More than 70 such diseases, most of which are inherited, affect approximately 500,000 people in the United States. Many of those affected are children, who, because they lack totally functional immune systems, are susceptible to serious, recurrent and often life- threatening infections. Information from the registry will be available to researchers for basic and clinical studies, to genetic counselors, and to individuals affected by the disease and the physicians who care for them.

"Medical research to help understand those deficiencies will be advanced by this resource," says Howard Dickler, M.D., chief of the Clinical Immunology Branch, "including studies of host defenses against infection, inflammation, autoimmune diseases and immunodeficiency in general."

The new registry is an outgrowth of an NIAID-supported pilot project begun in 1992 to establish a similar registry for United States residents affected by chronic granulomatous disease (CGD). In a 1996 review and evaluation of the pilot registry, participants concluded that the registry provided considerable information about CGD that had not been previously available. They recommended that an expanded clinical registry for additional primary immune deficiency diseases be established. New diseases will be added in stages to the existing registry, and the first patient information is expected to be entered in the latter half of 1998. Physicians and others interested in more information may call the Immune Deficiency Foundation at 1-800-296-4433.

The new registry will provide improved access to patients by researchers conducting both basic and clinical studies; accurate and up-to-date profiles useful to clinicians and to genetic counselors; and improved access by patients to information about the latest treatments.

Other types of information will be included in the registry: disease prevalence in the overall population and in various subgroups; the number and types of genetic defects that result in primary immune deficiency diseases; the clinical spectrum of these diseases; the correlation between the genetic defect and clinical picture; effects of current therapy on the course of these diseases; and causes and incidence of morbidity and mortality.

In contrast to secondary or acquired immune deficiency diseases caused by infectious, chemical or radiological agents, the primary immunodeficiency diseases are caused by intrinsic dysfunction in the cells of the immune system, often brought about by inherited genetic defects. The unifying characteristic of these diseases is increased susceptibility to infection, and they can cause other problems as well.

• Antibody deficiencies can hinder or prevent the immune system from recognizing and marking for destruction bacteria, viruses and other foreign invaders. X-linked agammaglobulinemia, an inherited deficiency that appears in the first three years of life, leaves infants and young children with recurrent infections of the ears, lungs, sinuses and bones, and increased susceptibility to such viruses as hepatitis and polio.

• Combined immunodeficiencies occur in people who lack the T lymphocytes that develop into killer cells that destroy infected cells or become helper cells that communicate with other immune cells. X-linked severe combined immunodeficiency, most often diagnosed during the first year of life, allows organisms that do not affect people with healthy immune systems to cause frequent and life-threatening infections.

• Complement deficiencies usually involve an absence of one or several of the proteins that contribute to the complement system's ability to attach to antibody-coated foreign invaders. In childhood or early adulthood, a complement deficiency can result in severe infections such as meningitis, or it can contribute to an autoimmune disease such as lupus erythematosus.

• Phagocytic cell deficiencies result in the inability of cells that engulf and kill antibody-coated invaders to act efficiently to remove pathogens or infected cells from the body. CGD, the most severe form of phagocytic deficiency, usually appears in early childhood. It causes frequent and severe infections of the skin, lungs and bones, leaving swollen collections of inflamed tissue called granulomas.

In addition to CGD, the diseases that will be included in the new registry are hyper-IgM syndrome, severe combined immunodeficiency disease, X-linked agammaglobulinemia, Wiskott-Aldrich syndrome, common variable immunodeficiency, leukocyte adhesion deficiency, and DiGeorge syndrome.

NIAID is a component of the National Institutes of Health (NIH). NIAID conducts and supports research to prevent, diagnose and treat illnesses such as AIDS and other sexually transmitted diseases, malaria, tuberculosis, asthma and allergies. NIH is an agency of the U.S. Department of Health and Human Services.

Press releases, fact sheets and other NIAID-related materials are available on the Internet via the NIAID home page at http://www.niaid.nih.gov.