[Immune reaction after penetrating keratoplasty depending on graft size and centration]. / Immunreaktion nach perforierender Keratoplastik in Abhängigkeit von der Transplantatgröße und -zentrierung.

BACKGROUND: Immune reaction (IR) after penetrating keratoplasty (PKP) is a serious complication with a high risk of graft failure. The aim of this study was to analyze and evaluate the risk factors for IR, in particular, the influence of graft size and centration. PATIENTS AND METHODS: A total of 2133 patients who underwent PKP between January 2009 and July 2019 were included in this retrospective study. The following endpoints were analyzed: frequency of IR, graft origin, donor and patient age, diagnosis, corneal diameter and ratio of the graft size to the recipient cornea size. In addition, the role of graft centration, with the help of distance measurements of the graft margins to the vascularized limbus at four locations, was investigated in detail. RESULTS: Overall, 8.25% of patients suffered from IR during the observational period. The frequency of IR was significantly correlated (p < 0.001) with the ratio of the graft size to the recipient cornea size. In addition, a statistically significant correlation was found between the occurrence of IR and a small distance to the limbal margins in the Y­axis (inferior and superior). In particular, the correlation coefficient was larger at the inferior limbus (p < 0.001). CONCLUSION: An IR after PKP is a not uncommon complication and is significantly related to graft size and centration. A large graft chosen in relation to the recipient cornea and the proximity of the graft to the vascularized limbus at the inferior and superior sites significantly correlate with the occurrence of IR. These are important risk factors for graft survival, which can be influenced by the corneal microsurgeon and could possibly be further optimized in the future.

[Can electronic measurement of total cell number in bronchoalveolar lavage replace conventional chamber counting?]. / Kann die elektronische Messung der Gesamtzellzahl in der bronchoalveolären Lavage die herkömmliche Kammerzählung ersetzen?

On average, the electronic technique for counting cells employing a Coulter counter produces higher, though comparable, numbers of cells than does manual counting in a Neubauer counting chamber. On the basis of cell size distribution, electronic counting permits a rough preliminary differentiation to be made. Owing to the much larger number of cells counted, an appreciably improved statistical analysis proves possible.