancer Register, and each patient was matched with 4 controls from the Register of Total Population for comparisons. Infections leading to hospital admissions were the primary outcome of interest.

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The hazard ratio (HR) for having any infection was 2.0 times higher with MPN than without (95% CI, 1.9-2.0). By type of infection, the HRs with MPNs were 1.9 (95% CI, 1.8-2.0) for bacterial infections, 2.1 (95% CI, 1.9-2.3) for viral infections, and 2.9 (95% CI, 2.5-3.5) for fungal infections. For sepsis, the HR with MPNs was 2.6 (95% CI, 2.4-2.9).

The subtype of MPN also appeared to be related to the level of infection risk. Although infection risk was elevated for each, it was highest with primary myelofibrosis (HR, 3.7; 95% CI, 3.2-4.1). Polycythemia vera and essential thrombocythemia both had HRs of 1.7.

In an analysis of therapies for patients with MPN diagnosed between the years of 2006 and 2013, the study investigators found no significant association between infection risk and whether MPN was untreated or treated with hydroxyurea, interferon-α, or anagrelide.

“In summary, we present clinically important findings that patients with MPN, particularly those with [primary myelofibrosis], are at a significantly higher risk of severe infections compared with population controls,” the study investigators concluded in their report.


Landtblom AR, Andersson TML, Dickman PW, et al. Risk of infections in patients with myeloproliferative neoplasms — a population-based cohort study of 8363 patients [published online June 16, 2020]. Leukemia. doi: 10.1038/s41375-020-0909-7