Value of monitoring serum immunoglobulins questioned.

Value of Monitoring Serum Immunoglobulins Questioned Our journal club's review of the recent article by Szczeklik al. (EHP 102:302304) found fault on many levels, especially with the concluding recommendation. It would be neither practical nor useful for workers exposed chronically to PAHs to have serum immunoglobulin levels monitored regularly. The use of cross-sectional data regarding serum immunoglobulin levels for detecting immune competence is not clinically sound. Except in patients with congenital deficiencies, there is no correlation between these levels and resistance to infection. There is no basis to compare mean values within the statistically normal range in the expectation that changes reflect immunosuppression. If humoral immune competence is to be evaluated, a useful test involves assessment of the dynamic response to a particular antigen challenge. This biological function has been shown to diminish following in vitro exposure to benzo[a]pyrene, but there is little basis for linking this effect to cancer consequences. Polycyclic aromatic hydrocarbons are not clinically linked to the development of opportunistic infections, the most significant sign of immune suppression. Even if this type of immune deficit had been shown in these workers, there is no basis to make the assertion that humoral immunocompetence has any role in carcinogenesis. Cancer immune surveillance is most significantly accomplished by tumor-infiltrating and T-cell lymphocytes, especially CD8 cells and the helper CD4 cells. Patients with early and even late-stage cancer usually have normal or elevated levels of total serum immunoglobulin, the opposite effect of Szczeklik's workers. Lastly, the paper's own data refute the routine monitoring of exposure with this biological tool. No correlation with duration or magnitude of exposure was identified among these heavily exposed workers. The published graph of the groups intensely overlapping IgG results provides a strong argument against any use of this test in worker monitoring. Critical scrutiny is necessary before introducing routine clinical tests, especially in workplace health and safety. In the setting described in the Szczeklik paper, expenditures on exposure evaluation and reduction by traditional industrial hygiene methods would be more useful than any biological monitoring. In the clinical arena, education and counseling to decrease the workers astonishing 75% prevalence of active smoking would be essential.