DiGeorge anomaly: a comparative study of the clinical and immunologic characteristics of patients positive and negative by fluorescence in situ hybridization.

BACKGROUND: DiGeorge anomaly (DGA) is defined as a field defect characterized by dysmorphic facies, hypoparathyroidism, congenital heart defects, and a deficiency in cell-mediated immunity, usually associated with a microdeletion in chromosome 22q11.2. Data correlating clinical and genetic information, especially in terms of the extent of the immunodeficiency and infectious complications, are scant. OBJECTIVE: The goal of this study was to define the severity of the immunodeficiency and infectious illnesses in DGA patients with characteristic clinical and genetic findings and compare them with a similar group of patients without a microdeletion in chromosome 22q11.2. METHODS: A retrospective chart review of patients referred for evaluation of DGA to our immunology service from 1989 to 1995 was conducted. Clinical and immunologic data were collected from their initial evaluation. Patients meeting at least 3 of 4 of these criteria were considered to meet strict clinical diagnostic criteria for DGA, and the results of analysis for a microdeletion in chromosome 22q11.2 for each patient was noted. RESULTS: Sixteen of the 22 patients meeting strict clinical criteria for DGA were available for analysis for the microdeletion at chromosome 22q.11.2. Of these, 13 (81%) were positive by fluorescence in situ hybridization (FISH); 9 of 13 (69%) had low CD3 numbers, 6 of 10 assayed (60%) had low thymulin levels; 10 of 13 (77%) had low CD4 numbers, and 10 of 12 (83%) had absent or small thymus glands. B cells were increased in 9 of 13 (69%) patients. Mitogen and antigen responses were normal in 6 of 7 (86%) patients tested. Eight of 13 (62%) had a history of increased frequency of infectious illnesses. All had recurrent respiratory infections, including sinusitis, otitis media, and pneumonia. Three of the 16 patients tested (19%) were FISH negative. Two of 3 (67%) had low CD3 and CD4 numbers. B cells were elevated in all patients. All had recurrent respiratory infections, low thymulin levels, and absent thymus glands. CONCLUSIONS: Contrary to traditional descriptions, this group of clinically and genetically defined patients with DGA had a predominantly mild cell-mediated immunodeficiency syndrome usually associated with infections characteristic of humoral immunodeficiencies. The patients who were FISH positive did not differ significantly from those that were FISH negative in terms of clinical and immunologic findings or infectious complications.

Extreme variation in X-linked agammaglobulinemia phenotype in a three-generation family.

BACKGROUND: X-linked agammaglobulinemia is typically a severe life-threatening disease characterized by the failure of B-cell differentiation and antibody production, which manifests in infancy and early childhood. Recently, we reported a novel mutation (Cys145-->STOP) in Bruton's tyrosine kinase in a 51-year-old man who was referred for evaluation because of chronic nasal congestion, recurrent sinusitis, sporadic pneumonia, and a family history suggestive of an X-linked immunodeficiency disease. He had not been treated with gammaglobulin. OBJECTIVE: This study was performed to investigate the clinical and immunologic phenotypes of this patient's other affected male family members. METHODS: A detailed family history and comprehensive review of medical records was carried out. Genetic mutation analysis of the gene encoding Bruton's tyrosine kinase was carried out in the proband's brother and nephew. RESULTS: Clinically affected male family members exhibit marked phenotypic variation with manifestations ranging from extremely mild to severe recurrent infections. Immunologic evaluation revealed extreme variation in immunoglobulin levels, B-cell numbers, and functional antibody titers. Genetic analysis documented a novel mutation in the gene encoding Bruton's tyrosine kinase in the proband, his brother, and his nephew. CONCLUSIONS: Despite their sharing the same genetic abnormality, extreme variation was noted in the immunologic findings and phenotypic expression of affected family members. This family study is extraordinary in that clinically affected male members who did not receive aggressive medical treatment died of the disease in childhood or survived into late adulthood.

Asymptomatic lymphoma associated with elevation of immunoglobulin E.

BACKGROUND: Elevation of immunoglobulin E (IgE) is rarely detected in patients with underlying malignancy. There has been only one report of such a finding in a patient with a T cell lymphoma and none to our knowledge in association with a B-cell lymphoma. OBJECTIVE: To report a patient with elevation of IgE associated with a B-cell lineage lymphoma. MATERIAL AND METHODS: Case report and review of literature. RESULTS: A 73-year-old woman was found to have elevated IgE (11,766 IU/mL) in a routine evaluation for rhinitis. No underlying allergic diathesis or disease associated with IgE elevation was noted. Because of an abnormal lymphocyte profile, an extensive malignancy evaluation was performed which revealed a B-cell lymphoma. CONCLUSION: B-cell lineage lymphoma can be associated with elevated of IgE and should be included in the differential diagnosis in a patient presenting with this finding.

Normalization of cellular zinc levels in patients with Downs syndrome does not always correct low thymulin levels.

Retrospective analysis of five Down's syndrome (DS) patients who presented with recurrent infection revealed that all had initial low thymulin levels. Three patients had low cellular zinc levels that normalized after zinc replacement. Contrary to previous studies, thymulin levels were persistently low in four of five DS patients despite maintaining or achieving normal cellular zinc levels. A primary thymic epithelial defect may be responsible for the persistent thymulin deficiency in DS patients.

A novel mutation (Cys145-->Stop) in Bruton's tyrosine kinase is associated with newly diagnosed X-linked agammaglobulinemia in a 51-year-old male.

BACKGROUND: X-linked agammaglobulinemia (XLA) is a severe, life-threatening disease characterized by failure of B cell differentiation and antibody production and is associated with mutations in Bruton's tyrosine kinase (Btk). The proband in this study is a 51-year-old male presenting with chronic nasal congestion, recurrent sinusitis, sporadic pneumonia, and pronounced B cell deficiency. A family history suggestive of an X-linked immunodeficiency disease was noted. MATERIALS AND METHODS: cDNA was synthesized from mRNA prepared from peripheral blood mononuclear leukocytes. Btk cDNA amplified by polymerase chain reaction (PCR) was subjected to both manual and automated DNA sequencing. A DNA sequence corresponding to exons 6 and 7 of Btk was amplified from genomic DNA. Western blot analysis employed both polyclonal and monoclonal antibodies to Btk and reaction patterns were obtained both by chemiluminescence and an in vitro kinase assay. RESULTS: A mutation (Cys145-->Stop) was identified in Btk cDNA and was confirmed in amplified exon 6 of genomic DNA from both the proband and an affected nephew. Neither Btk nor a truncated peptide was detected in Western blot analyses of peripheral blood mononuclear cell lysates. CONCLUSIONS: The C145A mutation reported here is novel. This family study is extraordinary in that affected male members who did not undergo aggressive medical management either succumbed to complications in early life or survived into later life. The proband is the oldest de novo diagnosed patient with XLA reported to date.

Shwachman-Diamond syndrome associated with hypogammaglobulinemia and growth hormone deficiency.

Shwachman-Diamond syndrome is a rare congenital disorder of unknown etiology. Characteristic abnormalities of this disease include pancreatic insufficiency, skeletal anomalies, growth retardation, recurrent infections, and hematologic abnormalities. Significant morbidity and mortality in these patients result from respiratory infections, which are not well explained on the basis of neutrophil defects. We have had the opportunity to perform an in-depth clinical immunologic and endocrinologic evaluation of a patient with this syndrome with recurrent respiratory tract infections. She was found to have profound humoral immunologic defects, and serum thymulin was absent. In addition, endocrinologic evaluation for growth retardation revealed growth hormone deficiency. The patient responded to treatment with supplemental growth hormone and intravenous gammaglobulin with accelerated growth and cessation of infections. This case is unique in that it links growth hormone deficiency and hypogammaglobulinemia in a non-X-linked manner and may provide the basis for treatment of other patients with this rare syndrome.

Genomic organization and structure of Bruton agammaglobulinemia tyrosine kinase: localization of mutations associated with varied clinical presentations and course in X chromosome-linked agammaglobulinemia.

X chromosome-linked agammaglobulinemia is a life-threatening disease that involves a failure in normal development of B lymphocytes and is associated with missense mutations in BTK, a gene encoding a cytoplasmic tyrosine kinase (Bruton agammaglobulinemia tyrosine kinase, EC 2.7.1.112), a member of the Tec family of protein-tyrosine kinases. The genomic organization has been determined by using conventional restriction fragment mapping, extended DNA sequencing, and PCR fragment-sizing approaches. The DNA sequences of the 18 coding exons composing BTK and their flanking-region sequences are reported; an additional exon(s) encodes a 5' untranslated segment. Single-base-pair substitutions and 4-nt deletions resulted in amino acid replacement, premature termination, frameshift, and exon deletion in a group of X chromosome-linked agammaglobulinemia patients exhibiting different clinical presentations and courses. The nature of the mutations is interpreted in terms of the genomic organization of the BTK gene and the disease course in individual patients. Several examples are found in which the same mutation occurs in unrelated patients, and one of these mutations occurs at the same codon that is substituted in the murine form of BTK, resulting in X chromosome-linked immunodeficiency disease. Considerable variation in presentation and disease course in X chromosome-linked agammaglobulinemia appears associated with the nature and position of different missense mutations.

Total parenteral nutrition-related infections. Prospective epidemiologic study using semiquantitative methods.

Studies of total parenteral nutrition-related infection have incorrectly relied on positive results on culture of the cannula tip to confirm the source. We undertook a prospective study of total parenteral nutrition-related infections in adult patients by obtaining blood from all total parenteral nutrition lines for pour-plate culture twice weekly and culturing intravascular line segments by the technique of Maki. Twelve of 100 courses of total parenteral nutrition (12 percent) in 69 patients resulted in infections--five (5.0 percent) had sepsis, and seven (7.0 percent) had local infection. In five of these 12, pour-plate culture gave positive results (five of 38 pour plates) with counts of 8 colony-forming units per ml (cfu/ml) for Candida tropicalis, and 25 to more than 1,000 for bacterial isolates. In nine of 12, culture of the intravascular line segment gave positive results with more than 50 cfu/ml. Pathogens isolated from intravascular line segments included Staphylococcus epidermidis (three cases), Candida species (three cases), Staphylococcus aureus (two cases), Serratia marcescens (one case) and mixed bacterial pathogens (one case). In contrast, pour-plate culture gave positive results in only seven of 88 uninfected (control) courses (318 pour plates), and culture of intravascular line segments gave positive results in two of 65 uninfected courses (p less than 0.001). No differences existed among patients with and without infection with regard to age, underlying disease, surgery, systemic antibiotic usage, or the presence of other infections. The duration of total parenteral nutrition was longer in courses without infection than in courses with infection (14.7 +/- 9.4 days versus 11.0 +/- 4.0 days; p less than 0.02). In six of 12 courses with infection, the line had been violated compared with 22 of 88 courses without infection (p less than 0.001). T-connectors for the centra administration of intralipid were associatd with infection (p less than 0.02). The value of routine pour-plate culture was illustrated in three courses in which the positive pour-plate culture results antedated positive blood culture results or line removal.

Relationship between the specificity of IgA proteases and serotypes in Haemophilus influenzae.

Haemophilus influenzae is one of five bacterial species known to produce IgA proteases, enzymes that specifically cleave the human IgA1 heavy chain. Strains of H. influenzae produce three distinct types of IgA proteases that cleave different peptide bonds within the IgA1 hinge region. Type 1 protease cleaves the prolyl-seryl bond at position 231-232; type 2 protease cleaves the prolyl-threonyl bond at position 235-236, the same bond attacked by Neisseria gonorrhoeae and Neisseria meningitidis type 2 proteases. Type 3 protease yields a unique double Fd cleavage pattern; the exact peptide bonds cleaved have not been determined. The type of protease produced correlates with the serotype, but not with the biotype, of the isolate; serotypes A, B, D, and F produce primarily type 1 protease, whereas serotypes C and E produce only type 2 enzyme. Each nontypable strain yields one of the three protease types. These data further extend our knowledge of the extreme specificity of the IgA proteases and suggest that IgA protease type may be useful in the taxonomy and epidemiology of H. influenzae.

Severe acquired immunodeficiency in male homosexuals, manifested by chronic perianal ulcerative herpes simplex lesions.

Four homosexual men presented with gradually enlarging perianal ulcers, from which herpes simplex virus was cultured. Each patient had a prolonged course characterized by eight loss, fever, and evidence of infection by other opportunistic microorganisms including cytomegalovirus, Pneumocystis carinii, and Candida albicans. Three patients died; Kaposi's sarcoma developed in the fourth. All were found to have depressed cell-mediated immunity, as evidenced by skin anergy, lymphopenia, and poor or absent responses to plant lectins and antigens in vitro. Natural-killer-cell activity directed against target cells infected with herpes simplex virus was depressed in all patients. The absence of a history of recurrent infections or of histologic evidence of lymphoproliferative or other neoplastic diseases suggests that the immune defects were acquired.

Secretory immunity and the bacterial IgA proteases.

The characteristics and functions of microbial IgA proteases are reviewed. These enzymes represent a structurally heterogeneous group of proteins that are secreted into the extracellular environment by bacteria capable of causing human disease. The IgA proteases, which vary in their requirements for metal ions, are neutral endopeptidases whose role in the infectious process is not known but whose pronounced substrate specificity for human proteins of the IgA1 subclass has repeatedly been demonstrated. As reagents, the IgA proteases are useful in cleaving IgA molecules to yield intact Fc alpha and Fab alpha fragments that will allow the study of the structure and function of the two large regions of IgA immunoglobulin proteins. The role, if any, of these enzymes in promoting infection by pathogenic members of the genera Neisseria, Hemophilus, and Streptococcus is not known, although the secretory immune system is primarily mediated by antibodies of the IgA isotype, among which are IgA1 subclass proteins, and these proteins are susceptible to cleavage by IgA protease. The determination of the role of these enzymes in the pathogenesis of human infection must await clearer understanding of antigenicity and antibody function at secretory sites and of the relative roles of the two subclasses of human IgA in immune defense.

Specific proteolysis of human IgA by Streptococcus pneumoniae and Haemophilus influenzae.

Streptococcus pneumoniae and Haemophilus influenzae are among the most common bacterial pathogens responsible for respiratory tract infections in otherwise healthy humans. Thirty-six strains of S. pneumoniae, 62 strains of H. influenzae, six hospital-acquired respiratory pathogens, and a strain of Streptococcus pyogenes were examined for production of IgA protease, a bacterial enzyme whose only known substrate is human IgA1. IgA protease was produced by 100% of the isolates of S. pneumoniae and 98% of the isolates of H. influenzae. The enzyme from both species cleaved human serum and secretory IgA1 proteins, but not human IgA2, IgG, or human serum albumin. None of the hospital-acquired pathogens had detectable IgA protease activity, a finding indicating that the production of this enzyme distinguishes S. pneumoniae and H. influenzae from the opporunistic respiratory pathogens.