T lymphocytes have various types of regulatory functions. Without special immunohistochemical stains, it is impossible to distinguish lymphocyte types morphologically. Plasma cells are responsible for production of immunoglobulins. The primary role of lymphocytes is in immune functions. Immunoglobulin is an important opsonin.
Lymphokines are soluble products of lymphocytes which mediate a variety of processes.
Major lymphokines involved in inflammation include chemotactic substances and cell growth and proliferation factors. Inflammatory and immune processes occur concurrently and are highly interdependent. Although mast cells have granules within their cytoplasm like granulocytes, they are conveniently placed into the mononuclear classification based on nuclear morphology. They are about 10-15 um in diameter and have an oval to round nucleus. Mast cells contain metachromatic granules which store a variety of inflammatory mediators.