Acute Bacterial Infection: This condition often leads to an increase in neutrophils as the body's first line of defense against bacterial infections. The stress response associated with infection can also cause a relative lymphopenia (low lymphocyte count). Basophilia can sometimes be seen in response to certain infections.

Chronic Stress or Corticosteroid Use: Prolonged stress or the use of corticosteroids can lead to lymphopenia due to the immunosuppressive effects of cortisol. Neutrophilia can also occur as cortisol promotes the release of neutrophils from the bone marrow. Basophils may be elevated in some cases due to the complex interplay of stress hormones on hematopoiesis.
Acute Inflammatory Conditions: Conditions like acute pancreatitis, burns, or severe trauma can cause a significant increase in neutrophils and a decrease in lymphocytes due to the systemic inflammatory response. Basophilia might be observed in the recovery phase or as part of the inflammatory process.
Myeloproliferative Neoplasms (MPNs): Certain MPNs, such as chronic myeloid leukemia (CML) or polycythemia vera, can lead to an overproduction of neutrophils and sometimes basophils. Lymphopenia can occur due to bone marrow replacement or suppression of lymphopoiesis.

Severe Sepsis or Septic Shock: Although this condition might initially present with neutrophilia, it can progress to a state where the bone marrow is exhausted, leading to a decrease in all cell lines, including lymphocytes. Early recognition is crucial as sepsis can be life-threatening.
HIV Infection: Especially in the acute phase, HIV can cause a significant drop in lymphocyte count, particularly CD4+ T cells. Neutrophilia and basophilia can sometimes be observed, especially during the initial immune response or due to opportunistic infections.

Basophilic Leukemia: A rare form of leukemia characterized by the excessive proliferation of basophil precursors. It can lead to elevated basophil counts and may be associated with lymphopenia and neutrophilia due to bone marrow involvement.
Lymphoma with Bone Marrow Involvement: Certain types of lymphoma can infiltrate the bone marrow, leading to lymphopenia in the peripheral blood. Neutrophilia and basophilia might be seen as a reactive process or due to cytokine release by the tumor cells.
Castleman Disease: A rare disorder that can cause an increase in neutrophils and basophils, along with lymphopenia, due to the abnormal production of cytokines, particularly IL-6.