kidney transplantation is the best form of renal replacement therapy ( rrt ) for end - stage renal disease ( esrd ) patients . only 10% of esrd patients receive any form of rrt in india and only 2% undergo renal transplantation . as per the indian chronic kidney disease ( ckd ) registry , 39% of ckd 5 abo incompatibility is an important limiting factor amongst willing donors , leading to rejection of approximately 35% donors . although it is being done at individual centers , there are no regional bodies to facilitate such exchanges between different centers and there is no national registry . also , many recipients are reluctant to accept kidney from donor outside their family in exchange of their own . abo - incompatible ( aboi ) transplant comes across as a viable alternative in such a scenario . although worldwide popularity of aboi renal transplant is increasing , experience from developing world is limited . major concerns are high cost , risk of antibody - mediated rejection and increased incidence of posttransplant infections . we hereby present experience of aboi renal transplant at our center , a tertiary care center in north india . this is a single center retrospective analysis of consecutive renal transplants from november 2011 , when the first aboi renal transplant was performed at our center , till august 31 , 2014 . a total of 20 aboi and 669 blood group compatible ( aboc ) renal transplants were done . once a suitable donor was identified , recipient serum was tested for igg and igm antibody titer against donor abo blood group antigens . this was done using column agglutination technology with low - ionic - strength saline - indirect antiglobulin test technique ( ortho - clinical diagnostics , johnson and johnson , usa ) . this method of antibody titer determination is known to be more sensitive than the conventional tube test . after a week , tacrolimus ( 0.05 mg / kg / day in two divided doses ) and mycophenolate sodium ( 720 mg twice daily ) were started , and patient was admitted for plasmapheresis . alternate day plasmapheresis was performed followed by administration of ivig ( 100 mg / kg / dose ) postplasmapheresis . low dose of rituximab and ivig were used based on previous published good outcomes with these doses . daily isoagglutinin igg titer was monitored , and transplantation was done once it reached 1:8 . of remaining 17 patients , first 5 received conventional plasma exchange while double filtration plasmapheresis ( dfpp ) was used for antibody removal in other 12 . dfpp leads to selective removal of the immunoglobulin fraction from the serum , minimizing the volume of substitution fluid required . intraoperatively , patients received intravenous methylprednisolone ( 500 mg ) and intravenous basiliximab ( 20 mg ) induction . dose of basiliximab was repeated on postoperative day four . one patient received anti - thymocyte globulin ( atg ) as inducing agent ( 1.5 mg / kg intravenous for two doses ) due to weakly positive b cell flowcytometry crossmatch and presence of donor specific antibodies . one of the renal transplant recipients did not receive any induction in view of presence of recent pulmonary tuberculosis . intravenous hydrocortisone was given on the day of transplant followed by oral prednisolone at 40 mg / day next day onward . isoagglutinin titer was monitored daily until discharge , and plasmapheresis was done in case of rising titers . all patients received trimethoprim - sulfamethoxazole prophylaxis for pneumocystis jiroveci infection and clotrimazole prophylaxis for fungal infection . valganciclovir prophylaxis was given to patients receiving atg induction or those with d+ r - cytomegalovirus ( cmv ) igg serology . but as patients pay for the cost of transplant and drugs , only 55% received basiliximab induction . thymoglobulin was offered to immunologically high - risk recipients such as those with previous history of multiple blood transfusions , second or more renal transplant , multiple pregnancies , and wife recipient . patients were followed up twice weekly for 1 month , weekly for next 1-month , once a fortnight till the 3 month and thereafter monthly for one year . after 1 year , follow - up was once in 23 months . during every visit , isoagglutinin titer was done twice weekly for 2 weeks post - discharge and weekly for next 2 weeks thereafter . tacrolimus / cyclosporine level was done as per the need , decided by the treating physician . tacrolimus trough level target was 812 ng / ml during first 3 months , 58 ng / ml from 3 to 6 months and < 5 ng / ml thereafter . cyclosporine trough target level was 250350 ng / ml during first 3 months , 100250 ng / ml from 3 to 6 months and < 100 ng / ml thereafter while c2 target level was 10001200 ng / ml during first 3 months and 6001000 ng / ml thereafter . prednisolone was tapered to 10 mg by the end of 3 months and 5 mg by the end of 6 months . protocol biopsy was performed at 3 months post - transplant for all aboi renal transplant recipients . graft biopsies were also performed whenever indicated such as in case of rising serum creatinine . acute cellular rejection was treated with intravenous methylprednisolone ( 500 mg od for three consecutive days ) . statistical analysis was done using medcalc for windows , version 12.7.8 ( medcalc software , belgium ) . continuous variables were compared using unpaired t - test while categorical values were compared using chi - square test or fisher 's exact test . this is a single center retrospective analysis of consecutive renal transplants from november 2011 , when the first aboi renal transplant was performed at our center , till august 31 , 2014 . a total of 20 aboi and 669 blood group compatible ( aboc ) renal transplants were done once a suitable donor was identified , recipient serum was tested for igg and igm antibody titer against donor abo blood group antigens . this was done using column agglutination technology with low - ionic - strength saline - indirect antiglobulin test technique ( ortho - clinical diagnostics , johnson and johnson , usa ) . this method of antibody titer determination is known to be more sensitive than the conventional tube test . patients received intravenous rituximab ( 200 mg ) 2 weeks pretransplant . after a week , tacrolimus ( 0.05 mg / kg / day in two divided doses ) and mycophenolate sodium ( 720 mg twice daily ) were started , and patient was admitted for plasmapheresis . alternate day plasmapheresis was performed followed by administration of ivig ( 100 mg / kg / dose ) postplasmapheresis . low dose of rituximab and ivig were used based on previous published good outcomes with these doses . daily isoagglutinin igg titer was monitored , and transplantation was done once it reached 1:8 . of remaining 17 patients , first 5 received conventional plasma exchange while double filtration plasmapheresis ( dfpp ) was used for antibody removal in other 12 . dfpp leads to selective removal of the immunoglobulin fraction from the serum , minimizing the volume of substitution fluid required . intraoperatively , patients received intravenous methylprednisolone ( 500 mg ) and intravenous basiliximab ( 20 mg ) induction . dose of basiliximab was repeated on postoperative day four . one patient received anti - thymocyte globulin ( atg ) as inducing agent ( 1.5 mg / kg intravenous for two doses ) due to weakly positive b cell flowcytometry crossmatch and presence of donor specific antibodies . one of the renal transplant recipients did not receive any induction in view of presence of recent pulmonary tuberculosis . intravenous hydrocortisone was given on the day of transplant followed by oral prednisolone at 40 mg / day next day onward . isoagglutinin titer was monitored daily until discharge , and plasmapheresis was done in case of rising titers . all patients received trimethoprim - sulfamethoxazole prophylaxis for pneumocystis jiroveci infection and clotrimazole prophylaxis for fungal infection . valganciclovir prophylaxis was given to patients receiving atg induction or those with d+ r - cytomegalovirus ( cmv ) igg serology . but as patients pay for the cost of transplant and drugs , only 55% received basiliximab induction . thymoglobulin was offered to immunologically high - risk recipients such as those with previous history of multiple blood transfusions , second or more renal transplant , multiple pregnancies , and wife recipient . patients were followed up twice weekly for 1 month , weekly for next 1-month , once a fortnight till the 3 month and thereafter monthly for one year . after 1 year , follow - up was once in 23 months . during every visit , renal function tests including serum creatinine and hemogram were monitored . isoagglutinin titer was done twice weekly for 2 weeks post - discharge and weekly for next 2 weeks thereafter . tacrolimus / cyclosporine level was done as per the need , decided by the treating physician . tacrolimus trough level target was 812 ng / ml during first 3 months , 58 ng / ml from 3 to 6 months and < 5 ng / ml thereafter . cyclosporine trough target level was 250350 ng / ml during first 3 months , 100250 ng / ml from 3 to 6 months and < 100 ng / ml thereafter while c2 target level was 10001200 ng / ml during first 3 months and 6001000 ng / ml thereafter . prednisolone was tapered to 10 mg by the end of 3 months and 5 mg by the end of 6 months . protocol biopsy was performed at 3 months post - transplant for all aboi renal transplant recipients . graft biopsies were also performed whenever indicated such as in case of rising serum creatinine . acute cellular rejection was treated with intravenous methylprednisolone ( 500 mg od for three consecutive days ) . statistical analysis was done using medcalc for windows , version 12.7.8 ( medcalc software , belgium ) . continuous variables were compared using unpaired t - test while categorical values were compared using chi - square test or fisher 's exact test . table 1 shows the demographic characteristics of the 2 groups ( i.e. , aboi and aboc ) . significantly more number of patients in aboi group had chronic glomerulonephritis as the native kidney disease . all the transplants in aboi group were live related ones while in aboc group 0.8% ( n = 6 ) were deceased donor transplants . demographic characteristics and clinical profile of patients table 2 shows the donor and recipient blood group distribution , starting antibody - titer and number of dfpp sessions required . the majority were o - blood group recipients ( 50% ) followed by a and b ( 25% each ) . blood group and titer distribution in aboi group recipient outcome is presented in table 3 . mean duration of follow - up was 10.15  9.34 months and 16.67  9.63 months in aboi and aboc groups respectively . patient and death censored graft survival was comparable between groups ( p = 1 ) . figures 1 and 2 show kaplan  meier curves comparing patient and death censored graft survival between the two groups . serum creatinine values at discharge and after 1-month were also comparable ( p = 0.23 and 0.24 respectively ) . although he had longstanding history of diabetes and hypertension , his pretransplant cardiac evaluation was normal . there were no neutrophils or mononuclear cells in peritubular capillaries or glomeruli ; neither there was any acute tubular injury . staining for c4d in peritubular capillaries was negative . upper gastro - intestinal endoscopy showed hemorrhagic and necrotic ulcerative lesions in esophagus and stomach . biopsy from these lesions revealed mucormycosis . also , there was evidence of intranuclear inclusion bodies in gastric mucosa suggestive of cmv gastritis . he was treated with intravenous liposomal amphotericin b ( 3 mg / kg / day ) and intravenous ganciclovir ( 2.5 mg / kg / day ) . exploratory laparotomy was done which showed 3 cm  3 cm rent in posterior wall of stomach . ( aboi : abo incompatible ; aboc : abo compatible ) kaplan  meier graph comparing death censored graft survival between aboi and aboc group . ( aboi : abo incompatible ; aboc : abo compatible ) on analysis , infection rates were not significantly different between the aboi and aboc groups ( p = 0.16 ) . of 8 patients whose biopsy was done for indication , two had delayed graft function . of these , one had thrombotic microangiopathy as described above while another had diffuse cortical necrosis secondary to graft renal vein thrombosis . one patient had slow decline of serum creatinine in posttransplant period . in him , first renal biopsy showed acute tubular necrosis and protocol biopsy after 3 months showed borderline cellular rejection , which did not require any treatment , as renal function was stable . in 1950s and 60s , initial attempts to do aboi transplant in usa were met with high failure rate and very poor graft survival . it was concluded that abo compatibility is a necessary prerequisite for successful renal transplant . in 1987 , alexandre et al . showed that successful aboi transplants with good graft outcome could be achieved using pretransplant desensitization ( or preconditioning ) protocol . he used plasma exchange to remove anti - a or anti - b antibodies and splenectomy to prevent further antibody production . subsequently , large number of aboi transplants was done in japan using preconditioning protocol of plasma exchange and splenectomy with good graft and patient outcome . later , it was realized that chemical splenectomy using anti - cd20 monoclonal antibody - rituximab can replace surgical splenectomy with good results and splenectomy associated complications could be avoided . the majority of the european centers have used immunoadsorption , ivig and rituximab based protocols with good success . in united states , selective methods of antibody removal such as immunoadsorption and dfpp is being preferred these days as large plasma volumes can be processed , and risk of bleeding due to elimination of coagulation factors is minimized . lately , in an effort to reduce overall immunosuppression , flint et al . and montgomery et al . have done aboi renal transplants without rituximab in their protocols with good graft and patient survival outcome . in our center , we have used preconditioning protocol of rituximab and conventional plasma exchange ( 5 patients)/dfpp ( 12 patients ) followed by ivig . ( 97% ) , flint et al.(100% ) , and lipshutz et al.(94.4% ) . in the present study , death censored graft survival and patient survival of aboi recipients were comparable to that of aboc group . these findings are similar to that of study by genberg et al . in our study , serum creatinine at 1-month was similar between the 2 groups without any significant difference . rate of biopsy proven acute rejection was comparable between the groups . this was better than the bpar of 40% in a study by wilpert et al . with similar immunosuppression protocol . reported bpar of 11% in their aboi recipients while it was 32% in a study by uchida et al . most of the studies have reported higher incidence of antibody - mediated rejection in aboi recipients , which has varied from 5 to 33% . in our study , although one patient had tma on biopsy , other features of amr such as neutrophils or mononuclear cells in peritubular capillaries or glomeruli , acute tubular injury and c4d deposition in peritubular capillaries , were missing . in addition , his renal function improved after stopping tacrolimus , which supported it to be drug induced tma . graft biopsies showed c4d staining in 53% of cases . in various studies , c4d positivity in protocol graft biopsies has been seen in 8094% of patients and does not necessarily indicate antibody - mediated rejection . in fact , it may represent the phenomenon of accommodation , in which the graft continues to function normally despite the presence of anti - blood group antibodies . the infection rate in aboi recipients was 15% , which was comparable to aboc group . most studies have shown a trend toward higher infection rate amongst aboi transplant recipients , varying from 18 to 50% . there are some limitations of our study : the sample size of aboi group is small . also , the immunosuppression protocol was variable for aboc group as mentioned in materials and methods . follow - up of patients is short , and hence long - term outcome can not be commented upon . concluding , published reports of aboi transplant experience from developing countries are very few . rate of biopsy proven acute rejection was at par with abo compatible ones and more importantly there were no antibody - mediated rejections . the incidence of posttransplant infections , which is a major concern in developing world , was acceptable and , in fact , lower than other similar studies . our experience has been encouraging so far and proves that it is the right time for widespread implementation of aboi transplants even in developing countries .
abo incompatibility has been considered as an important immunological barrier for renal transplantation . with the advent of effective preconditioning protocols , it is now possible to do renal transplants across abo barrier . 
 we hereby present a single center retrospective analysis of all consecutive aboi renal transplants performed from november 2011 to august 2014 . preconditioning protocol consisted of rituximab , plasmapheresis and intravenous immunoglobulin ( ivig ) and maintenance immunosuppression consisted of tacrolimus , mycophenolate sodium , and prednisolone . 
 the outcome of these aboi transplants was compared with all other consecutive abo - compatible ( aboc ) renal transplants performed during same time . 
 twenty aboi renal transplants were performed during the study period . 
 anti - blood group antibody titer varied from 1:2 to 1:512 . 
 patient and graft survival was comparable between aboi and aboc groups . 
 biopsy proven acute rejection rate was 15% in aboi group , which was similar to aboc group ( 16.29% ) . 
 there were no antibody - mediated rejections in aboi group . 
 the infection rate was also comparable . 
 we conclude that the short - term outcome of aboi and aboc transplants is comparable . 
 aboi transplants should be promoted in developing countries to expand the donor pool .