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Saudi Journal of Kidney Diseases and Transplantation
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Table of Contents   
CASE REPORT  
Year : 2020  |  Volume : 31  |  Issue : 1  |  Page : 289-293
Red herrings in crossmatching kidneys for transplant


1 Department of Nephrology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
2 Department of Pathology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

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Date of Submission28-Jan-2019
Date of Acceptance16-Mar-2019
Date of Web Publication3-Mar-2020
 

   Abstract 


Crossmatching of prospective renal transplant donors against recipients is a mandatory component of the transplant workup, being performed for over 40 years now. Allografting patients with human leukocyte antigens which are recognized by preformed antibodies constitutes the main cause of hyperacute or acute rejections. The existence of these donor-specific anti-human leukocyte antigen antibodies (DSAs) is regarded as a contraindication for graft trans-plantation, both cadaveric and live kidney. We present two unusual cases in which both complement-dependent cytotoxicity crossmatch and DSA by Luminex were falsely positive due to autoimmune and infectious causes, but single-antigen bead assay showed these antibodies to be against nondonor antigens. After treating their basic disease, thought to be responsible for false-positive DSA, these patients became DSA negative and underwent transplantation with an uneventful posttransplant period. Our aim through these examples is to highlight the problem of false-positive crossmatch in potential renal allograft transplant recipients. Further, we propose antigenic determination of donor-specific antibodies in such patients where we suspect the immune system to be chronically activated to pick up false-positive cases and therefore increase the donor pool without compromising the transplant outcome.

How to cite this article:
Wani A, Kaul A, Bhaduaria DS, Zahir Z, Prasad N, Gupta A, Sharma RK. Red herrings in crossmatching kidneys for transplant. Saudi J Kidney Dis Transpl 2020;31:289-93

How to cite this URL:
Wani A, Kaul A, Bhaduaria DS, Zahir Z, Prasad N, Gupta A, Sharma RK. Red herrings in crossmatching kidneys for transplant. Saudi J Kidney Dis Transpl [serial online] 2020 [cited 2020 Jun 2];31:289-93. Available from: http://www.sjkdt.org/text.asp?2020/31/1/289/279956



   Introduction Top


Crossmatching of prospective renal donors against potential renal transplant recipients is a mandatory component of the transplant work- up process and has been performed for over 40 years now. Allografting patients with human leukocyte antigens (HLAs) which are recognized by preformed antibodies constitutes the main cause of hyperacute or acute rejections. Over the years, techniques have evolved from complement-dependent cytotoxicity crossmatch (CDC-XM) to much advanced techniques to determine donor-specific antibody-mediated responses including flow crossmatching and the “virtual” crossmatch.[1] These techniques devised to detect donor-specific sensitization are predictive of rejection and serve as a guide to devise treatment strategy. The existence of these donor-specific anti-HLA antibodies (DSA) is regarded as a contraindication for graft transplantation, both cadaveric and live kidneys.[2]

The procedure (CDC-XM) requires incubation of donor-isolated B- and T-lymphocytes with the recipient serum. If anti-HLA-anti- bodies are present in the serum, then the donor cells lyse as a result of complement-dependent cytotoxicity.[3] Positive CDC-XM can be observed in other situations, notably in recipients with an autoimmune disease[2] or preexisting antibodies not detected by singleantigen bead array due to complement inter- ference[4] or previously treated by desensi- tization protocols such as rituximab (RTX), antithymocyte globulin, and intravenous immunoglobulins.[5] In the prospective setting, an unexpected positive CDC-XM must be rapidly documented to avoid nonaccessibility to the transplant.

We present two unusual cases in which both CDC-XM and DSA by Luminex were falsely positive due to autoimmune and infectious causes.


   Case Reports Top


Case 1

A 24-year-old male patient with Class IV lupus nephritis (LN), after treatment as per the Euro-Lupus Protocol followed by maintenance with azathiopine, progressed to end-stage renal disease (ESRD), and repeat kidney biopsy showed features of diffuse global glomerulo- sclerosis. The patient was started on maintenance hemodialysis (HD) after he developed uremic symptoms. He was advised renal transplant with his mother as a prospective donor. CDC-XM was done which came to be positive repeatedly. Further, HLA DSA by Luminex was also positive for both Class I and Class II antigens. In view of positive CDC as well as DSA, transplant workup with his father as donor was then started. With the second donor also, both CDC-XM and HLA DSA for both Class 1 and Class II antigens were positive. Single-antigen bead assay was done which revealed positivity against A29, B37, and Cw06 of HLA Class I antigens and also positivity against DQ2 HLA Class II antigens. However, these antigens were not positive in either of the prospective donors of the recipient as shown in [Table 1]. Due to the presence of nondonor antibodies, a suspicion of falsepositive antibodies was thought. Anti-dsDNA titer was >300 IU/mL, and both C3 and C4 levels were low. Almost all patients of LN who progress to ESRD have substantial decrease in their disease activity due to reduced innate and adaptive immune responses.[6] Some studies report that the clinical and/or serological activity persists in at least half of the patients studied.[7] Our patient was one among those who had persistence of disease activity even when on ESRD.
Table 1: HLA typing of recipient and donor of case 1.

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In view of persistently high disease activity, as evident from persistent hypocomplemen- temia and high antibody load, he was started on high-dose steroids with tapering over the next three months. After 1½ months of treatment, CDC-XM with his mother became negative. Complement levels this time were normal, and anti-dsDNA levels also reduced (25 IU/mL). Normocomplementemia and normal dsDNA levels persisted for another six months, after which the patient was planned for kidney transplant. Final CDC and HLA DSA, for both Class I and II, were negative, and the patient underwent renal transplant. The posttransplant period was uneventful with no history of rejections even at one year of follow-up.

Case 2

Our second case is a 34-year-old male, presumed to have chronic glomerulonephritis as native kidney disease, who had undergone 1st kidney transplant with his mother as donor. After five years of transplant, the patient developed proteinuric graft dysfunction, and graft kidney biopsy done was suggestive of transplant glomerulopathy which progressed relentlessly to graft loss in spite of optimized immunosuppression, antiproteinuric medications, and tight blood pressure control. The patient also developed anemia for which he was transfused three pints of packed red blood cells. In the meantime, he was initiated on maintenance HD and was planned for 2nd kidney transplant with his wife as a prospective donor. CDC-XM with his wife was positive for B-cell CDC-XM but negative for T-cell CDC-XM. High rate of false-positive results of B-cell CDC-XM (up to 50%)[8] should not be used alone to determine transplant suitability and should be interpreted only in light of accompanying DSA by Luminex results.[9] Hence, DSA was done which came to be positive for both Class 1 and Class II antigens. However, single-antigen bead assay tested negative for donor HLA antigens. HLA typing for patient and donor was done as shown in [Table 2].
Table 2: HLA typing of recipient and donor of case 2.

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Around the same time, he was detected to be hepatitis C positive, genotype 3, with a viral load of 640,612 IU/mL. The patient was started on pegylated interferon-based treatment. By six months, he had achieved sustained viral response with hepatitis C virus (HCV) RNA polymerase chain reaction, showing no DNA levels detected. Repeat CDC and DSA done were negative. The patient underwent kidney transplant successfully with uneventful postoperative period and no early graft rejections.


   Discussion Top


Conventionally, over 50% of potential living donors otherwise suitable for donation could not undergo donation because immunologic screening of the recipient revealed circulating donor-specific antibodies.[10] It has been validated in the past that the presence of DSA portends inferior graft survival in comparison to absence of DSA even when CDC-XM were negative.[11] Over the years, techniques have evolved from CDC-XM to much advanced techniques which determine donor-specific antibody-mediated responses. These modalities have their own sensitivities and specificities of detecting donor-specific antibodies. The CDC-XM assay detects only those antibodies which exert their allogeneic function via the activation of the complement system, finally leading to the lysis of donor cells. To include complement-independent DSA, flow cytometric XM was devised which detected both complement-activating and complement- independent DSA. Later on, DSA by Luminex came in vogue because of its advantage of removing false positives due to antibody binding to non-HLA antigens.

Usually, the higher the sensitivity of a crossmatch test, lesser will be its specificity. Like every serological test, false positivity in crossmatch is often found. The main issue in patients who have to undergo kidney transplantation is positive crossmatch by one or more modalities of testing. Earlier, we did not have much to offer to these patients in view of the fact that most transplant guidelines state positive crossmatch as a contraindication to transplant with that particular donor.

Our aim to discuss the above-cited two exemplary cases is to highlight certain situations in crossmatching where results are not reliable when conventional CDC-based technique or even solid-phase assays are used. A positive crossmatch in a “nondonor antigen sensitized” individual is not so a rare problem in renal transplantation. We aim to demonstrate the fact that positive crossmatch should not always be taken as an absolute contraindication to transplant, especially in patients with autoimmune or infectious diseases. Our cases demonstrated donor-specific antibodies, but neither of them had anti-HLA antibodies to the donor antigens. One case studied had a positive auto crossmatch indicating an autoimmune disease, such as lupus, that we suspect was causing the nonspecific binding of immunoglobulin G. In the second case, the pattern of crossmatch positivity and HCV levels coincided. When after treatment with anti-HCV drugs, the levels of HCV were undetectable, crossmatch, by both CDC and DSA by Luminex, became negative. There are case reports where systemic lupus erythema- tosus leading to false-positive crossmatch has been described.[2],[12] However, to our knowledge, there has been no case reported till date where HCV has been incriminated as a reason for false-positive crossmatch. The fact that both these patients had an uneventful course after transplantation is also an indirect evidence of the fact that crossmatch antibodies were falsely positive in them.


   Conclusion Top


We propose to go for the antigenic determination of donor-specific antibodies in such patients where we suspect the immune system to be chronically activated. This practice will enable us to pick up irrelevant false-positive antibodies which would have otherwise led to the exclusion of a donor for a much-needed transplant. This approach will thus increase the donor pool and would, to some extent, decrease the alarming crisis of organ shortage.

Conflict of interest: None declared.



 
   References Top

1.
Mulley WR, Kanellis J. Understanding crossmatch testing in organ transplantation: A case- based guide for the general nephrologist. Nephrology (Carlton) 2011;16:125-33.  Back to cited text no. 1
    
2.
Schlaf G, Pollok-Kopp B, Schabel E, Altermann W. Artificially positive crossmatches not leading to the refusal of kidney donations due to the usage of adequate diagnostic tools. Case Rep Transplant 2013;2013: 746395.  Back to cited text no. 2
    
3.
Desoutter J, Apithy MJ, Bartczak S, Guillaume N. False positive B-cells crossmatch after prior rituximab exposure of the kidney donor. Case Rep Transplant 2016;2016:4534898.  Back to cited text no. 3
    
4.
Visentin J, Vigata M, Daburon S, Contin- Bordes C, Fremeaux-Bacchi V, Dromer C, et al. Deciphering complement interference in anti-human leukocyte antigen antibody detection with flow beads assays. Transplantation 2014;98:625-31.  Back to cited text no. 4
    
5.
Milongo D, Vieu G, Blavy S, et al. Interference of therapeutic antibodies used in desensitization protocols on lymphocytotoxi- city crossmatch results. Transpl Immunol 2015;32:151-5.  Back to cited text no. 5
    
6.
Sabucedo AJ, Contreras G. ESKD, transplantation, and dialysis in lupus nephritis. Semin Nephrol 2015;35:500-8.  Back to cited text no. 6
    
7.
Mattos P, Santiago MB. Disease activity in systemic lupus erythematosus patients with end-stage renal disease: Systematic review of the literature. Clin Rheumatol 2012;31:897- 905.  Back to cited text no. 7
    
8.
Le Bas-Bernardet S, Hourmant M, Valentin N, et al. Identification of the antibodies involved in B-cell crossmatch positivity in renal transplantation. Transplantation 2003;75:477-82.  Back to cited text no. 8
    
9.
Eng HS, Bennett G, Tsiopelas E, et al. Anti- HLA donor-specific antibodies detected in positive B-cell crossmatches by Luminex predict late graft loss. Am J Transplant 2008; 8:2335-42.  Back to cited text no. 9
    
10.
Karpinski M, Knoll G, Cohn A, Yang R, Garg A, Storsley L. The impact of accepting living kidney donors with mild hypertension or proteinuria on transplantation rates. Am J Kidney Dis 2006;47:317-23.  Back to cited text no. 10
    
11.
Amico P, Hönger G, Mayr M, Steiger J, Hopfer H, Schaub S. Clinical relevance of pre- transplant donor-specific HLA antibodies detected by single-antigen flow-beads. Transplantation 2009;87:1681-8.  Back to cited text no. 11
    
12.
Schlaf G, Mauz-Körholz C, Ott U, Leike S, Altermann W. General insufficiency of the classical CDC-based crossmatch to detect donor-specific anti-HLA antibodies leading to invalid results under recipients’ medical treatment or underlying diseases. Histol Histopathol 2012;27:31-8.  Back to cited text no. 12
    

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Correspondence Address:
Anupma Kaul
Department of Nephrology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh
India
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DOI: 10.4103/1319-2442.279956

PMID: 32129228

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