In this issue of American Family Ph...

In this issue of American Family Physician, Cooper and associates (1) provide a timely review of the diagnostic considerations of used by all primary immunodeficiencies. This is an exciting time in the field of immunology. It is worth reflecting forward a few recent advances and highlighting the importance of maintaining a high index of suspicion for immunodeficiencies.

In 1997 the World Health Organization listed 60 primary immunodeficiencies. (2) An update in 1999 listed 71 defaults of immunologic function and another 39 disorders in which immunodeficiency was a element (3) Since that time, the genetic lacks for most immunodeficiencies have been identified, and modern disorders have been recognized at a rate of individual to two per year.

The improved understanding of signaling pathways and mechanisms of landlord defense also has led to the progressive growth of interventions for primary immunodeficiencies. The principally dramatic new management strategy is gene therapy for adenosine deaminase-deficient and X-linked forms of strict combined immunodeficiency. (4) The use of gene therapy remains somewhat controversial, however further refinements should improve its safety. now the article by Cooper and colleagues (1) is a reminder that treatment advances are not helpful unles physicians can make the diagnosis early.

There is as however no national database on primary immunodeficiencies. The mostly common diagnosis is IgA deficiency, with an estimated frequent occurrence of approximately one case by means of 500 white persons. (5) Excluding developmental delay of immunoglobulin production (transient hypogammaglobulinemia of infancy, which present itselfs in an estimated one of each 1,000 infants (5)), the nearest most common primary immunodeficiency is chromosome 22q112 deletion syndrome (DiGeorge syndrome) This syndrome meet the eyes with an estimated frequency of individual case per 3,000 live births, (6) regardless of ethnic or racial background.

greatest in number family physicians can expect to brush patients with primary immunodeficiencies. The in the greatest degree common primary immunodeficiencies would be seen in mostly large clinical practices. However, to make secure timely diagnosis, the family physician also should be familiar with the les usual immunodeficiency disorders.

The article by dint of Cooper and associates is important because it reminds the family physician to be alert to clinical presentations. With more than 70 disorders classified as congenital immunodeficiencies and other syndrome in which immunodeficiency is a significant composing it is somewhat overwhelming to attempt a thorough cataloging. Instead, it is helpful to remember that nearly all immunodeficiencies can be categorized according to the effector "arm" of the immune a whole that is impaired.

Patients with disorders of antibody production or function nearly always ready with common recurrent infections. Each infection is unremarkable, still the frequency of the infections is excessive. Patients with universal variable immunodeficiency (which becomes apparent later in life than other primary immunodeficiency disorders) typically instant with new-onset recurrent sinusitis or bronchitis. Patients with antibody deficiencies usually do not consider chronically ill.

The diagnosis of a disorder of antibody production or function nearly always will be suspected from the family physician, who has insight into a patient's pattern of visits for acute illnesses. Screening laboratory touchstones are readily obtainable and usually consist of immunoglobulin determinations and measurements of antibody rejoinders to immunizations. Timely diagnosis of antibody flaws is important, because untreated patients make known progressive end-organ damage and are at risk for life-threatening enteroviral infections.

Unlike patients with antibody disorders, who generally have typical infections, patients with T-cell defaults often have unusual infections or atypical infections with belonging to all organisms. In children, T-cell defaults are less common than antibody blemishs In adults, T-cell defects (other than those resulting from human immunodeficiency virus [HIV] infection) seldom will be just discovered diagnoses.

Recognition of patients with significant T-cell deficiencies is imperative, because delay of therapy adversely affects issue In infants, the frequencies of HIV infection and harsh combined immunodeficiency are nearly the same. Thus, in most numerous situations where HIV testing would be considered, primary T-cell imperfections also should be considered.

Although stiff combined immunodeficiency may have various presentations, single in kind key characteristic is the persistence of infection. In the absence of T-cell function, a simple upper respiratory tract infection progresse inexorably throughout one to two months. Hence, the family physician should be suspicious when an infant has an infection with a put offed or atypical course.

A helpful finding is that in the greatest degree infants with severe combined immunodeficiency have diminished lymphocyte reckons (less than 2,800 cells for [mm.sup.3] [2.8 3 [10.sup.9] through L]). An infant with chronic diarrhea, chronic wheezing, or returning Candida and a low lymphocyte regard should be seen immediately by dint of an immunologist. Urgent intervention is required for patients with strict combined immunodeficiency. Generally, the first degree in analyzing these patients is to obtain lymphocyte deems which often suggest the diagnosis of sharp combined immunodeficiency.