Screening After Pneumococcal Disease May Reveal Undiagnosed Blood Cancer or Immune Disorders
Posted on 01 Oct 2026
Severe pneumococcal disease requiring hospitalization often presents as pneumonia, particularly in older adults and people with cancer or compromised immune function. Because M protein testing and antibody measurements are not routinely performed after severe infection, underlying disorders may go undetected. New findings show that invasive pneumococcal disease can reveal previously undiagnosed blood cancer and immunodeficiency.
Researchers at the University of Gothenburg evaluated screening for M protein and antibody levels in adults hospitalized with invasive pneumococcal disease. Researchers examined the immune systems of patients by measuring antibody levels and assessing the presence of M protein, which is described as a risk marker for blood cancer. The approach identified patients with markers or immune abnormalities that were considerably less common among matched controls without invasive pneumococcal disease.

The multicenter prospective study followed 156 individuals hospitalized with invasive pneumococcal disease in Region Västra Götaland, Sweden, between 2018 and 2023. The median patient age was 70 years, and the control group included 64 age- and sex-matched individuals. Among patients with pneumococcal disease, one in four had M protein detected in the blood.
Further evaluation led to seven diagnoses of blood cancer, while another 12 patients were diagnosed with conditions that can, in some cases, progress to blood cancer. Eight patients were also found to have immunodeficiency, and seven were able to begin preventive treatment against future severe infections.
The results suggest that screening for M protein and antibody levels in adults with invasive pneumococcal disease should be considered. The study was published in Scientific Reports and involved the University of Gothenburg, NU Hospital Group, and Södra Älvsborg Hospital.
The findings were also connected to research showing that pneumococcal serotypes covered by the Swedish childhood vaccination program have decreased sharply but have largely been replaced by other serotypes against which the vaccine offers no protection.
“Currently, these tests are not routinely performed after a severe pneumococcal infection. As a result, we may miss patients with undiagnosed blood cancer or immunodeficiency and therefore miss the opportunity to initiate treatment,” said Tor Härnqvist, a doctoral student at the University of Gothenburg, an infectious disease physician at NU Hospital Group and one of the lead authors.
“The results show that recommendations on pneumococcal vaccines for adults need to take into account which vaccines are used in children and which bacterial serotypes subsequently circulate in the community,” said Karin Bergman, a doctoral student in the same research group and an infectious disease physician at Södra Älvsborg Hospital.
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