Cellular immune response in coccidioidomycosis

A chromosomal-level reference genome of the widely utilized Coccidioides posadasii laboratory strain "Silveira"

Coccidioidomycosis is a common fungal disease that is endemic to arid and semi-arid regions of both American continents. Coccidioides immitis and Coccidioides posadasii are the etiological agents of the disease, also known as Valley Fever. For several decades, the C. posadasii strain Silveira has been used widely in vaccine studies, is the source strain for production of diagnostic antigens, and is a widely used experimental strain for functional studies. In 2009, the genome was sequenced using Sanger sequencing technology, and a draft assembly and annotation were made available. In this study, the genome of the Silveira strain was sequenced using single molecule real-time sequencing PacBio technology, assembled into chromosomal-level contigs, genotyped, and the genome was reannotated using sophisticated and curated in silico tools. This high-quality genome sequencing effort has improved our understanding of chromosomal structure, gene set annotation, and lays the groundwork for identification of structural variants (e.g. transversions, translocations, and copy number variants), assessment of gene gain and loss, and comparison of transposable elements in future phylogenetic and population genomics studies.

Early Events in Coccidioidomycosis

Since its description nearly 130 years ago, hundreds of studies have deepened our understanding of coccidioidomycosis, also known as valley fever (VF), and provided useful diagnostic tests and treatments for the disease caused by the dimorphic fungi Coccidioides spp. In general, most of the literature has addressed well-established infections and has described patients who have experienced major complications. In contrast, little attention has been given to the earliest consequences of the pathogen-host interaction and its implications for disease manifestation, progression, and resolution. The purpose of this review is to highlight published studies on early coccidioidomycosis, identify gaps in our knowledge, and suggest new or former research areas that might be or remain fertile ground for insight into the early stages of this invasive fungal disease.

Coccidioidomycosis: host response and vaccine development

Coccidioidomycosis is caused by the dimorphic fungi in the genus Coccidioides. These fungi live as mycelia in the soil of desert areas of the American Southwest, and when the infectious spores, the arthroconidia, are inhaled, they convert into the parasitic spherule/endospore phase. Most infections are mild, but these organisms are frank pathogens and can cause severe lethal disease in fully immunocompetent individuals. While there is increased risk of disseminated disease in certain racial groups and immunocompromised persons, the fact that there are hosts who contain the initial infection and exhibit long-term immunity to reinfection supports the hypothesis that a vaccine against these pathogens is feasible. Multiple studies have shown that protective immunity against primary disease is associated with T-helper 1 (Th-1)-associated immune responses. The single best vaccine in animal models, formalin-killed spherules (FKS), was tested in a human trial but was not found to be significantly protective. This result has prompted studies to better define immunodominant Coccidioides antigen with the thought that a subunit vaccine would be protective. These efforts have defined multiple candidates, but the single best individual immunogen is the protein termed antigen 2/proline-rich antigen (Ag2/PRA). Studies in multiple laboratories have shown that Ag2/PRA as both protein and genetic vaccines provides significant protection against mice challenged systemically with Coccidioides. Unfortunately, compared to the FKS vaccine, it is significantly less protective as measured by both assays of reduction in fungal CFU and assays of survival. The capacity of Ag2/PRA to induce only partial protection was emphasized when animals were challenged intranasally. Thus, there is a need to define new candidates to create a multivalent vaccine to increase the effectiveness of Ag2/PRA. Efforts of genomic screening using expression library immunization or bioinformatic approaches to identify new candidates have revealed at least two new protective proteins, expression library immunization antigen 1 (ELI-Ag1) and a beta-1,3-glucanosyltransferase (GEL-1). In addition, previously discovered antigens such as Coccidioides-specific antigen (CSA) should be evaluated in assays of protection. While studies have yet to be completed with combinations of the current candidates, the hypothesis is that with increased numbers of candidates in a multivalent vaccine, there will be increased protection. As the genome sequences of the two Coccidioides strains which are under way are completed and annotated, the effort to find new candidates can increase to provide a complete genomic scan for immunodominant proteins. Thus, much progress has been made in the discovery of subunit vaccine candidates against Coccidioides and there are several candidates showing modest levels of protection, but for complete protection against pulmonary challenge we need to continue the search for additional candidates.

Successful treatment of a critically ill patient with disseminated coccidioidomycosis, using adjunctive interferon-gamma

Conventional antifungal therapy was not successful for a critically ill patient who had been hospitalized for 137 days in the intensive care unit with disseminated Coccidioides immitis infection and respiratory failure. The addition of interferon- gamma to the therapeutic regimen resulted in improvement and discharge from the hospital. Adjunctive interferon- gamma used in the successful treatment of severe coccidioidomycosis has not been reported previously.

In vitro whole-blood analysis of cellular immunity in patients with active coccidioidomycosis by using the antigen preparation T27K

Measurement of cellular immunity in human coccidioidomycosis has important diagnostic and prognostic implications. The coccidioidin skin test has been the standard for the measurement of this, but it is not available in the United States. We examined the utility of measuring surface expression of CD69 on T lymphocytes in whole blood incubated with the coccidioidal antigen preparation T27K as an alternative to the skin test. Seventy donors with active coccidioidomycosis were studied. The mean fluorescent intensity (MFI) of CD69 expression on CD3 lymphocytes in response to T27K was 28.61 +/- 1.77, significantly greater than the control response of 11.45 +/- 0.78 (P < 0.001). The MFI CD69 response to T27K above that for the control (MFI CD69 above control) was 6.35 +/- 2.18 for seven subjects with disseminated coccidioidomycosis who were studied within 5 months of diagnosis. This was significantly below the value of 20.17 +/- 3.17 for 18 subjects with pulmonary coccidioidomycosis studied within 5 months of diagnosis and the value of 19.58 +/- 2.91 for 27 subjects with disseminated coccidioidomycosis studied after 5 months of diagnosis (for both, P < 0.05). There was an inverse correlation between coccidioidal clinical score and MFI CD69 above control for all 34 subjects with disseminated coccidioidomycosis (r = 0.362; P = 0.036) but not for the 36 subjects with pulmonary disease (r < 0.001; P = 0.993). Among 30 subjects for whom data were available, there was a highly significant association between the MFI CD69 above control and the supernatant concentrations of gamma interferon, interleukin-2 (IL-2), and tumor necrosis factor alpha (for all, P < 0.001), but not for IL-4, IL-5, or IL-10. These data indicate that in vitro assessment of CD69 expression on T lymphocytes by using T27K may be a useful measure of cellular immune response among subjects with active coccidioidomycosis.

Influence of host genetics on the severity of coccidioidomycosis

Coccidioidomycosis, a mild flulike illness in approximately 40% of infected persons, progresses to severe pulmonary or disseminated disease in 1% to 10% of symptomatic cases. We examined host genetic influences on disease severity among class II HLA loci and the ABO blood group. Participants included African-American, Caucasian, and Hispanic persons with mild or severe disseminated coccidioidomycosis from Kern County, California. Among Hispanics, predisposition to symptomatic disease and severe disseminated disease is associated with blood types A and B, respectively. The HLA class II DRB1*1301 allele marks a pre-disposition to severe disseminated disease in each of the three groups. Reduced risk for severe disease is associated with DRB1*0301-DQB1*0201 among Caucasians and Hispanics and with DRB1*1501-DQB1*0602 among African-Americans. These data support the hypothesis that host genes, in particular HLA class II and the ABO blood group, influence susceptibility to severe coccidioidomycosis.

Intracranial fungal granuloma

BACKGROUND

Intracranial fungal granulomas are uncommon and their pathogenesis, clinical picture, and effectiveness of therapy remains unclear.

METHODS

Thirty-two cases were studied retrospectively in two groups: (1) Rhinocerebral group (22 cases) had a chronic paranasal sinus (PNS) disease with secondary involvement of skull base, cranial nerves, and/or brain. The granulomas were adherent to dura, firm, avascular, and tough, requiring a knife to cut. (2) Primary intracranial group (10 cases) had no detectable PNS lesion at initial presentation. The granulomas were soft, suckable, and contained pus or necrotic material.

RESULTS

Postoperative and overall mortality were 37.5% and 50%, respectively. Meningoencephalitis was the most common cause of death. Altered sensorium, pus in the granuloma, and/or severe brain edema were poor prognostic factors. All survivors except four have symptomatic residual or recurrent lesions.

CONCLUSION

Early diagnosis with MRI or stereotactic biopsy, radical surgery, and high dose and chronic suppressive chemotherapy may improve overall results in these cases.

Intracranial mycotic infections in neurosurgical practice

Intracranial mycotic infections requiring neurosurgical intervention are being diagnosed more frequently. This study is a review of 17 cases of intracranial mycotic infections that were treated in a neurosurgical unit in Saudi Arabia over an 8-year period. A primary focus of infection was identified in 41% of patients while 18% of patients had a predisposing factor. Forty-seven percent of patients presented with a brain abscess (solitary 29%, multiple 18%) while 35% had a granuloma. 18% meningitis and ventriculitis and 12% hydrocephalus. The Aspergillus species and Ramichloridium machenziei were the commonest pathogens. Following the appropriate surgical and antimicrobial treatment, the mortality rate was 41% and there was evidence of residual disease at follow-up in 18%. The reason for a fatal outcome was failure to consider a fungal aetiology and to obtain a tissue diagnosis early-because of late referral (2 cases), as well as failure to respond to antimycotic therapy (4 cases) and rupture of the internal carotid artery due to Aspergillus arteritis (one case). It is concluded that an early tissue diagnosis is crucial in the management of intracranial mycotic infection so that the appropriate surgical and antimycotic treatment can be started early.

Fluconazole in the treatment of chronic pulmonary and nonmeningeal disseminated coccidioidomycosis. NIAID Mycoses Study Group

PURPOSE

To determine the efficacy and safety of fluconazole as treatment for coccidioidomycosis.

PATIENTS AND METHODS

This was a multicenter, open-label, single-arm study. Of 78 patients enrolled, 22 had soft-tissue, 42 had chronic pulmonary, and 14 had skeletal coccidioidomycosis. Forty-nine had at least one concomitant disease, 7 of whom had HIV infection. Patients were given oral fluconazole 200 mg/d. Nonresponders were increased to 400 mg/d. Treatment courses were long: a mean of 323 +/- 230 days at 200 mg and 433 +/- 178 days at 400 mg. Predefined assessment of disease-related abnormalities was performed at the time of enrollment and repeated at least every 4 months. A satisfactory response was defined as any reduction of baseline abnormality by month 4 and at least 51% reduction by month 8.

RESULTS

Among 75 evaluable patients, a satisfactory response was observed in 12 (86%) of the 14 patients with skeletal, 22 (55%) of the 40 patients with chronic pulmonary, and 16 (76%) of the 21 patients with soft-tissue disease. Five patients (7%) required modification of treatment due to toxicity. Forty-one patients who responded were followed off drug. Fifteen (37%) of them experienced reactivation of infection.

CONCLUSION

Fluconazole 200 or 400 mg/d is well tolerated and a moderately effective treatment for chronic pulmonary or nonmeningeal disseminated coccidioidomycosis. The relapse rate following therapy is high. Treatment trials with higher doses appear warranted. The relative efficacy of fluconazole versus other azoles or amphotericin B remains unknown.

Killing of Coccidioides immitis by human peripheral blood mononuclear cells

The ability of human peripheral blood mononuclear cells (MNL) obtained from healthy donors to kill the fungus Coccidioides immitis was examined in vitro with an assay that uses a single fungal particle per well. MNL killed 25.0% +/- 3.5% of a coccidioidal arthroconidial target, compared with the 4.7% +/- 2.9% killed by polymorphonuclear leukocytes obtained from the same donors (P = 0.012). Arthroconidial killing by MNL was not dependent on donor delayed dermal hypersensitivity to spherulin. Killing of another fungal target, Candida glabrata, was not significantly different between MNL and polymorphonuclear leukocytes (P = 0.783). Depletion of monocytes from MNL with Sephadex G-10 resulted in a significant reduction in arthroconidial killing (21.4% +/- 13.6% versus 2.4% +/- 3.4%; P = 0.025), while enrichment of monocytes by Percoll density gradient centrifugation or plastic adherence resulted in significantly increased arthroconidial killing compared with that by MNL (P = 0.005 and 0.001, respectively). Killing of 96-h spherules by MNL was 7.3% +/- 3.1%, significantly less than the 21.4% +/- 2.8% killing of arthroconidia in the same experiments (P = 0.016). Incubation of MNL with human recombinant gamma interferon or tumor necrosis factor alpha did not result in increased MNL killing of coccidioidal arthroconidia under various conditions. These results suggest that MNL have an inherent ability to kill coccidioidal arthroconidia in vitro which is not dependent on prior host exposure to C. immitis. This activity appears to reside in peripheral blood monocytes.

Experimental coccidioidomycosis in the immunosuppressed rat

C. immitis inoculated rats are known to develop infection restricted to lung whereas cyclophosphamide (CY) treatment leads to widespread dissemination with considerable mortality. In this study, an attempt was made to elucidate the mechanisms involved in such behaviour. With this aim, spleen cells were transferred from infected CY-treated to infected untreated rats, achieving significant specific inhibition in footpad swelling to coccidioidin in recipients, attributable to a suppressor T cell subpopulation induced by greater fungal antigen concentration arising from widespread C. immitis dissemination in immunosuppressed animals. NK activity proved similar regardless of CY treatment. Lastly, chronically infected rats presented increased colony forming units count after several weekly doses of CY, as happens in immunosuppressed patients harbouring a previous infection.

Extraction of serologic and delayed hypersensitivity antigens from spherules of Coccidioides immitis

We have used an aqueous toluene extraction procedure to obtain antigens from mature spherules of Coccidioides immitis. This extract contained many antigens as determined by immunoblotting and two-dimensional immunoelectrophoretic studies. These included antigens with specificity for tube precipitin-type antibodies having molecular weights greater than or equal to 100 KDa. The extract also displayed lymphocyte-transforming activity when tested on human peripheral blood mononuclear leukocytes from donors who react to coccidioidal skin tests but elicited no such stimulation of cells from persons whose coccidioidal skin tests were nonreactive. At high concentrations of the extract, lymphocyte transformation did not occur, a finding that could not be explained by nonspecific toxicity. When gel filtration was employed to separate antigens by size, tube precipitin-like activity and specific coccidioidal delayed-type hypersensitivity displayed overlap, although only the latter activity was apparent in lower molecular weight pools.

Suppression of T-lymphocyte response by Coccidioides immitis antigen

Intravenous injection of BALB/c mice with coccidioidin or an alkali-soluble cell wall extract of Coccidioides immitis mycelia resulted in the induction of a splenic cell population(s) that suppressed delayed-type hypersensitivity response to coccidioidal antigen. To determine whether the levels of C. immitis antigen produced during the course of active coccidioidal disease might also cause suppression of T-lymphocyte response, BALB/c mice were infected by intranasal instillation of arthroconidia, and 2 weeks later, their sera were evaluated for suppression of T-lymphocyte response in syngeneic recipients. Intravenous transfer of sera, which were shown to contain high levels of coccidioidal antigen by an enzyme-linked immunoadsorbent assay, suppressed the delayed-type hypersensitivity response of recipients to immunization with coccidioidin. Solid-phase immunoadsorption of the sera with goat antibodies to C. immitis antigens removed the suppressive component(s). To determine whether the suppressive effect of circulating coccidioidal antigen(s) was associated with the activation of a splenic suppressor cell(s), as was observed in mice injected intravenously with coccidioidal antigen, spleen cell lysates were prepared from infected donors, and after filtration to remove viable fungi, the lysates were transferred to syngeneic mice. Recipients of lysates from infected but not noninfected donors were suppressed in their response to immunization with coccidioidin. Collectively, these results provide evidence that depressed T-cell responses observed in coccidioidomycosis are associated with, and may be attributable to, the activation of a suppressor cell or factor by circulating C. immitis antigens.

Clinical usefulness of lymphocyte transformation in patients with coccidioidomycosis

The development of an appropriate host defense in coccidioidomycosis is predicated on the presence of a positive delayed skin test reaction to coccidioidin. In severe and/or disseminated disease, coccidioidin reactions are routinely negative. By employing serial in vitro spherulin-induced lymphocyte blast transformation (LT) studies in a group of eight severely-ill coccidioidomycosis patients, prognostic clinical data were provided which could not have been obtained from their skin test status alone. Four of the eight demonstrated positive LT responses early in the course of their disease, quickly converted their skin tests to positive, and were cured of their disease. Two patients had negative LT responses until their skin test converted after several months of therapy. The final two have continued to demonstrate negative LT values despite several years of therapy and have experienced exacerbations of their disease when treatment was discontinued. The use of LT data in such patients can be very helpful in guiding therapeutic decisions in this difficult clinical problem.

Induction and expression of cell-mediated immune responses in inbred mice infected with Coccidioides immitis

Comparisons of the course of coccidioidomycosis in two strains of inbred mice established that BALB/c mice are significantly more susceptible to pulmonary infection with Coccidioides immitis than are DBA/2 mice. The susceptibility of BALB/c mice does not reside in their inability to mount a delayed-type hypersensitivity response to C. immitis antigen. That is, BALB/c mice manifested footpad hypersensitivity to coccidioidin early during the course of disease, to a level comparable to that of DBA/2 mice. In contrast to the more resistant DBA/2 mouse strain, however, BALB/c mice developed anergy by day 15 postinfection. Suppression of the delayed-type hypersensitivity response was not specific for C. immitis antigen, as evidenced by the finding that BALB/c mice immunized with mycobacterial purified protein derivative prior to infection with C. immitis were suppressed in their footpad response to mycobacterial antigen at day 15 postinfection. Taken together, these results establish that genetically determined susceptibility to this fungus is associated with an acquired suppression of cell-mediated immune reactivity.

Serum-mediated suppression of lymphocyte transformation responses in coccidioidomycosis

Lymphocyte transformation (LT) responses to coccidioidin (CDN) and spherulin were suppressed in 11 (73%) of 15 patients with active coccidioidomycosis when their mononuclear cells were assayed in autologous serum as compared to serum from healthy, CDN skin test-positive subjects. Suppressed LT responses were specific for Coccidioides immitis antigens in 7 (64%) of the 11 patients. Immunoaffinity chromatography of patient sera with Staphylococcus protein A adsorbed the suppressor component(s) and thereby established that suppression was attributed to immunoglobulin G, either alone or complexed with antigen. The possibility that suppression was mediated by immune complexes was examined by adding complexes formed in vivo or in vitro to mononuclear cell cultures of healthy CDN-reactive persons before LT assays. Although complexes prepared in this manner were reactive in an enzyme-linked immunosorbent assay designed to detect Coccidioides antigen-specific immune complexes, no suppression of LT responses was observed. We conclude that serum-mediated suppression of LT responses in coccidioidomycosis is attributed to monomeric and not immune-complexed immunoglobulin G antibody.

Experimental coccidioidomycosis: effects of cyclophosphamide in immunologic responses

Rats were infected with Coccidioides immitis and injected with cyclophosphamide three days pre or post infection. Administration of the drug before the infection caused enhancement of DTH response and decrease of the colony forming units (CFU). Conversely, injection of the drug three days post infection produced contrary effects, indicating that a normal T-cell function is essential as a defense mechanism in C. immitis infection.

Surgical treatment for fungal infections in the central nervous system

The hospital records of 78 patients who underwent surgical therapy for fungal infections of the central nervous system (CNS) between 1964 and 1984 are summarized. Nine different fungal types were identified, but Coccidioides immitis and Cryptococcus neoformans accounted for most (67.1%) of the infections. A variety of clinical syndromes were seen, including chronic basal meningitis (45 patients), intracranial mass lesions (12 patients), and communicating hydrocephalus (six patients). Thirteen patients had rhinocerebral forms of fungal infection, and two presented with spinal involvement. Delays in diagnosis were frequent and ranged from 2 months to 11 years. In 31 patients the CNS lesion was the first indication of a fungal infection, and lesion biopsy or cerebrospinal fluid (CSF) examination confirmed the diagnosis. A total of 144 surgical procedures were carried out, including lesion biopsy or excision in 13 patients, primary CSF shunting in 22, and placement of an Ommaya reservoir for administration of intraventricular or intracisternal antifungal agents in 48. All patients received parenteral and, in some cases, intrathecal or oral antifungal chemotherapy in addition to surgical therapy. Overall mortality was 43.6% (34 deaths). With prompt diagnosis and treatment, the mortality rate was 39% whereas, when appropriate treatment was delayed, the mortality rate was 64%. An additional 14 surviving patients (17.9%) exhibited permanent morbidity due to neurological deficits, seizure disorders, or renal toxicity following treatment with amphotericin B. The combined mortality and morbidity rate was 62.8%. Clinical symptoms were resolved completely in 29 patients, although in 10 evidence of disease persisted and chemotherapy was continued. Fungal infections of the CNS are being recognized with increased frequency. It is suggested that a high index of suspicion, aggressive attempts to obtain a diagnosis, and early and vigorous therapy may reduce the unfortunate outcome seen in a relatively high proportion of patients with CNS fungal infections.

Coccidioidomycosis in acquired immune deficiency syndrome. Depressed humoral as well as cellular immunity

Progressive pulmonary coccidioidomycosis has not been previously reported in the setting of acquired immune deficiency syndrome (AIDS). A patient with AIDS, progressive pulmonary coccidioidomycosis, Pneumocystis carinii pneumonia, and disseminated cytomegalovirus is described. Diagnosis of these opportunistic pathogens was made by bronchoalveolar lavage and transbronchial lung biopsy. Results of traditional complement fixation serologic testing for cytomegalovirus were negative; however, the more sensitive enzyme-linked immunosorbent assay did indicate infection. Coccidioidal complement fixation tests, precipitin tests, counter-immunoelectrophoresis, and immunodiffusion tests demonstrated negative findings. These results provide additional evidence that some patients with AIDS have defects in humoral as well as cellular immunity.

An evaluation of reactivity to Coccidioides immitis skin tests in subjects with diabetes mellitus

Persons with diabetes mellitus have an increased incidence of progression and dissemination of infection with Coccidioides immitis. This increased incidence of infection suggests that diabetic subjects may have a defect in cell-mediated immunity (CMI) to coccidioidomycosis. Skin test response is also determined by CMI. A negative coccidioidin skin test is often seen with serious infections and is used as evidence that therapy should be initiated. To evaluate CMI in diabetic subjects we investigated the reactivity to coccidioidin and spherulin of 54 diabetic and 56 nondiabetic subjects. There was no difference between the two groups in the prevalence or size of positive reactions to coccidioidin. These results support the continued use of coccidioidin to evaluate the need for therapy in diabetic subjects who have coccidioidomycosis. Spherulin antigen, however, produced fewer positive reactions in the diabetic group. This decreased spherulin reactivity may be associated with the increased incidence of severe coccidioidal infection in diabetic subjects.

Specificity of immunoglobulin E in coccidioidomycosis and correlation with disease involvement

Serum immunoglobulin E (IgE) antibodies were quantitated in 26 patients with active pulmonary coccidioidomycosis, 59 patients with active disseminated disease, 12 patients in clinical remission, and 91 healthy subjects. Significant differences were obtained in IgE serum levels of patients with active disease versus healthy subjects (P less than 0.0001). Patients with pulmonary coccidioidomycosis did not differ in their IgE levels when compared with patients with disseminated disease. However, serum IgE levels were significantly increased in patients with disease involving two or more organ systems when compared with patients with pulmonary disease or extrapulmonary disease involving a single organ system (P less than 0.02). Total serum IgE correlated with anti-Coccidioides IgE (P less than 0.001), but with only six exceptions, patients with anti-Coccidioides IgE also exhibited IgE antibodies to 1 or more of 12 common allergens. The correlation between hyperproduction of IgE and disease severity coupled with the depressed cell-mediated immune status of patients with this disease suggests a defect(s) in the T-lymphocyte population which functions to regulate IgE synthesis.

Disseminated coccidioidomycosis in children

In an effort to define the importance of extrapulmonary coccidioidomycosis in the pediatric age group, we have studied 14 cases and reviewed the literature. The available data suggest that children are as susceptible to dissemination as are adults. Most children with disseminated coccidioidomycosis have evidence, either by history or chest radiographs, of preceding or concurrent pulmonary infection. The most common sites of dissemination are skin, subcutaneous tissue, bone, and meninges. Coccidioides immitis may be detected in tissues or body secretions by microscopic examination or by appropriate culture. Serologic tests are also useful in making the diagnosis and in following the course of the infection. Skin tests are often negative. Infection is progressive in 60% without antifungal therapy. Coccidioidomycosis of bone, skin, or subcutaneous tissue can be managed effectively with combined surgical and antifungal therapy. Meningitis is much more difficult to treat and is fatal in 50% of cases even when treated with amphotericin B.

Course of coccidioidomycosis in intratracheally infected guinea pigs

Two hundred Hartley-inbred guinea pigs were infected intratracheally with 50 viable arthrospores of Coccidioides immitis. At weeks 1 through 10 postinfection, groups of 20 guinea pigs were assayed for skin test, macrophage migration inhibitory factor (MIF), and lymphocyte transformation (LT) responses to coccidioidin. Forty-eight hours after skin testing and just before MIF and LT assays, blood was obtained for complement-fixing (CF) antibody titers and the animals were autopsied to assess the extent of fungal dissemination. Immunological assays established that skin tests and MIF responses converted within 3 weeks of infection. LT responses were not demonstrable until week 5. Dissemination of C. immitis to the liver or spleen was an early event, with 21% of guinea pigs positive by week 2 and 70% positive by week 5. CF antibody titers were demonstrable at week 5, increased logarithmically through week 7, then increased at a slower rate thereafter. Concomitant with the decreased rate of antibody production, guinea pigs began to clear C. immitis from their extrapulmonary tissues. Skin test responses peaked at 6 weeks postinfection when CF antibody titers were less than or equal to 1:16 and then plateaued with increased CF titers. Although this overall immunological profile is consistent with the disease in humans, there was not a direct correlation between CF antibody titer and dissemination to the liver or spleen, nor was there an inverse correlation between CF antibody titers and skin test or MIF responses. Rather, CF antibody titers and cell-mediated immune responses were equally demonstrable in guinea pigs with disseminated or nondisseminated disease.

Circulating immune complexes in coccidioidomycosis. Detection and characterization

Estrogen-receptor-positive breast tumors are treated with anti-estrogen (AE) therapies but frequently develop resistance. Cancer stem cells (CSCs) with high aldehyde dehydrogenase activity (ALDH⁺ cells) are enriched following AE treatment. Here, we show that the interleukin-1β (IL-1β) signaling pathway is activated in ALDH⁺ cells, and data from single cells reveals that AE treatment selects for IL-1 receptor (IL1R1)-expressing ALDH⁺ cells. Importantly, CSC activity is reduced by an IL1R1 inhibitor in AE-resistant models. Moreover, IL1R1 expression is increased in the tumors of patients treated with AE therapy and predicts treatment failure. Single-cell gene expression analysis revealed that at least two subpopulations exist within the ALDH⁺ population, one proliferative and one quiescent. Following AE therapy the quiescent population is expanded, which suggests CSC dormancy as an adaptive strategy that facilitates treatment resistance. Targeting of ALDH⁺IL1R1⁺ cells merits testing as a strategy to combat AE resistance in patients with residual disease.

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Anti-estrogen-resistant ALDH⁺ cells have increased CSC activity in ER⁺ tumors

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The IL1R1-expressing ALDH⁺ CSC population expands after anti-estrogen treatment

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IL1R1 expression predicts anti-estrogen treatment failure

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Targeting of ALDH⁺IL1R1⁺ cells reverses anti-estrogen resistance

Circulating immune complexes in coccidioidomycosis. Detection and characterization

Sera of 22 patients with active and 13 with inactive coccidioidomycosis, as well as 15 healthy subjects who were skin-test positive to coccidioidin and 39 healthy subjects who were coccidioidin skin-test negative, were assayed for immune complexes. Circulating immune complexes were measured by the Clq-binding assay, the Clq-solid phase assay, the monoclonal rheumatoid factor inhibition assay, and the monoclonal rheumatoid factor solid phase assay. An increased concentration of circulating immune complexes was detected in 73% of those with active disease by at least one assay compared with 13% of the healthy controls. Significantly increased levels of immune complexes were detected in sera of patients with active coccidioidomycosis by the Clq-binding assay (P < 0.001), the Clq-solid phase assay (P < 0.001), the monoclonal rheumatoid factor inhibition assay (P < 0.005), and the monoclonal rheumatoid solid phase assay (P < 0.05) compared with the results obtained in the 54 healthy subjects. In contrast, those with inactive disease did not show significantly increased concentrations of circulating immune complexes. Sucrose density gradient ultracentrifugation of patients' sera established that the immune complexes were of intermediate size, sedimenting between the 6.6S and 19S markers. Immune complexes were shown to contain both coccidioidin antigen and anticoccidioidin antibody. In addition, a radioimmunoassay was developed to quantitate coccidioidin antigen-containing immune complexes. The latter assay proved highly sensitive in detecting immune complexes in patients with active coccidioidomycosis.

Lymphocyte function in relapsed pulmonary blastomycosis

Lymphocyte function was studied in two patients with multiple relapses of pulmonary blastomycosis following antifungal therapy. Neither patient was anergic to routine delayed hypersensitivity skin testing with common antigens. Both had normal in vitro lymphocyte transformation responses to standard mitogens and common microbial antigens. The ability of lymphocytes from the two patients to respond to antigens of the infecting organism was evaluated using a yeast phase Blastomyces dermatitidis extract in tests of in vitro lymphocyte function. Both patients demonstrated positive responses to this extract in standard assays of two in vitro parameters of lymphocyte function, lymphocyte transformation, and lymphokine production. Therefore if an immunologic defect is responsible for the repeated relapses of treated pulmonary blastomycosis in these two patients, it apparently is not one of deficient lymphocyte responsiveness against the infecting organism, as has been found using similar techniques in patients with disseminated deep infections caused by other fungal organisms.

Withdrawal of immunosuppresive agents in the treatment of disseminated coccidioidomycosis

Disseminated coccidioidomycosis is a systemic fungal infection that causes high mortality in the renal transplatn patient. Cell-mediated immunity, which appears to be the relevant host defense mechanism, is impaired by the immunosupressive agents used to prevent allograft rejection. In the case presented, immunosuppressive therapy was stopped as an adjunct to treatment of this infection. The patient has shown evidence of improvement, and his allograft has continued to function nine months after the withdrawal of immunosuppressive therapy and 18 months after the diagnosis. In vitro lymphocyte function studies indicate that the impairment in cell-mediated immunity detected prior to withdrawal of immunosuppressive therapy has persisted, probably accounting for allograft survival. Withdrawal of immunosuppressive therapy may prolong survival in renal transplant patients with disseminated coccidioidomycosis. Additionally, depression in cell-mediated immunity associated with the fungal infection itself may be sufficient to prevent allograft rejection in these patients.

In vitro lymphocyte responses of coccidioidin skin test-positive and -negative persons to coccidioidin, spherulin, and a coccidioides cell wall antigen

The biological activity of C-ASWS, an alkali-soluble, water-soluble cell wall antigen isolated from mycelial-phase cells of Coccidioides immitis, was compared with that of a commercial coccidioidin (CDN; Cutter Laboratories); CDN-TS, a toluene-induced lysate of mycelial-phase cells; and spherulin, a spherule-derived extract of C. immitis. Lymphocytes obtained from healthy CDN skin test-positive donors (group I), healthy skin test-negative donors (group II), and patients with active coccidioidomycosis (group III) were assayed for lymphocyte transformation and production of macrophage inhibitory factor in response to the Coccidioides antigens. C-ASWS, CDN CDN-TS, and spherulin were each effective in eliciting blastogenic responses in lymphocytes of group I subjects. However, only C-ASWS and CDN-TS were effective in eliciting macrophage inhibitory factor production. The responses of group III subjects (patients) were depressed and, in most instances, were indistinguishable from those obtained in lymphocytes of group II subjects.

Studies on mediators of cellular immunity in experimental coccidioidomycosis

The time course of delayed hypersensitivity (DH) to spherulin was regularly detected 3 days before and up to 140 days after sensitization of guniea pigs by repeated testing with the in vitro macrophage migration inhibition method. The properties of mycelial and spherule-derived coccidioidins in dermal sensitivity reactions were studied with regard to infected or vaccinated with Coccidioides immitis guinea pigs. The mediators for cellular immunity such as promotion of phagocytosis, skin reactive and fungicidal factors can be found in the supernatant of lymphocyte cultures from vaccinated or infected animals with mild disease in much greater quantity than those in control or infected with severe disease. Cell-mediated immunity to Coccidioides immitis involves both macrophages and lymphocytes, but the latter was the most likely mediator of the intracellular killing observedl

Dinitrochlorobenzene responsivity in disseminated coccidioidomycosis: an inverse correlation with complement-fixing antibody titers

The immunologic status of 25 patients with disseminated coccidiodomycosis was evaluated by serum anticoccidioidin complement-fixing antibody levels, coccidiodin skin tests, and dinitrochlorobenzene (DNCB) sensitization. In the 10 patients who had disseminated disease and a complement-fixing titer of 1:32 or less, responses to DNCB were similar to those of 20 controls. In the 15 patients with disseminated disease and a complement-fixing titer of 1:64 or more, responses to DNCB were statistically significantly diminished compared to controls (p = 0.002). Since the complement-fixing titer is associated with extent of dissemination, these results signify a relationship between diminished DNCB responses and extensive dissemination. Of the several hypotheses which might explain this relationship, we find the most attractive is that of a nonspecific deficiency of cell-mediated immunity developing secondarily to extensive disseminated disease.