Cutaneous-delayed hypersensitivity in nursing home and geriatric clinic patients. Implications for the tuberculin test

Cutaneous-delayed hypersensitivity was studied by one and two-step Mantoux-type skin tests to four standard antigens in 33 elderly nursing home residents, 34 geriatric clinic patients, and 20 healthy young adult controls. Demographic and anthropometric data were collected to determine the effects of nutrition and other variables on cutaneous-delayed hypersensitivity. Anergy (a lack of response greater than 5 mm of induration when read at 48 hours) to any of the four antigens occurred in 34% of nursing home residents, 17% of geriatric clinic patients, and none of the healthy young adults. Mean and maximal responses were less in the nursing home residents than the clinic patients or controls, even if anergic individuals were excluded from analysis, suggesting both a qualitative and quantitative decline in cell-mediated immune function in this elderly population. Repeat testing with each antigen for which there was a negative initial response revealed a "booster" affect of 7 to 19% and occurred as commonly in the healthy young adults as in the nursing home residents or geriatric clinic patients. The mumps antigen elicited strong responses in the healthy young adults, but weak reactions in the nursing home residents. An unexpectedly high prevalence of positive tuberculin (PPD) responses occurred in the nursing home residents, suggesting recent exposure. Analysis of anthropometric and demographic characteristics show that neither nutritional status nor age alone can account for differences in cutaneous-delayed hypersensitivity observed between populations. Cutaneous-delayed hypersensitivity may vary widely between elderly populations and have important practical implications for the tuberculin test.     

A new method for testing tuberculin skin reactivity--chamber test

The Mantoux test and a chamber tuberculin test applied to the surface of the skin in 4 concentrations were performed on 229 children and 516 adults. The results were recorded at 72 hours. There was a significant correlation between the two tests. The chamber tuberculin test is technically easy, painless and atraumatic. It gives an opportunity of using a full range of concentrations of tuberculin resulting in a quantitative measurement of sensitivity in one and the same test procedure.     

Evaluation of the tuberculin sensitivity test in a healthy Sudanese population.

Three-hundred and seventeen healthy individuals were investigated on a volunteer basis for tuberculin sensitivity using the dual-intradermal tuberculin test technique. 251 of them were in contact with dairy animals and 64.9 per cent of such people were found specific reactors. Those who were not in contact with dairy animals (66 persons) gave 65.2 per cent rate of specific reactivity. To interpret the tuberculin sensitivity reaction, non-specific reactivity must be excluded, especially in tropical countries. Positive tuberculin reaction is defined when the diameter of induration is 10 mm or more for persons in contact with dairy animals and tuberculous patients or consuming raw milk and 5 mm or more for other persons.     

Immunogenetic analysis of delayed hypersensitivity to tuberculin in mice by the method of local adoptive transfer

It has been demonstrated that a specific phase of DTH reaction to tuberculin is carried out (and in adoptive transfer-transferred) by T-lymphocytes with Lyt-1+, Lyt-2-, L3T4+ phenotype by a method of local adoptive transfer of this reaction from BCG-immunized mice to the pads of intact recipients. From genetic viewpoint, the above reaction is limited by 1-A beta, 1-A alpha genes. In a syngeneic apposition, monoclonal antibodies anti-1-A kappa beta (without complement) were blocking the reaction transfer to CBA mice A beta chain affected mutation bm12 failed to limit the reaction transfer in apposition B6----B6.C-H-2bm12.     

Interpretation of the tuberculin skin test

OBJECTIVE: To reinterpret epidemiologic information about the tuberculin test (purified protein derivative) in terms of modern approaches to test characteristics; to clarify why different outpoints of induration should be used to define a positive test in different populations; and to calculate test characteristics of the intermediate-strength tuberculin skin test, the probabilityMycobacterium tuberculosis infection at various induration sizes, the area under the receiver operating characteristic (ROC) curve, and optimal cutpoints for positivity. METHODS: Standard epidemiologic assumptions were used to distinguish M. tuberculosis-infected from -uninfected persons; also used were data from the U.S. Navy recruit and World Health Organization tuberculosis surveys; and Bayesian analysis. RESULTS: In the general U.S. population, the test’s sensitivity is 0.59 to 1.0, the specificity is 0.95 to 1.0, and the positive predictive value is 0.44 to 1.0, depending on the outpoint. Among tuberculosis patients, the sensitivity is nearly the same as in the general population; the positive predictive value is 1.0. The area under the ROC curve is 0.997. The probability ofM. tuberculosis infection at each induration size varies widely, depending on the prevalence. The optimal cutpoint varies from 2 mm to 16 mm and is dependent on prevalence and the purpose for testing. CONCLUSIONS: The operating characteristics of the tuberculin test are superior to those of nearly all commonly used screening and diagnostic tests. The tuberculin test has an excellent ability to distinguishM. tuberculosis-infected from -uninfected persons. Interpretation requires consideration of prevalence and the purpose for testing. These findings support the recommendation to use different cutpoints for various populations. Even more accurate information can be gotten by interpreting induration size as indicating a probability ofM. tuberculosis infection. Presented in part at the 1993 American Thoracic Society International Conference, San Francisco, California, May 1993. Supported in part by grant MH45686 from the National Institutes of Health.     

Biological characterisation of humoral antibodies in tuberculin hypersensitivity

Sera of BCG-sensitized guinea pigs were examined for antibody activities. When tested with erythrocytes sensitized with Old Tuberculin, hemagglutinins could be demonstrated in the 19S-fraction only, whereas hemolysins are located in the 7Sγ₁-and 7Sγ₂-fractions. In a complement consumption test, only the 7Sγ₁- and 7Sγ₂-antibodies fixed complement after contact with PPD or a sonicated BCG-extract as antigens. This was also stated, when no hemolysins were demonstrable in these fractions. It was concluded, that antibodies with different specifities are involved. Using sonicated BCG-extract as antigen, precipitation in agar gel was observed only with 7Sγ₁- and 7Sγ₂-antibodies, but not with the 19S-fraction. PCA-reactions were obtained with the 7Sγ₁-fraction only; 7Sγ₂- and 19S-fractions were inactive in this respect. The 7Sγ₂-fraction did not inhibit the PCA-reactivity of the 7Sγ₁-fraction.