Week 4: I Have Run Out of Songs for Titles

This week was particularly interesting as now I started to see some familiar faces in the clinic, many of whom recognized me from morning rounds during their stays in the hospital following transplantation. As I have written in previous blog posts, patients typically have appointments in the clinic twice a week for the month following transplantation before longer gaps between visits as the time after transplantation increases. These visits are important in making sure patients are adhering to their regimen of immunosuppressive, antiviral, antibiotic, and antifungal medications as well as changing dosage levels in response to clinical lab test results or side effects which patients are experiencing. One of the most important factors informing the choice of immunosuppression regimen is the matching of the donor kidney to the recipient. Briefly, a match is based both on ABO blood typing as well as six classes of HLA antigens, a set of cell-surface proteins encoded on chromosome 6. I encountered patients with a wide variety of matchings, including deceased donor kidneys with a few mismatched antigens, a two haplotype match of HLA antigens from a living related donor (a 25% probability for siblings and a less than 0.0001% chance for unrelated individuals), and even an ABO incompatible donor kidney.

I was also able to observe a renal biopsy procedure on a patient who was experiencing reduced kidney function. While some biopsies are performed regularly for surveillance, this particular biopsy was in response to elevated copy number of BK polyomavirus in the urine. This can cause nephropathy, which is treatable if detected early but can lead to graft loss if untreated. The procedure itself is aided by Doppler ultrasound to aid the nephrologist in selecting a good angle of approach for the biopsy needle to avoid major blood vessels as well as monitor the depth of the needle to obtain a sample with tissue from both the renal cortex and medulla. While local anesthetics aid in providing comfort for the patient, the procedure is still invasive and carries with it some complications, primarily bleeding or fistula formation if the biopsy needle intersects an artery and vein. While biopsy is currently the gold standard for diagnosing rejection and infection of the renal allograft, the nephrology lab is currently validating a set of urinary biomarkers that can be both prognostic and diagnostic of rejection. My next blog entry will be more focused on my role in this progress.