ABSTRACT
Follicular helper T cells (Tfh) are the T cell subset providing help to B cells for the generation of high-affinity antibodies and are therefore of key interest for the development of vaccination strategies against infectious diseases. In this review, we will discuss how the generation of Tfh cells and their interaction with B cells in secondary lymphoid organs can be optimized for therapeutic purposes. We will summarize different T cell subsets including Tfh-like peripheral helper T cells (Tph) capable of providing B cell help. In particular, we will highlight the novel concept of T cell/B cell interaction in non-lymphoid tissues as an important element for the generation of protective antibodies directly at the site of pathogen invasion.
ABSTRACT
BACKGROUND: No reliable predictive factors for treatment (Tx) success and outcome quality in Class II:1 Tx have been identified yet. OBJECTIVE: To assess the influence of pre-Tx Class II severity and skeletal maturity on outcome quality after Herbst-multibracket appliance (MBA) Tx. SUBJECTS AND METHODS: All Class II:1 patients who completed Herbst-MBA Tx between 1986 and 2014 at University of Giessen, Germany. Pre-Tx (T0), post-Tx (T1), and (if available) post-retention (≥24 months; T2) study casts were evaluated using the Peer Assessment Rating (PAR) index and the Ahlgren scale. Three occlusal severity (mild, moderate, and severe) and four skeletal maturity (pre-peak, peak, post-peak, and adult) subgroup categories were defined. RESULTS: Four hundred eight-five patients (age at T0: 14.4 ± 3.2 years) could be evaluated; post-retention (T3) data were available for 230 patients. For the total sample, the median PAR score was 32.4 ± 8.85 at T0, 8.0 ± 4.52 at T1, and 8.8 ± 5.11 at T2. Very low correlations between the subgroup categories (occlusal severity/skeletal maturity) and PAR-score reduction were detected both during Tx (r = 0.12/r = 0.05) and the total observation period (r = 0.17/r = 0.03). The overall outcome quality according to Ahlgren was: 17.0% excellent, 34.8% good, 43.8% acceptable, 2.2% unacceptable, and 2.2% not assessable. The association with the subgroup categories was: p = 0.019 (occlusal severity)/p = 0.820 (skeletal maturity). LIMITATIONS: Retrospective study design with follow-up data was not available from all subjects and no data from untreated controls. Tx was performed by several physicians using different kind of MBAs. CONCLUSION: Class II:1 Herbst-MBA Tx is an effective and successful Tx approach irrespective of pre-Tx skeletal maturity but dependent-to a certain extent-on Class II severity. Thus, when considering a Herbst appliance for Class II correction, neither of the two variables should considerably limit the indication.
