Page 85 - AIDSBK23C

Page 85

OTHER CAUSES OF IMMUNOSUPPRESSION

Disease processes may occur in a population at risk for HIV infection that are neither
caused by HIV, nor are potentiating factors, but which can lead to immunosuppression. These
conditions may account for acquired immunodeficiency states. Lymphoreticular malignancies
can occur in age groups in which HIV infection is prevalent, but such diseases have not been
linked with AIDS by definition, except for the high grade lymphomas in persons within whom an
HIV infection can be demonstrated. Among these are non-Hodgkin lymphomas, leukemias, and
Hodgkin lymphoma. Persons undergoing cancer chemotherapy may also have immune system
dysfunction and clinical findings similar to patients with AIDS. Patients undergoing organ
transplantation and persons with collagen vascular diseases may also be treated with
immunosuppressive regimens placing them at risk for opportunistic infections. Long-term
corticosteroid therapy can produce lymphopenia and immune dysfunction. The extreme
debilitation accompanying malnutrition, drug abuse, and dementia can also reduce immune
function, though the infections in these persons are usually bacterial.
Primary immunodeficiency states must be considered in the differential diagnosis of
AIDS, particularly in infants and children. Such conditions may include severe combined
immunodeficiency (SCID), partial or complete DiGeorge syndrome, Wiskott-Aldrich syndrome,
ataxia-telangiectasia, chronic granulomatous disease, and agammaglobulinemia or
hypogammaglobulinemia with raised IgM. Common variable immunodeficiency (CVID) may
occur at a variety of ages, including young to middle aged adults.
Appropriate laboratory testing, including tests for HIV when indicated, must be
employed to distinguish immunodeficiency states. A thorough history and physical examination
aids in this process. Immunodeficiency states can be multifactorial in origin. As always, to use
the CDC definition for diagnosis of AIDS, it is necessary to determine HIV status with certainty.
Without evidence for HIV infection, a search for other causes of immunosuppression should
always be done, regardless of the age of the patient. Both inherited as well as acquired
immunodeficiency states may occur.