Demonstration of mycobacterial antigens in skin biopsies fron suspected leprosy cases in the absence of bacilli.

Skin-biopsies from fifty-six patients suspected of early leprosy from Bahia State, Brazil, were examined histopathologically. The Fite-Faraco staining failed to demonstrate acid-fast bacilli in this material. The prominent features of the lesions were inflammation of the neurovascular bundles and sometimes inflammation of the skin appendages. The non-specific infiltrate was predominantly composed of histiocytes and lymphocytes. In 41 cases (73.2%) epidermal atrophy was also present. The avidin-biotin peroxidase technique was used with primary antibodies to detect bacillary antigens (anti-BCG serum) and nerve branches (anti-S-100 protein serum). Immunohistochemical detection of bacillary antigens using the anti-BCG serum was positive in 28 cases (50%). A positive staining for S-100 protein was observed in 40 cases (71.4%) in dendritic antigen-presenting cells of the skin. The detection of bacillary antigens, together with the clear demonstration of nerve bundles enhanced our capacity to fulfill morphologic criteria for the diagnosis of early leprosy. Our observations indicate that the use of immunohistochemical methods represent a useful tool for the early diagnosis of leprosy.

Treated-cured indeterminate leprosy: a search for predictive histopathological and immunohistochemical parameters in skin biopsies taken from patients at admission and at clinical discharge.

In a previous study an index (sigma 3) resulting from the summation of three parameters, i.e., presence of bacilli, even in small numbers, in various dermal structures, multiple positive antigen sites as detected by anti-BCG antiserum and dermal nerve involvement, identified 72.22% of cases of indeterminate leprosy which progressed to multibacillary leprosy. The present study was undertaken to investigate possible parameters which might be indicative of indeterminate leprosy which would persist unchanged or be cured (treated cured patients). Thirty treated cured indeterminate leprosy patients were selected from the files of the São Paulo Health Institute and studied by histopathological, immunohistochemical and statistical methods similar to those employed in the previous study. The sigma 3 index was 4.10 +/- 0.60, a finding that places this group of patients in a position close to that of patients changing to paucibacillary leprosy but statistically different from that of patients progressing to multibacillary leprosy. Moreover, it was found that patients belonging to this group have heterogeneous single parameters, some of them suggestive of multibacillary and others of paucibacillary leprosy. Immunologically based techniques mainly employing rabbit anti-BCG serum as the primary antibody have proved to be valuable to detect antigen sites in biopsies from indeterminate leprosy patients and should be used together with the bacillary index during the follow up and clinical discharge control of such patients. In the present study, we show that clinical discharge of these patients did not mean a complete clearance of bacillary antigens.

Indeterminate leprosy: histopathologic and histochemical predictive parameters involved in its possible change to paucibacillary or multibacillary leprosy.

In an attempt to find clinical, bacteriological, histopathological, and immunohistochemical parameters to predict the progress of indeterminate leprosy patients to either paucibacillary (PB) or multibacillary (MB) leprosy, skin biopsies from 51 patients with indeterminate leprosy were retrieved from the files of the São Paulo Health Institute (Brazil). All of these patients had progressed to either PB or MB leprosy over a period of time which varied from 2 months to 24 years. Clinical records were examined, and new sections were cut from the paraffin blocks and stained by hematoxylin-eosin and Fite-Faraco stains; the avidin-biotin peroxidase technique was used with primary antibodies to detect bacillary antigens (anti-BCG serum) and nerve branches (anti-S-100 protein anti-serum). A moderate (++) or strongly positive ( ) Mitsuda skin test was observed in some patients progressing to PB leprosy. Noteworthy is that even patients initially Mitsuda negative may evolve to PB leprosy. a) A 2+ bacterial index and/or the presence of bacilli, even though few in number, in various dermal structures; b) multiple positive antigen sites as detected by anti-BCG anti-serum; and c) dermal nerve involvement, when evaluated as single parameters, correlated with a progression indeterminate to MB leprosy. An index resulting from the summation of the above three parameters identified 13 (72%) of 18 of these cases which progressed to MB leprosy.

Leptospiral antigens (L. interrogans serogroup ictero-haemorrhagiae) in the kidney of experimentally infected guinea pigs and their relation to the pathogenesis of the renal injury.

The search for leptospiral antigens (L. interrogans serogroup icterohaemorrhagiae) was carried out in 24 guinea pigs experimentally inoculated with 1 ml of culture containing 10(7)-10(8) leprospires and sequentially sacrificed from the first until the 6th day of infection. Semiquantitative analysis of histopathological variables comprising kidney interstitium, tubules and glomeruli was done in 1 micron sections of tissue embedded in glycolmetacrylate. Leptospiral antigen (LAg) and its glycolipoprotein (GLP) expression were detected through PAP in paraffin embedded tissue. The mild interstitial involvement of the kidney, manifested chiefly by oedema and focal interstitial nephritis seen at the 4th day, progressed to tubular damage at the 6th day, characterized by either swelling or cytoplasmic acidophilia of epithelial cells with loss of cell cohesion and sloughing of cells into the tubular lumina. Brush border alterations and mitochondrial changes were observed. Endothelial cell injury was noted in the interstitial vessels. LAg expression was parallel to the kidney changes: small deposits of elongated forms of LAg were detected at the 4th day either within the vascular lumen or free in the interstitium. A rise in the antigen expression was observed at the 5th day when it was seen either around tubules or in their walls. LAg was detected inside the tubular lumina at the 6th day of infection when granular LAg and GLP were abundant. This sequence reproduces the pathway of leptospires in the kidney and the crescent amounts of antigens detected toward the end of the experiment, with antigen concentration in cases of major tissue damage suggesting a direct action of the microorganisms and/or their products in the pathogesis of the lesions.