Skip to main content
NCBI home page
NIHPA Author Manuscripts logoLink to NIHPA Author Manuscripts
. Author manuscript; available in PMC: 2013 May 30.
Published in final edited form as: Am J Transplant. 2008 Jun 28;8(8):1729–1736. doi: 10.1111/j.1600-6143.2008.02301.x

Factors affecting success of thymus transplantation for complete DiGeorge anomaly1

ML Markert 1,2, BH Devlin 1, IK Chinn 1, EA McCarthy 1, YJ Li 3
PMCID: PMC3667673  NIHMSID: NIHMS460880  PMID: 18557726

Abstract

Thymus transplantation shows promise for the treatment of athymia in complete DiGeorge anomaly. This report reviews the effects of dose of thymus tissue, ABO compatibility, HLA matching, culture conditions, age of donor, and immunosuppression of recipient on immune outcomes at one year after transplantation. Forty nine athymic subjects have been treated with cultured postnatal allogeneic thymus tissue; 36 (73%) survive with only one subject on immunosuppression at 1.5 years. Of 31 surviving subjects more than 1 year after transplantation, 30 (97%) developed naïve T cells, T cell proliferative responses to mitogens, and a diverse TCRBV repertoire. The dose of thymus tissue, HLA-matching, and use of immunosuppression had non significant effects on these outcome variables. Removal of deoxyguanosine from culture medium and length of culture did not adversely affect outcomes. Use of thymus tissue from donors over one month of age, versus under one month, resulted in higher total T cell numbers (p=0.03). However, this finding must be confirmed in a prospective trial. Although subtle immune effects may yet be associated with some of the factors tested, it is remarkable that consistently good immune outcomes result despite variation in dose, HLA matching, and use of immunosuppression.

Introduction

Thymus transplantation is being developed under an Investigational New Drug (IND) Application with the Food and Drug Administration (FDA) for congenital athymia, which occurs most frequently in DiGeorge anomaly. DiGeorge anomaly is characterized by abnormalities in the heart, thymus, and parathyroid glands [1–7]. Complete DiGeorge anomaly is defined by complete absence of the thymus [8]. Athymia is ascertained by studying the peripheral blood using flow cytometry. Infants with athymia demonstrate a lack of peripheral blood naïve T cells (recent thymic emigrants), characterized by the co-expression of CD45RA and CD62L [9]. Athymia is a fatal condition; athymic infants usually die by two years of age[8]. Thymus transplantation has shown very promising results with 73% survival in a group of 49 consecutive infants [10].

With time, infants born with complete DiGeorge anomaly may develop a rash and lymphadenopathy [11, 12] associated with oligoclonal expansions of “host” T cells. Infants with the phenotype of complete DiGeorge anomaly associated with rash and lymphadenopathy are described as having “atypical” complete DiGeorge anomaly. The oligoclonal T cells can be predominantly CD4 single-positive T cells, predominantly CD8 single-positive T cells, or double-negative (CD4−CD8−) T cells [11]. Total T cell numbers can reach markedly elevated levels in the blood (over 50,000/mm3) and can be associated with infiltration of the liver and elevated liver enzymes. These “atypical” infants need peritransplantation immunosuppression to prevent graft rejection [13].

The current study evaluated the effect of dose of thymus tissue, ABO compatibility, HLA matching, length of culture, use of deoxyguanosine in culture, age of donor, and immunosuppression of the recipient on immune outcomes at one year.

Materials and Methods

Research subjects

Subjects were enrolled consecutively from 1993 to 2006 in six clinical protocols approved by the Duke Institutional Review Board (IRB) and, beginning in 2001, reviewed by the FDA under an IND. Subjects were enrolled after informed consent was obtained from the subject’s parents. All subjects were under 2 years of age when transplanted. The demographics of the subjects have been described [10].

Overall, 14 of the 31 subjects described in this report were treated with immunosuppression in the peritransplantation period as previously detailed [10]. Rabbit antithymocyte globulin (RATGAM) was first used for atypical subjects in 2001. Fourteen received pre-transplantation RATGAM (2 mg/kg/d for 3 days, usually on days -5, -4 and -3) with concomitant steroids. Three of the 14 subjects (beginning in 2002) had typical DiGeorge anomaly but had proliferative responses over 20 fold above background. Two (beginning in 2005) received this treatment because of participation in a parathyroid transplantation protocol. Four of the 14 had atypical complete DiGeorge anomaly. Post-transplantation cyclosporine (in addition to pre-transplantation RATGAM) was given to subject DIG113 in 2004 when atypical T cells rose to over 12,000/mm3 on day 12 after transplantation; all 4 subsequent atypical subjects received RATGAM plus pre- and post-transplantation cyclosporine. The cyclosporine trough goal was 180–200 ng/ml. Cyclosporine was weaned after the naïve T cell percentage reached 5% of total T cells.

The thymus donors were infants undergoing heart surgery. The cardiac surgeon removed thymus tissue in order to have access to the surgical field. If the thymus tissue was to be used for transplantation, the parents of the infant undergoing cardiac surgery were approached for consent to use the thymus tissue. The testing of the tissue and the screening of the donor and donor’s mother have been described and follow FDA guidelines [10, 14]. Chromosome testing for 22q11 hemizygosity was performed in all donors and was an exclusion criterion. The cardiac defect of the donor was characterized as being conotruncal or not conotruncal by a pediatric cardiologist at Duke Hospital. Conotruncal defects involve the outflow tract and are thought to be common in DiGeorge anomaly.

The culturing of the thymus tissue has been described.[10, 15] The length of culture ranged from 12–21 days. Prior to November 2001, deoxyguanosine was included in the culture medium the entire time of culture. Between November 2001 and March 2006, the number of days for which deoxyguanosine was in the medium (at 1.34 mmol/L) was decreased incrementally from a maximum of 12 days to 0 days.

Before November 2001, the thymus tissue was weighed upon receipt without obtaining further measurements. Use of the total weight of thymus was not a good estimation of dose because not all of every thymus was sectioned and not all of every thymus was transplanted. Beginning in 2001, the thymus slices were measured on the day before transplantation by estimating the length, width and depth and by assuming that 1 cm3 was equivalent to 1 gram. Dose has been measured for 23 subjects who have reached 1 year after transplantation. The lowest dose used (4 g/m2) resulted in T cell development in the recipient. It was felt to be prudent to not drop the dose further. A severe adverse event of enteritis/colitis occurred in one child who received the highest dose given (23 g/m2). Thus the minimum and maximum doses were set at 4–18 g of tissue per m2 of body surface area.

All HLA typing with respect to the data reported here was conducted at the molecular level, most at high resolution. “Partial matching” indicted the sharing of one or more high resolution alleles (e.g., the sharing of HLA-A*0201 between the donor and recipient without other HLA-A and HLA-B alleles being shared). Use of low resolution typing that has ambiguity with respect to the exact amino acid sequence (e.g., HLA-A*02xx in both donor and recipient) is mentioned in the text.

The outcomes evaluated in this report include total CD3, CD4, and CD8 numbers, naïve CD4 and naïve CD8 numbers, proliferative responses to the mitogen phytohemagglutinin (PHA), and the diversity of the CD4 T cell receptor beta variable (TCRBV) repertoire assessed by spectratyping using the Kullback-Leibler divergence (DKL) measure [16]. Thirty two of 44 (73%) subjects survived past 1 year. Data from 1 subject was excluded because of continued immunosuppression (see below). Another survivor died at year 4; that subject’s one year data are included in this report. The data used for the analyses are the averages of 2 consecutive values obtained after one year if two values were available. Otherwise, a single value is used. For naïve T cells, only 1 subject has a single value. Of the 31 subjects evaluable at year 1, the first subject was not tested for naïve T cells until year 5, so a maximum of 30 subjects are in those analyses. Of these 30 subjects, 23 received measured thymus and are presented in the dose analyses. For PHA proliferative responses, data are reported for all 31 evaluable at one year of which 23 were transplanted after November 2001 and received measured thymus tissue. Six subjects’ PHA data represent single values. For the DKL score, which was obtained by spectratyping annually after transplantation, the single value at year one was used. The actual day of spectratyping testing ranged from day 301 - 726. Data from 5 of surviving subjects were not included in DKL analyses because these subjects did not have spectratyping samples assessed prior to 2 years after transplantation. Thus data are shown for 26 evaluable subjects at year one of whom 22 received measured thymus tissue.

Descriptive statistics such as mean and standard division (SD) were obtained for each outcome of interest. Linear regression was applied to assess the correlation coefficient (R) between two variables of interests (e.g., between dose and T cell numbers). Two sample t-tests with unequal variance were used to compare the differences between two groups of interest (e.g., subjects with immunosuppression versus without immunosuppression). Log transformation was used for the CD4, CD8, and naïve CD8 cell counts, the PHA responses, and DKL values prior to statistical analyses to better approximate a normal distribution. For the graphs of CD4, CD8, and naïve CD8 counts and PHA responses, the antilog of the log transformed mean is presented. For DKL, since only single DKL values were used for statistical analysis, the raw DKL was used for plotting as it is equivalent to the antilog of log transformed DKL. The statistics are given for this relationship but the DKL itself is plotted. Multivariate analyses could not be performed due to the small sample size. Because type 1 and type 2 errors may be high when multiple variables are evaluated with t tests, we discuss trends and emphasize the limitations throughout.

Results

Dose effects

Beginning in 2001, the estimated total volume of thymus tissue (dose) was assessed for all thymus tissue used for transplantation. Figure 1 shows the dose given to all 30 subjects between November 2001 and the end of 2006. The goal of evaluating dose effect was to determine if doses at the high end of this range would result in better outcomes than doses at the lower end.

Figure 1.

Figure 1

Open in a new tab

Dose of thymus tissue given to 30 consecutive subjects with complete DiGeorge anomaly.

The effect of dose was assessed on a variety of T cell measures at one year, including the CD4 count, naïve CD4 count, CD8 count, naïve CD8 count, TCR diversity (DKL) and the PHA response. Figure 2 illustrates the lack of effect of dose on these 4 parameters in subjects tested at the relevant time point. CD8 and naïve CD8 counts at one year (not shown in Figure 2) had negative correlation coefficients of −0.16 (p=0.48) and −0.06 (p=0.79), respectively, with dose. Overall, low correlation coefficients were observed for all parameters, which imply that doses of thymus tissues did not appear to play a significant role in the outcomes. Lastly, when the data for the group of subjects who did not receive immunosuppression and the group who received immunosuppression were calculated separately, no significant effects were seen for dose on immune outcomes.

Figure 2.

Figure 2

Open in a new tab

Lack of effect of dose on immune outcomes. A) Dose plotted versus the CD4 count at 1 year. B) The effect of dose on naïve CD4 cells at one year. C) The effect of dose on the statistical measure of TCRBV diversity, DKL, at one year. D) The effect of dose on the PHA response at one year. Trend lines and the Pearson correlation coefficients, R, are shown in each panel. The p values for these correlations were all ≥ 0.5. See Methods for explanation of subject numbers.

ABO compatibility

Since 1993, thymus transplantation has been done without regard to ABO typing. Figure 3A and 3B suggests that CD4 T cell numbers are higher at years 1 and 2 if compatible thymus grafts are used. Of interest, three of six subjects receiving incompatible grafts have developed isohemagglutinins toward a specificity on the donor at year 1 and two of four at year 2. Caution should be used in interpretation of this result because of the small number of subjects. In addition, the outlier in the incompatible group, DIG301, who is mosaic for trisomy 14q11.2, has T cell counts including CD4 counts markedly below all other subjects. The CD8, naïve CD4 and naïve CD8 differences did not reach significance at years 1 or 2.

Figure 3.

Figure 3

Open in a new tab

Effect of ABO compatibility of thymus graft and recipient pairs on T cell numbers at 1 and 2 years after transplantation. The “compatible” pairs included transplantation of blood group O thymuses into O (n=13), A (n=5) or B (n=2) subjects; A thymuses into A subjects (n=4); and B thymuses into B subjects (n=1). The “not compatible” pairs included transplantation of blood group A thymus into O subjects (n=4) or B thymuses into O subjects (n=2). Panels A and B thus show T cell numbers at one year in 25 subjects who received compatible thymus grafts and in 6 subjects who received incompatible grafts. Panels C and D show T cell numbers at 2 years in 20 subjects with compatible thymuses and 4 subjects with incompatible grafts. The horizontal lines indicate the mean of each group. In panel A, the mean CD4 counts were 610/mm3 and 396/mm3 for compatible and non-compatible pairs, respectively. In panel C, the mean CD4 counts were 690/mm3 and 422/mm3, respectively.

HLA-matching

The hypothesis that HLA matching would improve T cell numbers after thymus transplantation was tested. Surprisingly, partial HLA-DR matching (for 1 allele) or HLA-A or HLA-B partial matching (for 1 allele) did not increase CD4 or CD8 T cell numbers (Figure 4A, 4C) or naïve CD4 or CD8 T cell numbers (Figure 4A, 4C) or naïve CD4 or CD8 T cell numbers (Figure 4B, 4D), respectively. All subject:donor pairs with Class II matching had high resolution HLA-DR typing. Five of the 17 subject:donor pairs with 1–2 HLA-A or B alleles matching did not have high resolution typing. If these subjects were excluded, the findings persisted (no significant difference).

Figure 4.

Figure 4

Open in a new tab

Effect of HLA matching on thymus transplantation. The effect of matching for 0 or 1 HLA-DR alleles between recipient and thymus tissue was assessed examining A) the CD4 number at 1 year and B) the naïve CD4 number at 1 year. The mean CD4 T cell numbers were 605/mm3 without and 500/mm3 with HLA-DR matching. The mean naïve CD4 T cell numbers were 346/mm3 without and 318/mm3 with HLA-DR matching. The effect of matching for 0 or 1-2 HLA-A or HLA-B alleles was assessed examining C) the CD8 count and D) the naïve CD8 count at one year. The mean CD8 T cell numbers were 160/mm3 without matching and 183/mm3 with matching. The mean naïve CD8 numbers were 86/mm3 without matching and 127/mm3 with matching. In all cases the p value reflects the comparison of counts with no matching versus counts with 1 or more alleles matching. See Methods for explanation of subject numbers.

Characteristics of the Thymus Donor

We hypothesized that both the type of cardiac defect in the donor and the age of the donor could be associated with function of the thymus after transplantation. We considered that thymus from infants with conotruncal heart defects might be less effective at thymopoiesis after transplantation than thymus from infants without conotruncal heart defects because of the association of DiGeorge anomaly with conotruncal defects. Surprisingly use of thymuses from donors with conotruncal heart defects was not detrimental with respect to CD4 counts at one year (Figure 5A). The same lack of effect was observed for CD8 counts (p = 0.589) (not shown).

Figure 5.

Figure 5

Open in a new tab

The effect of donor factors on later CD4+ T cell development. The effect of A) conotruncal heart defects and B) age under 1 month on effectiveness of thymus later use for transplantation. In A, the mean CD4 counts are 652/mm3 with conotruncal donor vs. 539/mm3 without conotruncal donor. In B, the mean CD4 counts were 689/mm3 if the donor was > 1 month compared to 511/mm3 when the donor was < 1 month.

CD4 counts appeared to be elevated at one year if the donor was > 1 month compared to when the donor was < 1 month (Figure 5B). The effect of age of the thymus donor on CD8 counts at one year was also evaluated but did not reach a significance level of 0.05. In summary, thymuses from older donors did not yield significantly lower T cell numbers. Because of the small numbers of subjects involved, other donor variables (such as type of heart defect) could not be controlled for, and the effect of multiple comparisons was not applied. Thus, we cannot be sure that the age of the thymus donor alone is responsible for higher T cell numbers.

One might speculate that thymuses from younger donors are smaller, resulting in lower doses for the recipients. Linear regression showed that the age of the donor has a significant effect on the dose of thymus tissue (R= 0.54, p=0.008) The mean dose for donors under one month was 9.6 grams/m2, which was significantly lower than the mean dose for donors over one month (15.2 grams/m2) (p=0.003).

To remove the effect of dose and compare only the effect of age, we examined 13 thymuses of similar doses (all over 11 g/m2) and compared the thymuses from donors less than 1 month old (n=6) with the thymuses from donors older than 1 month (n=7). We found that the thymuses from younger donors resulted in lower CD4 counts after transplantation than CD4 counts obtained using older thymuses of similar size (means of 450/mm3 and 679/mm3, respectively, p = 0.03).

Culture conditions affecting thymus function

The length of culture of the thymus tissue prior to transplantation and the use of deoxyguanosine in the culture were both thought to be potential issues for reduced thymus function. The number of days in culture varied from 12 to 21. No significant decrease in CD4 counts for thymuses cultured for longer times was observed, R = −0.13 (p=0.50, Figure 6A). The correlations (R) for the two subgroups of subjects, without and with immunosuppression, were −0.28 (p=0.28) and - 0.11 (p=0.70), respectively. Similar data were obtained when the length of the culture period was compared against year one CD8 counts (R = 0.01, p=0.94). Thus, the length of culture of the thymus tissue did not appear to adversely affect T cell numbers at one year.

Figure 6.

Figure 6

Open in a new tab

Culture conditions and immune outcomes at one year. The effect of A) length of time in culture and B) length of time in culture with deoxyguanosine on the CD4 count at one year. The effect of time in deoxyguanosine also on C) the number of naïve CD4 T cells at one year and D) the T cell receptor diversity assessed by the CD4 DKL score at one year. See Methods for explanation of subject numbers.

After 2001, the length of time that deoxyguanosine was kept in the thymus culture was decreased because of the potential harmful effects of deoxyguanosine on epithelial function. We evaluated outcomes in the subjects after transplantation closely because we did not know if the deoxyguanosine had an unknown beneficial effect in the cultures. Our analyses showed no apparent adverse effect of shorter exposures of thymus tissue to deoxyguanosine on CD4 counts (Figure 6B, p=0.78), naive CD4 counts (Figure 6C, p=0.51), or the CD4 TCRBV diversity (Figure 6D, p=0.34) at one year after transplantation. A similar lack of effect was found with CD8 counts (correlation = −0.06) and naïve CD8 counts (correlation = −0.07) not shown. The trend was for higher CD4 counts or more diversity in subjects at one year when the thymus was exposed to fewer days in deoxyguanosine. The analysis did not change if the two subgroups (without immunosuppression and with immunosuppression) were evaluated separately.

Effect of immunosuppression on outcome

We were concerned that immunosuppression in the peritransplantation period might impair immune reconstitution. None of the comparisons at one year (CD4 counts, naïve CD4 counts, CD8 counts, naïve CD8 counts, PHA responses, DKL scores) between the group without immunosuppression and the group with immunosuppression reached significance.

Discussion

Forty nine infants with complete DiGeorge anomaly have been transplanted with cultured postnatal unrelated allogeneic thymus tissue in studies evaluating the efficacy of thymus transplantation to restore the immune system in infants with congenital athymia. The purpose of this report was to review the characteristics of the thymus tissue and donor that might affect outcomes. We focused on thymus dose, tissue matching, the age of the thymus donor, the type of heart defect in the thymus donor, the culture conditions used for the thymus tissue, and use of immunosuppression during the peritransplant period.

Dose

We initially hypothesized that a larger dose of thymus tissue would result in higher T cell counts. We found, however, that dose had no clear effect on the four outcome variables assessed. The use of high dose (23 g/m2) in one subject was associated with a severe adverse event of enteritis/colitis (data not shown). Because of that adverse event, we set a maximum dose for thymus tissue of 18 g/m2.

ABO compatibility

We were surprised to see any effect of ABO matching on CD4 and CD8 counts after thymus transplantation. One might suppose that ABO compatibility would not be important for thymus tissue transplants because there is minimal donor endothelium associated with the tissue. The detected statistical differences with respect to total and naïve CD4 counts may be false positives because of the multiple comparisons done. The subjects with incompatible grafts are doing well clinically. We will watch this correlation closely as we accrue more subjects.

HLA matching

The immune outcomes with respect to HLA matching were not expected. We hypothesized that HLA Class I matching would affect the development of CD8+ T cells since CD8+ T cells are positively selected on the MHC Class I molecules of the thymic epithelium. Similarly, we considered that HLA Class II matching would affect the development of CD4+ T cells. No effect of matching one HLA-DR allele or one HLA Class I allele was observed on CD4+ or CD8+ T cell counts, respectively. Based on animal studies, positive selection to “host” may occur on host MHC on developing genetically-host thymocytes [17, 18] or on host antigen presenting cells or fibroblasts that migrate to the donor thymus [19–22]. This process may have allowed equivalent numbers of T cells to develop without matching. Although we did not detect any adverse events when transplanting across HLA barriers, subtle defects in immunity may appear as we further dissect immune responses in these subjects.

Age of thymus donor

Prior to this study, we assumed that the thymuses from younger (<1 month) donors would exhibit more vigorous function than thymuses from older (1–9 month) donors. A model in which human fetal thymus tissue and fetal liver tissue were transplanted under the kidney capsule of C.B-17 scid/scid (SCID) mice [23] had shown optimal thymopoiesis using human fetal thymus that was less than 20 weeks gestation. Thus, we were surprised to find that thymuses from younger donors were not superior to those from older donors. To determine whether thymuses from older (1–9 months) donors are superior to thymuses from donors <1 month, we have begun to prospectively test this question in the next 20 transplants. If this finding is confirmed, the reason for the lower T cell counts with thymuses from younger donors may be the stress in the younger infants from heart failure and hypoxia leading to a permanent defect in the thymuses’ ability to function in thymopoiesis.

Because conotruncal heart defects can correlate with DiGeorge anomaly, we were concerned that use of thymuses from these donors would be associated with poor immune outcomes. In particular since up to half of infants with DiGeorge anomaly do not have a detectable deletion at 22q11, some of the donors with conotruncal heart defects might have DiGeorge anomaly despite our exclusion of all infants with 22q11 hemizygosity. To avoid using donors with partial DiGeorge anomaly, we analyzed all infant donors by flow cytometry for the percentage of T cells that were naïve (CD45RA+). No donors had less than 50% naïve T cells. Based on the results in Figure 5, donors with conotruncal heart defects do not appear to be associated with poor immune outcomes and thus we continue to include these donors.

Immunosuppression

The outcome of subjects treated without immunosuppression was compared to the outcomes of subjects treated with immunosuppression because of the concern that use of cyclosporine or steroids in the subjects during the peritransplant period would result in lower eventual T cell numbers. Our data showed no significant difference on total CD4 and naïve CD4 numbers, TCRBV variability (DKL scores), and proliferative responses to PHA between subjects who did and did not receive immunosuppression. As expected from these results, immunohistochemical evaluations of thymus graft biopsies performed after transplantation have demonstrated thymopoiesis in subjects receiving pre- and post-transplantation cyclosporine together with pre-transplantation rabbit antithymocyte globulin [23, 24]. The outcomes shown here are encouraging since immunosuppression is necessary to prevent graft rejection in atypical subjects.

Limitations of analyses

In assessing the data, it is important to note that both the processing of thymus and the clinical protocols evolved between 1993 and 2007. Thymus processing changes were made to enhance safety and to avoid the use of reagents that may have toxic effects (deoxyguanosine). Antibiotics were discontinued because of the concerns of hypersensitivity and possible microbial contamination of the thymus tissue. Changes in donor screening were instituted in response to FDA guidelines. Thus, although we present the effect of dose on a number of parameters, the changes in the processing of the thymus tissues through time should be considered.

This paper reports many correlations. For many of these analyses, we present the correlations separately for the subgroups with and without suppression. However, the suppression used was not uniform during the time of the studies reported (see Methods). The most significant change was the addition of cyclosporine in 2004 for subjects with atypical complete DiGeorge anomaly. The immunosuppression was used to control the rash and to prevent graft rejection and organ damage from oligoclonal genetically-host T cells. The small number of subjects in this study prevented robust statistical testing and corrections for multiple testing, limiting some of our various correlations.

In summary, thymus tissue for transplantation led to T cell and naïve T cell development, TCRBV repertoire diversity and proliferative responses to mitogens in the first year after transplantation. Surprisingly, these immune outcomes were not significantly affected by dose (within the range tested), HLA matching, culture conditions or immunosuppression of the recipient. A trend toward improved results found with use of donors over 1 month of age will be tested in a prospective trial.

Acknowledgements

The collaboration of surgeons James Jaggers, Andrew Lodge, Samuel Mahaffey, Michael Skinner, Henry Rice, and Jeffrey Hoehner is appreciated as is the technical assistance of Marilyn Alexieff, Jie Li, Chia-San Hsieh, Jennifer Lonon, and Julie Cox, and the clinical research assistance of Stephanie Gupton and Alice Jackson. The authors acknowledge the assistance of Dr. Michael Cook in the Duke Comprehensive Cancer Center flow cytometry facility and the molecular HLA typing by the Duke HLA laboratory. The excellent clinical care of the patients by the faculty and fellows of the Division of Allergy and Immunology and the nurses on the Duke General Clinical Research Center is appreciated.

Footnotes

1

Funding sources: National Institute of Health grants R01 AI 47040, R01 AI 54843, R21 AI 60967, M03 RR30 (Duke General Clinical Research Center, National Center for Research Resources, National Institute of Health), UL1 RR024128-01 (Duke Translational Medicine Institute), and Office of Orphan Products Development, Food and Drug Administration, grant FD-R-002606. MLM is a member of the Duke Comprehensive Cancer Center.

The authors have no conflicting financial interests.

References

  • 1.Sullivan KE, Jawad AF, Randall P, Driscoll DA, Emanuel BS, McDonald-McGinn DM, et al. Lack of correlation between impaired T cell production, immunodeficiency, and other phenotypic features in chromosome 22q11.2 deletion syndromes. Clin Immunol Immunopathol. 1998;86(2):141–146. doi: 10.1006/clin.1997.4463. [DOI] [PubMed] [Google Scholar]
  • 2.Conley ME, Beckwith JB, Mancer JF, Tenckhoff L. The spectrum of the DiGeorge syndrome. J Pediatr. 1979;94(6):883–890. doi: 10.1016/s0022-3476(79)80207-3. [DOI] [PubMed] [Google Scholar]
  • 3.Hong R. The DiGeorge anomaly. Clin Rev Allergy Immunol. 2001;20(1):43–60. doi: 10.1385/CRIAI:20:1:43. [DOI] [PubMed] [Google Scholar]
  • 4.Barrett DJ, Ammann AJ, Wara DW, Cowan MJ, Fisher TJ, Stiehm ER. Clinical and immunologic spectrum of the DiGeorge syndrome. J Clin Lab Immunol. 1981;6(1):1–6. [PubMed] [Google Scholar]
  • 5.Thomas RA, Landing BH, Wells TR. Embryologic and other developmental considerations of thirty-eight possible variants of the DiGeorge anomaly. Am J Med Genet Suppl. 1987;3:43–66. doi: 10.1002/ajmg.1320280508. [DOI] [PubMed] [Google Scholar]
  • 6.Muller W, Peter HH, Wilken M, Juppner H, Kallfelz HC, Krohn HP, et al. The DiGeorge syndrome. I. Clinical evaluation and course of partial and complete forms of the syndrome. Eur J Pediatr. 1988;147(5):496–502. doi: 10.1007/BF00441974. [DOI] [PubMed] [Google Scholar]
  • 7.Bastian J, Law S, Vogler L, Lawton A, Herrod H, Anderson S, et al. Prediction of persistent immunodeficiency in the DiGeorge anomaly. J Pediatr. 1989;115(3):391–396. doi: 10.1016/s0022-3476(89)80837-6. [DOI] [PubMed] [Google Scholar]
  • 8.Markert ML, Hummell DS, Rosenblatt HM, Schiff SE, Harville TO, Williams LW, et al. Complete DiGeorge syndrome: persistence of profound immunodeficiency. J Pediatr. 1998;132(1):15–21. doi: 10.1016/s0022-3476(98)70478-0. [DOI] [PubMed] [Google Scholar]
  • 9.Picker LJ, Treer JR, Ferguson-Darnell B, Collins PA, Buck D, Terstappen LW. Control of lymphocyte recirculation in man. I. Differential regulation of the peripheral lymph node homing receptor L-selectin on T cells during the virgin to memory cell transition. J Immunol. 1993;150(3):1105–1121. [PubMed] [Google Scholar]
  • 10.Markert ML, Devlin BH, Alexieff MJ, Li J, McCarthy EA, Gupton SE, et al. Review of 54 patients with complete DiGeorge anomaly enrolled in protocols for thymus transplantation: outcome of 44 consecutive transplants. Blood. 2007;109(10):4539–4547. doi: 10.1182/blood-2006-10-048652. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Markert ML, Alexieff MJ, Li J, Sarzotti M, Ozaki DA, Devlin BH, et al. Complete DiGeorge syndrome: development of rash, lymphadenopathy, and oligoclonal T cells in 5 cases. J Allergy Clin Immunol. 2004;113(4):734–741. doi: 10.1016/j.jaci.2004.01.766. [DOI] [PubMed] [Google Scholar]
  • 12.Selim MABJ, Herman CM, Turner JW, Markert ML. The cutaneous manifestations of atypical complete DiGeorge syndrome: A histopathologic and immunohistochemical study. J Cutan Pathol. 2008;35:380–385. doi: 10.1111/j.1600-0560.2007.00816.x. [DOI] [PubMed] [Google Scholar]
  • 13.Markert ML, Alexieff MJ, Li J, Sarzotti M, Ozaki DA, Devlin BH, et al. Postnatal thymus transplantation with immunosuppression as treatment for DiGeorge syndrome. Blood. 2004;104(8):2574–2581. doi: 10.1182/blood-2003-08-2984. [DOI] [PubMed] [Google Scholar]
  • 14.Title 21-Food and Drugs; Chapter I-Food and Drug Administration, Department of Health and Human; Subchapter L-Regulations Under Certain Other Acts Administered by the Food and Drug Administration. Part 1270 Human Tissue Intended for Transplantation, Code of Federal Regulations. 2006 [Google Scholar]
  • 15.Hong R, Moore AL. Organ culture for thymus transplantation. Transplantation. 1996;61(3):444–448. doi: 10.1097/00007890-199602150-00023. [DOI] [PubMed] [Google Scholar]
  • 16.Kepler TB, He M, Tomfohr JK, Devlin BH, Sarzotti M, Markert ML. Statistical analysis of antigen receptor spectratype data. Bioinformatics (Oxford, England) 2005;21(16):3394–3400. doi: 10.1093/bioinformatics/bti539. [DOI] [PubMed] [Google Scholar]
  • 17.Choi EY, Jung KC, Park HJ, Chung DH, Song JS, Yang SD, et al. Thymocyte-thymocyte interaction for efficient positive selection and maturation of CD4 T cells. Immunity. 2005;23(4):387–396. doi: 10.1016/j.immuni.2005.09.005. [DOI] [PubMed] [Google Scholar]
  • 18.Li W, Kim MG, Gourley TS, McCarthy BP, Sant'Angelo DB, Chang CH. An alternate pathway for CD4 T cell development: thymocyte-expressed MHC class II selects a distinct T cell population. Immunity. 2005;23(4):375–386. doi: 10.1016/j.immuni.2005.09.002. [DOI] [PubMed] [Google Scholar]
  • 19.Bix M, Raulet D. Inefficient positive selection of T cells directed by haematopoietic cells. Nature. 1992;359(6393):330–333. doi: 10.1038/359330a0. [DOI] [PubMed] [Google Scholar]
  • 20.Hugo P, Kappler JW, McCormack JE, Marrack P. Fibroblasts can induce thymocyte positive selection in vivo. Proc Natl Acad Sci U S A. 1993;90(21):10335–10339. doi: 10.1073/pnas.90.21.10335. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Martinic MM, Rulicke T, Althage A, Odermatt B, Hochli M, Lamarre A, et al. Efficient T cell repertoire selection in tetraparental chimeric mice independent of thymic epithelial MHC. Proc Natl Acad Sci U S A. 2003;100(4):1861–1866. doi: 10.1073/pnas.252641399. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Pawlowski T, Elliott JD, Loh DY, Staerz UD. Positive selection of T lymphocytes on fibroblasts. Nature. 1993;364(6438):642–645. doi: 10.1038/364642a0. [DOI] [PubMed] [Google Scholar]
  • 23.Markert ML, Devlin BH. Thymic reconstitution. In: Rich RR, Shearer WT, Fleischer T, Schroeder HW, Weyand CM, Frew A, editors. Clinical Immunology 3rd edn. Edinburgh: Elsevier; pp. 1253–1262. in press. [Google Scholar]
  • 24.Markert ML, Li J, Devlin BH, Hoehner JC, Rice HE, Skinner MA, Li YJ, Hale LP. Use of allograft biopsies to assess thymopoiesis after thymus transplantation. J Immunol. 2008 doi: 10.4049/jimmunol.180.9.6354. in press. [DOI] [PubMed] [Google Scholar]

RESOURCES