Diagnostic relevance of the determination of lymphocyte subpopulations in environmental medicine.

Earlier hopes that determination of lymphocyte subpopulations might become a strong diagnostic tool in environmental medicine have not been fulfilled in recent years. Analysis of the scientific literature rather shows that there are only few examples for environmental exposures causing reproducible shifts of lymphocyte subpopulations. Moreover, current knowledge suggests that "environmental diseases" are not associated with characteristic changes of subpopulation patterns. If lymphocyte subpopulations are analyzed, each diagnostic step, including indication, sample handling, analytic procedure and data-interpretation, should adhere to good quality criteria. Taking all together, the determination of lymphocyte subpopulations in the context of environmental medicine comes under category IV of the criteria of the Commission for Methods and Quality Assurance in Environmental Medicine of the German federal health authority (Robert Koch-Institute; RKI): "A procedure cannot be recommended because there is not sufficient information to justify it" (here: no solid trends in epidemiological examinations), "and because theoretical considerations speak against an application" (here: high physiological variability and missing exposure or substance specificity).