IMMUNOLOGICAL, GENETIC, AND MICROBIOLOGICAL STUDY OF FAMILY MEMBERS MANIFESTING EARLY-ONSET PERIODONTITIS

FROM THE STANDPOINT OF HOST-PARASITE INTERACTIONS, family studies help us understand the host defensive factors and the molecular mechanisms involved in the periodontal immune response. in this study, we report the immunological profile of host-defensive functions, human leukocyt e antigen (HLA) phenotypes, and the microflora of a mother (rapidly pr ogressive periodontitis), an older son (periodontally healthy), a youn ger son (localized juvenile periodontitis), and a daughter (localized juvenile periodontitis). We examined the peripheral neutrophil functio ns, phenotypic and functional analysis of peripheral lymphocytes, seru m immunoglobulin G (IgG) antibody titers against periodontopathic bact eria, serological type of HLA class TI antigens, and bacterial flora i n all periodontal pockets. The results showed that Actinobacillus acti nomycetemcomitans was dominant in the pockets of all subjects. The mot her and two sons showed a depressed neutrophil chemotaxis to N-formyl- methionyl-leucyl-phenylalanine. All subjects except the older son exhi bited low T4/T8 ratios. The mother and daughter had raised levels of I gG titers to Porphyromonas gingivalis, All subjects had HLA phenotypes of DRw52 and DQ1 in common. We found that the family members had simi lar disorders in certain defensive functions. This family has been a m odel for our understanding of the host defensive factors in the develo pment of early-onset periodontitis.