Pulmonary mycotic infections; allergic and immunologic factors

The mechanisms of immunity and allergy, at play in every infectious disease, must be comprehended before the pathogenesis of an infection can be appreciated.Immunity, allergy and serology are concerned with specific antigen-antibody reactions. In immunity the principal concern is with the final disposition of antigen (agglutination, lysis, and phagocytosis). In allergy attention is focused upon tissue damage resulting from antigen-antibody union. In serology interest is devoted to the presence of antibody as evaluated by certain visible in vitro reactions-precipitin, agglutination, opsonization and complement fixation tests. There are two types of allergic reaction-the immediate or anaphylactic type and the delayed type or the allergic disease of infection. Neither kind takes part in the mechanism of immunity. At this time the allergic antibody and the immune antibody must be considered as two different and distinct antibodies. Skin and serologic tests are important diagnostic aids in certain pulmonary mycotic infections-for example, coccidioidomycosis, blastomycosis, histoplasmosis and moniliasis. Clinical expressions of allergy may appear in coccidioidomycosis, histoplasmosis and moniliasis. Pulmonary mycoses are divided into three groups, that is, the endogenous mycoses (actinomycosis, moniliasis, geotrichosis), the endogenous-exogenous mycoses (cryptococcosis, aspergillosis, mucormycosis) and the exogenous mycoses (nocardiosis, coccidioidomycosis, histoplasmosis, North American blastomycosis). The diagnosis and treatment of the important mycotic infections that invade lung tissue are discussed.     

Histoplasmosis in Africa: Current perspectives,knowledge gaps,and research priorities

BackgroundHistoplasmosis is a chronic granulomatous disease caused by the thermally dimorphic fungus Histoplasma capsulatum. The 2 variants Histoplasma capsulatum var. capsulatum (Hcc) and Histoplasma capsulatum var. duboisii (Hcd) causes infection in humans and commonly termed classical or American histoplasmosis and African histoplasmosis, respectively. Histoplasma capsulatum var. farciminosum (Hcf) affects equines. In recent times, there have been heightened sensitization on fungal infections such as histoplasmosis in Africa, aimed at improving awareness among relevant stakeholders, particularly healthcare workers. This effort is expected to be paralleled with increased detection of both classical and African histoplasmosis, which has remained underdiagnosed over the years. In this narrative review, we describe the current perspectives of histoplasmosis in Africa, identify knowledge gaps, and suggest research priorities.MethodsA PubMed, Google Scholar, and Africa Journal Online (AJOL) literature search was conducted for studies on histoplasmosis in Africa between 2000 and 2020. Histoplasmosis essays in medical mycology textbooks were also consulted. This narrative review was prepared from the data gathered.FindingsIn the past 2 decades, histoplasmosis in general has seen a relative increase in case detection in some Africa countries, probably attributable to the gradually increasing medical mycology advocacy efforts in Africa. Histoplasmosis cases are dominated by African histoplasmosis mostly in Western and Central Africa, while classical histoplasmosis is more common in Southern and Northern Africa. Although both classical and African histoplasmosis are common in Africa, the latter is more restricted to Africa, and cases outside the continent usually have a travel history to the continent. Despite the clinical and laboratory difference between African histoplasmosis and classical histoplasmosis, it is not straightforward to distinguish them. The typical manifestation of African histoplasmosis is the appearance of lesions affecting the skin, bones, and lymph nodes and unusually linked to human immunodeficiency virus (HIV)/AIDS. By contrast, classical histoplasmosis mostly affects the lungs and is often associated with immunosuppression, mainly HIV/AIDS. The present perspectives of histoplasmosis in Africa highlight unclear details on the true burden, strain diversity, infection route and genetic basis of African histoplasmosis, availability of specie-specific diagnostic tools, and compliance with recommended antifungal therapy. These knowledge gaps represent research questions that require scientific exploration.ConclusionsDespite a subtle increase in identifying histoplasmosis cases in Africa, it remains underdiagnosed and neglected in some parts of the continent. Increasing awareness and training among healthcare workers, bridging diagnostic and therapeutic gaps, and encouraging more research in Africa are crucial to improve the current perspectives of histoplasmosis in Africa.     

宏基因组学诊断播散型组织胞浆菌病1例

播散型组织胞浆菌病是一种进行性肺外疾病好发于免疫缺陷者。该病诊断的应结合组织胞浆菌病的高危因素(免疫抑制剂、高龄、高风险的暴露等)与临床表现。本文报道一例播散型组织胞浆菌病但免疫功能健全的病例,其表现为亚急性起病,后期病程进展迅速,骨髓涂片及宏基因测序诊断为播散型组织胞浆菌病。予以两性霉素B去氧胆酸盐及伊曲康唑治疗后病情明显好转。     

Serology of paracoccidioidomycosis

This review provides the background for understanding the role of a battery of diagnostic methods in paracoccidioidomycosis (PCM). This systemic mycosis is a disease endemic in many regions of Latin America, with sporadic cases also occurring throughout the world (mycosis of importation). Although excellent laboratory methods for diagnosis are available, there are deficiencies that must be met by continued research. Understanding the uses and limitations of a battery of laboratory methods is essential to diagnose PCM. Clinicians and laboratory directors must be familiar with the uses and limitations of a battery of serologic and mycological tests to accurately diagnose of PCM. Antibody and antigen detections are valuable adjuncts to histopathology and culture. More recently, the gp43 and gp70 antigen detection assay have improved the methodology of diagnosis of this mycosis, which improves reproducibility and facilitates monitoring antigen clearance during antifungal treatment. Furthermore, detection of antigen in cerebrospinal fluid and in bronchoalveolar lavage fluid increases the sensitivity for diagnosis of PCM in central nervous system and in pulmonary infections, respectively.     

Histoplasmosis and Thrombocytopenic Purpura: Transmission by Renal Homotransplantation

Two patients with disseminated histoplasmosis are reported. One patient presented with severe thrombocytopenic purpura and splenomegaly. Histoplasmin skin test, blood and bone marrow cultures and smears, sputum cultures, and chest radiographs were negative for Histoplasma capsulatum. She died on the sixth hospital day from a massive intracerebral hemorrhage. Cardiorespiratory function was maintained until one kidney was removed for homotransplantation. The second patient, with chronic glomerulonephritis and uremia, received the renal homograft from the first patient. Initial signs of homograft rejection developed five days postoperatively. Diffuse thrombocytopenic purpura occurred shortly thereafter. Spores of Histoplasma capsulatum were observed in blood smears, in leukocyte concentrates, and in five-day leukocyte cultures from the blood obtained prior to death. Disseminated histoplasmosis was found in both patients at autopsy. The severe platelet deficit in both cases suggests that systemic histoplasmosis should be considered as a cause of thrombocytopenic purpura.To our knowledge, this is the first reported instance of direct transmission of Histoplasma capsulatum, and must be considered a hazard in homotransplantation.In vitro leukocyte cultures as a method for early diagnosis of certain disseminated fungous infections needs further investigation.     

Histoplasma capsulatum in the environment of sporadic histoplasmosis cases

Conclusions 1. Acute pulmonary histoplasmosis in adults is demonstrated to be associated with exogenous sources of infection in one-half of a series of cases. 2. No exogenous sources of infection were found in chronic pulmonary histoplasmosis in adults by methods comparable to those used in acute pulmonary histoplasmosis. 3. The significance of these findings for the pathogenesis of the three clinical forms of histoplasmosis is discussed. 4. In acute pulmonary histoplasmosis in adults, the isolation ofH. capsulatum from the environment at sites of exposure aided in specific diagnosis.Two acute pulmonary histoplasmosis cases were reported previously (2–3).     

Ocular Histoplasmosis

Case reports of three residents of Ontario with clinical histoplasmic chorioretinitis are presented. The diagnosis was made on the basis of the clinical appearance, the presence of calcified lesions in the chest, a negative skin test to tuberculin, and a positive skin test to toxoplasmin. All patients were treated with intravenous amphotericin B. Except for transitory elevation of blood urea nitrogen, there were no serious complications from the drug and in all cases the lesions in the eyes were improved. Histologic or cultural proof of the presence of fungus in the eye is not available, but clinical and laboratory findings can combine to point to the diagnosis of histoplasmosis. In such cases, since vision is at stake, treatment with amphotericin B should be considered.     

Commercially available histoplasmin sensitized latex particles in an agglutination test for histoplasmosis

Summary A commercial preparation of histoplasmin sensitized latex particles was tested in an agglutination test with sera from 50 culturally confirmed cases of histoplasmosis in varying stages of the infection. The reactions were superior to those obtained with collodion agglutination and complement fixation tests in which the antigen histoplasmin was also used. The latex agglutination test with the commercially available antigen is easy to do, and can be done in any laboratory equipped to carry out agglutination tests with the common bacterial antigens. It warrants more extensive trial in the general hospital laboratory as a screening test for histoplasmosis, especially the primary, pulmonary type.     

Feline Histoplasmosis in Brazil: Clinical and Laboratory Aspects and a Comparative Approach of Published Reports

The present study described clinical and epidemiological aspects of three cases of feline histoplasmosis and compared them to previously described cases. A detailed mycological identification and antifungal susceptibility profile of each isolate are presented. Secondarily, a serological survey for anti-Histoplasma antibodies was performed with domestic and wild cats. Diseased animals presented nodular to ulcerated skin lesions and respiratory disorders as main clinical signs. H. capsulatum var. capsulatum was isolated and the strains showed to be susceptible to antifungal drugs. Considering that feline histoplasmosis is uncommonly observed in veterinary clinics, diagnosis, and clinical management in endemic areas should be improved.     

Evaluation of a Microtiter Latex Agglutination Test for Histoplasmosis

Experiments were designed to evaluate a Microtiter latex agglutination (Micro-LA) test, as a serological aid in the diagnosis of histoplasmosis, and to compare this test with the conventional microtiter-complement fixation (CF) test for histoplasmosis. Sera tested were from cases of acute and chronic pulmonary and disseminated histoplasmosis, as well as from individuals not having histoplasmosis. Ninety-seven percent of the cases of acute pulmonary histoplasmosis had positive Micro-LA tests, whereas 91% had positive CF tests. Ninety-six percent of the patients having chronic pulmonary histoplasmosis showed positive Micro-LA tests and 91% had positive CF tests. In contrast, 64% of the cases of disseminated histoplasmosis had positive Micro-LA tests, whereas 82% had positive CF tests. None of these differences was statistically significant. Although there were no significant differences in complement fixing and agglutinating antibody cross-reactivity with Blastomyces antigens, more patients demonstrated CF titers than Micro-LA titers. Sera from patients with acute and chronic histoplasmosis showed higher Micro-LA titers than CF titers, whereas sera from cases of disseminated histoplasmosis showed higher CF titers. Histoplasmin skin testing has less of a boosting effect on agglutinating antibodies than on CF antibodies to histoplasmin. Anticomplementary sera can be used in the Micro-LA test. This test is simple to perform, and results can be obtained in 2 to 4 hr.     

Histoplasmosis as cause of penile ulcer in acquired immune deficiency syndrome (AIDS): three case reports

Background Histoplasma capsulatum is the causative agent of American histoplasmosis. The relationship between disseminated histoplasmosis and AIDS has been well established. Widespread hematogenous dissemination of Histoplasma capsulatum in HIV positive patients can cause a plethora of clinical manifestations; virtually any organic system can be affected. However, genital ulceration by H. capsulatum in patients with AIDS is a real challenge during investigation of the infection due to the great variety of differential diagnoses that are involved. Method The diagnosis was performed by histopathologic study; H. capsulatum was detected by silver staining (Grocott staining) and confirmed by immunocytochemistry. Results We report three cases of histoplasmosis in patients with AIDS, in which we observed genital ulcers, an unusual form of presentation of this disease. In one of these cases, the treatment resulted in total cure. Conclusion The cases reported herein are to illustrate the plurality of pathologies and clinical manifestations, which may affect immunocompromised patients. The correct diagnosis of fungal diseases in these patients following well established treatment will improve the prognosis.     

Cutaneous and Bone Marrow Histoplasmosis After 18 Years of Renal Allograft Transplant

The frequency of histoplasmosis among solid organ transplant (SOT) recipients appears to be low where there are only a few case series, mostly among renal and liver transplant recipients. Herein we report a case of a 44-year-old woman who underwent a living-related renal transplant 18 years prior to evaluation, developed a nodule after followed by ulceration upon her posterior right leg and a second one upon her left leg 3 months and 2 months before her hospitalisation, respectively. The biopsy of lesion revealed the presence of Histoplasma spp. Bone marrow aspiration was performed and also revealed the same organism. She had initially received itraconazole without improvement of lesions, while a new lesion appeared on her left arm. Healing of all lesions could be observed after 40 days of liposomal amphotericin B when she was submitted to skin grafts on the legs and a surgical treatment on the arms, and the myelosuppression improved simultaneously. Histoplasmosis seems to be very uncommon among patients who underwent to organ solid transplantation. Most cases occur within 12–18 months after transplantation, although unusual cases have been presented many years post-transplant. There are cases reported in the literature, occurring from 84 days to 18 years after organ transplantation, but without cutaneous involvement. Our patient developed lesions on limbs and myelosuppression after 18 years of chronic immunosuppression medication. This case suggests that besides cutaneous histoplasmosis is an uncommon infection following iatrogenic immunosuppression and even rarer over a long period after the transplantation. Clinicians who care SOT recipient patients must bear in mind histoplasmosis infection as differential diagnosis in any case of cutaneous injury with prolonged fever and try to use as many tools as possible to make the diagnosis, once this disease presents a good prognosis if it is diagnosed and treated promptly.     

Gastrointestinal disseminated histoplasmosis in HIV-infected patients: A descriptive and comparative study

Disseminated histoplasmosis is one the main AIDS-defining opportunistic infections in HIV-infected patients, notably in Latin America. The non-specific and proteiform clinical presentation leads to diagnostic delays that may lead to fatal outcomes. This retrospective multicentric study aimed to describe the frequency and manifestations of gastrointestinal histoplasmosis in French Guiana, and to compare patients with disseminated histoplasmosis with or without gastrointestinal involvement.Between January 1, 1981 and October 1, 2014 co-infections with HIV and histoplasmosis were enrolled. Inclusion criteria were: age >18 years, confirmed HIV infection; first proven episode of histoplasmosis.Among 349 cases of disseminated histoplasmosis, 245 (70%) had a gastrointestinal presentation. Half of patients with gastrointestinal signs had abdominal pain or diarrhea, mostly watery. Half of patients with abdominal pain had diarrhea (63/124) and half of those with diarrhea (63/123) had abdominal pain. A significant proportion of patients also had hepatomegaly and, to a lesser degree, splenomegaly. After adjusting for potential confounding, the presence of lymphadenopathies >2cm (AOR = 0.2, IC95 = 0.04–0.7, P = 0.01), Haitian origin (AOR = 0.04, IC95 = 0.004–0.4, P = 0.006) were associated with a lower prevalence of gastrointestinal signs and positive gastrointestinal presence of H. capsulatum. Persons with a gastrointestinal H. capsulatum were more likely to have a decreased prothrombin time, lower ferritin, lower liver enzymes, and lower concentrations of LDH than those without gastrointestinal signs and symptoms. They also had a shorter interval between symptoms onset and diagnosis. Patients with a positive gastrointestinal identification of H. capsulatum were less likely to die at 1 month than those without a gastrointestinal presentation (respectively, 4.6% vs 18.5%, P = 0.01).Subacute or chronic gastrointestinal presentations are very frequent during disseminated histoplasmosis, they seem less severe, and should lead to suspect the diagnosis in endemic areas. There were populational or geographic differences in the frequency of gastrointestinal manifestations that could not be explained.     

HIV-Associated Histoplasmosis Early Mortality and Incidence Trends: From Neglect to Priority

Background

Histoplasmosis is an endemic fungal infection in French Guiana. It is the most common AIDS-defining illness and the leading cause of AIDS-related deaths. Diagnosis is difficult, but in the past 2 decades, it has improved in this French overseas territory which offers an interesting model of Amazonian pathogen ecology. The objectives of the present study were to describe the temporal trends of incidence and mortality indicators for HIV-associated histoplasmosis in French Guiana.

Methods

A retrospective study was conducted to describe early mortality rates observed in persons diagnosed with incident cases of HIV-associated Histoplasma capsulatum var. capsulatum histoplasmosis admitted in one of the three main hospitals in French Guiana between 1992 and 2011. Early mortality was defined by death occurring within 30 days after antifungal treatment initiation. Data were collected on standardized case report forms and analysed using standard statistical methods.

Results

There were 124 deaths (45.3%) and 46 early deaths (16.8%) among 274 patients. Three time periods of particular interest were identified: 1992–1997, 1998–2004 and 2005–2011. The two main temporal trends were: the proportion of early deaths among annual incident histoplasmosis cases significantly declined four fold (χ2, p<0.0001) and the number of annual incident histoplasmosis cases increased three fold between 1992–1997 and 1998–2004, and subsequently stabilized.

Conclusion

From an occasional exotic diagnosis, AIDS-related histoplasmosis became the top AIDS-defining event in French Guiana. This was accompanied by a spectacular decrease of early mortality related to histoplasmosis, consistent with North American reference center mortality rates. The present example testifies that rapid progress could be at reach if awareness increases and leads to clinical and laboratory capacity building in order to diagnose and treat this curable disease.     

Selection and optimization of PCR-based methods for the detection of Histoplasma capsulatum var. capsulatum

BackgroundCurrent methods for the laboratory diagnosis of histoplasmosis are problematic in terms of their sensitivity, specificity and runtime.ObjectivesThus, in this study, we sought to select and optimize methods for the detection of Histoplasma capsulatum var. capsulatum by polymerase chain reaction (PCR).MethodsThree DNA extraction methods and three PCR methods were evaluated. We optimised the concentration of the components of this PCR reaction and determined its sensitivity and specificity using blood samples to which H. capsulatum had been added.ResultsThe DNA extraction method that yielded the highest-quality DNA used silica membranes (DNeasy Blood &; Tissue Kit, Qiagen, Hilden, Germany), and the amplification method with the best detection capacity used a target gene encoding a 100-kDa protein. Our optimisation of the PCR conditions indicated that the reaction works over a significant range of component concentrations; in addition, it was able to detect H. capsulatum better than traditional culture techniques, with a detection limit of only 10 pg of DNA.ConclusionsIn our experimental conditions, the PCR method selected in this work (instead of nested-PCR) is a tool sensitive enough for the diagnosis of histoplasmosis.     

Advances in the serodiagnosis of blastomycosis

Blastomyces dermatitidis, the etiologic agent of blastomycosis, is endemic to certain areas of North America and other continents and can cause a variety of clinical manifestations that range from subclinical to life-threatening infections. Delineation of its ecology and epidemiology has been difficult because of the lack of rapid, sensitive, and specific noninvasive diagnostic tests. Despite efforts to develop such tests for clinical use, diagnosis of infection is still based on direct visualization of the organism in histopathologic or cytologic specimens and growth in the microbiologic laboratory. Serologic tests and skin testing have been hampered by low sensitivity and specificity caused by cross-reactivity with other endemic mycoses and are not commercially available. An antigen assay is now commercially available, but it also has significant cross-reactivity with other mycoses, especially histoplasmosis. The keys to diagnosis remain a high index of suspicion and knowledge of the disease’s varied clinical manifestations.     

Chronic pulmonary histoplasmosis in the State of Rio de Janeiro,Brazil

Three cases of chronic pulmonary histoplasmosis affecting aged patients with chronic obstructive pulmonary disease are reported. They had a history of recurrent episodes of respiratory infection and presented radiological lung lesions inducing a misdiagnosis of chronic pulmonary tuberculosis of the adults. The diagnosis of histoplasmosis, suggested by the immunodiffusion test and the detection of yeastlike cells in smeared and stained sputum, was confirmed by the isolation and identification of Histoplasma capsulatum var. capsulatum in selective media. The treatment was carried out with amphothericin B and ketoconazole or itraconazole. Clinical, radiologic, mycologic and serologic improvement was obtained in all the patients. However, relapses occurred within a period of 1 to 18 months after the interruption of the treatment. Mycological diagnosis and the difficulties observed in the tretament were discussed. In addition data on the epidemiology of histoplasmosis in the state of Rio de Janeiro, Brazil, were presented. This revised version was published online in June 2006 with corrections to the Cover Date.     

Histoplasmosis—A Review of Three Cases Studied in San Diego County

Three cases of histoplasmosis, a disease seldom reported in California, were diagnosed clinically by the authors in San Diego County. It is probable that there is a higher incidence of this disease in California than is at present recognized.Travel history, histoplasmin skin testing and serologic studies for mycotic infection are important in the diagnosis. Cultures of secretions and biopsy material are of great value if positive; but negative cultures (at least in non-endemic areas) do not rule out the disease. Travel and migration to and from endemic areas present opportunities for this disease to constitute a diagnostic problem far from the geographic area in which the disease was acquired.Although usually benign, histoplasmosis may be severe in the acute state, may disseminate or may be chronically active and progressive. Amphotericin B is the only effective chemotherapeutic agent and it is usually reserved for these forms of the disease.     

Histoplasmosis in Montreal During the Fall of 1963, with Observations on Erythema Multiforme

Although Montreal is in an endemic area, significant clinical histoplasmosis with systemic manifestations has been, until recently, infrequently diagnosed. However, since the autumn of 1963, 31 cases of clinically significant histoplasmosis have been seen by the authors. These were divided into two groups: (1) patients in whom the diagnosis was established on the basis of histological and/or cultural demonstration of the fungus; (2) patients in whom the diagnosis was based on a positive histoplasmin skin test, a complement fixation antibody titre of 1:32 or greater and compatible clinical and radiological findings. An additional group of 11 patients who presented with erythema multiforme was investigated and a heretofore unrecognized relationship between histoplasmosis and erythema multiforme was established.