What condition is characterized by recurrent bacterial infections due to impaired leukocyte function despite normal B and T lymphocyte counts?

Leukocyte adhesion deficiency is characterized by recurrent bacterial infections resulting from impaired leukocyte function, even when B and T lymphocyte counts remain normal. This condition arises from a defect in the leukocyte adhesion molecules that are necessary for neutrophils and other white blood cells to effectively migrate to sites of infection. When these adhesion molecules are dysfunctional or absent, leukocytes cannot adhere to the endothelium of blood vessels, which is a critical step for their exit from circulation to tissues where they are needed to combat infections.

As a result, individuals with this condition experience difficulties in mounting a robust immune response against bacterial pathogens, leading to frequent and potentially severe infections. The normal counts of B and T lymphocytes indicate that the adaptive immune response is intact; however, the inability of leukocytes to reach infected areas due to adhesion defects highlights the importance of innate immune mechanisms in the body's defenses.

This makes leukocyte adhesion deficiency distinct from other conditions like chronic granulomatous disease, cyclic neutropenia, and myeloperoxidase deficiency, which involve different mechanisms and deficiencies in immune functionality.