From the Guidelines
Evaluation of high neutrophils and lymphocytes should prioritize identifying the underlying cause, with a focus on infections, inflammation, and malignancies, and guiding management based on the severity and duration of the elevation, as well as associated symptoms and risk factors, as outlined in recent guidelines 1. When evaluating high neutrophils and lymphocytes, it is essential to consider the clinical context, including recent infections, medications, travel, and constitutional symptoms.
Key Considerations
- Determine if the elevation represents an absolute increase or a relative increase
- Common causes of neutrophilia include bacterial infections, inflammation, stress, medications (corticosteroids), and certain malignancies
- Lymphocytosis typically occurs with viral infections, certain bacterial infections (pertussis, tuberculosis), lymphoproliferative disorders, and autoimmune conditions
- The evaluation should include a thorough history and physical examination, assessing for lymphadenopathy, hepatosplenomegaly, and signs of infection
- Additional testing may include inflammatory markers (ESR, CRP), blood cultures if infection is suspected, specific viral studies, and in persistent unexplained cases, bone marrow examination or flow cytometry
Risk Assessment
According to the 2018 guideline update by the American Society of Clinical Oncology (ASCO) and the Infectious Diseases Society of America (IDSA) 1, factors to consider in assessing the risk of a febrile neutropenic episode in patients undergoing cytotoxic chemotherapy for malignancy include patient characteristics, performance status, nutritional status, prior febrile neutropenia episode, comorbidities, underlying malignancy, cancer stage, remission status, cancer treatment response, and treatment of malignancy.
Management
The management of high neutrophils and lymphocytes should be guided by the underlying cause and severity of the elevation, as well as the patient's risk factors, with a focus on preventing complications, such as febrile neutropenia, and improving outcomes, as recommended by recent guidelines 1. In patients with cancer-related immunosuppression, antimicrobial prophylaxis may be considered to prevent febrile neutropenia, particularly in those with high-risk factors, such as advanced age, poor performance status, and certain types of cancer, as outlined in the 2018 ASCO and IDSA guideline update 1.
From the Research
Evaluation of High Neutrophils and Lymphocytes
- Neutrophils play a crucial role in the immune system, particularly in the clearance of bacteria and fungi, as well as shaping the host response to infection and immune system homeostasis 2.
- A high neutrophil count can be an indicator of infection or inflammation, while a low count can increase the risk of infection 3, 4.
- The neutrophil to lymphocyte ratio (NLR) has been shown to be a predictor of treatment response and mortality in septic shock patients, with an NLR of ≥15 on the 3rd day of antibiotic initiation indicating a high risk of mortality 5.
- Neutrophils have potent antimicrobial properties and can phagocytose and kill prokaryotic and eukaryotic organisms efficiently, but their activation must be tightly regulated to prevent damage to the host 6.
- Prolonged use of certain antibiotics, such as ceftaroline, has been associated with an increased risk of neutropenia, highlighting the need for careful monitoring of neutrophil counts in patients receiving these medications 3, 4.
Key Findings
- Neutropenia developed in 16 (9%) patients receiving ceftaroline or ceftriaxone, with ceftaroline use being independently associated with neutropenia 3.
- The NLR can predict mortality and antibiotic responsiveness in ICU patients with sepsis and septic shock, with a high NLR indicating a poor prognosis 5.
- Neutrophils play a complex role in the immune system, and their biology is influenced by a range of factors, including their ability to phagocytose and kill microbes, as well as their potential to contribute to autoimmune and inflammatory disease 2, 6.
Clinical Implications
- Clinicians should be aware of the potential for neutropenia in patients receiving prolonged courses of certain antibiotics, such as ceftaroline, and monitor neutrophil counts accordingly 3, 4.
- The NLR may be a useful prognostic tool in ICU patients with sepsis and septic shock, allowing for early identification of patients at high risk of mortality and guiding treatment decisions 5.
- Further research is needed to fully understand the complex biology of neutrophils and their role in the immune system, as well as the clinical implications of neutrophil dysfunction 2, 6.