F. Le Deist

Severe combined immunodeficiency: A retrospective single-center study of clinical presentation and outcome in 117 patients

We carried out a retrospective analysis of 117 patients with severe combined immunodeficiency who were examined in a single center between Jan. 1, 1970, and Jan. 1, 1992, for the purpose of evaluating disease onset, progression, and outcome. The frequency of case referral increased from 8 from 1970 to 1975 to 56 from 1986 to 1991. The most frequent phenotype was T-/B+ (absence of T lymphocytes and presence of B lymphocytes) (n = 51); there were 36 cases of alymphocytosis, 16 of adenosine deaminase deficiency, 13 of Omenn syndrome, and 1 of reticular dysgenesis. Protracted diarrhea and lung infections were the main infectious complications; infection with bacillus Calmette-Guérin occurred in 10 of 28 vaccinated patients, but none of the six recipients of oral polio vaccine subsequently had poliomyelitis. The presence of maternal T cells was suspected or proved in half the patients with alymphocytosis or T-B+ severe combined immunodeficiency but did not occur in the other forms of the disease. Of the 117 patients, 22 died before transplantation could be performed. Adenosine deaminase deficiency and Omenn syndrome were more frequently associated with death before hematopoietic stem cell transplantation was possible. Fetal liver transplantation was successful in 1 of 10 cases. The survival rate among the 30 recipients of bone marrow with identical human leukocyte antigens (HLA) was 80%, with a median follow-up of 129 months; 23 of 25 patients recovered full immune function. The survival rate among the 50 recipients of HLA-haploidentical T cell-depleted bone marrow was 56%, with a mean follow-up of 35 months. Of the latter patients, 10 (35%) still require immunoglobulin substitution. There has been a trend toward improvement in the survival rate of haploidentical bone marrow recipients, presumably because of more effective infection-control measures and better transplantation strategy.

Restricted heterogeneity of T lymphocytes in combined immunodeficiency with hypereosinophilia (Omenn's syndrome).

We report the immunological characteristics of five patients with Omenns syndrome, a rare inherited immunodeficiency also known as combined immunodeficiency with hypereosinophilia. The syndrome is characterized by T cell infiltration of skin, gut, liver, and spleen leading to diffuse erythroderma, protracted diarrhea, failure to thrive, and hepatosplenomegaly. Blood T cells as well as those infiltrating the skin and gut were found to express activation markers and were partially activated by mitogens but not by antigens. Although the lesions resembled those in graft-versus-host disease, the blood T cells were shown by DNA haplotype analysis using probes revealing variable number of tandem repeats to belong to the patients as well as the T cells infiltrating the gut and skin in one patient. A given T cell subset (TCR alpha beta+, CD4+/CD8+, or TCR gamma delta+) was predominant in each patient, with a specific distribution in the skin lesions. Moreover, the study of T cell receptor beta, gamma, and delta gene rearrangements in four patients revealed oligoclonality involving C beta 1, C beta 2, or different V gamma J gamma or V delta J delta genes. This indicates that restricted heterogeneity of the T cell repertoire, previously reported in one case, is a major feature of this syndrome. The occurrence of alymphocytosis-type severe combined immunodeficiency in the brother of one of the patients suggests that the restricted heterogeneity of T cell receptor gene usage in Omenns syndrome may arise from leakiness, within the context of a genetically determined faulty T cell differentiation.

Allogeneic bone marrow transplantation for erythrophagocytic lymphohistiocytosis

Chez un nourrisson de 25 mois presentant une lymphohistiocytose erythrophagocytaire refractaire au traitement medicamenteux, la transplantation de moelle osseuse compatible de son frere aine, associee a la chimiotherapie, a permis une remission complete stable

Increased radiosensitivity of granulocyte macrophage colony-forming units and skin fibroblasts in human autosomal recessive severe combined immunodeficiency.

We studied the radiosensitivity of granulocyte macrophage colony-forming units (GM-CFU) in patients with a severe combined immunodeficiency (SCID). Three patients lacking both mature T and B cells showed a twofold higher GM-CFU radiosensitivity calculated as the DO value (dose required to reduce survival to 37%), and an identical observation was made with fibroblasts from one of these patients. A patient with an SCID with hypereosinophilia, i.e., Omenns syndrome characterized by extremely restricted T cell heterogeneity and a lack of B cells, also showed abnormal GM-CFU radiosensitivity. In contrast, GM-CFU from a patient lacking only T cells (X-linked form of SCID) showed normal GM-CFU radiosensitivity. These data further support the similarity between human T(-) B(-) SCID and the murine acid mutation characterized by a defect in T cell receptor and immunoglobulin gene rearrangement, and by an abnormal double-strand DNA break repair function. In addition, they strongly suggest that the Omenns immunodeficiency syndrome may be a leaky T(-)B(-) SCID phenotype as previously indicated by the coexistence of the two phenotypes in siblings.

Intractable infant diarrhea associated with phenotypic abnormalities and immunodeficiency.

We report on eight children with severe diarrhea beginning in the first 6 months of life (< 1 month in six cases), who had a number of features in common. All were small for gestational age and had an abnormal phenotype, including facial dysmorphism, hypertelorism, and woolly, easily removable hair with trichorhexis nodosa. Two were products of consanguineous marriages. Severe secretory diarrhea persisted despite bowel rest (n = 7). Jejunal biopsy specimens showed total or subtotal villous atrophy with crypt necrosis, and inconstant T-cell activation in some cases (n = 3). Colon biopsy specimens showed moderate nonspecific colitis. All the patients had defective antibody responses despite normal serum immunoglobulin levels, and defective antigen-specific skin tests despite positive proliferative responses in vitro. Three had monoclonal hyper-immunoglobulinemia A. The course was marked by diffuse erythroderma in two cases and mental retardation in three. Treatment included bowel rest, intravenous administration of immune globulins, administration of corticosteroids (n = 6) and cyclosporine (n = 2), and bone marrow transplantation (n = 1). Five patients died between the ages of 2 and 5 years (of sepsis or cirrhosis), two are being fed enterally, and one continues to receive total parenteral nutrition. The cause of the combined low birth weight, dysmorphism, severe diarrhea, trichorrhexis, and immunodeficiency is unclear. These features may constitute a specific syndrome within the group of intractable diarrheas of infancy.

Deficiency of the adhesive protein complex lymphocyte function antigen 1, complement receptor type 3, glycoprotein p150,95 in a girl with recurrent bacterial infections. Effects on phagocytic cells and lymphocyte functions.

A patient presenting delayed umbilical cord detachment, severe recurrent bacterial infections, and inability to form pus exhibited a profound defect in the expression of alpha- and beta-chains of the receptor for the C3bi fragment of C3 (CR3), lymphocyte function antigen 1 (LFA-1) molecule, and the p150,95 molecule found on neutrophils, monocytes, and lymphocyte membranes. This was shown by immunofluorescence studies using specific monoclonal antibodies, rosette formation with C3bi-coated erythrocytes, and immunoprecipitation for the LFA-1 complex. These membrane defects were responsible for abnormal phagocytic cell functions including adherence to nylon wool, cell movement, phagocytosis, and opsonized particle-induced oxidative response and for defective natural killer cell activity. In addition, lymphocyte function deficiencies previously unobserved in this disease were found. Cytolytic T lymphocyte activity was profoundly reduced; alpha- and gamma-interferon production were impaired. Finally, there was no antibody production to vaccinal antigens whereas the antibody responses to polysaccharides and to cytomegalovirus were found to be normal. The cytotoxic T cell deficiency could be expected from previous blocking experiments of this function with monoclonal antibodies to LFA-1 and is probably related to an extremely severe deficiency in LFA-1 expression in this patient. Anomalies in interferon and in antibody production suggest additional role(s) of the LFA-1 complex in monocyte/T lymphocyte/B lymphocyte cell interactions that have not yet been envisaged.

Highly restricted human T cell repertoire in peripheral blood and tissue-infiltrating lymphocytes in Omenn's syndrome.

Omenns syndrome is an inherited human combined immunodeficiency condition characterized by the presence of a large population of activated and tissue-infiltrating T cells. Analysis of the TCRB repertoire revealed a highly restricted TCRBV usage in three patients. More strikingly, T cell clones from the three patients expressed TCRB chains with VDJ junction similarities, suggesting a common antigenic specificity. Analysis of the TCRA repertoire in one patient also revealed a restricted TCRAV usage. Finally, analysis of the TCRBV repertoire of tissue-infiltrating T cells in one patient suggested nonrandom tissue migration. These results suggest that the oligoclonal expansion of T cells observed in Omenns syndrome could be the consequence of autoimmune proliferation generated by a profound defect in lymphocyte development.

Prevention of EBV-induced B-lymphoproliferative disorder by ex vivo marrow B-cell depletion in HLA-phenoidentical or non-identical T-depleted bone marrow transplantation.

HLA‐mismatched bone marrow transplantation (BMT) is hampered by three major complications: graft rejection, acute graft‐versus‐host disease (aGVHD) and delayed immune reconstitution. Infusion of anti‐LFA1 plus anti‐CD2 monoclonal antibodies (MAb), combined with ex‐vivo T‐cell depletion of the graft, was efficient in preventing graft rejection and aGVHD. Nevertheless, disease‐free survival was limited by the high frequency of lethal infections, including EBV‐induced lymphoproliferative disease (BLPD), which originates mostly from donor B cells, with an incidence of 5–30%. To decrease the rate of this complication, ex‐vivo B‐cell depletion was attempted.

Treatment of Omenn syndrome by bone marrow transplantation.

We report the outcome of allogeneic bone marrow transplantation (BMT) in nine consecutive patients with Omenn syndrome treated between 1980 and 1989. Five patients received unmanipulated marrow from a related matched donor, and four received T cell-depleted marrow from a haploidentical donor. The patients were conditioned with cyclophosphamide (200 mg/kg) and, except in one case, busulfan (16 mg/kg). Antithymocyte globulin and etoposide were given to three patients each; three recipients of T cell-depleted haploidentical marrow also received intravenous injections of an anti-leukocyte function-associated antigen type 1 antibody as graft rejection prophylaxis. All the patients were fed parenterally for 1 to 5 months before BMT to improve nutritional status and received topical corticosteroids (n = 8), systemic steroids (n = 2), etoposide (n = 1), or cyclosporine (n = 1) to control T-cell activation. Engraftment occurred in four of five recipients of human leukocyte antigen (HLA)-identical marrow and three of four recipients of HLA-haploidentical marrow. One patient died with cytomegalovirus infection. The other six patients are alive 4 to 11 years after BMT, with full chimerism in all but one case. Chronic graft-versus-host disease persists in one patient; the other five survivors have fully restored immune function and have no manifestations of Omenn syndrome, including failure to thrive. We conclude that both HLA-identical and haploidentical BMT can cure Omenn syndrome, provided that parenteral nutrition and immunosuppressive therapy are given before transplantation.

Gene therapy of severe combined immunodeficiencies

Recent advances in gene transfer in human hematopoietic cells, combined with a better understanding of the genetic aspects of several immunodeficiencies, has offered new opportunities in the domain of gene therapy. Severe combined immunodeficiency (SCID) appear to represent a good model for the application of gene therapy, combining an expected selective advantage for transduced cells, an absence of immunological response to the vector and/or the therapeutic transgene, together with accessibility to hematopoietic stem cells (HSC). Ex vivo retroviral transduction of a therapeutic transgene in HSC prior to transplantation appears to be a particularly effective and long‐lasting means of restoring the expression of a mutated gene in the lymphoid lineage. Furthermore, encouraging therapeutic benefits as a result of a gene therapy protocol for the treatment of X‐linked severe combined immunodeficiencies (SCID‐X1) invites many questions as to the reasons for this therapeutic benefit. This review outlines the results that have been achieved in gene therapy for SCID‐X1, ADA‐SCID as well as other types of SCID, and discusses the possible relationship between the physiopathology of each disease and the success of relevant trials. Copyright