The effective regulation of T cell responses is dependent on opposing signals transmitted through two related cell-surface receptors, CD28 and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4). Dimerization of CTLA-4 is required for the formation of high-avidity complexes with B7 ligands and for transmission of signals that attenuate T cell activation. We determined the crystal structure of the extracellular portion of CTLA-4 to 2.0 angstrom resolution. CTLA-4 belongs to the immunoglobulin superfamily and displays a strand topology similar to Valpha domains, with an unusual mode of dimerization that places the B7 binding sites distal to the dimerization interface. This organization allows each CTLA-4 dimer to bind two bivalent B7 molecules and suggests that a periodic arrangement of these components within the immunological synapse may contribute to the regulation of T cell responsiveness.

Background: Mastectomy and implant-based reconstruction is typically performed in a hospital setting (HS) with overnight admission. The aim of this study was to evaluate postoperative complications and outcomes with same-day discharge from an ambulatory surgery center (ASC) compared with the same surgery performed in the HS. Methods: Patients who underwent mastectomy and immediate prepectoral tissue expander reconstruction were included in this retrospective study. Surgery was performed in an ASC with same-day discharge or the HS with overnight observation or same-day discharge. Patient demographics, operative details, outcomes, complications, and patient satisfaction were compared. Results: One hundred six women (183 breasts) underwent surgery in the HS, and 103 women (177 breasts) had their surgery in an ASC between August 2014 and September 2019. Demographics, comorbidities, and operative details were similar. Although there was no difference in the rates of most major complications, infectious complications requiring operative intervention were less frequent in the ASC [2.3% (n = 4) versus 11.5% (n = 21); P = 0.001]. Patient satisfaction, evaluated with a 5-point Likert scale, was higher in the ASC. Conclusions: Mastectomy and prepectoral reconstruction in an ASC is a safe alternative to the standard approach of performing this procedure in the HS. Although the rates of most surgical complications are similar between the HS and ASC, we have found a significantly reduced rate of major infectious complications requiring surgical intervention in the ASC which reduces overall cost and patient morbidity. Finally, patient satisfaction was higher in the ASC compared with the HS.

Post-mastectomy reconstruction is performed using implant-based or autologous techniques. Many women refuse or are poor candidates for implant-based reconstruction. We previously described a single-stage autologous technique that was most applicable in obese women with significant ptosis that made use of the mastectomy skin flap and subcutaneous tissue to reconstruct a breast mound. Here, we extend this technique to smaller breasted women by incorporating a second stage of skin tailoring and fat grafting. This technique does not require donor site surgery nor extended operative and recovery times. It extends the indications for autologous reconstruction to nonideal candidates and to developing countries where cost limits access.