European experience of bone-marrow transplantation for severe combined immunodeficiency

The outcome of bone-marrow transplantations (BMT) carried out between 1968 and March 1, 1989, in 183 patients with severe combined immunodeficiency (SCID) was analysed. Recipients of HLA-identical BMTs (70) had a 76% probability of survival (median follow-up 73 months). Of the 32 treated since 1983, 97% have been cured (median follow-up 41 months). This good prognosis was associated with rapid development of T and B cell function. HLA-non-identical, T-cell-depleted, BMT (n = 100) gave significantly lower survival (52%; median follow-up 47 months). Factors associated with poor prognosis were the presence of a lung infection before BMT, absence of a protected environment, and use of female donors for male recipients. Use of a conditioning regimen significantly increased the frequency of sustained engraftment (86% vs 50% for non-conditioned BMT) and resulted in more frequent engraftment of donor B lymphocytes and myeloid cells. Donor B-cell chimerism was strongly associated with the development of normal B-cell function.

[T-cell immunodeficiency and the status of the reparative processes in patients with Crohn's disease of the large intestine]

Clinico-immunological examination of 35 patients with chronic colostasis at the stage of subcompensation and 10 patients with Crohn's disease of the colon before and after operative treatment (subtotal colectomy) revealed that presence of marked T-cellular immunodeficiency mainly due to helper subpopulation and inversion of helper-suppressor index in patients operated on for Crohn's disease of the colon, inhibiting the reparative processes and weakening anti-infection defense in these patients.

Adherence issues in pediatric bone marrow transplantation

The procedure of bone marrow transplantation entails a prolonged, aversive regimen in which adherence problems often develop, particularly with administration of oral antibiotic medications. A retrospective chart review revealed that 52% of pediatric patients evidenced significant adherence problems during the procedure. The highest rates of noncompliance were found in preschool and school-age children, with a surprisingly lower frequency in adolescents. Case summaries are presented to illustrate significant clinical issues and intervention strategies. These are discussed in terms of both their practical and theoretical significance regarding the determinants of adherence behavior.

Bone marrow transplantation for genetic disorders

In 1967, a congenital disorder, severe combined immune deficiency disease, (SCID), was the first condition to be successfully corrected by bone marrow transplantation (BMT) from a histocompatible matched sibling donor. Since then the number of inherited disorders in which BMT has been used has been greatly extended. In preface, it should be stressed that BMT represents only one aspect of the management of genetic disorders which includes first and foremost detection and prevention by antenatal screening. Enzyme replacement treatment and the development of genetic engineering techniques to correct the underlying fault are being actively explored. However, reliable screening programmes are only feasible in a minority of disorders, of which thalassaemia is an example. Enzyme replacement treatment has been largely unsuccessful, and despite considerable advances in the understanding of gene regulation, at present BMT represents the only practice capable of correcting genetic disorders and improving the quality of life of affected individuals.

Bone marrow transplantation for genetic diseases

Bone marrow transplantation is the treatment of choice for a number of genetic diseases. Recently, bone marrow transplantation has been increasingly used for erythroid disorders, such as thalassemia and sickle cell anemia. A number of inherited metabolic disorders (i.e., storage diseases, leukodystrophies, and the like) may be corrected with a marrow transplant. Successful correction of genetic diseases with allogeneic bone marrow transplantation lays the groundwork for the use of specific gene therapy.

Bone marrow transplantation (BMT) for the syndrome of pigmentary dilution and lymphohistiocytosis (Griscelli's syndrome)

We report the successful treatment of the syndrome of pigmentary dilution and immunodeficiency (Griscelli's syndrome) with allogeneic bone marrow transplantation. Griscelli's syndrome includes silvery hair, recurrent infections, hepatosplenomegaly, progressive neurologic deterioration, and lymphohistiocytosis and is uniformly fatal. We present a family in which four of seven children of consanguinous parents were affected. The affected children were all born with silvery hair. Microscopic examination of the hair showed large clumps of pigment in the hair shaft. Skin biopsy revealed an accumulation of melanosomes in the melanocytes. Three of the affected children were deceased before 20 months of age. Pathology of liver and lung in two of the siblings showed an infiltration of lymphocytes and histiocytes. Immunologic studies in one of these cases were notable for a decreased number of T cells and poor T-cell mitogen stimulation with concanavalin A (Con A) and pokeweed mitogen (PWM). Recently, a fourth sibling with silvery gray hair was referred to us at 3 months of age for evaluation. T-cell function studies were normal and she appeared in overall good health. Because of the expected fatal outcome, allogeneic bone marrow transplantation was performed at 4 months of age. Two years later the patient remains in excellent health. This suggests that cells of hematopoietic origin are responsible for the fatal outcome in Griscelli's syndrome and that bone marrow transplantation early in the course of the disease is an important modality for treatment of this syndrome.

The use of locus-specific minisatellite probes to check engraftment following allogeneic bone marrow transplantation for severe combined immunodeficiency disease

The graft status of 14 patients, 13 of whom had received an allogeneic bone marrow transplant (BMT) for severe combined immunodeficiency disease (SCID) and one patient with SCID in whom intrauterine maternal engraftment was suspected, was examined using bone marrow or peripheral blood DNA and a combination of locus-specific minisatellite probes for the sex-matched and locus-specific and a Y specific probe for the sex-mismatched patients. The sensitivity of the assay systems was such that less than 0.1% recipient DNA was detectable in a background of donor DNA. Graft status could be satisfactorily documented by 2.5 weeks post-transplant and in one case was of particular value as immunological parameters were misleading. In the six long-term survivors of allogeneic BMT for SCID, the use of the locus-specific probes showed total donor lymphoid and myeloid haemopoietic engraftment in five cases and mixed host/donor populations in one case. The diagnosis in approximately 10% of cases of SCID may prove difficult due to engraftment of the fetus by maternal cells. Diagnosis may be facilitated by the use of the locus specific minisatellite probes and indeed we found specific evidence for such maternal engraftment in one patient at presentation. The combination of these probes together with a Y specific probe thus provides a rapid and accurate method of assessing graft take following allogeneic BMT for SCID. The simple pattern of inheritance obtained and the high level of sensitivity of detection of low numbers of allogeneic cells make the techniques amenable for use in any routine DNA diagnostic laboratory.

Both ongoing suppression and clonal elimination contribute to graft-host tolerance after transplantation of HLA mismatched T cell-depleted marrow for severe combined immunodeficiency

Lymphocytes from children with severe combined immunodeficiency who had been immunologically reconstituted with haploidentical T cell-depleted bone marrow were analyzed with regard to their immunologic recognition of donor, host, or third party alloantigens. When compared with freshly isolated donor lymphocytes, the engrafted donor cells exhibited markedly reduced to absent responses toward host Ag in primary or secondary MLC and cell-mediated lympholysis assays. However, under limiting dilution conditions, cytotoxic responses to host Ag could be demonstrated, indicating that small numbers of host reactive cells were present, although down-regulated at high responder cell doses. These results are consistent with prior observations in limiting dilution cultures that indicate that cells with the potential to lyse autologous target cells exist in the peripheral blood of all normal individuals. The number of host reactive cells present in these patients is significantly less than that present in cells isolated directly from the marrow donors, and is also less than the number of autocytotoxic cells normally seen in peripheral blood. Together, these observations indicate that two mechanisms contribute to donor host tolerance in these patients. The majority of host reactive cells appear to have undergone clonal deletion or inactivation, whereas the small residual host-reactive population appears to be under ongoing immunoregulatory control.

Development of multiple monoclonal serum immunoglobulins (multiclonal gammopathy) following both HLA-identical unfractionated and T cell-depleted haploidentical bone marrow transplantation in severe combined immunodeficiency

We have identified five patients with severe combined immunodeficiency (SCID) who developed multiple monoclonal serum immunoglobulin components (multiclonal gammopathy) following bone marrow transplantation. Four patients received haploidentical bone marrow stem cells depleted of T cells and other mature marrow cells by soy lectin agglutination and/or sheep erythrocyte rosetting. One patient received unfractionated HLA-identical bone marrow. Twenty-one distinct paraproteins were detected: 14 IgG, 5 IgM, and 2 IgA, all containing either kappa or lambda light chains. In the haploidentical stem-cell recipients, these monoclonal immunoglobulins appeared immediately prior to, or concomitant with, a rise in T-cell numbers and function. Resolution or diminution of this multiclonal gammopathy occurred as T-cell function was established. Posttransplant karyotypic analyses revealed PHA-stimulated T cells to be of donor origin in all patients. Karyotyping of B-cell lines posttransplantation revealed them to be 100% donor in the patient receiving unfractionated HLA-identical marrow and 100% host (1/4), 100% donor (1/4), mixed (1/4), or not tested (1/4) in the patients receiving haploidentical marrow stem cells. There was no evidence of Epstein-Barr virus (EBV) infection in any of the patients. All patients are currently alive and well. Immunoglobulin synthesis is normal in the patient who received the HLA-identical marrow but remains below normal in the four patients who received T cell-depleted haploidentical stem cells. The posttransplantation development of monoclonal immunoglobulins in the absence of EBV infection did not adversely affect the outcome of either HLA-identical marrow or haploidentical stem-cell grafting.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful treatment with an unrelated-donor bone marrow transplant in an HLA-deficient patient with severe combined immune deficiency ("bare lymphocyte syndrome")

An 8-month-old white female infant with Pneumocystis carinii pneumonia had a normal blastogenic response to mitogens but no response to a variety of antigens, as well as a poor response to allogeneic cells in one-way mixed lymphocyte culture assays. The patient's mononuclear cells had defective class I (HLA-A, -B, -C) and absent class II (HLA-D) antigen expression on their surface, thus establishing the diagnosis of HLA-deficient severe combined immune deficiency (bare lymphocyte syndrome). Family HLA typing, in vitro stimulation of patient mononuclear cells, and sequence-specific oligonucleotide probe hybridization allowed the patients HLA phenotype to be determined. An unrelated bone marrow donor whose phenotype matched at all but a single A locus was found. The patient was conditioned with busulfan and cyclophosphamide, followed by infusion of T-cell-depleted bone marrow cells. The patient has been infection free with a successful marrow graft documented by HLA typing and chromosomal analysis. Sequence-specific oligonucleotide probe hybridization allows determination of the HLA phenotype in patients with HLA-deficient severe combined immune deficiency which, in turn, makes marrow transplantation an option for the reconstitution of these patients' immune system.

Medical applications of fetal tissue transplantation. Council on Scientific Affairs and Council on Ethical and Judicial Affairs

Fetal tissue transplantation has been attempted for a limited number of clinical disorders, including Parkinson's disease, diabetes, immunodeficiency disorders, and several metabolic disorders. Fetal tissue has intrinsic properties--ability to differentiate into multiple cell types, growth and proliferative ability, growth factor production, and reduced antigenicity--that make it attractive for transplantation research. At this time the results from fetal tissue grafts for Parkinson's disease and diabetes have not demonstrated significant long-term clinical benefit to patients with these disorders. Further research will be necessary to determine the potential value of fetal tissue transplantation. For these clinical investigations to proceed, specific ethical guidelines are needed to ensure that fetal tissue derived from elective abortions is used in a morally acceptable manner. These guidelines should separate, to the greatest extent possible, the decision by a woman to have an abortion from her consent to donate the postmortem tissue for transplantation purposes. Such ethical guidelines are offered in this report.

Total body irradiation and bone marrow transplantation for immunodeficiency disorders in young children

Congenital immunodeficiency disorders such as severe combined immunodeficiency disease (SCID), Wiskott-Aldrich syndrome, and Chediak-Hegashi syndrome are almost uniformly fatal with most children dying before age one. Allogeneic bone marrow transplant (BMT) is the treatment of choice. Few of these children have matched donors. We use bone marrow processing techniques that allow us to utilize marrow from the parents. Children who lack HLA-identical donors are offered haploidentical, T-cell depleted parental BMTs. Some of these children do not have an immune deficiency severe enough to allow durable engraftment of processed mismatched bone marrow. Successful engraftment may necessitate the use of immunosuppression. Total body irradiation (TBI) is part of our intensive conditioning regimen for children with Wiskott-Aldrich and Chediak-Hegashi syndrome and most children with SCID who have undergone an unsuccessful prior mismatched, T-cell depleted BMT, or who have a high likelihood of donor marrow rejection based on pre-transplant immune function testing. TBI is considered extremely toxic therapy in infancy, with little information available on the acute and chronic effects. The 10 children presented in this report are among the youngest to have received TBI. Five patients were 2 to 6 months of age when they received TBI. The conditioning regimen for all patients was; antithymocyte globulin (25 mg/kg/day, x 3 days), cyclophosphamide (60 mg/kg/day, x 2 days), and TBI. 7.0 Gy TBI was given as a single dose AP-PA at approximately 15 cGy/min. Half value blocks shielded the brain, eyes and lungs. Six of 10 children were alive from 7 to 72 months post transplant.(ABSTRACT TRUNCATED AT 250 WORDS)

Mycobacterium avium-intracellulare infections after allogeneic bone marrow transplantation in children

Serious infections caused by the Mycobacterium avium-intracellulare (MAI) complex have been increasingly recognized in patients with acquired immunodeficiency syndrome (AIDS). Allogeneic bone marrow transplant recipients are prone to infections caused by a wide spectrum of organisms. However, infection with MAI has been reported only once in an allogeneic bone marrow transplant setting. We describe two allogeneic bone marrow transplant recipients with severe combined immunodeficiency syndrome (SCID) in whom MAI infections occurred. Thus, MAI must be added to the list of infectious pathogens that can infect allogeneic bone marrow transplantation (BMT) recipients. Aggressive multidrug antituberculosis therapy may be of benefit in such patients.

Development of immunologic functions after bone marrow transplantation in 33 patients with severe combined immunodeficiency

We retrospectively analyzed the development of lymphocytes and of the main immunological functions in 33 patients with severe combined immunodeficiency who survived at least 6 months after bone marrow transplantation (BMT). Eighteen patients received HLA-identical BM and 15 received HLA-nonidentical BM. Development of immune functions occurred faster after HLA-identical BMT as full T- and B-lymphocyte-mediated responses were present at day 186 versus 505, respectively (P = .05). In addition, antibody responses remain completely or partially absent in 8 of 15 patients of the second group. Detection of antibody response after HLA-incompatible BMT correlated with engraftment of donor B cells in informative cases. In patients who received an HLA-nonidentical BMT after chemotherapy (6 of 15), development of immune functions occurred more rapidly and 6 of 6 had B-cell functions, including normal antibody production. Autoimmunity was not uncommon and was found after HLA-incompatible BMT (4 of 15) or after HLA-partially phenotypically identical BMT (2 of 3). Antibodies were in most cases specific for blood cells. Occurrence of autoimmunity correlates with poor B-cell functions and to a lesser extent with defective T-cell responses. This type of study may lead to definition of a more accurate strategy for performing BMT in patients with severe combined immunodeficiency.

[Allogeneic bone marrow grafts in children. Indications and results]

Malignant hemopathies and immune deficiencies are the main indications for allogeneic bone marrow transplantation in children. Among the former, the most common condition is acute lymphoblastic leukemia, in which a bone marrow transplant can be performed during the second or first complete remission (CR). Thirty to 50% and 60 to 75% of these grafts, respectively, are successful. The success rate is 50 to 70% among patients with acute myeloblastic leukemia grafted during the first complete remission, and among patients with chronic myeloid leukemia grafted during the chronic phase. Severe medullary aplasia and Fanconi disease are undoubtedly good indications for bone marrow transplantation, which has a 60 to 70% success rate. Severe combined immune deficiencies (SCID) and Wiskott-Aldrich disease are also good indications for HLA-identical bone marrow transplantation, which is successful in 60% of cases. Among the metabolic diseases, good results have been obtained only in Hurler disease and Gaucher disease. Questionable indications include thalassemia, Blackfan-Diamond disease, and chronic granulomatous disease. Results are disappointing in most metabolic diseases, as well as in non-HLA-identical transplantations in diseases other than SCID.

Use of scid mice to identify and quantitate lymphoid-restricted stem cells in long-term bone marrow cultures

Mice homozygous for an autosomal recessive scid (severe combined immune deficiency) mutation on chromosome 16 exhibit a defect that specifically impairs lymphoid differentiation but not myelopoiesis. Consequently such mice are deficient in both humoral and cell-mediated immune functions. Despite their defect, scid mice survive under pathogen-free conditions and are fertile. The mutation does not impair the hematopoietic microenvironment necessary for lymphoid differentiation, since these mice can be cured with grafts of normal bone marrow (BM) or cells from long-term BM cultures (LTBMC); however, reconstitution requires sublethal (400 cGy) irradiation of recipients. Engraftment with cells from LTBMC gave near-normal levels of colony-forming B cells (CFU-B) in spleen and BM of the recipients by 6 weeks postgrafting. Since LTBMC are devoid of all mature B and pre-B cells but contain stem cells that restore lymphoid function in scid mice, we used a limiting-dilution assay to characterize and enumerate the number of stem cells in LTBMC capable of restoring lymphoid function. Curing was determined by the CFU-B-cell assay, since CFU-B are not detectable in normal scid mice. The results indicate that fewer cells from LTBMC than from fresh BM are required to obtain lymphoid reconstitution. As few as 10(3) LTBMC cells can repopulate significant B- and T-cell function in scid recipients. From these results we conclude that scid mice can be used as recipients to quantify lymphoid-restricted stem cells and that there is a functional separation of lymphoid- and myeloid-restricted stem cells in LTBMC with an enrichment for lymphoid-restricted stem cells in these cultures.

Successful bone marrow transplantation with split lymphoid chimerism in DiGeorge syndrome

A female infant with DiGeorge syndrome associated with severe T-cell immunodeficiency underwent a successful bone marrow transplantation from her HLA-identical, mixed leukocyte culture-nonreactive brother at 5 months of age. Mature circulating T cells and mitogen-induced proliferative responses were detectable at 10 days posttransplant, and by 8 months post-transplant functional T- and B-cell reconstitution was documented by normal responses to mitogens and normal levels of serum immunoglobulins as well as in vitro and in vivo T-cell reactivity to specific antigens and production of specific antibody to T cell-dependent antigens in vivo. Phytohemagglutinin-induced interleukin-2 production and cell surface interleukin-2 receptor expression improved posttransplant, with normal production values observed by 8 months posttransplant. Histologic examination of appendix and thoracic lymph node obtained 9 and 17 months posttransplant, respectively, revealed near-normal lymphoid architecture, with germinal center formation providing morphologic confirmation of reconstitution. Stable split lymphoid chimerism with T cells of donor origin and B cells remaining recipient in origin was documented by sex chromosome analysis. Two years posttransplant the subject remains free of serious infections. In conclusion, this case indicates that bone marrow transplantation can produce peripheral immunoreconstitution without need for significant thymic influence, most likely by providing a source of postthymic T cells, and that bone marrow transplantation should be considered a therapeutic option in patients with DiGeorge syndrome associated with severe T-cell deficiency.

Modified MHC restriction of donor-origin T cells in humans with severe combined immunodeficiency transplanted with haploidentical bone marrow stem cells

The choice of class II MHC determinants that serve as self-recognition elements for murine CD4+ T cells is thought to be determined by the environment in which T cells mature rather than their genotype. Patients with severe combined immunodeficiency (SCID) reconstituted with T cell depleted haploidentical parental stem cells provide an excellent model for studying this phenomenon in humans. After engraftment, the T cells that develop in these infants are all of donor origin. We sought to determine whether the successful immune reconstitution observed in two such SCID chimeras involved modification of the MHC restriction of Ag recognition by the genetically donor T cells as they matured to become competent T cells in the infants' microenvironment. A tetanus toxoid (TT)-specific T cell line and TT-specific T cell clones were established from the blood of two reconstituted SCID patients and from their maternal donors. T cell responsiveness was determined by [3H]thymidine incorporation after TT presentation by EBV-transformed B cell lines (EBV-B) from various donors. The TT-specific T cell line from patient 1 proliferated when presented Ag by patient, maternal donor, and paternal APC. A CD4+ donor origin clone that proliferated when presented TT by patient and paternal EBV-B, but not by maternal donor EBV-B, was isolated from each patient. TT recognition by these clones was shown to be restricted by the HLA DR determinant shared by patient and father, but not present in the donor. Four TT-specific clones isolated from maternal donors failed to proliferate when presented TT by the appropriate paternal EBV-B. These studies demonstrate that, in these human SCID bone marrow chimeras, engrafted donor-origin stem cells maturing to competent T cells in the recipient microenvironment are capable of utilizing recipient HLA determinants as restriction elements for Ag recognition. This suggests that human, as well as murine, MHC restriction patterns for Ag recognition by CD4+ T cells are environmentally determined.

HLA gene amplification and hybridization analysis of polymorphism. HLA matching for bone marrow transplantation of a patient with HLA-deficient severe combined immunodeficiency syndrome

The treatment of choice for certain immunodeficiency syndromes and hematological disorders is bone marrow transplantation (BMT). The success of BMT is influenced by the degree of HLA compatibility between recipient and donor. However, aberrant expression of HLA sometimes makes it difficult, if not impossible, to determine the patient's HLA type by standard serological and cellular techniques. We describe here the application of new molecular biological techniques to perform high resolution HLA typing independent of HLA expression. A patient with HLA-deficient severe combined deficiency was HLA typed using in vitro amplification of the HLA genes and sequence-specific oligonucleotide probe hybridization (SSOPH). Two major advances provided by this technology are:detection of HLA polymorphism at the level of single amino acid differences; and elimination of a requirement for HLA expression. Although the patient's lymphocytes lacked class II HLA proteins, polymorphism associated with DR7,w53;DQw2;DRw11a (a split of DR5), w52b (a split of DRw52);DQw7 were identified. The patient's class I expression was partially defective, and typing was accomplished by a combination of serological (HLA-A and -C) and SSOPH analysis (HLA-B). Complete patient haplotypes were predicted after typing of family members [A2;B35(w6); Cw4; DRw11a(w52b);DQw7 and A2;B13(w4); Cw6;DR7(w53); DQw2]. Potential unrelated donors were typed and a donor was selected for BMT.

The evolution of MHC restrictions in antigen recognition by T cells in a haploidentical bone marrow transplant recipient

We have longitudinally followed the major histocompatibility complex (MHC) restrictions that govern the response of T lymphocytes to specific Ag in a child with severe combined immunodeficiency who was successfully transplanted by using T cell depleted haploidentical maternal bone marrow cells and immunized shortly afterwards with tetanus toxoid (TT) Ag. In the first year post-transplant, monocytes were of both donor and recipient origin whereas T and B cells were of donor origin. Three years after transplant, all monocytes and T and B cells were of donor origin. T lymphocytes taken from the child at that time and depleted in vitro of alloreactivity to paternal Ag proliferated in response to TT presented by maternal as well as paternal monocytes. A TT-specific T cell line established from these cells in the presence of maternal monocytes cooperated with maternal but not with paternal monocytes, whereas a TT-specific T cell line established in the presence of paternal monocytes cooperated with paternal but not with maternal monocytes and with monocytes derived from a paternal uncle who shared the haplotype inherited by the recipient from her father. These results show that long-term memory T cells restricted to recipient MHC Ag not shared with the bone marrow donor continue to circulate long after the disappearance of accessory cells of recipient origin. These T cells could potentially participate in a secondary immune response because they were shown to recognize TT presented by recipient fibroblasts induced to express class II MHC molecules following treatment with IFN-gamma.

Bone marrow cells from young and old New Zealand black mice can reconstitute B lymphocytes in severe combined immunodeficient recipients

The formation of B lymphocytes in young New Zealand Black (NZB) mice proceeds at an accelerated rate, resulting in a deficiency of B lineage progenitors in mice of 15 weeks of age and older. Multiple studies have indicated that intrinsic defects in B lineage cells as well as in the hemopoietic microenvironment in which they develop contribute to these cellular abnormalities. To determine whether the B-cell hyperactivity observed in young mice could be observed in a normal environment, bone marrow cells from young (4 weeks or less) NZB donors were transplanted into Severe Combined Immunodeficient (SCID) mice that have a marked deficiency of lymphocytes but an apparently normal hemopoietic microenvironment. Engraftment of donor lymphoid cells can occur without pretransplant conditioning regimens, thus minimizing the chances of transferring microenvironmental elements. Marrow from young NZB donors reconstituted surface IgM-expressing B cells and CFU-B (B-cell colony-forming unit) in the marrow of SCID mouse recipients to levels comparable to that observed with donor NZB.xid marrow. The latter mice carry the xid gene that ameliorates the defects exhibited by B lineage cells of NZB mice. Both the number of surface IgM-expressing B cells and CFU-B were higher in the spleen of SCID mice that received NZB grafts than marrow cells from donor BALB/c or NZB.xid mice. Marrow from young NZB donors also reconstituted Thy-1, L3T4 and Lyt2-expressing cells in the spleen to levels higher than observed with young NZB.xid donor cells. The transplantation of marrow from 6-month-old NZB donors made it possible to test whether B lineage cells were present in that tissue and could mediate reconstitution in the normal SCID environment. Marrow from old NZB donors did reconstitute B cells in the marrow and spleen of SCID recipients. The level of reconstitution was comparable to that mediated by young BALB/c cells and twice that of old NZB.xid donor cells. The absolute number of splenic CFU-B was also higher in recipients of old NZB marrow as compared to young BALB/c cells. Old NZB.xid donor marrow reconstituted splenic Thy-1, L3T4 and Lyt2 T cells to levels less than observed with NZB donor cells. Analysis of serum Ig in recipients of old NZB cells indicated higher levels of total IgM as compared to mice engrafted with NZB.xid cells, and anti-single stranded DNA antibodies were detected.

Recent advances in bone marrow transplantation

An increasing number of diseases may be treated successfully by allogeneic bone marrow transplantation (BMT). Initially used for the treatment of immunodeficiency where a cell series or product is replaced, it has now become routine treatment for many forms of leukemia where the transplant provides the rescue after lethal marrow ablation. Recently, diseases such as thalassemia and other inherited metabolic diseases have also been treated by BMT. Formerly the problems of BMT were mainly concerned with graft versus host disease (GVHD) in HLA-matched transplants with HLA-mismatched ones not being possible as GVHD was usually fatal. Since the development of techniques for T cell removal the incidence of GVHD has greatly diminished. T cell removal has also allowed HLA haploidentical mismatched grafts to be performed successfully for immunodeficiency, but there is still a high graft rejection rate in leukemia. This also occurs to a lesser extent with HLA-matched grafts in leukemia. Furthermore, in certain forms of leukemia, particularly chronic granulocytic leukemia, the relapse rate after T cell-depleted BMT is much higher. Trials of better forms of bone marrow conditioning of the recipient are being attempted in order to prevent graft rejection and leukemia relapse. These include total lymphoid irradiation, heavier irradiation and chemotherapeutic regimens, or the use of in vivo monoclonal antibodies such as CAMPATH 1G or anti-LFA-1 (CD11a). In the future, positive selection of stem cells combined with hemopoietic growth factors may allow engraftment without graft versus host disease. This should become the method of choice for autologous transplantation for malignancy. Two monoclonal antibodies directed against the human progenitor cell antigen 1 (HPCA-1) (CD34) have been used for autologous positive stem cell selection in primates and these cells gave full hemopoietic reconstitution in the animals following lethal total body irradiation.

Combined immunodeficiency with abnormal expression of MHC class II genes

The MHC class II CID represents an example of immunodeficiency in which the defect in expression of membrane glycoproteins leads to abnormal cell to cell interactions and thus to abnormal immune responses. It represents an interesting model which confirms the importance of MHC molecules in all immune responses to foreign antigens. It also underlines the complexity of regulatory mechanism which control the expression of MHC class II genes. To elucidate these mechanisms, it is essential to identify and characterize the genes involved in control of MHC class II expression.

Role of stereotactic biopsy in the management of transplant patients with intracranial lesions

Appropriate treatment of an intracranial lesion is based upon establishing a definitive diagnosis. CT-stereotactic biopsy procedures are highly accurate, are associated with few complications, and are usually performed only with local anesthesia. Stereotactic biopsy is the preferred method for histologically confirming the nature of an intracranial lesion in the immunocompromised patient. The mortality and morbidity approach 1 per cent, respectively. In the large reported series of stereotactic surgery for biopsy, diagnostic accuracy is over 95 per cent. Stereotactic techniques can also be used to aspirate abscesses or localize abscesses or neoplastic lesions excised by craniotomy.

Encapsulated thymic epithelial cells as a potential treatment for immunodeficiencies

The epithelial cells of the thymus produce hormones that have been implicated in the maturation of T lymphocytes. Thymic epithelial cells can be encapsulated in a permselective polymer membrane that allows the passage of thymic hormones, but prevents the entry of antibodies, complement, cells, and viruses. A pure culture of thymic epithelial cells, identified as such by transmission electron microscopy and keratin staining, was obtained by low temperature organ culture of fetal mouse thymus. These cells remained intact and produced physiologic amounts of the thymic hormone thymosin alpha-1 after encapsulation in a permselective polymer membrane and in vitro culture for 5 days. An encapsulated implant of thymic epithelial cells may therefore promote reconstitution of an immune system in immunodeficiency diseases without allowing the rejection or destruction of the thymic tissue.

The peripheral nerve allograft: an assessment of regeneration in the immunosuppressed host

Regeneration across the nerve allograft in the immunosuppressed host was assessed using electrical and histologic parameters. The Lewis rat (RTIl) served as the recipient animal, and ACI rats (RTIa) provided the donor nerve allografts. Hydrocortisone and azathioprine were used in various dose schedules as the immunosuppressive agents. Animals were immunosuppressed for either 30 or 100 days. Histologic and electrophysiologic measurements of nerve regeneration were assessed at 30, 100, and 180 days. The degree of nerve regeneration was similar in all experimental groups. Short-term, low-dose immunosuppression was as successful as longer-term, higher-dose immunosuppression therapy. The degree of nerve regeneration in all experimental groups was significantly better than that in the fresh, untreated nerve allograft control group (Lewis/ACI) but was not as good as that seen in the autograft control group (Lewis/Lewis).

Immunological reconstitution in a patient with severe combined immune deficiency using non-sibling bone marrow depleted of T cells with HuLy-m1

An infant with severe immune deficiency received bone marrow from an HLA-A, -B, -DR matched, mixed leucocyte reaction non-reactive first cousin. The donor marrow was fractionated on a discontinuous Percoll gradient and before infusion was treated with the anti-human T lymphocyte antibody, HuLy-m1, and rabbit serum as a source of complement. Methotrexate was given during the following two weeks. A rise in the peripheral blood lymphocyte count, indicating engraftment, occurred six weeks after transplantation. There was no clinical evidence of graft versus host disease (GVHD). Engraftment has been sustained for one year and the patient is in normal health and has normal in vitro immunological function. In vitro treatment of human marrow with HuLy-m1 allows stable engraftment and may be useful in attempting to diminish or prevent GVHD.

[Allogeneic bone marrow transplantation in severe combined immune defects (SCID)]

Bone marrow transplantation (BMT) represents the therapy of choice in severe combined immunodeficiency (SCID). Besides a short description of the clinical picture and of the diagnostical criteria of the disorder, the basis and results of BMT in SCID are presented. This treatment can result in the complete immunological reconstitution with resulting cure of affected patients. Recently, the use of other than HLA-identical marrow donors has become possible, such as haploidentical parents. Threatening complications from graft versus host disease are preventable by depleting T-cells from marrow grafts. Early results of this new approach are very encouraging, and represent significant advance in clinical BMT.

[Bone marrow transplantation in the therapy of genetic diseases]

The technique of bone marrow transplantation (BMT) is now well established. Of now over 90 inborn errors of metabolism at least 45 have been treated by BMT. Among these some 35 have been proven to be curable by this procedure. The present paper reviews the respective literature and considers in particular the pertinent experiences of the Westminster Bone Marrow Transplantation Team.

Immuno-reconstitution by thymic transplant in DiGeorge's syndrome

Persistent hypocalcaemic tetany in a breast-fed neonate made us suspect DiGeorge's syndrome, particularly as the baby had an abnormal facies, and a ventricular septal defect. Immuno-reconstitution was successfully achieved by thymic transplant. Evidence of immuno-reconstitution on the basis of the histology of the post-transplant thymus has not been previously recorded.

Bone marrow transplantation for diseases of childhood

Bone marrow transplantation in childhood is an established treatment modality for aplastic anemia, the acute and chronic leukemias, and severe combined immune deficiency. Recently, experience with this treatment has also been favorable with small numbers of children who have Wiskott-Aldrich syndrome, several types of inherited storage diseases, Fanconi's anemia, thalassemia, infantile malignant osteopetrosis, and selected cases of lymphoma and other solid tumors. The psychosocial impact and financial costs of bone marrow transplantation can be substantial. Multi-institutional, prospective, randomized trials that would compare transplantation and conventional therapy are necessary to establish the indications and precise timing for this procedure. Further development of monoclonal antibodies, a better understanding of the histocompatibility antigen systems, and improvement in pretransplantation conditioning regimens should increase the spectrum of effectiveness for bone marrow transplantation in the coming years.

Immunoblastic sarcoma after thymus epithelial graft in an immunodeficient child

A 3 1/2-year-old girl with severe combined immunodeficiency received a thymus epithelial graft. After transient clinical and in vitro immunologic improvement, she developed fever, lung infiltrates and, terminally, massive gastrointestinal bleeding only 2 1/2 months after transplantation. Autopsy revealed widespread immunoblastic sarcoma involving both transplantation sites in the mesentery and thigh, lymph nodes, lung, liver, spleen and gastrointestinal tract. This B cell lymphoma was likely induced by the grafted thymus epithelium.

[Restoration of mixed and severe immunologic deficiency, by fetal liver and thymus graft]

A male infant with severe combined immunodeficiency but normal adenosine deaminase activity for whom no suitable bone marrow donor was available was given two separate grafts of both hepatic and thymic cells, the cells for each graft being taken from the same fetus aged 13 and 10 weeks respectively. Cell mediated and partial humoral immunity was restored 330 and 400 days respectively after the second transplant. No graft-versus-host reaction was observed and both red blood cell and lymphoid chimaerism could be demonstrated. The child was kept in strict bacterial isolation from the 3rd to the 537th day of life. Thirty months after the graft, the infant is in good health but has a defect of neutrophil chemotaxis and phagocytosis which requires prophylactic benzathine penicillin in addition to gammaglobulins. Fetal tissue transplantation may provide an alternative treatment for patients with severe combined immunodeficiency who do not have a histocompatible donor.

[Thymus implant in a case of DiGeorge syndrome (author's transl)]

A boy with III-IV pharingeal pouch malformative syndrome, hypocalcemia and recurrent infections is presented. The immunological work-up disclosed deficiency in the specific cellular immunity with normal serum immunoglobulin levels. An adult thymus in Millipore diffusion chambers was implanted in the rectus adominalis muscle. One week later clinical and analytical data suggesting immunological reconstitution was recorded. Two years later the patient remains in good health, T and B lymphocyte percentages are normal, being the only immunological abnormality a low serum level of IgG.

Immunologic reconstitution in man--present status

Recent advances in immunobiology have shed new light on our understanding of the essential role of immunity as it relates to body economy. Immunity, once thought to be the primary defense mechanism against microbial infection, appears to have a much broader function--recognition and elimination of foreign bodies and preservation of the integrity of the individual. As our understanding of the pathophysiology of the immune system became more clear, immunologic reconstitution emerged as a new, promising mode of treatment for a variety of diseases with immunodeficiency. Bone marrow transplantation, thymus transplanation, transfer factor therapy, infusion of leukocytes, BCG vaccination, and other specific or nonspecific immunostimulants have been tried, with dramatic beneficial results in some instances. Although still in its infant stage, this form of treatment appears to have great potential and wide application in the prevention and treatment, not only of primary immunodeficiency, but also of many other diseases such as cancer, the so-called autoimmune diseases, and even aging.