No further studies are indicated for TCE exposure. A workup for fatigue may indicate additional tests.

Based on limited evidence from animal studies, researchers believe teratogenicity does not occur at environmental TCE levels. Invasive procedures are not justified on the basis of the drinking water contamination.

No, a recent survey of infections in children under 3 years of age over a September to March period found an average of 2.5 total infections and more than one episode of otitis media per child (1.4 episodes per child for those in day care). Over 3% of the children in day care were hospitalized for tympanostomies. (Reference: Bell DM, Gleiber DW, Mercer AA, et al. Illness associated with child day care: a study of incidence and cost. Am J Public Health 1989;79:479–84.) The child described in the case study appears to have an above-average rate of infections, but they are not frequent enough to suggest immunologic impairment.

No, immunocompetence tests are not appropriate because no evidence of immune function abnormalities has been found in similar situations. Nevertheless, physicians may be asked to explain further why they are not performing the tests on their patients. Two references that may be of value are (1) Kahn E, Letz G. Clinical ecology: environmental medicine or unsubstantiated theory? Ann Intern Med 1989; 2:104–6; and (2) American College of Physicians. Clinical ecology. Ann Intern Med 1989;2:168–78.

If it had been indicated, laboratory evaluation of immunologic host-defense defects would consist of three phases. The preliminary screening is a complete blood count with differential smear and quantitative immunoglobulin levels. These tests, together with history and physical examination, will identify more than 95% of patients with primary immunodeficiencies. The second phase of testing consists of readily available studies including B-cell function (such as antibodies, response to immunization), T-cell function (skin tests, contact sensitization), and complement levels. The first two phases combined will detect most immunodeficiencies amenable to conventional treatment with gamma globulin or plasma. The third phase (in-depth investigation) consists of testing induction of B lymphocyte differentiation in vitro, stimulated by pokeweed mitogen and histologic and immunofluorescent examination of biopsy specimens; T-cell surface markers; assays of T-cell helper or killer cell functions; and functional assays using appropriate target cells. It is inappropriate to perform these latter tests on environmentally exposed patients except for epidemiologic research.

Primary immunodeficiency is suspected in an infant who has repeated upper respiratory tract or other infections. It is also suspected if repeated infection occurs in a child who has had little exposure to infectious agents, or any child with unusual infections, incomplete clearing of infections, growth failure, hepatosplenomegaly, or features associated with specific immunodeficiency disorders, such as ataxia or telangiectasia. The child described in the case study has none of these indications.

EPA has not issued an emission standard for TCE. Assuming discussions with the owner or operator of the shop adjacent to the day-care center have not been effective in reducing the level of ambient TCE, the community’s air pollution control center should be notified. States may allow this control under the jurisdiction of local air pollution control districts, county health departments, or other local agencies. The agency responsible for enforcement of air standards should be contacted to investigate possible release of TCE onto the day-care center property.