Alternative Donor SCT for the Treatment of MHC Class II Deficiency

ORIGINAL ARTICLE Alternative donor SCT for the treatment of MHC Class II deﬁciency

TN Small1, W Qasim2, W Friedrich3, R Chiesa2, JJ Bleesing4, A Scurlock5, P Veys2 and M Sparber-Sauer3

MHC Class II deficiency is a rare primary immunodeficiency disease characterized by absent HLA Class II expression resulting in CD4 lymphopenia, lack of Ag-specific responses and recurrent infection. Without successful allogeneic SCT, most children succumb to infection within the first decade of life. To date, alternative donor transplants for this disorder have been inferior to SCT for other forms of combined immunodeficiency disease due to an increased incidence of graft rejection, GVHD and death from infections generally acquired before haematopoietic cell transplantation. This study details the transplant outcome of 16 affected children consecutively transplanted at four centers since 1990, 8 of whom required mechanical ventilation pretransplant. Stem cells were derived from an HLA-mismatched family member (n ¼ 10), an HLA-matched unrelated adult donor (n ¼ 4), or an unrelated cord blood donor (n ¼ 2). Graft failure occurred in five children, all of whom underwent a second SCT. Six patients developed acute GVHD although no patient developed chronic GVHD after primary transplantation. CD4 T-cell reconstitution remained below the normal range for age, suggesting defective thymopoiesis after allo-SCT. Nonetheless, 69% of children survive without GVHD at a median follow-up of 5.7 years, indicating improved outcomes compared with previous studies.

Bone Marrow Transplantation (2013) 48, 226–232; doi:10.1038/bmt.2012.140; published online 24 September 2012 Keywords: immunodeﬁciency; MHC Class II deﬁciency; transplantation

INTRODUCTION rejection, and less than optimal CD4 T-cell reconstitution following MHC Class II deficiency, also known as Type II Bare Lymphocyte SCT in this condition. Syndrome, is a rare form of autosomal recessive combined 1–12 immunodeficiency disease currently curable only by allo-SCT. MATERIALS AND METHODS Patients with this disease possess normal MHC Class II genes, but Patient characteristics, preparative regimen, graft characteristics, have mutations within one of four transactivating genes that GVHD prophylaxis and supportive care control their expression (reviewed in Reith and Mach2 and Villard 3 Sixteen consecutive patients with MHC II Class deficiency were referred to et al. ). Over 85% of affected children have mutations in genes the University of Ulm (n ¼ 8), Great Ormond Street Hospital (n ¼ 4), encoding subunits of regulatory factor X (RFXANK, RFXAP or RFX5), Cincinnati Children’s Hospital Medical Center (n ¼ 2) and Memorial a protein complex that binds to the MHC Class II promoter and Sloan-Kettering Cancer Center (n ¼ 2) between 1990 and 2011 for SCT. activates transcription. The remaining patients have defects of the The demographics and clinical characteristics of the seven females and Class II transactivator, a factor that regulates constitutive and IFN-g nine males are shown in Table 1. All patients were diagnosed by upregulation of MHC Class II antigens (reviewed in Reith and the absence of MHC Class II expression on peripheral blood monocytes Mach2 and Villard et al.3). and B cells by flow cytometry. Patients 12 and 16 had mutations in the Patients with MHC Class II deficiency generally have severe CD4 RFXAP and RFXANK genes, respectively. Mutations in the other patients are unknown. Median age (range) at time of initial transplant was 1.6 (0.5–4) T-cell lymphopenia, hypogammaglobulinemia and lack Ag-specific years. All but one patient had X1 life-threatening infection before responses resulting in chronic diarrhea, recurrent viral, parasitic transplant, including pneumonia in 14 patients, 8 of whom required 1,4,5,7 and bacterial infections, and failure to thrive. Although recent mechanical ventilation before SCT. In addition to pneumonia, the reports of allo-SCT for this disease have shown improved survival majority of patients had infectious diarrhea and failure to thrive. Patient following HLA-matched related donor transplantation,8,9 for those 11 had two episodes of PCP pneumonia and 1 episode of ECHO virus patients lacking such a donor survival of p50% has been meningoencephalitis before SCT. Patient 15 had rubella viremia before reported.4,5,7–9 transplantation. The rarity of this disease challenges physicians making transplant decisions for affected children who lack a well-matched Stem cell donor and preparative regimen. Transplant donors were family donor. We have collected data for 16 consecutive patients HLA-Ag-mismatched family members (n ¼ 10), HLA-allele-matched (10/10) transplanted at four centers in Europe and North America since unrelated adult volunteer donors (n ¼ 4) or unrelated cord blood donors (n ¼ 2) (Table 2). HLA typing for cord blood units was defined by 1990 to characterize outcomes following alternative donor SCT for serological typing for HLA A and B antigens and high-resolution molecular this disorder. With 69% (11/16) overall survival at a median follow- typing for HLA DRb1. up of 5.6 years, our experience indicates improved outcomes after Seven patients received T-cell-depleted SCT, six of whom received BU such transplants, but we highlight notable difficulties with graft (X16 mg/kg over 4 days), combined with thiotepa and fludarabine (n ¼ 3),

1Department of Pediatrics, Bone Marrow Transplant Service, Memorial Sloan-Kettering Cancer Center, New York, NY, USA; 2Great Ormand Street Hospital, London, UK; 3University Children’s Hospital, Ulm, Germany; 4Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA and 5Arkansas Children’s Hospital, Little Rock, AR, USA. Correspondence: Dr TN Small, Department of Pediatrics, Bone Marrow Transplant Service, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA. E-mail: [email protected] Received 15 March 2012; revised and accepted 26 June 2012; published online 24 September 2012 Alternative donor SCT TN Small et al 227

Table 1. Pre-HCT patient characteristics

Patient Age Ethnicity Pretransplant infections Hx of Pre-HCT Pre-HCT B Pre-HCT T-cell no. (years)/ mechanical T cells/mL and NK proliferative sex ventilation cells/mL responses Pre-HCT

1a 4/M African PCP pneumonia Yes CD3: 3906 CD19: 160 PHA: nl American FTT, diarrhea CD4: 517 CD56: 172 MLC: nl CD8: 2929 NK: 100:1:nl 2 2/F Turkish Candida pneumonia Yes CD3: 1094 CD19: 880 PHA: 25–50% nl BCGitis, FTT CD4: 694 CD56: not Gastroenteritis (Enterovirus, CD8: 534 tested Rotavirus) 3 3/M Turkish Pneumonia (unspecified) No CD3: 1554 CD19: 627 PHA: nl Recurrent otitis, diarrhea, CD4: 600 CD56: 273 MLC: 50% nl FTT, UTI CD8: 764 4 0.5/F Italian PCP pneumonia Yes CD3: 1069 CD19: 732 PHA: 50% nl FTT CD4: 237 CD56: 59 MLC: nl CD8: 811 NK: 100:1:nl 5 0.8/F Greek Chlamydia pneumonia Yes CD3: 2486 CD19342 NK: 100:1:nl VZV infection CD4: 435 CD56: 186 CD8: 2020 6 0.5/F Turkish None No CD3: 2052 CD19: 142 PHA: 50–75% nl CD4: 1140 CD56: 456 MLC: nl CD8: 855 NK: 100:1: 11% 7 1/F Saudi PCP and CMV pneumonia No CD3: 1193 CD19: 1909 NK: 100:1: 11% Arabian FTT, diarrhea CD4: 443 CD56: 170 CD8: 579 8 1.5/F Turkish Adenovirus pneumonia Yes CD3: 2148 CD19: 3029 PHA: 50–75% nl CD4: 495 CD56: 165 MLC: nl CD8: 1487 9 3/M Turkish Pneumonia, bronchitis thrush, No CD3: 893 CD19: 85 NT otitis media, gonorrheal arthritis CD4: 110 CD56: 159 diarrhea, FTT CD8: 599 10 1/F Caucasian PCP and RSV pneumonia Yes CD3: 2040 CD19: 1350 PHA: o25% nl CD4: 620 CD56: 20 CD8 1310 11 3/M Caucasian PCP pneumonia x2 Yes CD3: 1152 CD19: 722 PHA: 25% nl Meningoencephalitis (ECHO virus) CD4: 497 CD56: 248 Diarrhea (Salmonella, Giardia), FTT CD8: 655 12 1.5/M Middle Pneumonia (unspecified) No CD3: 2130 CD19: 540 PHA: nl East/ Thrush CD4: 1250 CD56: 60 Arabic CD8: 740 13 0.5/M Middle Adenovirus pneumonia No CD3: 1610 CD19: 1060 NT East/ Recurrent pneumonias CD4: 1160 CD56: 330 Arabic (unspecified) CD8: 430 Viral gastroenteritis UTI 14 2/M Middle Recurrent pneumonia No CD3: 501 CD19: 310 PHA: 15% nl East/ (unspecified), bronchiectasis CD4: 290 Arabic CD8: 200 15 2.5/M Caucasian RSV pneumonia; pneumonia No CD3: 231 CD19: 880 PHA: o5% nl (unspecified), rubella-associated CD4: 80 CD56: 544 Con A: o5% nl skin rash and viremia CD8: 123 PWM: o5% nl HSV2 viremia, FTT Candid: 10% nl Tetanus: absent 16 1.9/M Saudi CMV pneumonia x2 Yes CD3: 4995 CD19: 2305 PHA: 59% nl Arabian CMV retinitis CD4: 692 CD56: 307 MLC: nl FTT CD8: 3842 Norovirus gastroenteritis Auto-immune hepatitis

Abbreviations: CMV ¼ cytomegalovirus; ECHO ¼ enteric cytopathic human orphan; F ¼ female; FTT ¼ failure to thrive; HCT ¼ haematopoietic cell transplantation; HX ¼ history of; M ¼ male; nl ¼ lower limit of normal control range or % of normal control of the day; NK ¼ natural killer; NT ¼ not tested; PCP ¼ Pneumocystis carinii; PWN ¼ pokeweed mitogen; RSV ¼ respiratory syncytial virus; UTI ¼ urinary tract infection; VZV ¼ varicella zoster virus. aPatients in bold rejected their primary graft.

thiotepa and CY (n ¼ 1), CY and fludarabine (n ¼ 1), or CY alone (n ¼ 1). (n ¼ 2), fludarabine, CY, anti-CD45 and anti-CD52 (n ¼ 1), or low-dose CY, Recipients of T-cell-depleted SCT received anti-thymocyte globulin (n ¼ 6) fludarabin 200 cGy of single-dose TBI and post-transplant CY. Post- or anti-CD52 (Campath 1H, n ¼ 1) to prevent graft failure. Recipients of an transplant prophylaxis against GVHD included combinations of cyclosporin unmodified BM or PBSCT were cytoreduced with BU, fludarabine, CY or tacrolimus and mycophenolic acid. The two cord blood recipients (n ¼ 2), thiotepa and CY (n ¼ 1), melphalan, fludarabine and anti-CD52 received treosulfan and fludarabine without serotherapy.13

& 2013 Macmillan Publishers Limited Bone Marrow Transplantation (2013) 226 – 232 228 oeMro rnpatto 21)26–232 – 226 (2013) Transplantation Marrow Bone Table 2. (a) Outcome of T cell depleted transplant recipients. (b) Outcome of non-T cell depleted (unmodiﬁed) transplant recipients

Patient Age (years)/ Donor HLA disparity Stem cell type Cytoreduction Rejection or GVHD Eng GVHD Outcome no. sex prophylaxis

1a 4/M Grandmother 1 (HVG, GVH) TCD BU: 16 mg/kg, (i.v.) r-ATG: 2.5 mg/kg Â 2 Tr NE Secondary GF PB TT: 10 mg/kg FLU: 160 mg/m2 1b 4.1/M UnR 1 (HVG, GVH) TCD FLU: 150 mg/m2 r-ATG:2.5 mg/kg Â 2 Yes N A&W, 5.2 years þ PB CY: 120 mg/kg 2 2/F Aunt 3 (GVH) TCD BU: 24 mg/kg h-ATG: 5 mL Â 4 Yes Grade I skin A&W, 22.1 year þ BM CY: 200 mg/kg 4a 0.6/F Father 3 (HVG, GVH) TCD BU: 16 mg/kg h-ATG: 5 mL Â 4 No NE Graft rejection PB TT: 10 mg/kg CY: 200 mg/kg 4b 0.7/F Father 3 (HVG, GVH) PartialTCD OKT3: 0.2 mg/kg Â 14 Yes Grade IV Ext Death, 3 years BM chronic Chr GVHD Aspergillus 5 0.8/F Father 2 (HVG, GVH) TCD BU: 20 mg/kg r-ATG: 5 mL 4 Yes, Grade I Boost, day 17

Â þ SCT donor Alternative PB TT: 10 mg/kg T, B cells Skin slow neutrophil FLU: 200 mg/m2 recovery A&W, 13.3 years

þ Small TN 6 0.6/F Father 3 (HVG) TCD BU: 20 mg/kg r-ATG: 5 mL Â 4 Yes, Grade I skin Boost day þ 29 PB TT: 10 mg/kg T, B cells Slow neutrophil FLU: 200 mg/m2 recovery

A&W, 13.3 years þ al et 7a 1/F Father 3 (HVG, GVH) TCD BU: 16 mg/kg, (i.v.) r-ATG: 5 mL Â 4 No NE Graft failure PB CY: 200 mg/kg FLU: 200 mg/m2 7b 1.1/F Father 3 (HVG, GVH) TCD OKT3: 0.1 mg/kg Â 10 2ndary 0 Autologous PB h-ATG: 5 mL Â 4 GF recovery 7c 1.7/F Father 3 (HVG, GVH) TCD BU: 16 mg/kg (i.v.) r-ATG: 3 mL Â 3 Yes 0 Death, 2.5 years PB MEL: 140 mg/m2 OKT3: 0.1 mg/kg Â 5 AIHA CMV 13 0.5/M Mother 1 (GVH) TCD FLU: 150 mg/m2 CyA/MMF Yes 0 Death, 0.9 years PB, add-back MEL: 140 mg/m2 Campath 1H Adenovirus T cells pneumonia

(b) Outcome of non-T cell depleted (unmodiﬁed) transplant recipients

Patient Age (years)/ Donor HLA disparity Stem cell type Cytoreduction GVHD prophylaxis Eng GVHD Outcome no. sex & 03McilnPbihr Limited Publishers Macmillan 2013 3a 3/M Father 1 (HVG) BM CY: 200 mg/kg CyA/MTX No NE Graft rejection TT: 20 mg/kg Early autologous recovery 3b 3.8/M Father 1 (HVG) BM BU: 16 mg/kg CyA/MTX Yes Grade IV Death, day þ 120 CY: 200 mg/kg h-ATG: (5 mL Â 2) GVHD Liver failure 8 1.6/F Father 3 (HVG) BM BU: 16 mg/kg (i.v.) r-ATG: 5 mL Â 4 Yes 0 Alive, 10.33 years þ 0 (GVH) CY: 200 mg/kg CyA Developmental FLU: 120 mg/m2 delay 9 3/M UnR None PB BU: 16 mg/kg (i.v.) CyA/MMF Yes Grade IV Death, day þ 39 CY: 200 mg/kg Campath 1H GVHD FLU: 120 mg/m2 Alternative donor SCT TN Small et al 229 Graft characteristics. Nine patients received a T-cell replete BM (n ¼ 5), peripheral blood (n ¼ 2), or cord blood (n ¼ 2) SCT. Seven patients þ þ þ þ þ rabbit þ received a T-cell-depleted SCT derived from peripheral blood (n ¼ 6) or ¼ BM (n ¼ 1). Peripheral blood was T cell depleted by CD34 þ selection

graft failure; followed by sheep red blood cells rosetting. BM was T cell depleted by

¼ soybean agglutination followed by sheep RBC rosetting. One patient received a CD34 þ selected PBSC transplant combined with 108/kg add- back T cells derived from the CD34 À fraction. A&W, 2.3 years A&W/1.33 years failure

GVHD prophylaxis and evaluation ﬂudarabine; GF All recipients of an unmodiﬁed graft received a calcineurin-based regimen ¼ peripheral blood; r-ATG

¼ to prevent GVHD (Table 2b). Patient 13 who received add-back T cells following a T-cell-depleted graft received additional GVHD prophylaxis with CyA, mycophenolic acid and Campath 1H. Acute GVHD was deﬁned Skin Skin 0 Secondary graft as any GVHD occurring o100 days post-transplant and was graded 14 female; FLU according to the Glucksberg criteria. Chronic GVHD was graded as ¼ limited or extensive according to the criteria of Sullivan et al.15 3 not evaluated; PB

Â Engraftment, graft failure and donor chimerism. Engraftment was ¼ defined as the first of three consecutive days of an ANC of X500 cells/mL. Yes DLI Yes 0Yes 0 A&W, 5.7 years A&W 1.8 years extensive; F Primary graft failure was defined as failure to achieve an ANC of X500 ¼ cells/mL by day 28 after haematopoietic cell transplantation (HCT).

male; NE Secondary graft failure was defined as failure to maintain an ANC ¼ 4500 cells/mL after achieving engraftment. Stem cell boosts were defined as transplants given to patients with evidence of T-and B-cell donor engraftment but slow recovery of neutrophils following a T-cell-depleted graft. Complete donor chimerism was defined by 495% MHC Class II

engraftment; Ext expression on circulating B cells and monocytes. Lineage-speciﬁc ¼ chimerism was performed in some patients by assessment of STRs in

T, B and monocytes. The bold entries refer to patients who rejected theircirculating primary lymphoid and myeloid cells. ¼ Campath 1H A&W, 6.0 years CyA/MMF Campath 1H FK/MMF Yes 0 A&W, 0.35 years CyA/steroids Campath 1H CyA/MMFCyA/MMFCyA/steroids Campath 1H Yes Yes Grade II Grade I

2 Supportive care. All patients were transplanted in single room reverse

Â isolation with ﬁltered air. Routine HSV, fungal and PCP prophylaxis was 2 2

Â given to all patients. Neutropenic patients with persistent fever despite 2 2 2 2 2 2 2 2

2 2 72 h of broad-spectrum antibiotics received empiric anti-fungal therapy. unrelated; Yes

¼ Pre-emptive or prophylactic treatment to prevent CMV was given as per

cyclophosphamide; Eng institutional guidelines. All patients received intravenous gammaglobulin

¼ (IVIG) pre and post SCT, the duration of which was guided by trough IgG

disparity in host-versus-graft direction; M levels and response to post SCT immunizations. ¼ CY: 200 mg/kg CY: 1200 mg/m CD45: 1600 mg/kg MEL 140 mg/m TREO: 42 g/m TREO: 42 g/m MEL: 140 mg/m CY post: 50 mg/kg FLU: 150 mg/m

thiotepa; UnR Biostatistics. Fisher’s exact test for qualitative variables and the ¼

busulfan; CY Wilcoxon rank-sum test for quantitative variables were used for

¼ comparisons between groups. Only P-values o0.05 were considered statistically signiﬁcant. treosulfan; TT

¼ RESULTS Pretransplant immunological studies

alive and well; BU Table 1 shows the pre-HCT immunophenotype and function of ¼ the transplanted patients. At the time of SCT, the median (range) CD4 and CD8 T cells/mL were 507 (80–1250) and 740 (123–3842) horse anti-thymocyte globulin; HVG transient; TREO ¼ cells/mL, respectively. There was no signiﬁcant difference in CD4 ¼ T, CD8 T, or CD56 CD16 natural killer cell numbers in patients who did or did not achieve durable engraftment following an initial graft. Six patients had a PHA X50% of normal and four patients had a severely impaired PHA response. A pooled mixed lymphocyte response was normal in ﬁve of six patients in whom Donor HLA disparity Stem cell type Cytoreduction GVHD prophylaxis Eng GVHDit was Outcome tested. T cell depleted; Tr ¼ Engraftment

autoimmune hemolytic anemia; A&W Thirteen patients engrafted following their initial transplant, two ¼

sex of whom developed secondary graft failure (Tables 2a and b). Durable engraftment was observed in four of seven and seven of Age (years)/ nine recipients of a T-cell-depleted or unmodified grafts, respectively (P ¼ NS). Five patients underwent a second trans- (Continued) plant, four derived from the original donor (Table 2). Time to second transplant was a median (range) of 58 days (19–651) days after the first SCT. Despite engraftment, only two of five 10a 1/F UnR None PB FLU: 150 mg/m 11 3/F UnR None BM FLU: 150 mg/m 15 3/M UnR None BM FLU: 150 mg/m 12 1/M UnR None Cord blood FLU: 150 mg/m 14 2/M UnR 1 (GVH) Cord blood FLU: 150 mg/m 16 1.9/M UnR None BM CY: 14.5 mg/kg 10b 1.6/M UnR None PB BU: 16 mg/kg Patient no. transplant. anti-thymocyte globulin; TCD GVH: disparity in graft-versus-host direction; h-ATG Abbreviations: AIHA Table 2. recipients of a subsequent graft survive for long-term.

& 2013 Macmillan Publishers Limited Bone Marrow Transplantation (2013) 226 – 232 Alternative donor SCT TN Small et al 230

Acute GVHD CD4 recovery 1st two years CD4 recovery 1st two years Six of 16 patients developed acute GVHD following primary post T cell-depleted HCT post T-replete HCT transplantation (Table 2). Three patients developed grade I skin 1000 #1 1000 #3 #2 #8 GVHD following HLA-mismatched related TCD PBSC transplant, 800 #5 800 #11 #12 600 #6 600 one patient developed fatal grade IV following unmodiﬁed #7 #14 unrelated peripheral blood transplant, and two patients devel- 400 400 #15 CD4 cells/ul oped grade I (n ¼ 1) or II (n ¼ 1) GVHD following unrelated cord 200 CD4 cells/ul 200 blood SCT. One patient developed grade IV GVHD following a 0 0 0.0 0.5 1.0 1.5 2.0 0.0 0.5 1.0 1.5 2.0 secondary graft which was partially T-cell-depleted. Years post HCT Years post HCT

CD4 recovery 0–5 years CD4 recovery 0–5 years post Chronic GVHD post T cell-depleted HCT T-replete HCT 1000 #1 1000 #3 Of the 11 patients evaluable for chronic GVHD, none developed #2 #8 800 #5 800 #11 this complication following a primary HCT. One patient developed #12 600 #6 600 fatal chronic GvHD after a subsequent transplant for graft #7 #14 400 400 #15 CD4 cells/ul rejection (Table 2a). CD4 cells/ul 200 200 0 0 012345 1.0 1.5 Survival Years post HCT 0.0 0.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Years post HCT As of 6/25/12, 11 of 16 patients survive, one with developmental delay at a median of 5.8 (0.35–22.1) þ years post HCT. Seven Figure 1. (a–d) Early (0–2years) and extended (0–5year) recovery of patients survive following their initial SCT, two following a second CD4 cells following T-cell-depleted (a, b) and T-replete (c, d) SCT for SCT and two following a TCD boost because of slow engraftment MHC Class II deﬁciency. Lower limit of normal for age groups included: 650–1300 CD4 cells/mL. following the primary SCT.

Cause of death Absolute CD4+ CD45RA+ cells/ul Percentage of CD4+CD45RA+ cells Five of 16 patients died. Following a primary transplant, the post T cell-depleted and post T cell-depleted and T-replete HCT T-replete HCT causes of death were GVHD and multi-organ failure (day þ 39), #1 400 100 adenovirus pneumonia (day þ 329) or complications from acute #5 350 #6 80 GVHD (day þ 120). Two children died following a second SCT, one 300 #7 because of chronic GVHD with invasive Aspergillus after 3 years 250 #8 60 and the other because of autoimmune hemolytic anemia and CMV 200 #11 disease 2.5 years after SCT (Tables 2a and b). 150 #12 40 100 #14 20 50 #15 % CD4+CD45RA+

#CD4+CD45RA+ cells/ul 0 0 Chimerism 012345 012345 Ten of 11 surviving patients have 495% class II expression on B Years post HCT Years post HCT cells and monocytes after allo-SCT (data not shown). The most Figure 2. Kinetics of absolute numbers and percentage of CD4 þ recently transplanted patient achieved 100% donor T-cell chimer- CD45RA þ T cells following T-cell-depleted and T-replete HCT for ism and 50% donor monocytes 3 months post HCT. MHC Class II deficiency. Lower limit of normal for age groups included: 46–63% (1–12 years of age): Absolute numbers: 320–1000 cells/mL. Immune reconstitution Figure 1 demonstrates the early (0–2 years) and extended (0–5 year) recovery of CD4 cells/mL in T-cell-depleted (Figures 1a and b) compared with T-cell replete (Figures 1c and d) SCT recipients. The DISCUSSION majority of surviving patients achieved CD4 cell counts 4200 cell/mL, MHC Class II deficiency is difficult to transplant, with increased but levels remained below the normal range for age.16 Although regimen-related toxicity, serious opportunistic infections, graft some patients developed circulating CD4 T cells within the first 2 rejection and GVHD, even in the context of an HLA-matched years post HCT (Figures 1a and c), counts in many of these sibling graft.1–4,6–12 For certain inherited T-cell immuno- patients subsequently declined. The most robust early CD4 T-cell deficiencies, unconditioned transplantation using HLA-identical count was observed in patient 12 who received a cord blood SCT grafts can be successful because host cellular immunity is without serotherapy. Figures 2a and b. demonstrate the absolute insufficient to cause graft rejection (reviewed in Small et al.17). number (Figure 2a) and proportion of CD4 þ CD45RA þ However, in MHC class II deficiency, residual host immunity is (Figure 2b) cells, respectively. In all patients, these values were sufficient to reject donor grafts in the absence of preconditioning. below the normal range for age.16 Table 3 shows the immuno- Experience from animal studies confirms that MHC Class II- logical and clinical status of surviving patients at last follow-up. All deficient mice are capable of rejecting allogeneic grafts as rapidly patients immunized with tetanus toxoid seroconverted as did 5/5 as MHC intact mice.18 Our data combined with published patients immunized with the protein-conjugated Haemophilus literature suggest that the use of BU (albeit without routine influenza vaccine. Patient 1 responded to all vaccines administered quantification of levels or dose adjustment) combined with CY including measles and rubella following the live attenuated even in the presence of additional immunosuppression is measles, mumps and rubella (MMR) vaccine administered at 27 insufficient to yield reproducible engraftment in patients with months post HCT. He responded to mumps following a second this disease. Although four of seven recipients of a T-cell-depleted MMR. His titers against measles, mumps and rubella were 0.05, HCT in this series survive, three patients required a subsequent 0.03 and 0.04 (before the first vaccine), 1.45, 0.11 and 124 IU/mL transplant for graft failure and two patients required (following the initial MMR), and 3.28, 2.18 and 237 IU/mL after the T-cell-depleted boosts for delayed neutrophil engraftment. second MMR, respectively. Following a T-replete graft, 2/9 patients rejected their transplant.

Bone Marrow Transplantation (2013) 226 – 232 & 2013 Macmillan Publishers Limited Alternative donor SCT TN Small et al 231 Table 3. In vitro immune phenotype and function and infectious complication in survivors

Patient Time post HCT % #CD4/ #CD8/ #CD19/ Serum IgG/ Normal PHA Positive Infections post HCT no. studied (year) Donora mL mL mL IgA/IgM (yes/no) vaccine (%) (mg/dL) response

1 1.4 100 298 392 300 1010/o7/ Yes Diphtheria RSV URI-resolved 58 Tetanus Pertussis H. influenza Prevnar polio Influenza MMR 2 16 100 250 520 120 930/134/ Yes Diphtheria 110 Tetanus H. influenza 5 10.2 100 323 847 NT NT Yes Diphtheria Tetanus H. influenza 6 8 100 257 589 219 1120/120/ Yes Diphtheria 90 Tetanus H. influenza 8 4.66 100 341 1424 237 1170/200/ Yes Diphtheria 230 Tetanus H. influenza 10 2 100 280 1170 840 431/72/40 Yes Tetanus Diss varicella with pneumonia (resolved) 11 5.4 100 360 758 284 799/155/ Yes Diphtheria 73 Tetanus Prevnar 12 1.5 100 1520 830 580 350/164/ Yes Not S. viridans sepsis (resolved) 108 vaccinated 14 0.6 100 110 90 140 NT NT Not Norovirus vaccinated Colitis-resolved 15 1.49 100 693 177 352 1000 (on Yes Not Pre and post rubella IVIG)/16/ vaccinated viremia with rash (resolved) 63 16 0.3 T cells: 369 1579 2675 Still on No, 40% Not CMV viremia resolved on 100 IVIG Lower limit vaccinated therapy Monos: of normal 5

Abbreviations: H. inﬂuenza ¼ Haemophilus inﬂuenza; HCT ¼ haematopoietic cell transplantation; MMR ¼ measles, mumps and rubella; Monos ¼ monocytes; NT ¼ not tested; RSV ¼ respiratory syncytial virus; S. viridians ¼ Streptococcus viridians. aPercent donor chimerism based on peripheral blood chimerism, either HLA Class II expression on monocytes and B cells or in the case of patient 16 on STR performed on peripheral blood isolated populations. The shaded areas serve to clearly differentiate one patient from another, even in cases of patients who had more than one transplant.

This has been seen in previous reports in which 6/19,(ref. 5) 2/6,(ref. 4) of 30 children with MHC Class II deficiency who received 2/15(ref. 10) and 3/30(ref. 9) patients have required second SCTs. HLA-matched related family grafts, 1-Ag HLA-mismatched family Conditioning regimens incorporating post-transplant CY19 may grafts (n ¼ 3) or unrelated cord blood donation (n ¼ 1). The help address the problem of residual host-mediated immunity. majority of patients received myeloablative conditioning, primarily This approach may preferentially eradicate host T cells capable of with combinations of BU, CY and etoposide. Twelve patients rejecting donor cells. Patient 16 transplanted with this regimen received reduced intensity conditioning consisting of fludarabine, achieved T cell and monocyte donor chimerism of 98 and 50% by melphalan and ATG. At a median follow-up of 6.3 years, survival day 69 post HCT, without GVHD or regimen-related toxicity was 66% for the entire group and 76% in HLA-matched related (despite severe pre-existing norovirus gastroenteritis, and biopsy- HCT recipients. None of the patients who received reduced proven hepatic fibrosis) using this approach. intensity conditioning followed by an HLA-mismatched related Following HLA-matched related SCT for MHC Class II deficiency HCT survived, nor did the cord blood graft recipient. Two of three disease, survival rates of 40–80% have been reported. In contrast, patients transplanted before the onset of infection due to unrelated and HLA-mismatched transplant outcomes of p50% previous family history developed graft failure, one of whom died. have been observed.1–4,6–10 Ouedeerni et al.7 recently published Despite successful engraftment, immune reconstitution, in results of a single-center study of 23 patients with MHC Class II particular CD4 T-cell recovery, has been suboptimal in the deficiency due to a RFXANK mutation. Despite myeloablative majority of patients transplanted for MHC Class II deficiency.2,7,9 conditioning (BU/CY) in all patients followed by a T-replete graft, In our study, most patients only achieved CD4 levels in the only 40% of patients survived following HLA-mismatched related 200–400/mL range, although T-cell responses to mitogens transplantation. One recipient of an unrelated cord blood graft normalized in all long-term survivors, and the majority of (HLA 9/10 ) in this series achieved only 1% donor chimerism and immunized patients have had satisfactory vaccine responses. survives in poor condition. Successful cord blood SCTs following Caution should, however, be exercised in deciding when to rejection of TCD HLA-mismatched related SCT for this disease withdraw antimicrobial prophylaxis and Ig-replacement therapy, have been reported.11,12 Al Mousa et al.9 evaluated the results as well as the time to initiate immunization with live attenuated

& 2013 Macmillan Publishers Limited Bone Marrow Transplantation (2013) 226 – 232 Alternative donor SCT TN Small et al 232 vaccine in this patient population. Patient 10 developed late REFERENCES disseminated wild-type varicella zoster infection necessitating 1 Elhasid R, Etzioni A. Major histocompatibility complex class II deficiency: a clinical mechanical ventilation despite evidence of active thymopoiesis review. Blood Rev 1996; 10: 242–248. (based on the presence of naive cells and TREC levels), normal 2 Reith W, Mach B. The Bare lymphocyte syndrome and the regulation of MHC T-cell responses to mitogens and Ab response following tetanus Expression. Annu Rev Immunol 2001; 19: 331–373. vaccination. This patient required reinstitution of Ig-replacement 3 Villard J, Masternak K, Lisowska-Grospierre B, Fischer A, Reith W. MHC class II therapy. Although patient 1 responded fully to measles and deficiency: a disease of gene regulation. 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In: Forman S, Blume KG, Thomas ED (eds) Hematopoietic Cell Transplantation. 4th edn vol. 75, Blackwell Science: Malden, MA, 2009; pp 1105–1124. 18 Grusby MJ, Glimcher LH. Immune responses in MHC class II-deficient mice. Ann CONFLICT OF INTEREST Rev Immunol 1995; 13: 417–435. The authors declare no conflict of interest. 19 Munchel A, Kesserwan C, Symons HJ, Luznik L, Kasamon YL, Jones RJ et al. HLA- haploidentical bone marrow transplantation with high dose, post-transplantation cyclophosphamide. Pediatr Rep 2011; 3(Suppl 2): e15. ACKNOWLEDGEMENTS 20 Li W, Kim M-G, Gourley TS, McCarthy BP, Sant’Angelo DB, Chang CH. An alternate We are grateful to all the nurses and physicians dedicated to the care of these pathway for CD4 T cell development: thymocyte-expressed MHC class II selects a children. distinct T cell population. Immunity 2005; 23: 375–386.

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