Humoral response to mycobacterial heat shock proteins in patients with constrictive pericarditis caused by tuberculosis and its implications for pathogenesis

Constrictive pericarditis--a curable diastolic heart failure

Constrictive pericarditis can result from a stiff pericardium that prevents satisfactory diastolic filling. The distinction between constrictive pericarditis and other causes of heart failure, such as restrictive cardiomyopathy, is important because pericardiectomy can cure constrictive pericarditis. Diagnosis of constrictive pericarditis is based on characteristic haemodynamic and anatomical features determined using echocardiography, cardiac catheterization, cardiac MRI, and CT. The Mayo Clinic echocardiography and cardiac catheterization haemodynamic diagnostic criteria for constrictive pericarditis are based on the unique features of ventricular interdependence and dissociation of intrathoracic and intracardiac pressures seen when the pericardium is constricted. A complete pericardiectomy can restore satisfactory diastolic filling by removing the constrictive pericardium in patients with constrictive pericarditis. However, if inflammation of the pericardium is the predominant constrictive mechanism, anti-inflammatory therapy might alleviate this transient condition without a need for surgery. Early diagnosis of constrictive pericarditis is, therefore, of paramount clinical importance. An improved understanding of how constrictive pericarditis develops after an initiating event is critical to prevent this diastolic heart failure. In this Review, we discuss the aetiology, pathophysiology, and diagnosis of constrictive pericarditis, with a specific emphasis on how to differentiate this disease from conditions with similar clinical presentations.

Fungal heat-shock proteins in human disease

Heat-shock proteins (hsps) have been identified as molecular chaperones conserved between microbes and man and grouped by their molecular mass and high degree of amino acid homology. This article reviews the major hsps of Saccharomyces cerevisiae, their interactions with trehalose, the effect of fermentation and the role of the heat-shock factor. Information derived from this model, as well as from Neurospora crassa and Achlya ambisexualis, helps in understanding the importance of hsps in the pathogenic fungi, Candida albicans, Cryptococcus neoformans, Aspergillus spp., Histoplasma capsulatum, Paracoccidioides brasiliensis, Trichophyton rubrum, Phycomyces blakesleeanus, Fusarium oxysporum, Coccidioides immitis and Pneumocystis jiroveci. This has been matched with proteomic and genomic information examining hsp expression in response to noxious stimuli. Fungal hsp90 has been identified as a target for immunotherapy by a genetically recombinant antibody. The concept of combining this antibody fragment with an antifungal drug for treating life-threatening fungal infection and the potential interactions with human and microbial hsp90 and nitric oxide is discussed.

A 77-kilodalton protein of Cryptococcus neoformans, a member of the heat shock protein 70 family, is a major antigen detected in the sera of mice with pulmonary cryptococcosis

Heat shock proteins (HSPs) from several pathogenic microbes have been shown to be target molecules of humoral responses as well as cellular immune responses. However, little is known about target molecules in pulmonary cryptococcosis. Western blotting analysis revealed that experimentally induced pulmonary cryptococcosis in (BALB/c x DBA/2)F1 mice was associated with the appearance of serum antibodies to a 77-kDa protein derived from Cryptococcus neoformans as well as to 18-, 22-, 25-, 36-, and 94-kDa proteins. Since the 77-kDa band also reacted with rabbit polyclonal antibodies against 70-kDa HSP (HSP70) family members, the protein was predicted to be a member of the HSP70 family. We also purified HSP70 directly from a C. neoformans cell extract by Mono Q fast protein liquid chromatography and ATP-agarose affinity column chromatography and showed that it was positive in immunoblot analysis using either serum from C. neoformans-infected mice or rabbit anti-HSP70 antibodies. N-terminal amino acid sequencing of this purified protein confirmed that the 77-kDa protein was a member of the HSP70 protein family. A 66-kDa protein, which coincidentally purified with the HSP70 protein and was identified as a member of the HSP60 family by N-terminal amino acid sequencing, was not reactive with sera from C. neoformans-infected mice. Thus, a protein associated with the HSP70 family and derived from C. neoformans was a major target molecule of the humoral response in murine pulmonary cryptococcosis.