Mp Chacko

Nonspecific positivity on the Luminex crossmatch assay for anti-human leukocyte antigen antibodies due to antibodies directed against the antibody coated beads

Two cases are described of previously unreported false positivity on the Luminex crossmatch assay due to non HLA specific antibodies directed against the beads. In both cases the Luminex crossmatch indicated the presence of donor specific antibodies to class II HLA antigens, which was not substantiated by the clinical scenario or other assays. We could demonstrate the non specificity of these antibodies through using the same assay in a modified form where beads were unexposed to cell lysate and therefore did not carry HLA antigens at all. These cases further serve to emphasize the absolute necessity of correlating positive results with the priming history, and confirming their relevance using other platforms.

Significance of pre-transplant anti-HLA antibodies detected on an ELISA mixed antigen tray platform

This study aims at examining the clinical impact, of antibodies detected on an ELISA mixed antigen tray format (LATM, One Lambda) in the absence of complement dependent cytotoxicity (CDC) positivity. All patients who underwent renal transplantation in 2007 and 2008 had their final pre-transplant sera retrospectively analyzed by the LATM assay. These patients were then followed-up with clinical, biochemical, and histopathological end points defined by elevation of serum creatinine and/or histopathological criteria. Among 164 patients who were studied, 149 received grafts from live related donors and 15, from deceased donors. 31 (19%) of the transplanted patients demonstrated pre-transplant anti-HLA IgG antibodies on the assay. Totally, 15 were positive for class I antibodies, 4 for class II antibodies, and 12 for both class I and class II antibodies. 44 patients (36%) experienced rejection. 8 out of 31 (26%) ELISA positive patients and 36 out of 133 (27%) ELISA negative patients experienced rejection. Among 15 patients who received deceased donor transplants, 4 were positive for ELISA, and 11 were negative. All 4 (100%) of the ELISA positive patients experienced rejection as compared to 3 out of 11 (27%) ELISA negative patients (P = 0.01). The ELISA LATM assay did not show any predictive value for rejection in our overall patient population; however, results in the specific setting of deceased donor transplants merit further exploration.

Correlation of pretransplant donor-specific antibody assay using luminex crossmatch with graft outcome in renal transplant patients

The significance of pretransplant anti-human leukocyte antigen antibody levels that are detectable by more sensitive platforms (including the Luminex platform) yet undetected by complement-dependent cytotoxicity (CDC) assay remains unclear. The aim of this study was to determine the clinical significance of the donor-specific antibody (DSA) assay Luminex crossmatch and its impact on short-term renal graft outcome such as acute rejections, graft survival, and graft function. The results of pretransplant DSA-lymphocyte crossmatching (LCXM) assay in 126 renal allograft recipients whose CDCs crossmatches were negative were retrospectively analyzed for correlation with posttransplant outcomes. Of the 126 recipients, 32 (25.4%) had pretransplant DSA positive. Statistically significant association was found between DSA-LCXM positivity with 14th day estimated glomerular filtration rate (eGFR) (P = 0.05), DSA Class I with 3rd (P = 0.014) and 6th month (P = 0.02) eGFR, DSA Class II with 14th day (P = 0.06) and 1st month (P = 0.10) eGFR, mean fluorescent intensity (MFI) DSA with 7th day (P = 0.08) and 14th day (P = 0.09) eGFR, and maximum MFI DSA with 7th day eGFR (P = 0.09). The posttransplant eGFR was higher at various time intervals in DSA-LCXM-negative patients as compared to DSA-positive patients. However, pretransplant DSA-LCXM results did not predict the rejection episodes, graft loss, and 1-year posttransplant 24 h urine protein. Pretransplant DSA detected by LCXM in patients with a negative CDC does not predict adverse short-term outcomes. However, the difference in posttransplant eGFR supports further investigation in long-term effects.

Acute monoblastic leukemia with abnormal eosinophils and inversion (16): A rare entity

Acute myeloid leukemia (AML) is a malignant hematopoietic stem cell disorder which is sub-classified based on bone marrow morphology and the presence of specific genetic abnormalities. One such cytogenetic abnormality is the pericentric inversion (inv) of chromosome 16 which is typically seen in AML M4 with eosinophilia and is associated with a favorable prognosis. We report the inv (16) in a young woman with AML M5 and abnormal eosinophils. This is a rare entity with only about 20 cases being reported till date.

Pseudothrombocytopenia observed with ethylene diamine tetra acetate and citrate anticoagulants, resolved using 37°C incubation and Kanamycin.

Pseudothrombocytopenia (PTP) is defined by falsely low platelet counts on automated analyzers caused by in vitro phenomena including large platelet aggregates in blood samples. Diagnosis and resolution of PTP is crucial as it can lead to unwarranted interventions. We discuss a case of PTP in a pre-surgical setting, which was resolved using 37°C incubation and Kanamycin.