The maternal immune response in coccidioidomycosis. Is pregnancy a risk factor for serious infection?

Skin infections in pregnancy

A wide array of infectious diseases can occur in pregnancy. Their acquisition, clinical presentation, and course during gestation may be altered due to an impairment of the maternal cellular immunity. Some infectious diseases can lead to serious consequences for the mother or the offspring, including congenital malformations. This review describes in detail the clinical presentation, course, management, and associated maternal and fetal risks of selected viral (varicella-zoster virus infections, condylomata acuminata), fungal (candida vulvovaginitis), bacterial (Lyme borreliosis), and parasitic (scabies) infections. The treatment options are critically reviewed. First-line therapies include acyclovir and varicella-zoster virus immunoglobulin for varicella-zoster virus infections, surgical modalities for genital warts, topical clotrimazole and oral fluconazole for Candida vulvovaginitis, amoxicillin and cefuroxime for Lyme borreliosis, and permethrin for scabies. A synopsis of maternal and fetal risks of other important infections is also included.

Parity and placental infection affect antibody responses against Plasmodium falciparum during pregnancy

Women are at higher risk of Plasmodium falciparum infection when pregnant. The decreasing risk of malaria with subsequent pregnancies is attributed to parity-dependent acquisition of antibodies against placental parasites expressing variant surface antigens, VAR2CSA, that mediate placental sequestration through adhesion to chondroitin sulfate A (CSA). However, modulation of immunity during pregnancy may also contribute to increase the risk of malaria. We compared antibody responses among 30 Mozambican primigravidae and 60 multigravidae at delivery, 40 men, and 40 children. IgG levels were measured against the surface antigens of erythrocytes infected with P. falciparum isolated from 12 pregnant women (4 placental and 8 peripheral blood isolates) and 26 nonpregnant hosts. We also measured IgG levels against merozoite recombinant antigens and total IgG. Placental P. falciparum infection was associated with increased levels of total IgG as well as IgG levels against merozoite antigens and parasite isolates from pregnant and nonpregnant hosts. We therefore stratified comparisons of antibody levels by placental infection. Compared to multigravidae, uninfected primigravidae had lower total IgG as well as lower levels of IgGs against peripheral blood isolates from both pregnant and nonpregnant hosts. These differences were not explained by use of bed nets, season at delivery, neighborhood of residence, or age. Compared to men, infected primigravidae had higher levels of IgGs against isolates from pregnant women and CSA-binding lines but not against other isolates, supporting the concept of a pregnancy-specific development of immunity to these parasite variants. Results of this study show that parity and placental infection can modulate immune responses during pregnancy against malaria parasites.

Mycelial forms of Coccidioides spp. in the parasitic phase associated to pulmonary coccidioidomycosis with type 2 diabetes mellitus

Pulmonary coccidioidomycosis shares characteristics with other pulmonary pathologies. In tissue, spherules containing endospores are markers of Coccidioides immitis and C. posadasii infection. Mycelial forms presenting without classical parasitic structures are often misdiagnosed. The study was performed at the National Institute of Respiratory Diseases (INER) of Mexico between September 1991 and June 2005 and analyzed the association between cases, controls, and risk factors, including co-morbidity. A case was defined as any patient who presented mycelial forms and a control as any patient who presented only spherules or no parasitic forms. All patients (n = 44) with pulmonary coccidioidomycosis were diagnosed by culture, histopathology, cytology, and immunology. Type 2 diabetic patients with pulmonary coccidioidomycosis were four times more likely than non-diabetics to develop parasitic mycelial forms (95% confidence interval [CI], 0.85-20.10; P < 0.01). We formulated a comprehensive definition based on the results as follows: patients with pulmonary coccidioidomycosis with an evolution longer than 8 months, cough, hemoptysis, radiological evidence of a cavitary lesion, and type 2 diabetes mellitus, develop parasitic mycelial forms of Coccidioides spp. Based on microscopic images of patient specimens, we propose incorporating mycelial forms into the parasitic phase of Coccidioides spp. in patients with type 2 diabetes mellitus and chronic and cavitary pulmonary coccidioidomycosis.

Immune reconstitution syndrome and exacerbation of infections after pregnancy

Pregnancy is a state of subtle immunosuppression characterized by physiologic suppression of proinflammatory host responses that are meant to promote embryonic implantation. Rapid reversal of these changes and a rebound of inflammatory responses during the postpartum period can result in quiescent or latent infection manifesting as symptomatic disease. Infections due to several microbial pathogens and noninfectious diseases with an autoimmune basis have been shown to worsen or begin during the postpartum period. Awareness that symptoms resulting from immune reconstitution can occur in any host with a rapidly changing immunologic repertoire, including women in the postpartum phase, is a critical first step in fully understanding this phenomenon. Future studies to discern the precise pathophysiologic basis of immune reconstitution, to identify pregnant women at risk, and to determine markers that may be diagnostically helpful have significant implications for optimizing treatment of these patients.

Disseminated Coccidioidomycosis in Pregnancy

Coccidioidomycosis is a fungal infection contracted through the inhalation of airborne spores, which are most frequently present in desert areas of the southwestern United States and Mexico. Primary immune response to infection is by TH1, a subset of helper T cells. Although pulmonary symptoms are most common, hematogenous systemic spread can also occur. Pregnancy is a well-noted risk factor for disseminated Coccidioides infection. The objective of this review is to provide an overview of coccidioidomycosis and to review immunologic and hormonal factors that increase risk of dissemination in pregnancy. Dissemination may occur more frequently in pregnant patients than in nonpregnant women because of shifts in T-cell immunity, changes in cytokine production, and increased hormone levels. There is disagreement regarding the precise incidence of systemic spread in pregnancy, but most sources agree that risk is substantially increased and vigilance must be high in patients with exposures in endemic areas.

Dendritic cell-based vaccine against coccidioides infection

Coccidioides causes coccidioidomycosis in the southwestern United States. Its clinical manifestations range from the primary asymptomatic to progressive pulmonary and extrapulmonary disease. Because of endemicity, frequent relapse, and virulent nature of Coccidioides, there is an urgent need for the development of effective therapy or vaccine. It has been recognized from studies in human patients and in murine models that the divergence in their susceptibility to Coccidioides infection is related to differences in T cell response. Dendritic cells (DCs) are most potent antigen-presenting cells that play a critical role in activating naïve T cells. On account of their unique immunostimulatory capacity, DCs have been used for the development of immunotherapy and vaccines against cancer and infectious diseases. We recently investigated the immunostimulatory potential of a DC-based vaccine in a murine model against Coccidioides posadasii (C. posadasii). Our results suggest that DCs act as a potent adjuvant and activate protective responses in mice against C. posadasii.

Iritis presumed as secondary to disseminated coccidioidomycosis

BACKGROUND

Coccidioidomycosis is a systemic disease caused by a fungus found in soil and transmitted through inhalation. It is prevalent in western and southwestern United States, Mexico, and South and Central America. Results of skin testing, serologic testing, and tissue cultures confirm the diagnosis. Coccidioidomycosis can manifest in various ways: the infected individual may present asymptomatically, with an acute respiratory infection, or, in more severe or chronic cases, with a multiorgan presentation. Ocular involvement may include anterior segment, posterior segment, or extraorbital involvement.

CASE REPORT

A case concerning a patient with iritis presumed as secondary to disseminated coccidioidomycosis is discussed. The patient initially presented to our clinic with signs and symptoms of acute, unilateral iritis and a recent history of iritis in the contralateral eye. The active inflammation was treated topically with Pred Forte and cyclopentolate and resolved without sequelae. Because the presentation was bilateral with an asymmetric timecourse, laboratory tests were ordered to rule out systemic association. Because all tests yielded negative results, the known history of disseminated coccidioidomycosis was presumed to be the etiology of this iritis.

CONCLUSION

Although eye findings are rare, disseminated coccidioidomycosis is an important differential to consider when a patient presents with uveitis. For this reason, awareness and recognition of ocular signs and symptoms of this disease is significant in proper patient care and management.

Respiratory physiologic changes in pregnancy

In summary, the major physiologic changes that occur in pregnancy are the increased minute ventilation, which is caused by increased respiratory center sensitivity and drive; a compensated respiratory alkalosis; and a low expiratory reserve volume. The vital capacity and measures of forced expiration are well preserved. Patients who have many lung diseases tolerate pregnancy well, with the exception of those who have pulmonary hypertension or chronic respiratory insufficiency from parenchymal or neuromuscular 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.

Case Report. Disseminated aspergillosis complicating pregnancy

We report a case of disseminated aspergillosis in a hitherto healthy 24-year-old woman during her 24th week of pregnancy. Relevant findings at autopsy revealed innumerable septate, dichotomously branched (45 degrees ) hyphae compatible with Aspergillus in lung and liver tissues. Cerebral histology showed cerebral vessels occluded by hyphae causing cerebral infarction. There was no evidence of invasive aspergillosis in the placenta and fetal tissues. Aspergillus sp. was confirmed by amplification of a specific 357-base-pair amplicon from a paraffin block containing lung tissue. This case illustrates a previously uncharacterized spectrum of disseminated aspergillosis, indicating the need for a heightened awareness that Aspergillus species are opportunistic agents for invasive and disseminated infection in pregnancy.

Does patient sex affect human immunodeficiency virus levels?

We undertook a critical epidemiological review of the available evidence concerning whether women have lower levels of human immunodeficiency virus (HIV) RNA than do men at similar stages of HIV infection. The 13 studies included in this analysis reported viral load measurements in HIV-infected men and women at a single point in time (cross-sectional studies) or over time (longitudinal studies). Seven of the 9 cross-sectional studies demonstrated that women had 0.13-0.35 log(10) ( approximately 2-fold) lower levels of HIV RNA than do men, despite controlling for CD4(+) cell count. Four longitudinal studies revealed that women had 0.33-0.78 log(10) (2- to 6-fold) lower levels of HIV RNA than do men, even when controlling for time since seroconversion. Adjustment for possible confounders of the relationship between sex and viral load, including age, race, mode of virus transmission, and antiretroviral therapy use, did not change this outcome. This finding is significant, because viral loads are frequently used to guide the initiation and modification of antiretroviral therapy.

Pneumonia in pregnancy

Although the advent of broad-spectrum antibiotics has markedly improved the maternal outcomes of pneumonia complicating pregnancy, pneumonia remains a significant condition that may complicate pregnancy. This article has reviewed the inherent physiologic respiratory changes that accompany pregnancy and the common causes of pneumonia in the pregnant woman. The clinical course of bacterial pneumonia seems to be minimally altered by pregnancy, whereas viral pneumonia carries a significantly worse prognosis when encountered during gestation. Prompt diagnosis, the initiation of respiratory support, and appropriate antimicrobial/antiviral therapy are key components of therapy for women in whom pregnancy is complicated by pneumonia. Because preterm labor frequently accompanies pneumonia, women should be monitored closely for the occult onset of preterm labor and appropriate interventions initiated if indicated. Perhaps even more important than interventions to treat acute pneumonia are efforts directed at active immunization or prophylactic therapy to prevent the development of pneumonia in select patient populations. The combination of these efforts is essential to optimize medical care for pregnant women.

T-lymphocyte subsets in acute illness

OBJECTIVES

To determine the range of T-lymphocyte subsets (CD4, CD8, and CD4/CD8 ratios) in acutely ill, hospitalized patients and to determine whether these concentrations correlate with illness severity, survival rate, or immunodepression.

DESIGN

Cross-sectional study, comparing Acute Physiology and Chronic Health Evaluation II (APACHE II) scores and the calculated, disease-specific, predicted mortality rate with T-lymphocyte subsets.

SETTING

Urban county hospital intensive care unit (ICU), serving as the designated trauma center.

PATIENTS

One hundred two consecutively admitted ICU patients (72 medical and 30 surgical).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patient clinical data, APACHE II scores, and their associated predicted mortality rate were recorded. Blinded human immunodeficiency virus (HIV) and lymphocyte testing was performed on samples from all patients on ICU admission. Despite only three (2.9%) of 102 patients testing positive for HIV antibodies, 41% (42/102) of patients had CD4 concentrations of < 400 cells/microL, and 29% (29/102) had CD4 concentrations of < 300 cells/microL. Mean CD8 concentrations were even lower, compared with normal laboratory values, resulting in a slight increase in CD4/CD8 ratios, although 16% (16/102) of patients had a CD4/CD8 ratio of < 1. CD4 counts were linearly related to total lymphocyte concentrations (Pearson correlation coefficient = 0.948), but no relationship was found between total lymphocyte or lymphocyte subset counts and APACHE II score, predicted mortality rate, or survival rate.

CONCLUSIONS

Acute illness alone, in the absence of HIV infection, can be associated with profound decreases of T-lymphocyte populations. This problem is unpredictable and does not correlate with severity of illness, predicted mortality rate, or actual mortality rate. No conclusions regarding HIV serostatus or survival can be made based on single measurements of T-cell concentrations in acutely ill hospitalized patients.