Renal involvement in Mycobacterium leprae infected mice. Histopathological, bacteriological and immunofluorescence study.

Swiss albino mice were inoculated in the footpads with Mycobacterium leprae obtained from untreated lepromatous patient. The kidneys obtained from the animals sacrificed during different periods were processed for histopathology, presence of AFB and immunofluorescence studies. Renal lesions, AFB and immune complex deposits were seen in the infected animals. Such findings have not been studied in great detail in experimental leprosy earlier.

Venous involvement in leprosy: a venographic and histopathological correlation.

Venous system involvement was studied by venography and vein histology in 30 leprosy patients irrespective of age, sex, duration of the disease, and treatment. Vascular abnormalities by venography were seen in 96.3% and by histopathological studies in 76.6% of patients. The percentage and severity of radiological and histological changes increased from tuberculoid to lepromatous in the disease spectrum. Perfect correlation of histology and venography was found in 40% of the paucibacillary patients and good correlation was found in 100%. In multibacillary patients perfect correlation was found in 29.4%, good correlation in 41.1%, and no correlation in 29.4% of the patients.

Primary dapsone resistance in leprosy.

20 carefully selected untreated patients of bacilliferous leprosy were investigated for primary dapsone resistance by foot pad inoculation. Mice were fed on 0.001 g% and 0.01 g% of dapsone during the period of study. Mice in the control group were given normal rodent feed only. Animals were sacrificed from 6 month onwards at 6 week intervals upto 9 months. In two animals the growth of M. leprae was not inhibited by 0.001 g% concentration of dapsone in diet, but was completely inhibited by 0.01 g% of dapsone.

Influence of levamisole on lymphocytes and M. leprae in mice.

Normal uninfected (N) and M. leprae infected mice (NI) were given levamisole in the dose of 2.5 mg/kg body weight. The animals were observed over a period of nine months for bacillary load, T and B cell counts and blast transformation with PHA. Significant increase in B cell counts was observed in the levamisole treated normal (NL) compared to normal control (N) group. T cell counts and blast transformation, however, remained unaffected. However, T-cell counts and blast transformation improved significantly in the infected and levamisole treated (NIL) as compared to the infected group (NI) not given levamisole. Bacillary loads remained unaltered in both, the infected (NI) and levamisole treated (NIL) group.

Trophic changes and extensive dissemination in normal mice infected with human Mycobacterium leprae.

Closely bred Swiss albino normal mice (Lecca Strain) were inoculated in the footpad with M. leprae, at room temperature. The animals were harvested at 3, 6 and 9 months post inoculation, and bacillary counts were made. Trophic changes were observed in the tail-tips, ears, footpads and forepaws 12-14 months post inoculation in a group which was allowed to survive. The histopathological changes and bacillary infiltration was found in many tissues/organs. The possibility of studying this normal strain of mice as an experimental model for human leprosy has been discussed.

Effect of dapsone (DDS) on T-cells and their response to PHA and lepromin in tuberculoid leprosy patients.

T and B cell counts and their response to PHA and lepromin were studied in 46 patients of polar tuberculoid leprosy (TT), divided into two age and sex matched groups. Twenty five normal healthy controls were similarly investigated. While one group consisted of 26 untreated TT patients, the other included 20 individuals who had taken dapsone, 50 mg daily, for 12 to 14 months. There was significant decrease in the number of T-lymphocytes and their response to PHA and lepromin was lower in the treated, as compared to the untreated patients and normal persons. No significant change was found in the number of B-lymphocytes in any of the groups.

Lymphocyte subpopulations in mice infected with Mycobacterium leprae.

T and B cells were quantitated from the spleen of M. leprae infected mice and correlated with bacillary count in the foot pad. Lymphocyte transformation with PHA and M. leprae (armadillo) antigens was also studied during different months of infection. T cell counts dropped gradually but significantly throughout the course of infection. B cells had a concomitant rise up to 6 months and then registered a fall as compared to the initial control figures. Transformation of lymphocytes with PHA fell significantly after 4th month til the end of the experiment, whereas stimulation index for armadillo antigen rose gradually from 3rd month onwards to reach a peak at 6th month and then fell till the end of the experiment with increasing bacterial population whereas B-cell counts showed little change.

Viability of M. leprae under normal and adverse atmospheric conditions.

Harvested bacilli from fresh lepromas were subjected to drying at room temperature for varying periods, were exposed to direct sun-rays, UVR, and were then injected into the foot pads of thymectomised irradiated mice for checking the viability. The organisms could survive UVR for 30 minutes, direct sunlight for 2 hours and room temperature for 7 days. Details are presented.

Total and differential serum proteins and globulins in leprosy.

Total and differential serum proteins were estimated in 177 adult male patients and globulins in 135 patients. Total serum proteins were slightly lowered in BB, BL and LL patients. Total albumin was low in all types of leprosy, especially in the BL group. Alpha-1 and alpha-2 fractions were unchanged all through the leprosy spectrum. Beta globulins were significantly lowered in LL patients as compared to the controls. Gamma globulins were elevated in all types of leprosy more so in BB, BL and LL patients. Details are presented.

Myco. leprae infection in normal, thymectomised irradiated and thymus transplanted mice.

Normal mice and thymectomised, X-irradiated and thymic transplanted groups of mice were challenged with 10(3) Myco. leprae in the foot pad. Course of infection was studied for a period of seven months by sacrificing animals every month and counting the bacilli from the pooled tissues. In the thymectomised irradiated group the counts showed a plateau from 5th month onwards, whereas in control and thymus implant group the counts rose in 6th and 7th months.

BCG induced immunity to Mycobacterium leprae in mice.

One to three BCG vaccinations were given to various groups of mice--25 to 2 days preceding challenge with Myco. leprae. Harvesting of Myco. leprae was done every month upto a period of 7 months. Lymph node enlargement was taken as an indicator of successful vaccination. An increasing degree of protection was noted in BCG immunised mice as observed by a reduced number of bacilli harvested. Protection afforded was proportional to the number of doses of BCG given.

Peripheral arteriographic studies in leprosy.

There is a considerable controversy regarding the frequency and significance of vascular lesions in leprosy. Twenty-six cases of leprosy below the age of 40 years, without any local or systemic arterial disease and normal looking hands were subjected to brachial arteriography. One patient had posterior tibial arteriography also. The diagnosis of leprosy was confirmed by histology or bacteriological staining techniques. Biopsy material was studied from the involved areas and similar material was obtained from nine matched control subjects at autopsy. Skin thermometry and reflex vasodilatation was studied in eight cases. Arteriographic abnormalities such as occlusion, narrowing, tortuosity, dilatation, irregularity and incomplete filling were seen in more than two vessels in the hand in 50%, and in the digits in 75% of the cases. The ulnar artery was more frequently involved than the radial. Superficial and deep palmar arches were equally affected. Marked increase in arcuate vessels was noticed in nearly three-quarters of the patients, and in some, arcuate vessles were serving as collaterals. Histologically all sizes of vessles, including the capillaries, showed changes in nearly half the cases. Reflex vasodilation was lost in three cases of dimorphous leprosy and impaired or absent in three out of five cases of lepromatous leprosy. There was no predilection for any form of leprosy to show arterial changes more than the other. This study clearly demonstrates that the arterial involvement in leprosy is very frequent and must be playing an important role in causing mutilation and deformities of hands and feet.

Peripheral vascular deficit in leprosy.

There is considerable controversy regarding the frequency and significance of vascular lesions in leprosy. Thirty-five patients of leprosy under 40 years of age, without any local and systemic arterial disease, with normal looking hands and feet, were subjected to brachial arteriography. One patient also had posterior tibial arteriography. Diagnosis of leprosy was confirmed by bacteriologic and histopathologic technics. Biopsy material was studied from the area of radiographic abnormality, similar material was obtained from nine matched control subjects at autopsy. Skin thermometry and reflex vasodilatation were studied in eight cases. Various fractions of serum lipids and cholesterol were estimated in all patients and found to be within normal range. Arteriographic abnormalities such as occlusion, narrowing, tortuosity, dilatation, poststenotic dilatation, irregularity and incomplete filling of the lumen by radio-opaque material, were seen in more than two vessels in 50% of the arteriograms in wrist and palm; digital vessels showed abnormality in 75% to 94% of cases. The ulnar artery was more frequently involved (74%) than the radial (50%). Superficial and deep palmar arches were equally affected. Increased vascularity in hypothenar eminence area was seen in three arteriograms. Marked increase in arcuate vessels was noted in 60% of patients. Some arcuate vessels were serving as collaterals. Histologically, all grades of vessels including capilaries showed changes in nearly half of the patients. Reflex vasodilatation was lost in three patients of dimorphous leprosy, and impaired or absent in three of five patients of lepromatous leprosy. There was no predilection for any form of leprosy to show arterial changes more than others. This study clearly demonstrates that the vascular involvement in leprosy is very frequent and must be playing an important role in causing mutilations and deformities of hands and feet.