Suppressor thymus-derived lymphocytes in fungal infection

Production and function of cytokines in natural and acquired immunity to Candida albicans infection

Host resistance against infections caused by the yeast Candida albicans is mediated predominantly by polymorphonuclear leukocytes and macrophages. Antigens of Candida stimulate lymphocyte proliferation and cytokine synthesis, and in both humans and mice, these cytokines enhance the candidacidal functions of the phagocytic cells. In systemic candidiasis in mice, cytokine production has been found to be a function of the CD4+ T helper (Th) cells. The Th1 subset of these cells, characterized by the production of gamma interferon and interleukin-2, is associated with macrophage activation and enhanced resistance against reinfection, whereas the Th2 subset, which produces interleukins-4, -6, and -10, is linked to the development of chronic disease. However, other models have generated divergent data. Mucosal infection generally elicits Th1-type cytokine responses and protection from systemic challenge, and identification of cytokine mRNA present in infected tissues of mice that develop mild or severe lesions does not show pure Th1- or Th2-type responses. Furthermore, antigens of C. albicans, mannan in particular, can induce suppressor cells that modulate both specific and nonspecific cellular and humoral immune responses, and there is an emerging body of evidence that molecular mimicry may affect the efficiency of anti-Candida responses within defined genetic contexts.

Autoimmune hemolytic anemia in chronic mucocutaneous candidiasis

Chronic mucocutaneous candidiasis is an immunodeficiency disease characterized by T-cell dysregulation and chronic superficial candidal infections. We report on three patients with chronic mucocutaneous candidiasis who developed autoantibodies to erythrocytes. Our first patient, a 19-year-old female, developed autoimmune hemolytic anemia (AIHA) that required multiple courses of treatment, including corticosteroids, intravenous immunoglobulin, and danazol. During the last exacerbation of AIHA, intensive treatment with corticosteroids and intravenous immunoglobulin failed and yet the patient responded to plasmapheresis. Our second patient, a 21-year-old male, developed AIHA which responded to oral corticosteroid therapy. Our third patient, a 6-year-old female without evidence of hemolysis, was found to have erythrocyte autoantibodies on routine screening. These three patients had positive direct antiglobulin tests, and the first patient had both immunoglobulin G (IgG) and IgM erythrocyte autoantibodies, while the remaining two patients had only IgG autoantibody. This is the first report of the association of AIHA with chronic mucocutaneous candidiasis. We suggest that all patients with chronic mucocutaneous candidiasis be screened periodically for erythrocyte autoantibodies. Plasmapheresis, a safe ancillary procedure in the management of AIHA, may be life-saving in some cases. The occurrence of erythrocyte autoantibodies in mucocutaneous candidiasis may be related to immunoregulatory disorders in this disease.

Idiopathic CD4+ T-lymphocytopenia--four patients with opportunistic infections and no evidence of HIV infection

BACKGROUND AND METHODS

We describe four patients without major risk factors for human immunodeficiency virus (HIV) infection, each of whom presented with severe opportunistic infections and was found to have idiopathic CD4+ T-lymphocytopenia. We performed assays to detect the presence of retroviruses and undertook immunophenotyping of subgroups of peripheral-blood lymphocytes.

RESULTS

The opportunistic infections at presentation included Pneumocystis carinii pneumonia, cryptococcal meningitis (two patients, one with concurrent pulmonary tuberculosis), and histoplasma-induced brain abscess. During 10 to 68 months of observation, none of the four patients had evidence of infection with HIV type 1 or 2 or human T-cell lymphotropic virus type I or II on the basis of epidemiologic, serologic, or polymerase-chain-reaction studies or culture, nor was there any detectable reverse transcriptase activity. Although all the patients had severe, persistent CD4+ T-lymphocytopenia (range, 12 to 293 cells per cubic millimeter), the CD4+ cell count progressively declined in only one and was accompanied by multiple opportunistic infections. All four patients had significantly reduced numbers of circulating CD8+ T cells, natural killer cells, or B cells (or all three).

CONCLUSIONS

These four patients had idiopathic CD4+ T-lymphocytopenia with opportunistic infections but no evidence of HIV infection. Instead of the progressive, selective depletion of CD4+ T cells characteristic of HIV infection, some patients with idiopathic immunodeficiency have stable CD4+ cell counts accompanied by reductions in the levels of several other lymphocyte subgroups.

Evidence that specific high mannose structures directly regulate multiple cellular activities

Previous studies have demonstrated that much of the immunomodulatory activity of the glycoprotein uromodulin can be attributed to attached oligosaccharides. Structural studies of isolated and purified saccharides derived from uromodulin suggest that the structure Man6GlcNAc2-asn can inhibit in vitro assays of antigen driven T cell proliferation. Based on these observations, we isolated a series of high mannose glycopeptides from a variety of natural sources and tested them for biological activity in a number of assays. We found that purified mannose rich glycopeptides are able to activate the hexose monophosphate (HMP) shunt, induce prostaglandin synthesis, and directly stimulate IL-1 synthesis. These in vitro effects appear to have in vivo counterparts. Thus in a species-restricted fashion, high mannose compounds are able to directly activate a delayed mononuclear cell infiltrate after intradermal injection. Our data suggest that specific mannose oligosaccharides may activate as well as inhibit cellular immune responses at several different levels. These findings support the hypothesis that specific saccharide structures could participate in the physiologic regulation of the immune response.

Requirement for cell-to-cell contact for the immunosuppressive activity of human alveolar macrophages

The ability of alveolar macrophages (AM) obtained by bronchoalveolar lavage of healthy volunteers to suppress T lymphocyte responses to the mitogen phytohemagglutinin (PHA) in vitro was investigated. AM but not monocytes (MN) inhibited responses of peripheral blood mononuclear cells (PBMC) to PHA as measured by incorporation of [3H]thymidine [( 3H]TdR) and interleukin-2 (IL-2) expression. Supernatants of AM generated for various periods and with various concentrations of cells did not, however, inhibit PBMC responses to PHA. To examine the role of cell contact in the inhibitory activity of AM, AM or MN were added to PBMC in 6-well plates either directly (in co-culture) or separated by a 0.45-micron filter. MN did not inhibit PBMC blastogenic responses under either condition. AM at a 1:2 ratio with PBMC inhibited blastogenesis by 75 +/- 11% (mean +/- SD, n = 3, P less than 0.01) when cultured directly with PBMC but had no inhibitory effect on blastogenesis when physically separated from target PBMC. AM in co-culture with PBMC also inhibited PHA-stimulated IL-2 production by 70% but did not inhibit IL-2 production when AM were separated from PBMC in dual chambers. To assess the role of the cell surface in the inhibitory activity of AM, AM and MN were fixed with 2% paraformaldehyde. Neither fixed nor unfixed MN inhibited PBMC blastogenic responses, but both fixed and unfixed AM inhibited responses similarly (77 to 95%).(ABSTRACT TRUNCATED AT 250 WORDS)

Murine candidiasis: cell-mediated immune responses correlate directly with susceptibility and resistance to infection

Cell-mediated immune responses were evaluated after immunization in two inbred mouse strains, CBA/H and BALB/c, that are respectively susceptible and resistant to infection with the yeast Candida albicans. Local immune responses, as measured by leucocytic infiltration into the draining lymph node, were similar; however, both delayed-type hypersensitivity responses and candida-specific lymphocyte proliferation in vitro were significantly stronger in the resistant strain. The response was controlled by genes mapping outside the major histocompatibility complex. A possible explanation for the down regulation of the immune response in CBA/H mice is discussed.

Dermatophytosis of the scalp: incidence, immune response, and epidemiology

Tinea capitis remains a common infection among the pediatric population of North America. The 'gray patch' Microsporum audouinii infections of the 1950's have been supplanted by the 'black dot' ringworm of Trichophyton tonsurans. The clinical presentation of T. tonsurans infection is quite variable and may be related to specific host T-lymphocyte response. This dermatophytosis is most frequently incurred from contact with an infected child either directly or via a variety of fomites. Current studies indicate that an asymptomatic adult carrier state may also exist which could contribute to the morbidity of this mycosis.

Host-parasite interaction in fungal infections

The outcome of host-parasite interactions in fungal infections is determined by the balance between pathogenicity of the organism and the adequacy of the host defenses. A wide variety of host defense mechanisms are involved in protection against fungal infections. These include nonspecific mechanisms such as intact skin and mucus membranes, indigenous microbial flora, and the fungicidal activity of neutrophils and monocytes. Such mechanisms constitute the major host defense against opportunistic fungal infections caused by ubiquitous organisms of low virulence. The effective role of immunoglobulins and complement as opsonins varies with the fungal pathogen involved. Specific immune responses of both the humoral and cell-mediated type develop in response to infections by pathogenic fungi. Antibodies, in general, are not of major importance in protection against these infections. Specifically sensitized T lymphocytes produce lymphokines that activate macrophages. Activated macrophages are the major line of defense against systemic fungal pathogens. The type and degree of impairment in immune responses determines the susceptibility and severity of diseases. The type of immune response also determines the tissue reactions in these diseases and sometimes may be involved in the pathogenesis of the disease process. The role of natural killer cell activity, antibody-dependent cellular cytotoxicity, and biological response modifiers in various fungal infections has been described recently. The microbial factors of importance in fungal infections are adherence, invasion, presence of an antiphagocytic capsule, and ability to grow under altered physiological states of the host. The differences in the virulence of fungal strains is of minor importance in determining the outcome in general. The seriousness of the alteration of the host state rather than the pathogenic properties of the fungus determine the severity of the disease.

Correlative studies of blastogenic responses and interleukin 1 production by mononuclear cells from patients with zoopathogenic fungal infections

The production of interleukin 1 (IL 1) by adherent peripheral blood mononuclear cells (PBMC) was quantitated in 16 individuals infected with Histoplasma capsulatum or Blastomyces dermatitidis and 16 age-matched controls. In parallel, we measured blastogenic responses to phytohemagglutinin (PHA) by PBMC from patients and controls. Of the 16 patients, six had pulmonary histoplasmosis, six had disseminated histoplasmosis, two had pulmonary blastomycosis, and two had disseminated blastomycosis. At the time of study, none of the patients were receiving immunosuppressive agents or had an underlying debilitating illness. Proliferative responses by PBMC from patients to PHA were significantly (P less than 0.05) less than the mean response by PBMC from an equal number of controls. In the 16 controls, the increase in secretion of IL 1 by lipopolysaccharide (LPS)-stimulated adherent cells over unstimulated cells ranged from 18 to 40 units of IL 1 activity per 10(5) adherent cells. The increment in IL 1 levels between LPS-stimulated adherent PBMC and unstimulated cells was diminished (less than 18 units of IL 1 activity per 10(5) adherent cells) in five of the 16 patients. Diminished IL 1 secretion in response to LPS was associated with impaired PHA responses in four of 10 patients.

Seronegative Lyme disease. Dissociation of specific T- and B-lymphocyte responses to Borrelia burgdorferi

The diagnosis of Lyme disease often depends on the measurement of serum antibodies to Borrelia burgdorferi, the spirochete that causes this disorder. Although prompt treatment with antibiotics may abrogate the antibody response to the infection, symptoms persist in some patients. We studied 17 patients who had presented with acute Lyme disease and received prompt treatment with oral antibiotics, but in whom chronic Lyme disease subsequently developed. Although these patients had clinically active disease, none had diagnostic levels of antibodies to B. burgdorferi on either a standard enzyme-linked immunosorbent assay or immunofluorescence assay. On Western blot analysis, the level of immunoglobulin reactivity against B. burgdorferi in serum from these patients was no greater than that in serum from normal controls. The patients had a vigorous T-cell proliferative response to whole B. burgdorferi, with a mean ( +/- SEM) stimulation index of 17.8 +/- 3.3, similar to that (15.8 +/- 3.2) in 18 patients with chronic Lyme disease who had detectable antibodies. The T-cell response of both groups was greater than that of a control group of healthy subjects (3.1 +/- 0.5; P less than 0.001). We conclude that the presence of chronic Lyme disease cannot be excluded by the absence of antibodies against B. burgdorferi and that a specific T-cell blastogenic response to B. burgdorferi is evidence of infection in seronegative patients with clinical indications of chronic Lyme disease.

Cellular autoimmunity in psoriasis and lichen planus

The objective of this investigation was to determine whether specific cellular recognition of the epidermis is associated with the human skin diseases, psoriasis and lichen planus. Epidermal cells (EC) obtained from biopsies of involved and uninvolved skin of patients with these diseases were used as stimulators and targets for autologous peripheral blood mononuclear cells (PBMC) in assays of three conventional manifestations of cellular immunity: lymphocyte transformation, leukocyte migration-inhibition and cell-mediated cytotoxicity. Parallel tests were conducted with autologous PBMC as stimulators to ascertain the tissue specificity of the reactions evoked by autologous EC. Similar assays were conducted with EC and PBMC from a large group of normal subjects, and the results were compared to those of the dermatology patients by rigorous statistical analyses. No evidence of lymphocyte-mediated cytotoxicity towards autologous EC was obtained with any of the subject groups, but autologous EC, and to a lesser extent PBMC, of the psoriasis patients, but not of the other two groups, evoked significant lymphocyte transformation. These results were obtained only with patients on Goeckerman therapy, raising the possibility that they were a manifestation of the treatment (topical coal-tar and ultraviolet light irradiation) rather than of the disease, although reasons are presented why this is unlikely. Clearer evidence of disease-associated autoimmunity was obtained in the leukocyte migration-inhibition assays, where autologous EC, and to a lesser extent, PBMC, of the psoriasis patients in general, not just those on Goeckerman therapy, and not those of the lichen planus patients or of the normal subjects, stimulated the release of a leukocyte migration-inhibition factor. These results support the concept of a central role for T-cell mediated autoimmunity in the pathogenesis of psoriasis.

Immunosuppression transfer by spleen cells from young to adult mice previous to Histoplasma capsulatum infection

The passive transfer of spleen cells from 1 month old mice into adult syngeneic mice, abrogates their resistance to histoplasmal infection. This suppressive state was detected in two cell populations, one non-adherent and another adherent with radioresistant characteristics. The transferred spleen cells were treated by different anti-sera: anti-theta, anti-adherent cells (produced in rabbits) and monoclonal anti-Thy 1.2 respectively. The irradiated and non-irradiated adult recipient mice were infected with Histoplasma yeasts utilizing the Lethal Dose50 for 1 month old mice. The infection course was determined by death percentage, the histoplasmosis murine signs and the number of the fungal colony forming units (CFU) from the infected spleens. The results of the anti-sera treatment suggest that non-adherent as well as adherent cells participate in the suppressive phenomena. A lower number of CFU was identified in infected animals which received cells treated with anti-Thy 1.2 anti-sera.

Host response to myeloma: I. Induction of cytotoxic and suppressor T cells by in vivo immunization with MOPC 104E plasmacytoma

Spleen cells from BALB/c mice immunized with mitomycin C-treated MOPC 104E plasmacytoma cells demonstrated negligible cytotoxic activity (less than 10% specific cytotoxic activity) in the 51Cr release assay. These cells exhibited increased cytotoxic activity when they were secondarily sensitized in vitro with mitomycin C-treated MOPC 104E cells. Spleen cells from normal mice showed tumor-specific cytotoxic activity when cocultured with mitomycin C-treated tumor cells at the optimal responder to stimulator ratio of 25:1. The level of cytotoxic activity obtained by in vivo primed and secondarily in vitro sensitized spleen cells did not exceed the level of activity obtained by in vitro primary sensitized cells. Significant suppression of the cytotoxic activity of in vitro primary sensitized cells was observed when cocultured with in vivo primed spleen cells during primary sensitization in vitro at a responder to suppressor cell ratio of 1:1. Suppressor cells of in vivo primed mice were removed by treatment with anti-Thy 1.2 and complement. These results suggest that spleen cells from in vivo primed mice consisted of at least two subpopulations of cells, a cytotoxic (prekiller) and suppressor T cells. Attempts to induce cytotoxic cells in vivo might have failed because of the appearance of suppressor T cells.

Epidemiologic and immunologic evaluation of an outbreak of canine blastomycosis

Five confirmed cases of canine blastomycosis occurred over the 10-month period of December 1983 to September 1984 in a south-eastern Wisconsin colony of 30 dogs maintained for sled competition. Contrary to other published reports of canine blastomycosis, the sex-specific attack rates were higher among females than males. Four of the five confirmed cases and all four deaths occurred among young female dogs. Differences in the age distribution and/or the micro-environment of the females may have contributed at least in part to the difference in sex-specific attack rates. The serologic response and leukocyte function of the clinically affected and apparently healthy dogs from this colony were assessed during the outbreak. A survey of the adult dogs in the colony suggested that the mitogen-induced lymphocyte blastogenesis of dogs with clinical signs of blastomycosis was suppressed compared with that of dogs that remained free of clinical signs. In contrast to previous reports that autologous sera from dogs and humans with clinical blastomycosis inhibited mitogen-induced lymphocyte blastogenesis, lymphocyte responsiveness was similar to, or greater in the presence of autologous canine serum than it was in the presence of fetal bovine serum.

Selective deficiency in IL-2 production and refractoriness to extrinsic IL-2 in immunodeficiency with hyper-IgM

Various lymphokines are inducible by the stimulation of T-cell mitogens, phytohemagglutinin, and concanavalin A. A 32-year-old female with an atypical type of immunodeficiency with hyper-IgM was evaluated for possible defects in the production of several immunoregulatory lymphokines. Although the mitogens appeared to bind effectively to the specific surface receptors of patient peripheral blood lymphocyte (PBL), the proliferative responses were significantly decreased. The culture supernatant of patient PBL stimulated by the mitogens contained only a trace amount of interleukin 2 (IL-2) activity. Addition of recombinant IL-2 to the cultures concomitantly with the mitogens could not restore the decreased responses of patient PBL. Tac antigen expression of patient PBL induced by the mitogens was moderately impaired. These data suggest that there is a defect in both IL-2-producing and IL-2-responding cells. In contrast, the culture supernatant of mitogen-stimulated patient PBL contained B-cell growth and differentiation factors as well as interferon-gamma activities equal to those of the control. These results suggest that there are independent regulatory pathways for the production of IL-2 and other T-cell-derived lymphokines.

Murine candidiasis. III. Host inflammatory responses are regulated in part by class I MHC genes

Host responses to experimental Candida albicans infection in mice have been shown previously to be regulated by genes in the major histocompatibility complex (MHC). Results reported here show that at least part of this control can be mapped to class I MHC genes.

Immunology of recurrent vaginitis

Recent evidence suggests that recurrent vaginitis can arise as a consequence of a transient and localized inhibition of cell-mediated immunity. Lymphocytes from many women with this disorder manifest a reduced in vitro proliferative response to Candida albicans. The inhibition appears to be due to increased production by the patients' macrophages of prostaglandin E2, which inhibits interleukin-2 production and thereby blocks lymphocyte proliferation. When lymphocyte responses are impaired, C. albicans can readily proliferate and initiate a clinical infection. Prostaglandin E2 production can arise as a consequence of a vaginal allergic response. IgE antibodies to C. albicans, ryegrass, contraceptive spermicides, and seminal plasma have been detected in vaginal fluids from recurrent vaginitis patients. The role of male factors in inducing immune alterations and vaginitis in the female partner has been underestimated. Medications or chemicals ingested by the male and present in his semen may be transmitted to sensitized females by coitus. In addition, male-specific allergic responses may be induced in females through the seminal transfer of specific IgE antibodies. Future efforts both to eliminate clinical vaginal infections and to reduce susceptibility of the host to vaginal immunosuppression should improve the efficacy of treatment for this disorder.

Spectrum of immunoregulatory functions and properties of human alveolar macrophages

In health, pulmonary alveoli are maintained free of inflammatory responses to inhaled foreign antigens. The specific role of alveolar macrophages (AM) in modulating the local cellular immune response to antigens is controversial. Immunoregulatory function and properties of AM and blood monocytes (MN) were compared. The AM were obtained by bronchoalveolar lavage of healthy volunteers, MN by adherence of peripheral blood mononuclear cells to plastic. These accessory cells were added in increasing ratios to a responder population rendered rigorously accessory cell-dependent by nylon wool adherence and depletion of cells bearing the surface Class II MHC determinant, HLA-DR. At low ratios of mononuclear phagocytes to lymphocytes (less than or equal to 1:10), MN and AM supported significant and comparable blastogenic responses to tetanus toxoid (3H-thymidine incorporation at a 1:10 ratio was 9,697 +/- 2,508 for MN and 8,969 +/- 1,454 for AM, mean cpm +/- SE, n = 9, p = NS) and other antigens. Interleukin-1 (IL-1) activity in supernatants of MN stimulated with lipopolysaccharide (LPS), 10 micrograms/ml, was 115 +/- 28 versus 67 +/- 21 U/ml in supernatants of AM (n = 9, p greater than 0.2). At suboptimal concentrations of LPS, however, MN expressed more IL-1 activity than did AM. The specific mean fluorescence intensity of surface expression of HLA-DR determinants as assessed by flow cytometry was similar for MN and AM. At the higher ratio of 1:2, MN supported 32% increased responses to tetanus toxoid compared with that at 1:5 (p less than 0.05). In contrast, AM at a ratio of 1:2 suppressed lymphocyte response by 69% (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of age, sex and health status on human lymphocyte functions: demonstration of a sex-related defect in suppressor cell function

The mitogenic response of human lymphocytes and the short-lived suppressor cell function on concanavalin A response were studied as dependent variables in 194 patients using multiple regression analysis, with health status and sex as dummy variables, and age as an explicative one. This study confirms a decrease of the lymphocyte functional response to mitogens with aging. A sex-related defect in suppressor cell function is put forward in females independently of age. An inverse linear relationship is found between the functional response to pokeweed mitogen (T and B mitogen) and suppressor cell function in males but not in females. No such relationship is found with the pure T mitogens (Con A and phytohemagglutinin-A). The present study suggests that a defect in short-lived suppressor cells can play some role in the greater incidence and prevalence of autoimmune diseases in women while the depressed lymphocyte response of old people cannot be explained by modifications of the activity of these suppressor cells.

Characteristics of DTH suppressor cells in mice infected with Candida albicans

Inoculation of 10(8) C. albicans intraperitoneally into Balb/c mice at given dosage was reported to induce suppression of antigen-specific delayed-type hypersensitivity. Adoptive transfer of spleen cells into normal syngeneic mice pre-treated with Cyclophosphamide confirmed the existence of suppressor cells in mice. Such cells were sensitive to treatment with anti-theta serum and complement, non-adherent to Sephadex G-10. A pretreatment of the mice with Cyclophosphamide eliminated DTH suppression. Treatment with antimacrophage agents via intraperitoneal abrogated suppression only if being effected before inoculation of alive 10(8) Candida albicans. It is concluded that the spleen suppressor cell is a T-lymphocyte whose precursor is Cyclophosphamide-sensitive, requiring the macrophage to be induced.

Stimulation of murine lymphocyte blastogenesis by mitogens in heat-killed Histoplasma capsulatum yeast cells

In vitro blastogenesis by normal murine splenocytes from several mouse strains has been detected after exposure to heat-killed Histoplasma capsulatum yeast cells. Maximal lymphocyte stimulation induced by 10(4) heat-killed cells resulted in 20- to 45-fold increases in [3H]thymidine uptake by splenocytes when compared with responses by normal unstimulated lymphocytes. The kinetics for this response to heat-killed H. capsulatum cells has shown peak mitogenesis 3 days after culture. Examination of the mitogenic potential of soluble antigen preparations from H. capsulatum has revealed stimulation of lymphocyte blastogenesis with yeast cell sonicates and autolysates but not substances from autoclaved yeast cells. The levels of lymphocyte blastogenesis induced by sonicates or autolysates were comparable to mitogen responses stimulated by heat-killed cells. Preliminary biochemical characterization of the mitogenic factor(s) associated with yeast cell sonicates show two peaks of activity, at 178,000 and less than 12,000 Mr, which have a protein or glycoprotein nature. Finally, analysis of lymphocyte blastogenesis in cultures enriched for selected lymphocyte subpopulations has shown that T lymphocytes are preferentially stimulated by yeast cell mitogens.

Mouse candidiasis. II. Host responses are T-cell dependent and regulated by genes in the major histocompatibility complex

Administration of a Thy-1.2-specific monoclonal antibody to BALB/c mice resulted in a significant decrease in the efficiency of clearance of Candida albicans from the spleen. The rate of clearance of organisms from the spleen of congenic mice was determined by genes in the major histocompatibility complex, as was the magnitude of the inflammatory response in the popliteal lymph node after footpad immunization. These results formally demonstrate the involvement of T cells in host responses to primary candida infection.

Suppressor T cell activity in lymphoid interstitial pneumonia

A case of lymphoid interstitial pneumonia was investigated for immunological abnormalities. Suppressor T cells were found. The abnormality in the lymphoid system could be corrected in vitro with levamisole. The patient thereafter developed histiocytic lymphoma and soon died without any response to chemotherapy.

HLA-D restriction of "naturally occurring" MLR suppressor cells in acquired common variable hypogammaglobulinemia

Cells with capacity to suppress the mixed lymphocyte response (MLR) were detected in two patients with acquired common variable hypogammaglobulinemia (ACVH). No specificity with respect to the stimulating HLA type was observed. In one case of ACVH available for extensive study, there was evidence for HLA-D restriction of the suppressor cells. The patient's lymphocytes specifically suppressed the MLR of subjects who carried the same HLA-D type. Family studies confirmed that the suppressor activity was restricted to HLA-D, not DR, and segregated with the appropriate HLA haplotype. These observations suggest that an immune suppressor gene mapping in the HLA region may be involved in the pathogenesis of common variable hypogammaglobulinemia.

Meningoencephalitis caused by Histoplasma capsulatum complicating pregnancy

We report what appears to be the first established case of disseminated histoplasmosis in pregnancy. Involvement of the central nervous system made treatment difficult, and the course of disease required iatrogenic preterm delivery of an uninfected fetus. Aspects of pathogenesis, diagnosis, interaction with pregnancy, and treatment for this common infection, hitherto unreported in pregnancy, are presented.

Parasitic adaptation of pathogenic fungi to mammalian hosts

Pathogenic fungi involved in medical and veterinary mycology can be classified in three different groups according to their level of adaptation to parasitism. Only a few species belonging to dermatophytes can be considered genuine parasites as opposed to molds or fungi involved in systemic mycoses. Ecological, ethological, biochemical, and immunological factors can play a role in preadaptation or adaptation to parasitic life and are discussed.

Active substance of Histoplasma capsulatum that inhibits blastogenic response of lymphocytes

A substance inhibiting blast transformation of murine spleen lymphocytes stimulated with various mitogens, such as LPS, PHA, and PWM, was obtained from yeast-form cells of Histoplasma capsulatum. This active substance was partially purified from the cell-free extract by DEAE-Sepharose CL-6B column chromatography. As a result of this partial purification, the inhibitory activity was 1.26 micrograms/ml in terms of ID50. Materials from H. capsulatum also inhibited blast transformation of murine spleen lymphocytes stimulated with the antigen PPD as well as mitogens LPS, PHA, and PWM. However, the con A-induced proliferative response was only slightly affected. A similar result was observed for the MLR. These inhibitory activities were abolished by heating at 70 C for 30 min. These results suggest that the heat-labile active substance produced by H. capsulatum might directly affect the lymphocytes, leading to inhibition of their blast transformation.

Immunology of fungal infections in animals

The nature of immunity to fungal infection is discussed predominantly for mammals and birds. T-cell-mediated immunity seems essential for recovery both from cutaneous and mucosal infections (Candida, Malassezia and dermatophytes) and from infections of systemic fungal pathogens (Cryptococcus, Blastomyces, Histoplasma, and Coccidioides). Often chronic progressive disease caused by these fungi is associated with a depression or absence of T-cell-mediated immunity to antigens of the infecting fungus. In contrast recovery from disease, or absence of clinical disease after exposure to these fungi, is associated with the presence of strong T-cell-mediated immune responses to the fungus. The activation of macrophages and the stimulation of epidermal growth and keratinization are the processes induced by T-cell-mediated immunity which result in the resolution of systemic or cutaneous and mucosal disease. Other cell types, for example NK cells and PMNs (polymorphonuclear leucocytes), may be important in these diseases in reducing the effective amount of inoculum to which an animal is exposed and thereby reducing the likelihood of disseminated disease. Invasive opportunistic fungi (Candida, Aspergillus, Mucorales) are resisted by PMNs which attach to the hyphae or pseudohyphae and damage them via an extracellular mechanism. Other host cell types may be important in natural resistance, fungal spores being handled by the macrophages which, under conditions when animals are not immunosuppressed, are likely to be an effective first line of defense. Subcutaneous pathogens and miscellaneous other fungal diseases are discussed from a point of view of host immunity and immunodiagnosis. Vaccine development for ringworm and for other mycoses is discussed.

Lymphocyte subpopulations of blood and alveolar lavage in blastomycosis

Patients with blastomycosis were found to have differing lymphocyte populations depending on the extent of disease manifestations and whether or not therapy had been started. Patients with recovering pulmonary blastomycosis who had been receiving antifungal treatment for at least four weeks had lymphocyte subpopulations no different from control donors. Patients with treated extrapulmonary blastomycosis had similar T helper (TH) to T suppressor (TS) ratios compared to recovering pulmonary patients and control subjects; this ratio gives a false impression because extrapulmonary blastomycosis patients had a reduced absolute number of lymphocytes with either marker. In bronchoalveolar lavage fluid, pulmonary blastomycosis patients who were clinically improved while receiving antifungal therapy had fewer TH cells and a greater number of lymphocytes with the TS marker than did control subjects. Patients with pulmonary blastomycosis prior to therapy had a smaller TH/S ratio than the other groups in peripheral blood primarily due to a reduction in the circulating TH fraction in both absolute numbers of cells and in the percentage of total T lymphocytes. Pulmonary blastomycosis patients re-evaluated after at least four weeks of antifungal therapy had TH/S ratios that were similar to normal persons. This increase in TH lymphocytes corresponded to clinical improvement and in a temporal correlation to that described for the development of specific immunity in this illness.

Macrophage-related fibrinolysis in experimental disseminated histoplasmosis

A model of disseminated histoplasmosis in CBA/J mice was developed. Cultures of Histoplasma capsulatum from the spleens of infected mice suggested almost complete clearance of fungi by week 3. The adherent spleen cells from infected mice showed a 2- to 20-fold increase in fibrinolysis. The increase in activity was maximal around 1 to 2 weeks and disappeared after week 3 of infection, and this paralleled the progressively decreasing number of culturable fungi from the spleen. In vitro coculture of infected spleen cells or nylon wool-purified immune T cells and proteose peptone-induced macrophages resulted in increased fibrinolysis. Peritoneal exudate cells from infected mice also showed increased fibrinolysis. The addition of soluble antigen to an in vitro culture system resulted not only in an increase in fibrinolytic activity of peritoneal exudate cells derived from infected mice but also of proteose peptone-induced macrophages. These observations suggest that spleen and peritoneal macrophages from H. capsulatum-infected mice exhibit increased fibrinolysis which in turn is indicative of macrophage activation. The mechanism of activation occurs as a result of immunologically specific T cell-macrophage interaction and by the action of histoplasma products on the macrophages. The significance of these findings and the role of the plasminogen activator assay in studies of disseminated fungal infection are discussed.

T cell subpopulations in inflammatory bowel disease: evidence for a defective induction of T8+ suppressor/cytotoxic T lymphocytes

Abnormal immune responses associated with inflammatory bowel disease may reflect a defect in immunoregulatory functions. To analyse T-T cell cooperation, we examined the influence of polyclonal activation with the mitogen phytohaemagglutinin on the distribution of the T4+ helper/inducer and the T8+ cytotoxic/suppressor T cell subset. Compared to controls, lymphocytes from patients with Crohn's disease displayed a slight reduction in T3+ cells; neither in patients with ulcerative colitis nor in patients with Crohn's disease a significant difference in T4+ and T8+ cells and the T4/T8 ratio was observed. Phytohaemagglutinin stimulation of normal lymphocytes resulted in a decrease of the T4 subset and a clear increase of the T8 subpopulation. In contrast, the subset distribution pattern was not changed by the mitogenic stimulation in any of the patients. This abnormal reaction pattern could not be influenced by the addition of interleukin-2. Small numbers of normal lymphocytes, however, were able to restore the predominant proliferation of T8+ cells. Thus, the reduced response of T8+ lymphocytes cannot be attributed to an altered composition of this subset in patient with inflammatory bowel disease; our results provide evidence for a defective induction of T8+ suppressor/cytotoxic T cells, which is independent from disease activity.

Immunoregulation in experimental murine candidiasis: specific suppression induced by Candida albicans cell wall glycoprotein

Immune regulation in candidiasis is inferred from studies of both human and animal infection, with a suppressive role suggested for cell wall polysaccharide. To study the immunosuppressive potential of Candida albicans in a murine model, whole blastoconidia or purified cell wall components of C. albicans were tested for their effects on the development of acquired immune responses by superimposing a pretreatment regimen upon an established immunization protocol. CBA/J or BALB/cByJ mice were pretreated twice intravenously with 100 micrograms of mannan (MAN), 100 or 200 micrograms of glycoprotein (GP), or 5 X 10(7) heat-killed C. albicans blastoconidia, followed 1 week later by an immunization protocol of two cutaneous inoculations of viable C. albicans blastoconidia given 2 weeks apart. Delayed hypersensitivity (DTH) to GP or to a membrane-derived antigen, B-HEX, was tested 7 days after the second inoculation, and lymphocyte stimulation was tested with mitogens and Candida antigens after 12 days. To assess protection, mice were challenged intravenously with viable C. albicans blastoconidia 14 days after the second cutaneous inoculation and sacrificed 28 days later for quantitative culture of kidneys and brains. Sera were obtained for enzyme-linked immunosorbent assays at selected intervals. Pretreatment with GP resulted in specific in vivo suppression of DTH to GP but not to B-HEX antigen and specific in vitro suppression of lymphocyte stimulation to GP but not to other Candida antigens or mitogens. MAN and heat-killed C. albicans blastoconidia had no such effects. GP pretreatment also diminished the protective effect of immunization against challenge, demonstrable in the brain, while not altering significantly the production of antibody in response to infection. Contrary to clinical evidence, MAN was not immunosuppressive in this model, and in fact, the immunosuppressive potential of GP, which is composed largely of MAN, was found to be dependent upon the presence of its heat-labile protein moiety.

Infectious antecedent of immunoblastic lymphoma. Progressive immunosuppression in a patient with lymphogranuloma venereum

Angioimmunoblastic lymphadenopathy is a nonmalignant disease of unknown etiology often progressing to immunoblastic lymphoma. Immunologic deficiency is evident in these patients as well as in those with various infections found in association with the acquired immune deficiency syndrome (AIDS). This report describes a previously healthy young woman in whom angioimmunoblastic lymphadenopathy developed in association with lymphogranuloma venereum, with progressive loss of immunologic competence. This deterioration paralleled the evolution of angioimmunoblastic lymphadenopathy into a rapidly fatal immunoblastic lymphoma.

Correlation between cell-mediated immunity and clinical forms of paracoccidioidomycosis

Cellular immune response to specific and non-specific stimulants was investigated, both in vivo and in vitro, in 29 healthy controls and in 53 previously untreated patients with the chronic isolated organic form (CIOF), the chronic mixed form (CMF) and the acute progressive form (APF) of paracoccidioidomycosis. The study included skin tests to Paracoccidioides brasiliensis antigen (PbAg) and phytohaemagglutinin (PHA), DNCB sensitization, determination of T lymphocytes and complement rosette-forming cells, lymphocyte transformation and leucocyte migration inhibition tests using PbAg and PHA. Patients displayed staggered cutaneous response to PHA and to PbAg, with marked decrease in intensity in the APF group. DNCB sensitization test and proliferative response of lymphocytes to PHA and PbAg were severely depressed in most of the patients. Leucocyte migration inhibition indices to PbAg were highly positive, while response to PHA was slightly decreased regardless of the clinical form. The number of T lymphocytes was reduced in most of patients and in them the number of complement-rosette forming cells was normal. The distribution of patients according to a suppression index, based in the results of the tests employed, revealed a tendency towards an increased degree of cellular immunosuppression from the least severe (CIOF) to the most severe (APF) clinical form of the disease. On the whole, the present study demonstrated a gamut of immunological reactivity in paracoccidioidomycosis.

Immunological observations before and after successful treatment of chronic mucocutaneous candidiasis with ketoconazole and transfer factor

A girl, 13 months of age, presented with generalised granulomatous skin, hair and mucosal candidiasis. Her lymphocytes failed to respond in vitro to Candida antigen (CA); the intradermal test with CA was also negative. Serum immunoglobulins, complement components, granulocyte functions (phagocytic and fungicidal), T-cell subsets, mitogenic and allogenic lymphocyte stimulation, natural killer cell activity and immune interferon production were all found to be normal. No circulating immune complexes were detected. Ketoconazole, an antimycotic drug, 5 mg/kg twice daily for 1 month and 2.5 mg/kg twice daily for another month spectacularly cleared all lesions. Afterwards, 4-monthly injections with transfer factor (TF) were given. Intradermal reactivity to CA was observed after the second TF injection. The lymphocyte responsiveness to CA in vitro became strongly positive 3 months after the last TF injection. The level of CA precipitins in serum, which was very high (11 lines) before ketoconazole treatment, decreased to 4 lines. No serum inhibitor of lymphocyte proliferation to CA could be demonstrated in the patient's serum before or after treatment. This specific CA unresponsiveness was not due to an excess of OKT8 + (suppressor) cells; macrophage migration inhibiting factor (MIF) production was normal. The nonresponsiveness might be due to antigenic overload or to suppressor cell induction not demonstrable in the present studies. The child has remained free of lesions during 3 years of follow-up without any further treatment.

Suppression of humoral response during the course of Candida albicans infection in mice

This paper aims at demonstrating the non-specific immunosuppression as regards thyme-dependent antigens sheep erythrocytes (SRBC) during the course of Candida albicans systemic infection. Three lots of syngeneic/BALB/c mice, 8-12 weeks of age, were used. The first normal lot was inoculated via the intraperitoneal route with a (SRBC) suspension (4 X 10(8) cells ml) in a Hank's balanced saline solution. The primary response of antibodies formed by splenic cells was measured from 4 to 8 days after inoculation using the direct plaque forming cells technique. The second lot was infected by the same route with a suspension of Candida albicans (1 X 10(7) cells). Positive retrocultures from the blood and kidneys of these infected mice were obtained. These yeasts cultivated in a Sabouraud medium were harvested after 20 h at 37 degrees C. Following the same methodology the immune response to SRBC was determined. The serum obtained from infected mice was transferred to a third lot of mice at different intervals during the course of the infection. The immune response to SRBC was done by the direct plaque-forming cells technique. Controls were carried out using normal donors and recipients. A suppression of the immune response was obtained as from the 2nd day of inoculation up to the 28th day. It was not possible to transfer such suppression passively by means of the serum. These results suggest that the systemic infection by Candida albicans induce a non-specific immunosuppression in the organism, already demonstrated in viral infections, bacteria, protozoaria and metazoaria in mammals. In some way, this will contribute to explain the mechanisms of immune response to Candida albicans.

Disseminated histoplasmosis

A case of chronic disseminated histoplasmosis, presenting 16 years after returning to Scotland from West Bengal, is reported. The difficulties and pitfalls in diagnosis and management are emphasised.

Characterization of multiple immune defects in human malignant lymphoma

Sixty-three patients with Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL) were studied to analyze the mechanisms responsible for impaired in vitro lymphocyte reactivities to the mitogen concanavalin A. Lymphocytes from 43 of the 52 untreated patients acquired enhanced in vitro responsiveness after preculturing in media alone for 3 days. However, 38 of the untreated patients failed to achieve entirely normal lymphocyte responses after preculturing . Suppressor cells were detected in 25 patients, but the intensity of suppression was much less than expected when compared with the severity of in vitro impairments. Suppressor activity did correlate with certain clinical characteristics in NHL, whereas no correlation was observed for HD. In contrast to the untreated patients, successfully treated patients demonstrated either normal responses or profound, irreversible impairments. The data indicate that several mechanisms which usually coexist can contribute to the impaired in vitro lymphocyte responses in untreated HD and NHL, and that a single, irreversible type of mechanism explains the impaired reactivities in successfully treated patients.