What is the definition or description of: immune deficiency?

Immune defect: Immune deficiency simply means that there is an impairment in your immune system. You may have a decrease in the quantity of antibody(ies) or immune cells or impaired immune response (quality) to many or just a few foreign invaders. The severity varies as are the actual sites of the defects. Frequent infections are the most common presentation (sinus , pulmonary) . Many studies in progress.