**3.4 Immunosuppressive therapy**

#### *3.4.1 Induction therapy*

Induction therapy is determined at the time of listing and is modified for the patient as medically indicated. Induction therapy is administered in the operating room by the

*Perioperative Care for Organ Transplant Recipient*

VXM performed during July–December 2016 for lung candidates with CPRA>10%. Twenty-eight patients had no DSAs or had acceptably weak DSAs; they proceeded to transplant based VXM. All retrospective flow crossmatches were negative. The other 30 patients had positive VXM due to one or more moderate to strong DSAs, and the organ offers were refused. We found that 7 out of 30 (23.3%) VXM were called unacceptably positive due to the presence of antibody against denatured antigens [31]. Among these seven patients, three patients had antibodies against class I denatured antigens (2500–3500 MFI), and four patients had antibodies against class II denatured antigens (2000–14,000 MFI). We also found that by using LSPRA (Phenotypic Bead) and FlowPRA Screen assays along with SAB, we can preemptively recognize antibodies against denatured antigens not to deny organ offers unnecessarily. Instead of performing VXM using only SAB results, we now confirm that donor's antigens are positive by other assays as well (**Figure 3A**). Whenever antibody is detected only by SAB assay, it is considered to be directed against a cryptic epitope and, therefore, to be clinically irrelevant and not able to cause positive flow cytometry crossmatch (**Figure 4A**). DSAs detected by both SAB and phenotypic bead assays are considered as antibody against native HLA antigens (**Figure 4B**). The "true" DSAs undergo evaluation for strength as described below. Using this strategy we successfully transplanted five out of seven patients who were denied offers during July–December 2016 period. Since January 2017, all transplant candidates undergo antibody testing by SAB and LSPRA/FlowPRA Screen assays, so the presence of antibodies against cryptic epitopes can be easily recognized at the time of donor evaluation. This strategy results in reducing the number of unacceptable antigens and reduces percentage

**106**

**Figure 4.**

*Accuracy of virtual crossmatch can be improved by performing SAB alone with screening assays.*

anesthesiologist. Exceptions to the standard therapy are documented in the patient's medical record. Alemtuzumab (Campath) is the first-line induction therapy (**Table 1**). Basiliximab (Simulect) is given to patients with cytomegalovirus (CMV) mismatch, Hepatitis B virus (HBV)/HCV/HIV infection, and/or a history of malignancy (**Table 2**).
