Transplantation Reviews 29 (2015) 135–138

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Anti-human leukocyte antigen DQ antibodies in renal transplantation: Are we underestimating the most frequent donor specific alloantibodies? Paolo Carta ⁎, Lorenzo Di Maria, Leonardo Caroti, Elisa Buti, Giulia Antognoli, Enrico Eugenio Minetti Nephrology Unit, Careggi University Hospital, Florence, Italy

a b s t r a c t The role of anti-human leukocyte antigens DQ region (HLA-DQ) in transplantation is historically less studied than HLA-DR and HLA class I regions, but several studies are demonstrating that anti HLA-DQ antibodies are among the most frequent anti HLA antibodies that develop after transplantation and can have great influence on the developing of humoral rejection and graft loss. In this article we review the gene structure and nomenclature of the HLA-DQ region, the role of anti HLA-DQ antibodies after and before transplantation and briefly the associations of particular HLA-DQ alleles and other diseases. © 2015 Elsevier Inc. All rights reserved.

1. Introduction

1.1. HLA DQ gene structure and nomenclature

The role of anti human leukocyte antigens DQ (HLA-DQ) donor specific alloantibodies (DSA) in transplantation is historically less studied than anti HLA-DR, anti HLA-A and HLA-B antibodies. DQ matching between donors and recipients is not considered in organ allocating algorithms, and donor and recipients DQ serotyping is not routinely performed also because of the assumption that HLA DR is often inherited together with a particular DQ (linkage disequilibrium) across the same ethnic or racial group [1] (see the dbMHC database for a detailed report of the frequency of HLA DRB1 and DQ haplotype http://www. ncbi.nlm.nih.gov/projects/gv/mhc/ihwg.cgi). With the widespread use of more sensible techniques (single antigen beads solid phase based assay) that automatically detect all classes and families of anti HLA antibodies including anti HLA-DQ and DP, evidences now exist that DQ antibodies are found more frequently than previously expected. The importance of HLA DQ antigens is underlined by the 2010 United Network for Organ Sharing (UNOS) histocompatibility committee amended report in which the authors stated that a complete HLA DQ (together with HLA-DP and HLA-C) is required before transplantation. In this article we briefly review the structure of the HLA-DQ gene and the studies that have evaluated the importance of anti HLA-DQ DSA in renal transplantation. The HLA system, the role of the other classes of HLA antibodies and the pathogenesis of acute and chronic antibody mediated rejection are reviewed elsewhere [2–5].

The genes of HLA complex (also called major histocompatibility complex MHC) are located in the short arm of chromosome 6 at position 6p21.3 (Fig. 1). The MHC is a locus composed by 3.6 Mb subdivided into three regions. Briefly, the first and the second ones encode for HLA components involved in antigen presentation, respectively class I (HLA A, B or C), and class II molecules (DP, DQ, DR). The third region (located between the first and the second) encodes for other important proteins involved in the immune system like heat shock proteins, tumor necrosis factor or complement components. This article will focus on class II and in particular on DQ molecules. Class II antigens DQ, DP and DR have similar structure and are mostly expressed in antigen presenting cells (APC), like B lymphocytes, dendritic cells, macrophages and on the surface of endothelial cells (peritubular capillaries, that is why they are involved in the mechanism of rejection). They are composed of two transmembrane proteins called respectively α and β glycoproteins that bind together to form a site where antigens are presented to the T lymphocytes. Each α and β chain is composed by two domains α1 α2 and β1 β2 respectively and a transmembrane domain. The DQ locus consists of two genes (DQA1 and DQB1) that encode the α and β glycoproteins of DQ molecules respectively. These two genes are highly polymorphic and this explains the higher probability for the immune system to develop specific antibodies directed toward HLA-DQ alloantigens after pregnancies, blood transfusions or a transplant. The international immunogenetics project (http://www.ebi.ac.uk/ipd/ imgt/hla/), the most important HLA gene typing database, reports 51 alleles for the DQA chain and 509 for the DQB chain detected by genotyping. Gene nomenclature is important to characterize such a relevant number of alleles and was developed by the World Health Organization Nomenclature Committee for Factors of the HLA System. The name of a HLA gene is defined by a series of letters and digits, for example HLA DQB1*03:05:01. The letters DQB1 refer to class II molecule of Q family,

⁎ Corresponding author at: Nephrology Unit, Careggi University Hospital, Viale Pieraccini 18, 50134 Florence, Italy. Tel.: +39 0557949268; fax: +39 0557949794. E-mail address: [email protected] (P. Carta). http://dx.doi.org/10.1016/j.trre.2015.04.003 0955-470X/© 2015 Elsevier Inc. All rights reserved.

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P. Carta et al. / Transplantation Reviews 29 (2015) 135–138

Chromosome 6

Long arm

Short arm HLA region 6p21.3

DQ

Class I

Class III

Class II DP

DR

B

C

A

HLA DQ region B2

A2

B1

A1

n

ra emb ma m Plas Cytoplasm

α1

β1

α2

β2

TM

TM

Fig. 1. Structure of the gene of the HLA DQ in the chromosome 6 (top). Structure of the HLA DQ molecule (bottom).

up time, study design and the technique used to detect anti HLA antibodies. These studies report that DSA develop in 15%–30% of patients. Anti HLA-DQ DSA develops in 55–77% of patients with DSA and in 50%–66% of patients who lost their graft [6–17]. In most of these studies the development of DSA was associated with worst graft outcomes. To our knowledge only three studies were specifically designed to compare renal graft outcomes in patients who develop anti DQ antibodies with those who do not. The study of Willicombe [16] showed that 18% of 505 kidney graft recipients developed anti HLA DSA. DQ antibodies were detectable in 54% of patients who developed anti HLA DSA (of whom 52% in association with other DSA and 48% alone) and were associated with a significantly higher risk of developing acute mediated rejection (AMR), transplant glomerulopathy (TG) and allograft failure when compared with patients with non-DQ DSA. Mean time to detection of DQ DSA was 9.8 months ± 14. The mean MFI in the patients who lost their graft was 6583 compared to 3210 in the other group. Furthermore they found a significant discordance between matching for DR and DQ and that there seems to be an enhanced immunogenicity when DQ and DR are both mismatched. DeVos [15] monitored for 3 years 347 renal allograft recipients and found that 18% developed DSA, of whom 77% were DQ antibodies. Patients with anti DQ antibodies had a increased risk of graft loss and worse renal function and proteinuria compared to patients without antibodies, especially when mean fluorescence index (MFI) was higher than 4000. The mean time for developing DQ antibodies was 7.2 ± 11 months after transplantation. Freitas [17] showed that the presence of de novo persistent, complement-binding DQ DSA negatively impacts kidney allograft outcome in terms of more acute rejections, increased risk of allograft loss and a lower 5 years graft survival. Therefore, early post transplantation detection, monitoring, and removal of complement-binding DQ might be crucial for improving long-term kidney transplantation outcomes. 1.3. DQ antibodies before transplantation

coding for the B chain. The set of digits after the asterisk defines the allelic variants, in this case 03:05:01. The first two digits refer to the type which usually corresponds to the antibody recognizing the antigens. The second two digits describe the subtype, number being assigned in the order in which DNA sequences have been determined. Every subtype differs in one or more nucleotide substitution. If (as in the example) the alleles differ by synonymous nucleotide substitution (a substitution that code for the same amino acid sequence) a third set of digits is used. Eventually a fourth set of digits describes a polymorphism of a non-coding region. Transplant physicians in clinical practice refer to antigen nomenclature which is based on serological studies. Antigens are named in accordance with the antibodies that recognized them. Nine serological typing for DQ antigens were reported, named from DQ1 to DQ9. DQ1 and DQ3 are not used today because they were found to be poorly sensible and are replaced by the more specific split forms respectively DQ5 and DQ6 for DQ1 and DQ7, DQ8 and DQ9 for DQ3. Since the α chain is less polymorphic than the β chain, common practice is to identify a class II molecule based on its β chain typing. This is appropriate for DR molecules (only 7 DRA alleles and 1512 DRB) but may be more cumbersome for DP and DQ molecules that are more polymorphic. 1.2. Role of anti DQ antibodies after transplantation Few studies have addressed the influence of anti DQ HLA antibodies on graft outcomes. Most of the information can be extrapolated from studies in which the authors in addition to analyzing the frequency of de novo DSA after kidney transplantation have given details on the classes of the antibodies that have been found. Table 1 shows the studies where the percentage of patients developing anti HLA DQ antibodies was reported. Table 2 summarized more briefly the overall results of the studies included in this review. These papers are difficult to compare because of the differences in the immunosuppressive regimens, follow-

Sensitized patients are very difficult to match owing to the immunologic barrier created by DSAs and if transplanted these patients are at much higher risk of acute and chronic AMR [18,19,22,23,25,26]. With the increasing number of patients entering the waiting list for a failed graft, the percentage of sensitized patients is in great expansion. The 2011 UNOS annual report [20] shows that from 2001 to 2011 patients with a PRA N 20% increased from 13163 (28%) to 28594 (33%). To our knowledge no study has directly evaluated the influence of anti DQ HLA antibodies on the time spent on the waiting list. Nonetheless anti DQ antibodies are reported in around 50–60% of patients who lost their graft [7,10]. In a Turkish study Karahan [21] showed that anti DQ antibodies were detectable in 23.4% of patients on the waiting list with a positive PRA. Since anti DQ are among the most frequent HLA DSA found in patients with a failed graft, it is extremely likely that they have an influence in prolonging the time spent on the waiting list. 2. Guidelines The recently published European guidelines [24] suggest to match donor and recipient for HLA A, B and DR (level of evidence 2C) and recommend performing HLA DQ, DP, and C typing of the donor only when the intended recipient has HLA antibodies against those antigens (level of evidence 1D). QDIGO latest guidelines do not address this issue. 2.1. Anti-HLA DQ antibodies in non-kidney transplantation Although this topic has been studied less extensively, some study suggests that the developing of anti HLA DQ antibodies has a detrimental effect even in non-kidney transplant. The largest experience has been described with heart transplantation. In his study Smith [27] reported that 17% of 243 heart transplants who developed anti DQ antibodies had a poorer patient survival. In the setting of liver transplantation,

Table 1 Articles included in the review. Number of patients

Follow-up

De novo DSA

Patients with DSA and DQ-DSA antibodies

Method of DSA detection

Willicombe [16]

505

NA

Yes

DSA: 18% DQ: 54.3%

Luminex

DSA: 17.8% DQ: 77%

Luminex

DSA 44% DQ 69%

Luminex

DSA 25%. CLASS II: 68% of whom 91% DQ DQ 53% of patients with graft loss DSA 5.5% DQ 55%

Luminex

DSA: 10% (all class II)

ELISA

DeVos [15]

Freitas [17]

347

284

3 years

5 years

Yes

Yes

Everly [6]

189

10 years

Yes

Ozawa [7] Hourmant [8]

266 1229

NA 10 years

NA

Theodoraki [9]

110

6 months

20% presensitized

Luminex Luminex

DQ and DR 20%

Minimum 5 years 5.9

Yes

Kobayashi [11]

112 after transplant failure 586

Lachmann [12]

1014

5.5 years

No

Ntokou [13]

597

From 14 months to 10 years

Yes

Walsh [14]

28 patients with AMR

No

DSA 50.9% with DSA after transplant failure. 1.6% in patient on follow-up. DSA: 20% class II, 14.5% class I DQ: 90% of patients with class II DSA 31% class II 74% DQ: ¾ of class II DSA 12.7% class II 69.7% of DSA DQ 14.4% of 446 patients mismatched for class II DQ: 38% and 76% of early (b6 months) and late acute mediated rejection respectively

P value

DQ DSA Non DQ DSA 53.2% 75.7% 70% 72.3% 76% 95% No DSA DQ only Serum creatinine 1.3 mg/dl 1.6 mg/dl Urine Pr/Cr ratio N0.5 9% 24% AMR 0.4% 9% No DSA DQ only acute rejection 19% 41% graft loss 8% 21% 24% with DSA had graft loss 3 year after their detection. Patients without DSA had 5 years graft survival of 96%.

AMR free survival TG free survival Graft Survival

DQ alone 80%

Worthington [10]

Outcome of transplantation/conclusions

No Ab DSA Graft survival 6.5% 15% Cr Clearance (ml/min) 57 48 Proteinuria (g/day) 0.4 1.5 DSA not associated with rejection or deterioration of graft function 6 months after transplantation. Anti DQ were present in 90% of patients who lost their graft for chronic rejection. DQ were detectable in 7 patients for 2–3 months and were undetectable thereafter. DQ DSA were persistently present in 4 cases.

0.002 0.005 0.012 DQ + non-DQ 2.6 mg/dl 31% 60% DQ+ non-DQ 55% 40%

No DSA 18% 51 0.5

b0.01 0.03 b0.001 b0.05 b0.05 NA

NA b0.001 b0.001

ELISA Luminex Luminex

Chronic antibody mediated rejection associated with anti DR Ab and not with anti DQ graft survival: 49% for DSA + Vs 83% of DSA −

Luminex Graft failure HR Serum creatinine N 4 mg/dl

No Ab 1.0 22.5 5%

DSA + 22.5 5.9 31.8%

P. Carta et al. / Transplantation Reviews 29 (2015) 135–138

Author

b0.001

DSA− Ab+ 5.9 12%

b0.001 b0.05

Luminex

137

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P. Carta et al. / Transplantation Reviews 29 (2015) 135–138

Table 2 This table summarize the overall results of the studies included in this review. No. of patients

% DQ

Acute AMR

Chronic AMR

Transplant glomerulopathy

Graft survival

Follow-up (months)

28–1014

5%–60%

9%–100%

64%–90%

30%–72%

49–92%

1–66

Table 3 Association with HLA DQ alleles and diseases. Disease

Allele

Author

Insulin dependent diabetes mellitus Multiple sclerosis Celiac disease

DQA1*0301–DQB1*0302 DQA1*0501–DQB1*0201 DQB1*0602 DQA*0501, DQB*0201 DQA*03, DQB*0302 DQB1*06:02

Eringsmark Regnéll S [29],

Narcolepsy

Luckey D [30], Jon JM [31] Mahlios J [32]

Musat [28] reported that 51% of 43 patients with sign of humoral rejection in the liver biopsy had anti-DQ antibodies. 2.2. HLA DQ region and other disease Extensive data from epidemiological studies have demonstrated that particular alleles of the HLA DQ region are clearly associated with the developing of several autoimmune diseases including for example type I diabetes mellitus, celiac disease and multiple sclerosis. Table 3 shows the association between these alleles and the relative disease. Whether any allele of the HLA DQ is associated with the developing of any disease or complication after transplantation is not studied and might be a stimulating area of research. 3. Conclusions Since anti-DQ antibodies are the most common antibodies after transplantation, the HLA-DQ antigens of the donor and recipient should be typed and probably the kidney allocated taking into account also of the match DQ. This will reduce the rate of development of HLA-DQ antibodies, and in the event it occurs, will allow us to understand whether these antibodies are directed against the antigens of the donor or less. While we are waiting for a more definitive evidence on the role of anti HLA-DQ antibodies, its development should warrant the diagnosis of an initial humoral process and a histological evaluation should be considered even in patients with stable renal function. The authors declare no conflict of interest. References [1] Fernandez-Viña MA, Gao XJ, Moraes ME, et al. Alleles at four HLA class II loci determined by oligonucleotide hybridization and their associations in five ethnic groups. Immunogenetics 1991;34:299–312. [2] Klein J, Sato A. The HLA system. First of two parts. N Engl J Med 2000;343:702–9. [3] Tinckam KJ, Chandraker A. Mechanisms and role of HLA and non-HLA alloantibodies. Clin J Am Soc Nephrol 2006;1:404–14. [4] McKenna RM, Takemoto SK, Terasaki PI. Anti-HLA antibodies after solid organ transplantation. Transplantation 2000;69:319–26. [5] Loupy A, Hill GS, Jordan SC. The impact of donor-specific anti-HLA antibodies on late kidney allograft failure. Nat Rev Nephrol 2012;8:348–57. [6] Everly MJ, Rebellato LM, Haisch CE, et al. Incidence and impact of de novo donorspecific alloantibody in primary renal allografts. Transplantation 2013;95:410–7.

[7] Ozawa M, Rebellato LM, Terasaki PI, et al. Longitudinal testing of 266 renal allograft patients for HLA and MICA antibodies: Greenville experience. Clin Transpl 2006: 265–90. [8] Hourmant M, Cesbron-Gautier A, Terasaki PI, et al. Frequency and clinical implications of development of donor-specific and non-donor-specific HLA antibodies after kidney transplantation. J Am Soc Nephrol 2005;16:2804–12. [9] Iniotaki-Theodoraki AG, Boletis JN, Trigas GCh, Kalogeropoulou HG, Kostakis AG, Stavropoulos-Giokas CG. Humoral immune reactivity against human leukocyte antigen (HLA)-DQ graft molecules in the early post-transplantation period. Transplantation 2003;75:1601–3. [10] Worthington JE, Martin S, Al-Husseini DM, Dyer PA, Johnson RW. Posttransplantation production of donor HLA-specific antibodies as a predictor of renal transplant outcome. Transplantation 2003;75:1034–40. [11] Kobayashi T, Maruya E, Niwa M, et al. Significant association between chronic antibody-mediated rejection and donor-specific antibodies against HLA-DRB rather than DQB in renal transplantation. Hum Immunol 2011;72:11–7. [12] Lachmann N, Terasaki PI, Budde K, et al. Anti-human leukocyte antigen and donorspecific antibodies detected by luminex post-transplant serve as biomarkers for chronic rejection of renal allografts. Transplantation 2009;87:1505–13. [13] Ntokou IS, Iniotaki AG, Kontou EN, et al. Long-term follow up for anti-HLA donor specific antibodies post renal transplantation: high immunogenicity of HLA class II graft molecules. Transpl Int 2011;24:1084–93. [14] Walsh RC, Brailey P, Girnita A, et al. Early and late acute antibody-mediated rejection differ immunologically and in response to proteasome inhibition. Transplantation 2011;91:1218–26. [15] DeVos JM, Gaber AO, Knight RJ, et al. Donor-specific HLA-DQ antibodies may contribute to poor graft outcome after renal transplantation. Kidney Int 2012;82: 598–604. [16] Willicombe M, Brookes P, Sergeant R, et al. De novo DQ donor-specific antibodies are associated with a significant risk of antibody-mediated rejection and transplant glomerulopathy. Transplantation 2012;94:172–7. [17] Freitas MC, Rebellato LM, Ozawa M, et al. The role of immunoglobulin-G subclasses and C1q in de novo HLA-DQ donor-specific antibody kidney transplantation outcomes. Transplantation 2013;95:1113–9. [18] Lefaucheur C, Loupy A, Hill GS, et al. Preexisting donor-specific HLA antibodies predict outcome in kidney transplantation. J Am Soc Nephrol 2010;21:1398–406. [19] Terasaki PI, Ozawa M. Predicting kidney graft failure by HLA antibodies: a prospective trial. Am J Transplant 2004;4:438–43. [20] 2011 Annual Report of the U.S. Organ Procurement and Transplantation Network and the Scientific Registry of Transplant Recipients: Transplant Data 1998-2011. Department of Health and Human Services, Health Resources and Services Administration, Healthcare Systems Bureau, Division of Transplantation, Rockville, MD; United Network for Organ Sharing, Richmond, VA; University Renal Research and Education Association, Ann Arbor, MI [21] Karahan GE, Seyhun Y, Oguz F, et al. Anti-HLA antibody profile of Turkish patients with end-stage renal disease. Transplant Proc 2009;41:3651–4. [22] Song EY, Lee YJ, Hyun J, et al. Clinical relevance of pre-transplant HLA class II donorspecific antibodies in renal transplantation patients with negative T-cell cytotoxicity cross-matches. Ann Lab Med 2012;32:139–44. [23] Sengar DP, Couture RA, Raman S, Jindal SL. Beneficial effect of HLA-DQ compatibility on the survival of cadaveric renal allografts in cyclosporine-treated recipients. Transplantation 1990;49:1007–9. [24] European Renal Best Practice Transplantation Guideline Development Group. ERBP Guideline on the Management and Evaluation of the Kidney Donor and Recipient. Nephrol Dial Transplant 2013:ii1–ii71. [25] Caro-Oleas JL, González-Escribano MF, González-Roncero FM, et al. Clinical relevance of HLA donor-specific antibodies detected by single antigen assay in kidney transplantation. Nephrol Dial Transplant 2012;27:1231–8. [26] Poli F, Cardillo M, Scalamogna M. Clinical relevance of human leukocyte antigen antibodies in kidney transplantation from deceased donors: the North Italy transplant program approach. Hum Immunol 2009;70:631–5. [27] Smith JD, Banner NR, Hamour IM, et al. De novo donor HLA-specific antibodies after heart transplantation are an independent predictor of poor patient survival. Am J Transplant 2011;11:312–9. [28] Musat AI, Agni RM, Wai PY, et al. The significance of donor-specific HLA antibodies in rejection and ductopenia development in ABO compatible liver transplantation. Am J Transplant 2011;11:500–10. [29] Eringsmark Regnéll S, Lernmark A. The environment and the origins of islet autoimmunity and type 1 diabetes. Diabet Med 2013;30:155–60. [30] Luckey D, Bastakoty D, Mangalam AK. Role of HLA class II genes in susceptibility and resistance to multiple sclerosis: studies using HLA transgenic mice. J Autoimmun 2011;37:122–8. [31] Jon JM, van Bergen J, Koning F. Celiac disease: how complicated can it get? Immunogenetics 2010;62:641–51. [32] Mahlios J, De la Herrán-Arita AK, Mignot E. The autoimmune basis of narcolepsy. Curr Opin Neurobiol 2013;23:767–73.