For successful renal transplantation, the recipient should not have donor specific Ig G antiboies (DSA). Ig M is inconsequential. Therefore the technique for renal cross match (XM) should be able to differentiate between Ig G and Ig M antibodies. Ordinarily three methods are available viz (a) flowcytometry cross match (FCXM) (b) Dithiothreitol (DTT.XM) and heat inactivation (H.I.XM).
METHODS: This study is based on 300 cases for whom renal XM was performed during the year 2004 with all three techniques. Efficiency of H.IXM to differentiate between DS Ig G and Ig M was evaluated against the other two techniques and the outcome of renal transplantation. H.IXM was done using two patient sera. One normal (N.XM) and the other is heat inactivated (H.I.XM). H.I is done by incubating patient serum at 63 °C for 10 minutes. Cases with positive N.XM, negative H.I.XM were reported as negative XM. In the last year we had 50 cases of positive B cell XM . Thirty nine became negative after heat inactivation while 11 remained positive. While only 34 cases became negative after DTT. XM and 16 remained positive. H.IXM was exactly comparable with FCXM. No hyperacute, acclerated or acute rejection (within 3 months) happened after transplantation of these 39 cases. Our study shows that H.IXM is highly effective in excluding DS Ig M antibodies. Not only that the results of H.I are fully comparable with FCXM that detects only Ig G DSA, but also all the patients testing negative with this technique had successful renal transplantation. H.I that is simple, cheap, speedy, and easy to perform and does not involve any extra-equipments or cost is highly recommendable.