HUMAN IMMUNODEFICIENCY VIRUS-CELL INTERACTIONS
The HIV is cytopathic for many of the lymphocytes in which the virus actively
replicates. The primary targets for HIV are the T4 helper (also called Th) lymphocytes.
However, other cells, including some of the monocyte/macrophage lineage,
B lymphocytes, dendritic reticular cells, and some glial and endothelial cells in the brain
may become infected.
DAMAGE TO THE IMMUNE SYSTEM
The HIV virus destroys many of the body's T4 helper cells. The infected T4 cells,
that are not destroyed, are functionally defective. The infected monocytes appear to be
nonfunctional. The virus appears to stimulate all B cells into producing antibodies,
thereby, leaving no unstimulated B cells available to respond to new infections.
The most widely used screening tests for HIV are ELISA or EIA procedures.
These procedures test for antibodies formed against various proteins or glycoproteins
from HIV. There are new procedures available now to test directly for HIV antigens.
This allows for earlier and more definitive detection of the disease. The procedure,
which is presently used for confirmation of positive screening tests (ELISA, EIA), is the
Section III. VIRAL HEPATITIS
Viral hepatitis has been recognized by the medical community for almost two
centuries and remains a disease of major significance in the world today. It is an
infection which results in inflammation of the liver caused by one of at least four distinct
viral agents. The diagnosis of acute viral hepatitissometimes can be made on the basis
of clinical features and history that suggest a particular causative agent. In most cases
and because of recent immunological advances, specific tests exist which accurately detect,
diagnose, and monitor the progression of hepatitis.
7-11. SYMPTOMS OF HEPATITIS
Early symptoms of hepatitis are similar to the common flu with accompanying
fatigue, joint and muscle pain, and loss of appetite. Low-grade fever, nausea, vomiting,
and diarrhea or constipation may occur. As the disease progresses, the liver may
enlarge and become tender. Jaundice (the yellowing of the skin and eyes) appears as
bilirubin accumulates in the blood. The severity of the symptoms varies from patient to
patient, and symptoms are not specific for the causative agent.