Lymphopenic Community Acquired Pneumonia (L-CAP), an Immunological Phenotype Associated with Higher Risk of Mortality

The role of neutrophil and lymphocyte counts in blood as prognosis predictors in Community Acquired Pneumonia (CAP) has not been adequately studied. This was a derivation-validation retrospective study in hospitalized patients with CAP and no prior immunosuppression. We evaluated by multivariate analysis the association between neutrophil and lymphocyte counts andmortality risk at 30-days post hospital admission in these patients. The derivation cohort (n=1550 patients) was recruited in a multi-site study. The validation cohort (n=2846 patients) was recruited in a single-site study. In the derivation cohort, a sub-group of lymphopenic patients, those with b724 lymphocytes/mm3, showed a 1.93-fold increment in the risk ofmortality, independently of the CURB65 score, critical illness, and receiving an appropriate antibiotic treatment. In the validation cohort, patients with b724 lymphocytes/mm3 showed a 1.86-fold increment in the risk of mortality. The addition of 1 point to the CURB-65 score in those patientswith b724 lymphocytes/mm3 improved the performance of this score to identify non-survivors in both cohorts. In conclusion, lymphopenic CAP constitutes a particular immunological phenotype of the disease which is associated with an increased risk of mortality. Assessing lymphocyte counts could contribute to personalized clinical management in CAP. (C) 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.