Security coverage apply to certain. types of work. If you are self-employed, you earn. Social Security credits the same way. employees do (one credit for each $1,260. in net earnings, but no more than four. credits per year). Special rules apply if. you have net annual earnings of less. than $400.
White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders.All leukocytes are produced and derived from a multipotent cell in the bone marrow known as a hematopoietic stem cell.onocytes and neutrophils are phagocytic. The number of leukocytes in the blood is often an indicator of disease, and thus the WBC count is an important subset of the complete blood count. The normal white cell count is usually between 4 and 11 Ã 10 9 /L.
Main articles: T cell and B cell. T cells (thymus cells) and B cells (bone marrow-or bursa-derived cells) are the major cellular components of the adaptive immune response. T cells are involved in cell-mediated immunity, whereas B cells are primarily responsible for humoral immunity (relating to antibodies).December 2007). A lymphocyte count is usually part of a peripheral complete blood cell count and is expressed as the percentage of lymphocytes to the total number of white blood cells counted. A general increase in the number of lymphocytes is known as lymphocytosis, whereas a decrease is known as lymphocytopenia.