This was a retrospective study of renal allograft biopsies performed at our center from January 2004 to December 2007. Out of 1699 patients transplanted from January 1998 to October 2007, 727/1171 (62.1%) ATIP and 312/528 (59.1%) controls with functioning grafts are on follow-up.
ATIP comprised of administration of donor leucocyte transfusions, target specific irradiation to sub-diaphragmatic lymph nodes, spleen, part of pelvic bones and lumbar vertebrae (200 CgY × 5 days), anti-T cell antibody, 1.5 mg/kg BW and anti-B cell antibody, 6 mg/kg BW intravenously respectively followed by unmodified cytokine stimulated donor derived bone marrow (BM) administration intraportally fortified with cultured BM derived hematopoietic stem cells, human adipose tissue derived mesenchymal stem cells and peripheral blood stem cells to recipients. Renal transplantation was performed following negative lymphocytotoxicity cross-matching (LCM) (serology).
Patients belonging to the control group were transplanted following negative LCM reports. Recipient maintenance immunosuppression of ATIP comprised of Cyclosporin, 1.5 ± 0.5 mg/kgBW/day or Azathioprine, 2 mg/kg BW/day or Mycofenolate mofetil, 1 gm/day and Prednisolone, 7.5 ± 2.5 mg/day. Control group patients were on standard triple drug immunosuppression of Cyclosporin, 4.5 ± 1.5 mg/kgBW/day/Azathioprine, 2 mg/kg BW/day/Mycofenolate mofetil 2 gm/day and Prednisolone, 15 ± 5 mg/day.
Demographics of both groups were comparable.
Biopsies were performed whenever there was a sustained rise of > 10% baseline serum creatinine (SCr) for 10 days. Biopsies with chronic changes were included in this study and diagnosed as per modified Banff criteria. [3, 4] Morphological evaluation was carried out using hematoxylin and eosin, periodic acid Schiff, Jones' silver methaneamine and Gomori's trichrome stains on 3 μm paraffin sections. C4d antibodies were tested using polyvalent anti-human C4d antiserum (Biomedica Gruppe, Beckman Coulter, Germany) by both techniques, immunofluorescence (IF) and immunohistochemistry (IHC) (using their working protocol). Membranous nephropathy slides were used as outside positive controls.
Chronic changes were classified into 2 patterns; those with presence of stripped interstitial fibrosis, subintimal diffuse/segmental arteriolar hyalinosis, negative C4d deposits, absence of transplant glomerulopathies and presence of periglomerular fibrosis were labeled as chronic changes attributed to calcineurin inhibitor (CNI) toxicity. The other group with variable fibrosis (and absence of stripped fibrosis) with superadded lymphoplasmacytic and/or neutrophilic infiltrates, with/without chronic transplant glomerulopathy, C4d deposits (diffuse/focal) across peritubular capillary membranes (by IF or IHC) and chronic transplant vasculopathy were attributed to chronic B-cell (antibody) mediated rejections with/without ongoing acute injuries. A subset of these biopsies was also subjected to CD20 stain by IHC to confirm B-cell involvement.