Study: Lymphoma Patients Recover Longer for Pneumonia

Individuals with lymphoma community-acquired pneumonia (L-CAP) have a prolonged recovery time and a more broadly dysregulated response, according to the authors of a study published in the Journal of Infection. Investigators of the study aimed to determine whether those with L-CAP, who were hospitalized but not critically ill, had poorer clinical outcomes. They authors noted that they hoped that the results can improve understanding of the clinical relevance of L-CAP.

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Investigators of the study included individuals aged 18 years and older from October 2016 until March 2020 in either the ELDER-BIOME study (NCT02928367) or the OPTIMACT study, according to the study authors. Individuals were included if admitted to the general hospital ward with a suspected acute respiratory tract infection with at least 1 respiratory symptom, such as new cough, chest pain, dyspnea, tachypnea, abnormal lung examination, or respiratory failure; 1 systemic symptom such as documented fever, leukocytosis, or leukopenia; and a chest X-ray or computed tomography scan. The patients were excluded if their hospital stay exceeded 48 hours in the previous 2 weeks, were in a resident in a long-term care facility, or had suspected aspiration pneumonia. Furthermore, some individuals were excluded if their lymphocyte counts were not measured upon presentation or if they suffered immune deficiency that affected the counts, according to the study authors.

There were 226 individuals who consented to be included, but 77 were excluded, with 44 due to missing lymphocyte counts. Of the 149 individuals included, 30.2% had a lymphocyte count greater than 0.1724x109 and were classified as L-CAP. These individuals were slightly older, had a lower body mass, and had increased disease severity of 2 of 4 of the disease severity scores compared to individuals with CAP, according to the study authors.

Investigators of the study found that clinical stability for those with L-CAP was longer at a median of 5 days compared to those with CAP at a median of 3 days, with the association still present after evaluating for competing risks mortality and hospital transfers. The findings were also robust when adjusting for age, sex, and disease severity.

In an analysis of a subset of 29 individuals, with 48.3% having L-CAP, investigators found, in those with L-CAP, there were “co-expression of human leukocyte antigen-DR and CD38, and higher expression of programmed death on CD4 T_CM cells,” according to the study authors. They stated this indicated that there was an activated exhausted CD4 T­_CM­ cell phenotype. Furthermore, they said the results showed there was no difference for CD4 T_EM cells, CD8 T_EM or CD8 T_CM cells.

Investigators found that there were no differences in the expression of memory T-cells in the expression of CD95/Fas or CD57 based on the results. This showed that L-CAP primarily affects the proportion of T cell subsets and activated CD4 T­_CM­ cell, but there is no association for advanced Fas-mediated apoptosis, according to the study authors.

Investigators also aimed to determine an association between lymphopenia and the patient’s response to pneumonia. They measured 34 biomarkers of the 4 pathophysiological domains to individual’s response, including inflammation, endothelium, coagulation, and checkpoints, according to the study authors. They found that those with L-CAP had higher interleukin (IL)-6, IL-8, IL-1RA, and IL-10 levels. Those patients also had a high level of endothelial cell and a higher angiopoietin-2:angiopoietin-1 ratio.
However, the study authors said there were no differences in coagulation activation, including soluble tissue facto or D-dimer, nor were there differences in plasma levels in checkpoint regulators. They added that the only exception was the levels of soluble P-selectin glycoprotein ligands, which was lower for those who had L-CAP compared to those with CAP.

References

Doeleman SE, Reijnders TDY, Joosten SCM, et al. Lymphopenia is associated with broad host response aberrations in community-acquired pneumonia. J Infect. 2024. doi:10.1016/j.jinf.2024.106131