Chen Jinsong

Clinical and Pathological Study of Polyomavirus-Associated Nephropathy after Renal Transplantation

Polyomavirus infection has emerged as an important cause of polyomavirus-associated nephropathy (PVAN) leading to allograft dysfunction and loss. The aim of this study is to investigate pathological features and clinical characteristics of PVAN. We prospectively investigated 351 renal allografts performed in Jinling Hospital. PVAN was diagnosed by light microscopic examination and a positive immunohistochemistry staining of anti-SV40 large T antibody in a biopsy specimen. 31 patients were diagnosed with PVAN (8.8%). The patients with PVAN typically presented as allograft dysfunction with an asymptomatic rise in serum creatinine about 3 to 39 months posttransplant. Urinary decoy cells were positive in 4 patients (12.9%). The histologic changes of PVAN are not pathognomonic and can be mistaken for allograft rejection, i.e. tubulointerstitial nephritis with varying degrees of inflammatory infiltrates, tubulitis, tubular atrophy and fibrosis. Typical findings on histology are focal interstitial mononuclear inflammatory cell infiltrates, presence of plasma cells, necrotic tubular epithelium, and presence of homogenous intranuclear inclusion bodies. Immunohistochemistry with SV40 staining is positive in allograft. CD3, CD4, CD8, CD68 positive cells are increased in PVAN group than the non-PVAN group, but none of HLA-DR and IL-2R expression is positive in PVAN patients. MPA AUC 0-12 and TAC trough levels are increased in PVAN group than non-PVAN group at biopsy. We have treated 31 patients with biopsy-proven PVAN with leflunomide. Increased intensity of immunosuppression appears to increase the likelihood of PVAN. The definitive diagnosis of PVAN requires renal biopsy. Immunohistochemistry with SV40 staining has been used as an indirect method to document the presence of PVAN.

CD20+ B-cell infiltration is related to the time after transplant and poor prognosis of acute cellular rejection in renal transplant.

OBJECTIVES This study sought to determine the relation between CD20+ B-cell infiltration and time after transplant and outcome of acute cellular rejection in renal allografts. MATERIALS AND METHODS Fifty-five patients with acute cellular rejection were categorized into 3 groups: very early, early, and late rejection. The density of CD4+, CD8+, CD20+, and CD68+ cells and HLA-DR expression were characterized and quantified using immunohistochemical staining. Histologic changes were compared between high-density and low-density CD20+ B-cell groups. Poor prognosis factors were analyzed with Cox proportional regression. RESULTS Density of CD20+ cells in the very-early rejection group was lower than it was in the early- and late-acute rejection groups (P = .03); the density of CD4+, CD8+, and CD68+ cells and HLA-DR expression did not differ between the groups. Mesangial matrix increase, tubular atrophy, arteriolar hyaline thickening, and tubulitis were more prevalent in the high CD20+ density group. Cox regression analysis demonstrated that HLA-DR expression on the tubules, arteriolar hyaline thickening, and CD20+ cell density were associated with an elevated risk of acute cellular rejection. CONCLUSIONS Expansion aggregation of CD20+ B cells occurred mostly after 2 weeks. When combined with HLA-DR expression and arteriolar hyaline thickening, these influence the outcome of acute cellular rejection in renal allograft.

Biorthogonal mode analysis for cavity scattering problems

Biorthogonal mode method is employed to analyze the cavity scattering problems(resulting in a unique solution to the electric field integral equation). A number of numerical examples are analyzed and compared with the published literatures.<<ETX>>