In vitro T- and B-cell reactivity in cartilage hair hypoplasia.

We have investigated and parameters of cellular immunity in ten patients with cartilage hair hypoplasia, CHH. All ten patients displayed a negative skin test to 1 Tu tuberculin, eight patients did not respond to 10 Tu and seven not even to 100 Tu. Six patients were skin test-negative to 1:50 oidiomycin; and three were negative to even 1:10 oidiomycin. The absolute and relative distribution of blood T lymphocytes was normal. The absolute distribution of blood B lymphocytes was slightly decreased in three patients, but all patients had normal levels of IgM, IgG and IgA. Major changes were observed in the proliferative responses of blood leucocytes to mitogens and antigens. Five patients responded suboptimally to phytohaemagglutinin (PHA), two to concanavalin A, three patients were hyporesponsive to strain Cowan I bacteria, six to tuberculin (PPD) and six to oidiomycin. The responses of two patients were entirely normal. Except for three patients responding suboptimally to PPD or oidiomycin only, the reduced responses were all confined to the five patients responding suboptimally to PHA. The suboptimally responding patients displayed normal dose–response profiles to both PHA and Con A. The hyporeactivity was a persistent phenomenon, as the pattern of PHA and Con A reactivity was essentially similar when the same patients had been tested to the same mitogens 5 years earlier. Except for the skin test hyporeactivity, none of these patients displayed any detectable clinical handicap, suggesting that the Finnish variant of the syndrome is dissimilar from the Amish variant, where the deficiency to mitogens and antigens is related to susceptibility to severe and often fatal infections, especially to varicella and vaccinia.