Geoffrey A. Land

Donor-specific HLA-DQ antibodies may contribute to poor graft outcome after renal transplantation

Increasing evidence suggests a detrimental effect of donor-specific antibodies directed against the human leukocyte antigen (HLA)-A, -B, and -DR loci on renal allograft outcomes. Limited data exist on the impact of de novo HLA-DQ antibodies. Over a 3-year period, we prospectively monitored 347 renal transplant recipients without pre-transplant donor-specific antibodies for their development de novo. After 26 months of follow-up, 62 patients developed donor-specific antibodies, of which 48 had a HLA-DQ antibody either alone (33 patients) or in combination with an HLA-A, -B, or -DR antibody (15 patients). Only 14 patients developed a donor-specific HLA-A, -B, or -DR antibody without a HLA-DQ antibody present. Acute rejection occurred in 21% of the HLA-DQ-only patients, insignificant when compared with 11% of patients without donor-specific antibodies. At the last follow-up, the mean serum creatinine and the fraction of patients with proteinuria were significantly higher in those that developed only HLA-DQ than those without antibodies. The 3-year graft survival was significantly worse when HLA-DQ antibodies were combined with non-DQ antibodies (52%) compared with HLA-DQ alone, non-DQ antibodies alone, or no antibodies (92-94%). Thus, our prospective monitoring study found that donor-specific HLA-DQ antibodies were the most common type detected and these antibodies may contribute to inferior graft outcomes. Ongoing surveillance is necessary to determine the long-term outcome of patients developing HLA-DQ donor-specific antibodies.

Strategy for Rapid Identification and Antibiotic Susceptibility Testing of Gram-Negative Bacteria Directly Recovered from Positive Blood Cultures Using the Bruker MALDI Biotyper and the BD Phoenix System

ABSTRACT Decreasing the time to species identification and antibiotic susceptibility determination of strains recovered from patients with bacteremia significantly decreases morbidity and mortality. Herein, we validated a method to identify Gram-negative bacteria directly from positive blood culture medium using the Bruker MALDI Biotyper and to rapidly perform susceptibility testing using the BD Phoenix.

Intermediate-Term Graft Loss After Renal Transplantation is Associated With Both Donor-Specific Antibody and Acute Rejection

Background Renal transplant recipients with de novo DSA (dDSA) experience higher rates of rejection and worse graft survival than dDSA-free recipients. This study presents a single-center review of dDSA monitoring in a large, multi-ethnic cohort of renal transplant recipients. Methods The authors performed a nested case-control study of adult kidney and kidney-pancreas recipients from July 2007 through July 2011. Cases were defined as dDSA-positive whereas controls were all DSA-negative transplant recipients. DSA were determined at 1, 3, 6, 9, and 12 months posttransplant, and every 6 months thereafter. Results Of 503 recipients in the analysis, 24% developed a dDSA, of whom 73% had dDSA against DQ antigen. Median time to dDSA was 6.1 months (range 0.2–44.6 months). After multivariate analysis, African American race, kidney-pancreas recipient, and increasing numbers of human leukocyte antigen mismatches were independent risk factors for dDSA. Recipients with dDSA were more likely to suffer an acute rejection (AR) (35% vs. 10%, P<0.001), an antibody-mediated AR (16% vs. 0.3%, P<0.001), an AR ascribed to noncompliance (8% vs. 2%, P=0.001), and a recurrent AR (6% vs. 1%, P=0.002) than dDSA-negative recipients. At a median follow-up of 31 months, the death-censored actuarial graft survival of dDSA recipients was worse than the DSA-free cohort (P=0.002). Yet, for AR-free recipients, there was no difference in graft survival between cohorts (P=0.66). Conclusions Development of dDSA was associated with an increased incidence of graft loss, yet the detrimental effect of dDSA was limited in the intermediate term to recipients with AR.

Organ procurement and transplantation network/united network for organ sharing histocompatibility committee collaborative study to evaluate prediction of crossmatch results in highly sensitized patients.

Background. The requirement for a prospective crossmatch limits some organ allocation to local areas. The delay necessitated by the crossmatch restricts the distance across which offers can be made without unduly increasing the ischemia time. A collaborative study involving 14 transplant centers was undertaken by the Organ Procurement and Transplantation Network/United Network for Organ Sharing (OPTN/UNOS) Histocompatibility Committee to evaluate the accuracy with which the detection of unacceptable human leukocyte antigen (HLA) antigens by most advanced solid phase immunoassays can predict crossmatch results. In addition, using actual patients’ unacceptable HLA antigens, the number of compatible donors that would have been available from the OPTN deceased kidney donors during 2002 to 2004 were investigated. Methods. Panel reactive antibodies were performed by conventional or solid phase assays, and crossmatches were performed by cytotoxicity or flow cytometry. Analyses were stratified for T and B cell and by method of identifying unacceptable HLA antigens and crossmatch techniques. Results. Combination of solid phase immunoassays and flow cytometry crossmatches resulted in a higher prediction rates of positive T cell (86.1%–93.5%) and B-cell crossmatches (91%–97.8%). Prediction of negative crossmatches based on different combination of panel reactive antibodies and crossmatch techniques varied from 14.3% to 57.1%. Furthermore, numerous potential compatible donors were identified for each patient, regardless of their ethnicity, in the OPTN database, when predicted incompatible ones were excluded. Conclusions. The above results showed that with the advent of solid phase immunoassays, HLA antibodies can now be accurately detected resulting in prediction of crossmatch outcome. This should facilitate organ allocation and prevents shipment of organs to distant incompatible recipients.

Improved definition of human leukocyte antigen frequencies among minorities and applicability to estimates of transplant compatibility

Background. HLA population data can be applied to estimates of waiting time and probabilities of donor compatibility. Registry data were used for derivation of HLA antigen and haplotype frequencies in a 1996 report. At that time there were several instances of significant deviation from Hardy Weinberg Equilibrium (HWE). Because molecular typing has been increasingly used since 1996, analysis of recent donor phenotypes should provide more accurate HLA frequencies. Methods. HLA frequencies were derived from the phenotypes of 12,061 donors entered into the Organ Procurement and Transplantation Network registry from January 1, 2003 to December 31, 2004. Frequencies for HLA-A;B;DR and HLA-A;B, DR, DQ haplotypes were derived from 11,509 and 10,590 donors, respectively. Frequencies of the allele groups encoding serologic antigens were obtained by gene counting and haplotype frequencies were estimated using the expectation maximization algorithm. Fit to HWE was evaluated by an exact test using Markov Chain Monte Carlo methods. Results. There was clear evidence of improved definition of rarer HLA antigens and haplotypes, particularly among minorities. The reported frequencies of broad antigens decreased overall for HLA-A, B, and DR, with concomitant increases in split antigens. Allele group genotypes among the major ethnic groups were in HWE with the single exception of HLA-A locus alleles among Asians. Improved HLA definition also permitted the first report of DR;DQ and A;B;DR;DQ haplotypes among U.S. donors. Conclusions. The noted improvements in HLA definition and the overall lack of significant deviation from HWE indicate the accuracy of these HLA frequencies. These frequencies can therefore be applied for representative estimates of the U.S. donor population.

Mycobacterial synovitis caused by slow-growing nonchromogenic species : Eighteen cases and a review of the literature

CONTEXT Slow-growing nonchromogenic mycobacterial species are an infrequent cause of soft tissue infection. Because these organisms are rare, they are not often initially considered in the differential diagnosis of synovitis. OBJECTIVE To evaluate the clinical and pathologic characteristics of patients with synovitis resulting from slow-growing nonchromogenic mycobacterial species. DESIGN A 20-year retrospective review of records from The Methodist Hospital Microbiology Laboratory identified 18 culture-positive cases of synovitis that resulted from slow-growing nonchromogenic mycobacteria, including 14 caused by Mycobacterium avium complex, 1 caused by Mycobacterium malmoense, 1 caused by Mycobacterium haemophilum, and 2 caused by Mycobacterium nonchromogenicum isolates. In addition, a comprehensive literature search revealed an additional 48 cases of synovitis caused by slow-growing nonchromogenic mycobacteria. RESULTS The historic literature described the majority of the 48 patients as previously healthy, elderly individuals with a several-month history of monoarticular pain and swelling in the small joints of the upper extremity. In contrast, the current series demonstrated the probable role of multiple chronic coexisting medical conditions in promoting disease susceptibility. These patients were also unique in their significantly younger age distribution and diversity of infection sites. Histologic examination and direct acid-fast bacteria stains generally did not aid the diagnosis. Amputation was performed in 2 patients because of delayed identification of disease. CONCLUSIONS The current series demonstrates that difficult identification and infrequent occurrence cause these organisms to be overlooked by physicians and laboratory personnel. A heightened clinical suspicion for slow-growing nonchromogenic mycobacterial species is necessary when routine culture and histopathologic findings do not readily isolate an organism, or when the patient does not respond to antibiotic and anti-inflammatory treatment.

Comparison of panel-reactive antibody levels in Caucasian and African American renal transplant candidates

PRA levels from 58 Caucasian and 70 African American ESRD patients were compared against a panel of cryopreserved lymphocytes from 60 donors (40 Caucasian, 15 African American, 5 others) to determine whether there was significant racial influence on PRA outcome. African Americans were found to have significantly higher mean PRA levels than Caucasians (27% vs. 18%, P=0.02). Restricting this analysis to only 1° transplant candidates showed predictably lower mean PRAs: 6% in Caucasians and 15% in African Americans, but the difference between the two groups remained significant (P=0.015). The percentage of patients with PRA≥10% was also greater among African Americans than Caucasians (43% vs. 24%, P=0.026). For patients not previously transplanted, the difference between these frequencies remained significant: 11% in Caucasians, 30% in African Americans (P=0.025). Untransplanted African American patients with positive PRAs (a 10%) had significantly higher PRA against African American cell donors (mean = 55%) than against Caucasian cell donors (mean = 44%) (mean difference = 10.6%, P=0.0056). African Americans were more frequently transfused than Caucasians. The percentage of patients not previously transplanted receiving 0, 1–5, and >5 transfusions were 69%, 22%, and 9% for Caucasians and 43%, 44%, and 13% for African Americans (P=0.03). This higher transfusion rate is the most likely contributor to the elevated PRA levels observed in African Americans.

The Presence of Anti-HLA Donor-Specific Antibodies in Lung Allograft Recipients Does Not Correlate With C4d Immunofluorescence in Transbronchial Biopsy Specimens

CONTEXT C4d immunofluorescence (IF) is a surrogate for development of donor-specific antibodies (DSAs) against human leukocyte antigen (HLA) class I and II antigens in kidney and heart biopsy specimens for monitoring of antibody-mediated (humoral) allograft rejection (AMR). Use of C4d IF in monitoring of lung allografts has shown conflicting results. OBJECTIVE To determine if C4d IF can be used as a reliable marker for AMR and if it correlates with the presence of DSAs and histologic findings on biopsy. DESIGN All transbronchial biopsies in lung allograft recipients, performed at our institution in a 3-year period, were reviewed. A cohort of 92 patients with 110 corresponding biopsies met the inclusion criteria of (1) having a resulted DSA within 2 weeks of biopsy and (2) having C4d immunofluorescence studies performed and confirmed. RESULTS Twenty-nine patients (31.5%) were positive for DSAs and 63 patients (68.5%) did not develop DSAs. Positive C4d capillary IF was seen in 18 of 110 total biopsy specimens (16.4%). Eight of these biopsy samples were from patients positive for DSAs and 10 were from patients negative for DSAs. The correlation coefficient between the presence of DSAs and C4d IF was 0.1628 (P = .09). CONCLUSIONS A significant proportion of DSA-positive patients had negative C4d IF results and frequently have no histologic changes on biopsy specimens. DSA-negative patients can be positive for C4d and may show the same histologic changes as reported for DSA-positive patients. Diagnosis of AMR in lung may require a collaborative approach combining clinical data, DSA status, and histology.

Outcomes of living donor renal transplants with a negative cross-match and pretransplant donor-specific antibody

INTRODUCTION Management of renal transplant recipients with a negative complement-dependent cytotoxicity-antihuman globulin (CDC-AHG) cross-match and pretransplant donor-specific antibody (DSA) is controversial. We sought to compare outcomes of immunologically high-risk living donor (LD) renal transplant recipients with and without DSA. METHODS We conducted a single-center, retrospective review of all high immune-risk LD renal transplant recipients with a negative CDC-AHG cross-match performed between January 2008 and December 2010. Pretransplant desensitization for DSA was not utilized. Immunosuppression consisted of thymoglobulin induction, followed by tacrolimus, myeophenolate mofetil, and prednisone. DSA was assessed pretransplant and at 1, 3, 6, 9, and 12 months, and every 6 months thereafter. RESULTS Between January 2008 and December 2010, 44 LD renal transplants were performed in high immune-risk recipients with a negative CDC-AHG cross-match. Outcomes of 14 recipients with pretransplant DSA were compared with 30 recipients with no DSA. After a median follow-up of 26 months (range, 12-40), overall death-censored graft survival was 100%, with no acute rejection episodes in the DSA group and 1 antibody-mediated rejection in the non-DSA cohort. Mean serum creatinines of the DSA and non-DSA groups at 1 year post-transplant were 1.0 ± 0.4 and 1.2 ± 0.6 mg/dL (P = NS), respectively. Among the pretransplant DSA cohort, 5 of the 14 (36%) developed persistent post-transplant DSA at a median of 9 months (range, 3-24) versus 2 of 30 (7%; P = .025) at a median of 12 months post-transplant in the non-DSA cohort. All recipients in the pretransplant DSA group underwent renal biopsy for persistent post-transplant DSA. Three of 5 biopsies showed C4D deposition in peritubular capillaries without glomerulopathy or arteriopathy. CONCLUSIONS Early post-transplant outcomes for LD recipients with a negative cross-match and pretransplant DSA were excellent. In recipients with good and stable renal function, the significance of persistent post-transplant DSA in combination with C4D deposition on biopsy is unclear at this time.

Performance Assessment of the Fecal Leukocyte Test for Inpatients

ABSTRACT Traditionally, fecal leukocyte testing detects large bowel inflammation or disruption, conditions that allow leukocytes into the stool. However, test usefulness with inpatients is unclear. Two hundred five inpatients who had undergone one to three tests were identified, and their FLT results were compared to their gastrointestinal disease diagnoses at time of discharge. A specificity of 92% for detecting intact colonic mucosae in inpatients was found.