Clinical investigation of patients with agammaglobulinemia and hypogammaglobulinemia

Primary B-cell immunodeficiencies

Primary B-cell immunodeficiencies refer to diseases resulting from impaired antibody production due to either molecular defects intrinsic to B-cells or a failure of interaction between B-cells and T-cells. Patients typically have recurrent infections and can vary with presentation and complications depending upon where the defect has occurred in B-cell development or the degree of functional impairment. In this review, we describe B-cell specific immune defects categorized by presence or absence of peripheral B-cells, immunoglobulins isotypes and evidence of antibody impairment.

The strategic use of novel smallpox vaccines in the post-eradication world

We still face a threat of orthopoxviruses in the form of biological weapons and emerging zoonoses. Therefore, there is a need to maintain a comprehensive defense strategy to counter the low-probability, high-impact threat of smallpox, as well as the ongoing threat of naturally occurring orthopoxvirus disease. The currently licensed live-virus smallpox vaccine ACAM2000 is effective, but associated with serious and even life-threatening adverse events. The health threat posed by this vaccine, and other previously licensed vaccines, has prevented many first responders, and even many in the military, from receiving a vaccine against smallpox. At the same time, global immunity produced during the smallpox eradication campaign is waning. Here, we review novel subunit/component vaccines and how they might play roles in unconventional strategies to defend against emerging orthopoxvirus diseases throughout the world and against smallpox used as a weapon of mass destruction.

Postexposure prevention of progressive vaccinia in SCID mice treated with vaccinia immune globulin

A recently reported case of progressive vaccinia (PV) in an immunocompromised patient has refocused attention on this condition. Uniformly fatal prior to the licensure of vaccinia immune globulin (VIG) in 1978, PV was still fatal in about half of VIG-treated patients overall, with a greater mortality rate in infants and children. Additional therapies would be needed in the setting of a smallpox bioterror event, since mass vaccination following any variola virus release would inevitably result in exposure of immunocompromised people through vaccination or contact with vaccinees. Well-characterized animal models of disease can support the licensure of new products when human studies are not ethical or feasible, as in the case of PV. We chose vaccinia virus-scarified SCID mice to model PV. As in immunocompromised humans, vaccinia virus-scarified SCID animals develop enlarging primary lesions with minimal or no inflammation, eventual distal virus spread, and lethal outcomes if left untreated. Postexposure treatment with VIG slowed disease progression, caused local lesion regression, and resulted in the healthy survival of most of the mice for more than 120 days. Combination treatment with VIG and topical cidofovir also resulted in long-term disease-free survival of most of the animals, even when initiated 7 days postinfection. These results support the possibility that combination treatments may be effective in humans and support using this SCID model of PV to test new antibody therapies and combination therapies and to provide further insights into the pathogenesis and treatment of PV.

Impact of ST-246® on ACAM2000™ smallpox vaccine reactogenicity, immunogenicity, and protective efficacy in immunodeficient mice

Although a highly effective vaccine against smallpox, vaccinia virus (VV) is not without adverse events, some of which can be life-threatening, particularly in immunocompromised individuals. We have recently demonstrated that the immunogenicity and protective efficacy of Dryvax(®) in immunocompetent mice is preserved even when co-administered with ST-246, an orally bioavailable small-molecule inhibitor of orthopoxvirus egress and dissemination. In addition, ST-246 markedly reduced the reactogenicity of the smallpox vaccine ACAM2000 and the highly neurovirulent VV strain Western Reserve (VV-WR). Here, we evaluated the impact of ST-246 co-administration on ACAM2000 reactogenicity, immunogenicity, and protective efficacy in seven murine models of varying degrees of humoral and cellular immunodeficiency: BALB/c and B-cell deficient (JH-KO) mice depleted of CD4(+) or CD8(+) or both subsets of T cells. We observed that ST-246 reduced vaccine lesion severity and time to complete resolution in all of the immunodeficient models examined, except in those lacking both CD4(+) and CD8(+) T cells. Although VV-specific humoral responses were moderately reduced by ST-246 treatment, cellular responses were generally comparable or slightly enhanced at both 1 and 6 months post-vaccination. Most importantly, in those models in which vaccination given alone conferred protection against lethal VV challenge, similar levels of protection were observed at both time points when vaccination was given with ST-246. These data suggest that, with the exception of individuals with irreversible, combined CD4(+) and CD8(+) T-cell deficiency, ST-246 co-administered at the time of vaccination may help reduce vaccine reactogenicity--even in those lacking humoral immunity--without impeding the induction of protective immunity.

Good's syndrome remains a mystery after 55 years: A systematic review of the scientific evidence

Good syndrome (GS) is a rare association of thymoma and immunodeficiency first described more than 50 years ago. However, this syndrome still remains a mystery to clinicians. We systematically reviewed all the clinical, laboratory and immunologic findings from 152 patients with Good syndrome. The syndrome has a worldwide distribution and approximately half of the cases (47%) have been described in Europe. The diagnosis of thymoma preceded the diagnosis of hypogammaglobulinemia, infection, or diarrhea in 42% of patients whereas in 38% of patients the diagnoses were made almost simultaneously within 2 months of each other. We found significant mortality in patients with this syndrome (44.5%). Astute clinical acumen and increased awareness about the clinical and immunological profile of this syndrome may increase early recognition of this syndrome and prevent mortality. Further studies are needed to elucidate this clinical entity.

Pathogenesis and potential antiviral therapy of complications of smallpox vaccination

Vaccination against smallpox may result in a variety of complications, ranging in severity from benign to lethal. Universal vaccination was halted in the US in 1972, so almost half the present population has never been vaccinated. Because side effects occur most often in first-time vaccinees, current plans for rapid large-scale vaccination in the event of bioterrorist attack raise concerns about the occurrence of a large number of adverse events. Most complications result from the excessive replication of vaccinia virus, making them potential targets for antiviral therapy. Effective treatment is especially needed for persons with atopic dermatitis or eczema, who are unusually susceptible to the initiation and spread of vaccinia infection because of defects of innate immunity in the skin, and for individuals with defective cell-mediated immunity, who are unable to eliminate vaccinia infection once it has begun. In the past, many complications were treated with vaccinia immune globulin (VIG) and/or the antiviral drug methisazone, but neither was tested in placebo-controlled trials. New antiviral drugs are now available, but have not yet been evaluated for treating vaccinia infections in humans. Both laboratory research and clinical studies are needed to help prevent serious complications in any major vaccination campaign.

Progressive vaccinia

The resumption of smallpox vaccination for health care workers and other first responders has raised concern about the occurrence of complications in people with immunodeficiency disorders, including those infected with human immunodeficiency virus. During the era of universal vaccination, roughly 1 person per million vaccinees in the general population developed progressive vaccinia, which is characterized by the relentless outward spread of infection from the vaccination site and eventual dissemination to other areas on the body. Review of 56 cases reported in the English-language medical literature from 1893 through 1997 indicates that the condition occurred only in persons with severe cell-mediated immunodeficiency. Progressive vaccinia was found to be lethal in infants who completely lacked cellular immune function, but infection resolved in many adults with acquired immunodeficiency. Almost all cases were treated with vaccinia immune globulin, but its efficacy has never been tested in a placebo-controlled trial. Further research is needed to develop effective forms of therapy.

Herpes infections in the immunosuppressed host

Very recent studies indicate that a primitive immune system plays an important role in resisting herpesvirus infections in the mouse. This system appears to be reflected by the NK cell assay and preliminary data suggest that this test reflects resistance in man to herpesvirus infections. We propose that ths system may be responsible for resistance to reactivated herpesvirus infections and its suppression might result in clinically apparent disease. Studies in our laboratory are currently aimed at evaluating this possibility.

Widespread eczema vaccinatum acquired by contacts. A report of an autopsy case

A 4-month-old male infant predisposed to allergic dermatitis acquired wide-spread eczema vaccinatum by contacts with a recently vaccinated sibling. He died of acute purulent peritonitis following a perforation of multiple duodenal ulcers. Fluorescence immunocytochemical and electron microscopic studies on the skin lesions revealed the presence of viral antigens and numerous virus particles compatible morphologically with those of the mature form from the same batch of smallpox vaccine given to the sibling. A large number of virus particles in the developmental form were also predominantly scattered in the cytoplasm of cells at the stratum malpighii of the epidermis as well as in neutrophils and macrophages in the skin lesions. The virus isolation from the skin lesions was done by using the HeLa cells and the human embryonic lung fibroblasts. No abnormal laboratory data were noted in immunoglobulins. On the basis of atrophy of the thymus and other lymphatic tissues and an appearance of large pyroninophilic cells in association with blastoid transformation, the authors discussed a possible participation of the disturbance of cellular immunity secondary to the virus infection in the development of the disease.

Leukocytic function in hypogammaglobulinemia

The phagocytic, bactericidal, and metabolic capabilities of circulating blood leukocytes from three adults (two males, one female) with hypogammaglobulinemia and recurrent pneumonia, chronic sinusitis, and intestinal giardiasis were studied. These functions were found to be normal when leukocytes from the patients were incubated in media containing normal human serum. Phagocytosis of Staphylococcus albus and polystyrene balls by both patient and normal leukocytes was diminished when the cells were incubated in hypogammaglobulinemic plasma. A similar defect in opsonization by patient plasma was also noted for pneumococci, Escherichia coli and variably with Staphylococcus aureus. Both patient and normal sera had equivalent levels of heat-labile S. albus opsonins; normal serum, however, contained heat-stable S. albus-specific absorbable opsonins in significantly greater quantities to account for its superior opsonic capacity. The addition of commercial gamma globulin or purified IgG to hypogammaglobulinemic sera restored full S. albus opsonic activity. The relevancy of these observations to the impaired host defenses in these patients will be discussed.

Infective hepatitis and acquired hypogammaglobulinaemia during pregnancy with complete recovery

Images