In 29 cases, CSA were directed against DQB1 and DQA1, in 6 cases only against DQB1, and in 2 cases only against DQA1. iScoreBinary. AbV, antibody\verified eplet; T, theoretical eplet TAN-97-30-s001.pdf (123K) GUID:?3EA36966-DFCC-4F31-BEED-E63BA9D9CCE5 Data Availability StatementThe data that support the findings of this study are available from the Coelenterazine corresponding author upon reasonable request. Abstract Eplets are defined as distinct amino acid configurations on the surface of HLA molecules. The aim of this study was to estimate the immunogenicity of HLA\DQ eplets in a cohort of 221 pregnancies with HLA\DQ mismatches. We defined the immunogenicity of an eplet by the frequency of antibody responses against it. Around 90% of all listed DQB1 or DQA1 eplets were at least five times mismatched and thus included for the calculation of their immunogenicity. The DQB1 eplets with the five highest immunogenicity scores were 55PP, 52PR, 52PQ, 85VG and 45EV; 25% of all DQB1 eplets were not reacting. The DQA1 eplets with the five highest immunogenicity scores were 25YS, 47QL, 55RR, 187T and 18S; 17% of all DQA1 eplets were not reacting. The immunogenicity score had a slightly higher area under the curve to predict development of child\specific antibodies than various molecular mismatch scores (eg, eplet mismatch load, amino acid mismatch load). Overlapping eplets were identified as a barrier to unambiguously assign the immunogenicity score based on HLA antibody reaction patterns. In this conceptual study, we explored the immunogenicity of HLA\DQ eplets and created a map of potentially immunogenic regions on HLA\DQ molecules, which requires validation in clinical transplant cohorts. [1UVQ]). 2.7. Statistical analysis We used JMP software (SAS Institute Inc., Cary, North Carolina) for statistical analysis. For categorical data, Fisher’s exact test or Pearson’s chi\square test was used. For nonparametric continuous data, the Wilcoxon rank\sum test was used for analysis and data are presented Coelenterazine as median (interquartile range) unless stated otherwise. A and In total, 41 different mismatched DQ heterodimers were noticed in 221 mismatched mother\child pairs. Eighteen mismatched HLA\DQ heterodimers with a frequency of 1% are shown. They account for 195/221 HLA\DQ heterodimer mismatches (88%) and 33/37 cases with child\specific antibodies (CSA). The remaining four cases with CSA were against the following HLA\DQ heterodimers: (twice mismatched, once with CSA; both cases are first pregnancies), (once mismatched with CSA; second pregnancy), (once mismatched with CSA; second pregnancy), (once mismatched with CSA; second pregnancy). 3.3. Frequency of child\specific antibodies Thirty\seven of 221 cases had CSA (17%). In 29 cases, CSA were directed against DQB1 and DQA1, in 6 cases only against DQB1, and in 2 cases only against DQA1. The frequency of CSA among the 41 different DQ heterodimer mismatches ranged from 0% to 100%. Due to low numbers for many DQ heterodimer mismatches, a statistical evaluation regarding the CSA frequency is not reliable. Table ?Table11 summarized the frequency of CSA among the 18 most prevalent DQ heterodimer mismatches. Overall, the frequency of CSA was significantly higher in second pregnancies compared to first pregnancies (22/79 [28%] vs 15/142 [11%]; = .001). However, on the COL4A1 level of individual DQ heterodimer mismatches, CSA were observed more often in first pregnancies in 5/18 DQ heterodimer mismatches, equally frequent in 5/18 DQ heterodimer mismatches, and less frequent in 8/18 DQ heterodimer mismatches (Table ?(Table11). 3.4. Molecular mismatch score in mothers with/without child\specific antibodies All three different DQ eplet loads (antibody\verified, theoretical and total) were significantly higher in mothers, who developed CSA, compare to mothers without CSA. The amino acid mismatch load and the EMMA load for the DQ heterodimer were also significantly higher in CSA positive mothers (Table ?(Table2).2). Despite the significant differences, we noticed large overlaps of all molecular mismatch scores between CSA positive and CSA negative mothers. Furthermore, all molecular mismatch scores correlated strongly with each other (Sixty\three DQB1 eplets Coelenterazine were at least five times mismatched and included for the calculation of the two immunogenicity scores (ie, iScoreBinary and iScoreGradual). Forty\five of 63 DQB1 eplets (71%) were reacting, while 18/63 DQB1 eplets (29%) were not reacting. Reacting eplets are sorted by the iScoreGradual. Abbreviations: AbV, antibody\verified eplet; T, theoretical eplet. The used eplet definition from HLAMatchmaker V2.1 includes 44 DQA1 eplets (11 antibody\verified plus 33 theoretical). In our cohort, 41/44 DQA1 eplets (93%) were at least five times mismatched and thus included for the calculation of the two immunogenicity scores. These 41 eplets included all antibody\verified DQA1 eplets. Thirty\four of 41 DQA1 eplets (83%) were reacting, while 7/41 DQA1 eplets (17%) were not reacting (Table ?(Table4).4). The DQA1 eplets with the five highest iScoreGradual were 25YS, 47QL, 55RR, 187T and 18S. Antibody\verified eplets accounted for 8/20 eplets (40%) with Coelenterazine the highest iScoreGradual. TABLE 4 DQA1 eplet immunogenicity Forty\one DQA1 eplets were at least five times mismatched and included for the calculation of the two immunogenicity scores (ie, iScoreBinary and iScoreGradual). Thirty\four of 41 DQA1 eplets (83%) were.