From the Guidelines

Lymphopenia is a common complication of chemotherapy.

Chemotherapy can induce lymphopenia, a condition characterized by an abnormally low level of lymphocytes in the blood, due to its immunosuppressive effects 1.
The development of lymphopenia during chemotherapy is often associated with an increased risk of infections, as lymphocytes play a crucial role in the immune system.
HLH (Hemophagocytic Lymphohistiocytosis) During Chemotherapy is a life-threatening condition that can occur in patients undergoing chemotherapy, characterized by an overactive and inappropriate immune response, which can lead to lymphopenia and other cytopenias 1.
The treatment of HLH During Chemotherapy is challenging, and the use of immunosuppressive agents, such as etoposide, glucocorticosteroids, and cyclosporin A, must be carefully considered, as they can exacerbate lymphopenia and increase the risk of infections 1.
In patients with lymphoma, the presence of HLH is prognostic of a poorer survival and early death, highlighting the need for prompt and effective treatment of both the underlying malignancy and the associated HLH 1.

From the Research

Lymphopenia is a common side effect of chemotherapy, and it has been shown to be associated with poor prognosis in various types of cancer 2, 3, 4, 5, 6.
Studies have found that chemotherapy-induced lymphopenia can lead to a higher risk of infection, disease recurrence, and mortality 2, 3, 5.
The severity and duration of lymphopenia can vary depending on the type and dose of chemotherapy, as well as individual patient factors such as age and performance status 4, 5.

Chemotherapy has been shown to significantly decrease lymphocyte counts, with some studies finding that the minimum absolute lymphocyte count (ALC) is significantly lower in patients receiving concurrent chemoradiotherapy compared to those receiving sequential chemoradiotherapy 2.
The impact of chemotherapy on lymphocyte counts can be influenced by the type of chemotherapy regimen used, with some studies finding that certain regimens are more likely to cause severe lymphopenia than others 3, 4.

Lymphopenia has been identified as an independent prognostic factor for overall survival in various types of cancer, including breast cancer, soft tissue sarcoma, and non-Hodgkin's lymphoma 5.
Studies have found that patients with lymphopenia have a higher risk of disease recurrence and mortality compared to those with normal lymphocyte counts 3, 5, 6.
The prognostic value of lymphopenia can be influenced by other factors, such as performance status, tumor stage, and treatment response 5, 6.