Immunological aspects of fungal pathogenesis

Canine keratomycosis in 11 dogs: a case series (2000-2011)

Keratomycosis is rarely reported in dogs. The purpose of this study was to review the signalment, clinical characteristics, predisposing factors, and outcome of 11 cases of canine keratomycosis. Medical records of included dogs were reviewed and follow-up information was obtained by re-examination of patients following their initial diagnosis. All 11 patients possessed predisposing factors for fungal keratitis, including an underlying endocrinopathy, pre-existing corneal disease, intraocular surgery, and/or prolonged use of either topical antibiotics or corticosteroids at the time of initial examination. Diagnostic techniques included corneal cytology demonstrating yeast or hyphae in 6 of 11 eyes, and fungal cultures with positive results in 7 of 11 eyes. Fungal organisms isolated included Cladosporium spp. (n = 1), Chrysosporium spp. (n = 1), Curvularia spp. (n = 2), Aspergillus spp. (n = 1), Penicillium spp. (n = 1), and Phialemonium spp. (n = 1). Of the 11 patients, 6 responded to medical management alone. Two resolved after a superficial keratectomy, and three were enucleated due to either endophthalmitis or progression of corneal disease. This study identified potential risk factors for developing fungal keratitis.

Increased risk of mortality and loss to follow-up among HIV-positive patients with oropharyngeal candidiasis and malnutrition before antiretroviral therapy initiation: a retrospective analysis from a large urban cohort in Johannesburg, South Africa

OBJECTIVE

We investigated the effect of oropharyngeal candidiasis (OC) and body mass index (BMI) before antiretroviral therapy (ART) initiation on treatment outcomes of human immunodeficiency virus (HIV)-positive patients.

STUDY DESIGN

Treatment outcomes included failure to increase CD4 count by ≥50 or ≥100 cells/μL or failure to suppress viral load (<400 copies/mL) at 6 or 12 months in addition to loss to follow-up (LTFU) and mortality by 12 months. Risk and hazard ratios (HRs) were estimated with the use of log-binomial regression and Cox proportional hazards models, respectively.

RESULTS

Baseline CD4 <100 cells/μL, low BMI (<18.5 kg/m(2)), low hemoglobin, and elevated aspartate transaminase were associated with OC at ART initiation. Patients with low BMI with and without, respectively, OC were at risk of mortality (HR 2.42, 95% CI 1.88-3.12; HR 1.87, 95% CI 1.54-2.28) and LTFU (HR 1.36, 95% CI 1.02-1.82; HR 1.55, 95% CI 1.30-1.85).

CONCLUSIONS

Low BMI (with/without OC) at ART initiation was associated with poor treatment outcomes. Conversely, normal BMI with OC was associated with adequate CD4 response and reduced LTFU compared with without OC.

Treatment of dematiaceous fungal keratitis in a dog

CASE DESCRIPTION

A 9-year-old castrated male Bichon Frise was evaluated because of a 3-week history of a nonhealing corneal ulcer and corneal pigmentation of the left eye.

CLINICAL FINDINGS

Ophthalmic examination of the left eye revealed conjunctival hyperemia, corneal neovascularization, corneal edema, corneal ulceration, and central corneal pigmentation. Intraocular structures of the left eye could not be visually examined because of the diffuse nature of the corneal lesions. The right eye had anterior cortical incipient cataracts, nuclear sclerosis, and an inactive chorioretinal scar.

TREATMENT AND OUTCOME

Superficial lamellar keratectomy of the left eye was performed for both therapeutic and diagnostic purposes. Histologic evaluation of corneal biopsy specimens revealed dematiaceous fungal keratitis of the left eye, and topical administration of voriconazole was used to successfully resolve the keratitis. Seven months after diagnosis of dematiaceous fungal keratitis, the dog had no clinical signs or history of recurrence of the keratitis.

CLINICAL RELEVANCE

Dematiaceous fungal keratitis should be considered as a possible cause of nonhealing corneal ulceration with heavy pigment deposition in dogs. Results suggested that lamellar keratectomy along with topical administration of voriconazole can be used successfully to treat dematiaceous fungal keratitis in dogs.

Usefulness of molecular biology performed with formaldehyde-fixed paraffin embedded tissue for the diagnosis of combined pulmonary invasive mucormycosis and aspergillosis in an immunocompromised patient

Immunocompromised patients who develop invasive filamentous mycotic infections can be efficiently treated if rapid identification of the causative fungus is obtained. We report a case of fatal necrotic pneumonia caused by combined pulmonary invasive mucormycosis and aspergillosis in a 66 year-old renal transplant recipient. Aspergillus was first identified during the course of the disease by cytological examination and culture (A. fumigatus) of bronchoalveolar fluid. Hyphae of Mucorales (Rhizopus microsporus) were subsequently identified by culture of a tissue specimen taken from the left inferior pulmonary lobe, which was surgically resected two days before the patient died. Histological analysis of the lung parenchyma showed the association of two different filamentous mycoses for which the morphological features were evocative of aspergillosis and mucormycosis. However, the definitive identification of the associative infection was made by polymerase chain reaction (PCR) performed on deparaffinized tissue sections using specific primers for aspergillosis and mucormycosis. This case demonstrates that discrepancies between histological, cytological and mycological analyses can occur in cases of combined mycotic infection. In this regard, it shows that PCR on selected paraffin blocks is a very powerful method for making or confirming the association of different filamentous mycoses and that this method should be made available to pathology laboratories.

RNA interference in Histoplasma capsulatum demonstrates a role for alpha-(1,3)-glucan in virulence

Histoplasma capsulatum is a fungal pathogen that causes respiratory and systemic disease by proliferating within macrophages. While much is known about histoplasmosis, only a single virulence factor has been defined, in part because of the inefficiency of Histoplasma reverse genetics. As an alternative to allelic replacement, we have developed a telomeric plasmid-based system for silencing gene expression in Histoplasma by RNA interference (RNAi). Episomal expression of long RNAs that form stem-loop structures triggered gene silencing. To test the effectiveness of RNAi in Histoplasma, we depleted expression of a gfp transgene as well as two endogenous genes, ADE2 and URA5, and showed significant reductions in corresponding gene function. Silencing was target gene specific, stable during macrophage infection and reversible. We used RNAi targeting AGS1 (encoding alpha-(1,3)-glucan synthase) to deplete levels of alpha-(1,3)-glucan, a cell wall polysaccharide. Loss of alpha-(1,3)-glucan by RNAi yielded phenotypes indistinguishable from an AGS1 deletion: attenuation of the ability to kill macrophages and colonize murine lungs. This demonstrates for the first time that alpha-(1,3)-glucan is an important contributor to Histoplasma virulence.

A morphological and cytochemical study of the interaction between Paracoccidiodes brasiliensis and neutrophils

Paracoccidioidomycosis is a systemic granulomatous disease caused by the dimorphic fungus Paracoccidioides brasiliensis. It is the most prevalent systemic mycosis of Latin America and 80% of the reported cases are from Brazil. Because of the great number of neutrophils found in the P. brasiliensis granuloma, studies have been done to evaluate the role of these cells during the development of the infection. Scanning and transmission electron microscopy of thin sections showed that the neutrophils ingest yeast cells through a typical phagocytic process with the formation of pseudopodes. The pseudopodes even disrupt the connection established between the mother and the bud cells. Neutrophils also associate to each other, forming a kind of extracellular vacuole where large yeast cells are encapsulated. Cytochemical studies showed that once P. brasiliensis attaches to the neutrophil surface, it triggers a respiratory burst with release of oxygen-derived products. Attachment also triggers neutrophils degranulation, with release of endogenous peroxidase localized in cytoplasmic granules. Together, these processes lead to killing of both ingested and extracellular P. brasiliensis.

Corneal fungal disease in small animals

Corneal fungal diseases, including fungal keratitis and stromal abscess, are uncommon in small animals. Ocular infection secondary to systemic mycosis is reported far more frequently. Suspicion of a fungal corneal ulcer should be raised based on a history of underlying trauma, especially with plant material, geographic location, chronic use of topical antibiotics or corticosteroids, or an extremely prolonged course of disease despite appropriate treatment. Clinical signs observed with fungal keratitis may include blepharospasm, epiphora, miosis, corneal opacity, and vascularization. Unfortunately, none of these signs is specific to fungal infection. If fungal keratitis is suspected or confirmed, then aggressive medical therapy should be instituted. Medications used include topical antifungals, parasympatholytics, anticollagenases, and antibacterials as well as systemic anti-inflammatory drugs. Because there are very few fungicidal medications, the course of medical treatment for fungal corneal disease requires a prolonged duration with frequent re-examination and assessment. Surgical treatment is sometimes required to save the eye and vision. Surgeries to be considered include debridement, conjunctival graft placement, and corneal transplantation.

Life-threatening histoplasmosis complicating immunotherapy with tumor necrosis factor alpha antagonists infliximab and etanercept

OBJECTIVE

Two tumor necrosis factor alpha (TNFalpha) antagonists were recently licensed in the US. Infliximab was licensed in 1998 for the treatment of Crohn's disease (CD), and since 1999, it has been licensed in combination with methotrexate for treatment of rheumatoid arthritis (RA). Etanercept was licensed in 1998 for treatment of RA and, more recently, for juvenile RA and psoriatic arthritis. Because of potential immunosuppression related to use of anti-TNFalpha agents, we sought to identify postlicensure cases of opportunistic infection, including histoplasmosis, in patients treated with these products.

METHODS

The US Food and Drug Administration's (FDA) passive surveillance database for monitoring postlicensure adverse events was reviewed to identify all reports received through July 2001 of histoplasmosis in patients treated with either infliximab or etanercept.

RESULTS

Ten cases of Histoplasma capsulatum (HC) infection were reported: 9 associated with infliximab and 1 associated with etanercept. In patients treated with infliximab, manifestations of histoplasmosis occurred within 1 week to 6 months after the first dose and typically included fever, malaise, cough, dyspnea, and interstitial pneumonitis. Of the 10 patients with histoplasmosis, 9 required treatment in an intensive care unit, and 1 died. All patients had received concomitant immunosuppressive medications in addition to infliximab or etanercept, and all resided in HC-endemic regions.

CONCLUSION

Postlicensure surveillance suggests that acute life-threatening histoplasmosis may complicate immunotherapy with TNFalpha antagonists, particularly infliximab. Histoplasmosis should be considered early in the evaluation of patients who reside in HC-endemic areas in whom infectious complications develop during treatment with infliximab or etanercept.

Molecular mycology: a genetic toolbox for Histoplasma capsulatum

Research in medical mycology has traditionally been a mix of exciting biology and frustrating genetics, although the excitement has been steadily increasing as genetic obstacles have been successfully overcome. Now, a variety of fungal pathogens can be studied using molecular techniques derived from classical bacterial and yeast genetics, but with selective and strategic adaptations. Histoplasma capsulatum is the best-studied of the primary pathogens known as 'dimorphic' fungi, and tailored molecular genetic strategies are beginning to reveal a repertoire of genes and gene products intimately associated with pathogenesis.

Lactoferrin peptide increases the survival of Candida albicans-inoculated mice by upregulating neutrophil and macrophage functions, especially in combination with amphotericin B and granulocyte-macrophage colony-stimulating factor

To develop a new strategy to control candidiasis, we examined in vivo the anticandidal effects of a synthetic lactoferrin peptide, FKCRRWQWRM (peptide 2) and the peptide that mimics it, FKARRWQWRM (peptide 2'). Although all mice that underwent intraperitoneal injection of 5 x 10(8) Candida cells with or without peptide 2' died within 8 or 7 days, respectively, the survival times of mice treated with 5 to 100 microg of intravenous peptide 2 per day for 5 days after the candidal inoculation were prolonged between 8.4 +/- 2.9 and 22.4 +/- 3.6 days, depending on the dose of peptide 2. The prolongation of survival by peptide 2 was also observed in mice that were infected with 1.0 x 10(9) Candida albicans cells (3.2 +/- 1.3 days in control mice versus 8.2 +/- 2.4 days in the mice injected with 10 microg of peptide 2 per day). In the high-dose inoculation, a combination of peptide 2 (10 microg/day) with amphotericin B (0.1 microg/day) and granulocyte-macrophage colony-stimulating factor (GM-CSF) (0.1 microg/day) brought prolonged survival. With a combination of these agents, 60% of the mice were alive for more than 22 days. Correspondingly, peptide 2 activated phagocytes inducing inducible NO synthase and the expression of p47(phox) and p67(phox), and peptide 2 increased phagocyte Candida-killing activities up to 1.5-fold of the control levels upregulating the generation of superoxide, lactoferrin, and defensin from neutrophils and macrophages. These findings indicated that the anticandidal effects of peptide 2 depend not only on the direct Candida cell growth-inhibitory activity, but also on the phagocytes' upregulatory activity, and that combinations of peptide 2 with GM-CSF and antifungal drugs will help in the development of new strategies for control of candidiasis.

Intracellular parasitism by Histoplasma capsulatum: fungal virulence and calcium dependence

Histoplasma capsulatum is an effective intracellular parasite of macrophages and causes the most prevalent fungal respiratory disease in the United States. A "dimorphic" fungus, H. capsulatum exists as a saprophytic mold in soil and converts to the parasitic yeast form after inhalation. Only the yeasts secrete a calcium-binding protein (CBP) and can grow in calcium-limiting conditions. To probe the relation between calcium limitation and intracellular parasitism, we designed a strategy to disrupt CBP1 in H. capsulatum using a telomeric linear plasmid and a two-step genetic selection. The resultingcbp1 yeasts no longer grew when deprived of calcium, and they were also unable to destroy macrophages in vitro or proliferate in a mouse model of pulmonary infection.

Histoplasma acquisition of calcium and expression of CBP1 during intracellular parasitism

A highly adapted parasite of macrophages, the yeast phase of Histoplasma capsulatum, survives and proliferates within phagolysosomes, while the mycelial phase exists only as a saprophyte in the soil. We have shown previously that these two phases of Histoplasma differ in their calcium requirements for growth and in the production of a released calcium-binding protein (CBP). Cloning and sequencing the CBP1 gene revealed two introns, a putative signal peptide and potential calcium-binding sites. We also evaluated CBP1 expression by reverse transcription-polymerase chain reaction (RT-PCR) of yeasts grown in broth culture and within two host cell types, a macrophage-like cell line and respiratory epithelial cells. H. capsulatum yeasts expressed CBP1 in all of these settings. Splenocytes from mice immunized with H. capsulatum yeasts responded to purified CBP in proliferation assays, providing evidence for the production of CBP during the infection of mammalian hosts. In addition, after H. capsulatum yeasts were subjected to a calcium-free shock, exogenously added CBP allowed yeasts to incorporate more calcium than yeasts incubated without added CBP. These results suggest that CBP may function to provide yeasts with calcium when they are in a low-calcium environment, such as the phagolysosomal compartment within macrophages.

Oral diseases, mycology and periodontal microbiology of HIV-1-infected women

HIV-1 infection is increasing more rapidly among heterosexual women. Relatively limited information is available on HIV-related oral pathoses in these individuals. To gain insight into the type and occurrence of oral lesions in this population, 25 HIV-1 infected women including asymptomatic, symptomatic and AIDS patients were examined clinically and sampled for detection of oral yeast and characterization of their subgingival microbial flora. Sixty percent of the subjects were African-American, with 80% infected via heterosexual contact. Oral candidiasis was the most common nonperiodontal oral lesion, observed in 44% of the patients. Oral yeast was cultured from all women with candidiasis and 76% of the total subjects. Oral hairy leukoplakia was clinically diagnosed in 16% of the subjects. Clinically mild to moderate gingivitis and periodontitis were observed in 84% and 52% of the patients, respectively. Candidiasis and the presence of cultivable yeast were observed in patients with low, intermediate, and high CD4+ T lymphocyte numbers. Plaque samples were collected from each subject and enumerated by predominant cultivable methods, selective media and microscopy. No differences were detected in the microflora associated with seropositive women with existing periodontitis relative to those without periodontitis or to seronegative women with periodontitis. Candidiasis was the most notable oral clinical manifestation in the HIV-1-infected women and may be a useful clinical indicator of early immune dysfunction mediated by HIV-1.

Specific and non-specific parameters of the host defence system in patients with superficial fungal infections

Some measures of systemic host defences, i.e. white cell counts, lymphocyte subsets, delayed-type hypersensitivity and polymorphonuclear leucocyte functions, were evaluated in 42 patients suffering from cutaneous superficial mycoses and in 35 healthy volunteers. Patients were divided according to the extent of their lesions into two groups: group A (30 patients) with skin involvement > or = 30% and group B (12 patients) with skin involvement < or = 1%. No significant abnormalities in systemic defence mechanisms were observed in group B patients, whereas multiple alterations of polymorphonuclear phagocyte activities, i.e. chemotaxis, phagocytosis, mitogen-induced superoxide anion production, were observed in patients with extensive lesions. The values of these phagocytic functions remained significantly reduced (P < 0.01) in these patients after recovery and during a 6-month follow-up period.

Comparative analysis of phagocytosis of fungal cells by insect hemocytes versus horse neutrophils

In this study, the phagocytic ability of Spodoptera exigua hemocytes was compared to horse neutrophils. In vitro assays showed that the insect granulocytes and horse neutrophils actively phagocytose FITC-labeled Paecilomyces farinosus blastospores opsonized with S. exigua hemolymph lectin or horse serum, respectively. Killing of fungal cells by the neutrophils and hemocytes was analyzed under in vitro conditions. Neutrophils reduced the growth of P. farinosus up to 65% whereas no fungicidal activity was observed with hemocyte monolayers. The production of oxygen metabolites by both phagocytic cells incubated with various elicitors (fungal cells, bacteria, phorbol myristate acetate) was examined using luminol-enhanced chemiluminescence. Phagocytosis of opsonized microbes by horse neutrophils resulted in marked increase of chemiluminescence activity whereas no chemiluminescence was detected in similarly challenged phagocytic insect hemocytes. Electron microscopy was used to examine phagocytic events and confirmed that insect phagocytes were unable to kill tested microbes.

Combined effect of fluconazole and thymosin alpha 1 on systemic candidiasis in mice immunosuppressed by morphine treatments

Treatment of systemic infection with Candida albicans with a combination of an antifungal agent (i.e. fluconazole) and a thymus-derived immunostimulant (i.e. thymosin alpha 1 (T alpha 1)) in mice immunosuppressed by morphine treatments was investigated. In normal mice, fluconazole given after infection with 10(6) C. albicans cells was more effective than in mice treated with morphine. Combination treatment with fluconazole and T alpha 1 prolonged survival and reduced the fungal burden in the kidneys of immunosuppressed mice. We also investigated the influence of this combined treatment on killing properties of polymorphonuclear leucocytes (PMN) and natural killer (NK) cell activity, inhibited by morphine administrations. Treatment with T alpha 1 or fluconazole as single agents promoted a recovery of normal NK cell activity and intracellular killing of C. albicans by PMN, while the combination significantly increased both of these responses, probably through the modulation of lymphokine production. Our data suggest that the additive effect of T alpha 1 and fluconazole is due to a direct antifungal action and activation of the immunocompetence.

Cytokine profiles associated with induction of the anticryptococcal cell-mediated immune response

Previous studies with a murine model have shown that immunization with cryptococcal culture filtrate antigen (CneF) emulsified in complete Freund adjuvant (CFA) induces two populations of anticryptococcal reactive CD4+ T cells. One population (TDH cells) transfers anticryptococcal delayed-type hypersensitivity (DTH), and the other population (Tamp cells) amplifies the anticryptococcal DTH response of given to recipient mice at the time of immunization of the recipient. Treatment of mice with cyclosporin A (CsA) ablates the induction of Tamp cells but not TDH cells. The present study focused on assessing the cytokines produced by spleen cells taken from CsA-treated and control (solvent-treated) mice at days 1, 2, 4, and 6 after immunization. Supernatants from the spleen cells cultured in vitro for 24 or 48 h in medium alone or with CneF, concanavalin A, or phorbol 12-myristate 13-acetate plus calcium ionophore were assessed for the presence of interleukin-2 (IL-2), gamma interferon (IFN-gamma), IL-4, IL-5, and tumor necrosis factor. Spleen cells from CneF-CFA-treated mice produced IL-2 and IFN-gamma, but not IL-4 or IL-5, constitutively and in response to CneF, indicating that CneF-CFA induces a Th1 response. Tumor necrosis factor was not produced. Anticryptococcal TDH cells developed in spleens in which there were low levels of IFN-gamma and IL-2 (CsA-treated, immunized mice), whereas anticryptococcal Tamp cells along with TDH cells matured in spleens in which production of IFN-gamma and IL-2 was high (solvent-treated, immunized mice). The data also suggest that IL-2 and IFN-gamma produced by Tamp cells early after adoptive transfer are influential in the development of the amplified anticryptococcal DTH response that has been observed in Tamp cell-recipient mice.

Interferon-gamma activates the oxidative killing of Candida albicans by human granulocytes

Although granulocytes are essential for the resistance against infections with Candida albicans, these cells do not kill the ingested yeast optimally. Various cytokines can enhance functional activities of granulocytes, but until now only interferon-gamma (IFN-gamma) has been applied more widely, namely in patients with chronic granulomatous disease. Since it is not certain whether IFN-gamma is able to enhance the candidacidal activity of granulocytes the present study was undertaken. Human granulocytes incubated with various concentrations of recombinant human IFN-gamma (rIFN-gamma) were studied for the phagocytosis and intracellular killing of C. albicans and their oxygen metabolism after stimulation with opsonized Candida. Results showed a small increase in the rate of phagocytosis and a dose-dependent increase of the intracellular killing of C. albicans and the production of H2O2. The increased candidacidal activity and H2O2 production by rIFN-gamma-stimulated granulocytes were inhibited by diphenylene iodonium (DPI). From these results it is concluded that the increased candidacidal activity of granulocytes activated by rIFN-gamma is caused by the increased production of reactive oxygen radicals.

Binding of Trichophyton rubrum mannan to human monocytes in vitro

We recently reported that the mannan component of Trichophyton rubrum cell wall (TRM) has an inhibitory influence on cell-mediated immune function in vitro. We now describe experiments designed to identify the target cell for this effect of TRM. T. rubrum mannan labeled with fluorescein (FITC-TRM) was incubated with peripheral blood mononuclear leukocytes, monocytes, or lymphocytes. Binding and uptake of the FITC-TRM were monitored by fluorescence microscopy and flow cytometry. Approximately 10% of mononuclear leukocytes were stained with this reagent and the fluorescent cells appeared to be monocytes by morphology. Virtually all purified monocytes and no purified lymphocytes stained with FITC-TRM. Flow cytometry to analyze FITC-TRM monocyte-specific binding of FITC-TRM involved the use of a phycoerythrin-labeled anti-CD14 antibody to identify monocytes. The only cells stained with FITC-TRM were those stained with the monocyte-specific antibody. The ability of monocytes to endocytose mannan was assessed by fluorescence microscopy. Cells were exposed to FITC-TRM and washed, and the staining pattern recorded periodically over a 48-h incubation period. After 15 min, staining was homogeneous and involved the entire cell surface; by 30 min, "patching" was observed; by 90 min, bright granules had formed along the cell border and a large number of small granules were present in the cytoplasm; by 8-12 h, the fluorescent granules were enlarged in size and reduced in number; by 24-36 h, the intensity of cytoplasmic fluorescence began to diminish; and, after 48 h, all fluorescent staining had disappeared. An additional feature of staining during the 8-12-h period was the appearance of a large round bright spot in the nuclear region of each cell, which may represent nucleolar staining. A role for "mannan receptors" is suggested by observations that FITC-TRM binding was prevented by unlabeled TRM or pretreatment of the monocytes with trypsin. Our finding that monocytes selectively and specifically bind TRM appears to identify the monocyte rather than the lymphocyte as the target cell for the inhibitory effect of mannan on cell-mediated immune function.

Host factors associated with HIV-related oral candidiasis. A review

Human immunodeficiency virus (HIV)-related oral candidiasis affects approximately one third of HIV-seropositive patients and more than 90% of patients with AIDS. It is necessary to identify patients who have a greater risk of candidiasis developing, so that interventions can be designed to reduce the frequency. This is particularly important because there is evidence that Candida species are immunosuppressive and therefore candidiasis may adversely affect the prognosis of patients with HIV. Susceptibility to HIV-related oral candidiasis is associated with xerostomia, severity of disease, depression of cell-mediated immunity, and older age (greater than 35 years). The frequency of HIV-related oral candidiasis is notably increased when the CD4 lymphocyte count falls to less than 300 cells/mm3. Xerostomia appears to be a better predictor of HIV-related oral candidiasis than CD4 count and should be prevented (e.g., by avoiding xerogenic drugs) and treated, when necessary, to minimize the risk of oral candidiasis.

Factors associated with increased frequency of HIV-related oral candidiasis

HIV-related oral candidiasis was investigated in 71 HIV-seropositive patients who received interviews, oral examinations and hematologic investigation. Diagnosis of candidiasis was based on clinical signs and examination of PAS-stained smears. The frequency of candidiasis was 24/71 (34%). The clinical presentations were pseudomembranous 8 (11%), erythematous 14 (20%), angular cheilitis 3 (4%). Twenty-six patients (37%) had candidiasis or were receiving antifungal treatment for recurrent pseudomembranous type. Twelve of 13 (92%) patients with AIDS and 14/58 (24%) without AIDS were affected. Bivariate analyses showed significant associations with AIDS, the use of zidovudine, low T4-count, xerostomia; marital status (sometime married), restricted performance status and age of greater than 35 yr. Multivariate logistic regression analysis showed that the presence of xerostomia was an independent and statistically significant predictor of HIV-related oral candidiasis. T4-count and restricted performance status were the second and third most important predictors.