The germinal center reaction is a key event of humoral immunity, providing long-lived immunological memory. Follicular helper T (T(FH)) cells are a specialized subset of CD4⁺ T cells located in the follicles, which help B cells and thus control the germinal center reaction. T(FH) cell development is achieved by multi-step processes of interactions with dendritic cells and B cells along with the coordination of various transcription factors. Since the T helper cell fate decision program is determined by subtle changes in regulatory molecules, fine tuning of these dynamic interactions is crucial for the generation functional T(FH) cells. MicroRNAs (miRNAs) have emerged as important post-transcriptional regulatory molecules for gene expression, which consequently modulate diverse biological functions. In the last decade, the miRNA-mediated regulation network for the germinal center reaction has been extensively explored in T cells and B cells, resulting in the identification of several key miRNA species and their target genes. Here, we review the current knowledge of the miRNA-mediated control of the germinal center reaction, focusing on the aspect of T cell regulation in particular. In addition, we highlight the most important issues related to defining the functional target genes of the relevant miRNAs. We believe that the studies that uncover the miRNA-mediated regulatory axis of T(FH) cell generation and functions by defining their functional target genes might provide additional opportunities to understand germinal center reactions.
B-Lymphocytes ; Dendritic Cells ; Gene Expression ; Germinal Center ; Immunity, Humoral ; Immunologic Memory ; MicroRNAs ; T-Lymphocytes ; T-Lymphocytes, Helper-Inducer* ; Transcription Factors

BACKGROUND: Slim patients or those with large breasts may be ineligible for breast reconstruction with an abdominal flap, as the volume of the flap may be insufficient. This study aimed to establish that abdominal tissue–based breast reconstruction can be well suited for Korean patients, despite their thin body habitus. METHODS: A total of 252 patients who underwent postmastectomy breast reconstruction with an abdominal flap from October 2006 to May 2013 were retrospectively reviewed. The patients' age and body mass index were analyzed, and a correlation analysis was performed between the weight of the mastectomy specimen and that of the initial abdominal flap. RESULTS: The average weights of the mastectomy specimen and initial abdominal flap were 451.03 g and 644.95 g, respectively. The ratio of the weight of the mastectomy specimen to that of the initial flap was 0.71±0.23. There was a strong positive linear relationship between the weight of the mastectomy specimen and that of the initial flap (Pearson correlation coefficient, 0.728). Thirty nulliparous patients had a final-to-initial flap weight ratio of 0.66±0.11. The 25 patients who underwent a contralateral procedure had a ratio of 0.96±0.30. The adjusted ratio of the final flap weight to the initial flap weight was 0.66±0.12. CONCLUSIONS: Breast weight had a strong positive relationship with abdominal flap weight in Koreans. Abdominal flaps provided sufficient soft tissue for breast reconstruction in most Korean patients, including nulliparous patients. However, when the mastectomy weight is estimated to be >700 g, a contralateral reduction procedure may be considered.
Body Mass Index ; Breast* ; Female ; Free Tissue Flaps ; Humans ; Korea ; Mammaplasty* ; Mastectomy* ; Retrospective Studies ; Weights and Measures

BACKGROUND: Microvascular complications after free-flap breast reconstructions are potentially devastating problems that can increase patient morbidity and lead to flap loss. To date, no comprehensive study has examined the rates of salvage and the methods of microvascular revision in breast reconstruction. We reviewed the treatment of microvascular complications of free-flap breast reconstruction procedures over a seven-year period. METHODS: A retrospective review of all patients who underwent microvascular breast reconstruction at our institution between April 2006 and December 2013 was conducted. Based on their surgical records, all patients who required emergency re-exploration were identified, the rate of flap salvage was determined, the factors associated with flap salvage were evaluated, and the causes and methods of revision were reviewed. RESULTS: During the review period, 605 breast reconstruction procedures with a free lower abdominal flap were performed. Seventeen of these flaps were compromised by microvascular complications, and three flaps were lost. The overall salvage rate was 82.35%. No significant differences between the salvaged group and the failed group were observed with regard to age, BMI, axillary dissection, number of anastomotic arteries and veins, recipient vessel types, or use of the superficial inferior epigastric vein in the revision operation. Successful salvage of the flap was associated with a shorter time period between recognizing the signs of flap compromise and the take-back operation. CONCLUSIONS: The salvage rate of compromised lower abdominal flaps was high enough to warrant attempting re-exploration. Immediate intervention after the onset of flap compromise signs is as important as vigilant postoperative monitoring.
Arteries ; Breast* ; Emergencies ; Female ; Free Tissue Flaps ; Humans ; Mammaplasty* ; Perforator Flap ; Retrospective Studies ; Salvage Therapy ; Surgical Flaps ; Veins