Diagnostic utility of lymphocyte subset analysis in AIDS case finding

Area of Science:

• Immunology
• Virology
• Epidemiology

Background:

• Abnormalities in lymphocyte subsets, particularly low helper T cell counts, are characteristic of acquired immune deficiency syndrome (AIDS).
• Similar immune dysregulations are observed in persistent generalized lymphadenopathy (PGL), AIDS-related complex (ARC), and asymptomatic individuals exposed to human T-lymphotropic virus type III (HTLV-III).
• A common belief suggests lymphocyte subset analysis aids in AIDS case detection within high-risk groups.

Purpose of the Study:

• To evaluate the diagnostic utility of absolute helper T cell counts and helper to suppressor T cell ratios for AIDS case finding.
• To determine if lymphocyte subset analysis can significantly revise the probability of AIDS in individuals with varying pretest probabilities.

Main Methods:

• Analysis of lymphocyte subsets, specifically absolute helper T cell counts and helper to suppressor T cell ratios.
• Study included patients with AIDS, PGL (referred for biopsy and not), asymptomatic HTLV-III exposed individuals, and male homosexual controls.
• Conventional cutoff levels for lymphocyte subset parameters were applied.

Main Results:

• At conventional cutoff levels, lymphocyte subset analysis did not significantly increase the probability of AIDS when the pretest probability was low.
• The diagnostic utility of these tests was limited in identifying AIDS within the studied populations.

Conclusions:

• Lymphocyte subset analysis is not a cost-effective method for AIDS case finding in identified at-risk groups with low AIDS prevalence.
• The study questions the widespread perception of lymphocyte subset analysis as a primary diagnostic tool for early AIDS detection in these settings.