Introduction: Leprosy is a leading cause of physical disability due to weakness of muscles and loss of sensation. Due to the difference in immune response in the various forms of leprosy, Langerhans cells (antigen presenting cells) in the skin show a graded number in the various forms of leprosy patients. Materials and methods: a total of 44 cases were considered analysed by categorising according to Ridley and Joplin criteria. Paraffin blocks sections were stained with CD1A antibody using green coloured chromosen. Immuno - histochemistry studies where done using UltraVision LP detection system made by ThermoFisher Scientific. The number of epidermal, dermal and hair follicle Langerhans cells were counted. Result: There was no statistical significance between leprosy types on comparing with the dermal LC score. Whereas Mean value of epidermal LC score was significantly less in lepromatous leprosy (LL) (1.78) and was gradually increasing from borderline lepromatous type (BL) (2.44), borderline tuberculoid type(BT) (5.25) to tuberculoid leprosy (TT) (5.50). There was a statistically significant difference in number of Langerhan cells between BL and BT and between LL and TT (p=0.000). Conclusion: Progressive reduction in the number of Langerhans cells from tuberculoid subtype to lepromatous subtype was noted. Atrophy, epitheloid cells, giant cells, and nerve changes was seen more in tuberculoid pole than lepromatous pole. There is a statistically difference in the number of Langerhans cells between BL and BT and between LL and LT.
Infection by intracellular organism Mycobacterium leprae leads to host immune response which ranges from apparently none to severe manifestations resulting in a spectrum of clinical pathological manifestations in leprosy.
The most common method of infection appears to be direct or indirect contact with infective patients of leprosy. In skin, although infections may possibly take place through respiratory and alimentary routes.1 The transmission of leprosy is not yet fully understood.
After the anti-leprosy work in the country has been intensified, especially in the post-independence years after 1948 and particularly after the initiation of the National leprosy eradication program in 1955 by the Govt of India, the estimated number of cases has been rising. The main reason for the increase in the estimated number of cases is increased activity in the case finding program. A contributory factor in this respect is that, because of availability of the potent drugs for the treatment of the disease, an increase number of patients are voluntarily seeking treatment.
With various intervention introduced under NLEP in the last few years, number of new leprosy cases detected have come down to 75,394 in 2021-22 from 1,25,785 in 2014-15, accounting for 53.6% of global new leprosy cases.2
Though Leprosy is eliminated from India in a statistical point of view but from disease point of view it is still a challenge there are no active case finding strategies as it still depends on self-reporting or case detection at common health facility. There is a delay in self-reporting due to financial constraints and social stigma associated with the disease which can lead to hiding the disease. Sometimes ignorance about the disease can also lead to undetected cases in the rural setup.
Langarhans cells are important in pathogenesis of leprosy. 3 Langarhans cells represent unique dendritic antigen presenting cell populating epidermis. They are important contributors to the ongoing immune response through cellular and humoral interactions. 4,5 Langerhans cells make use of CD1a proteins to induce cellular immune response.
There is marked variation in clinical, histological and immunological features of leprosy from tuberculoid pole (TT) to lepromatous pole (LL). Due to difference in immunological responses, there is wide range of clinical expression in the various forms of leprosy which is caused by varied presentation of antigen. Langerhans cells show diverse number in various forms of leprosy and also significant difference in number in skin biopsy from healthy and affected sites in both lepromatous and tuberculoid leprosy.
CD1a is a non-polymorphic beta macroglobulin associated transmembrane glycoprotein. As an immune response in leprosy, T cells recognize lipid antigen and glycoprotein antigen presented by CD1a cells.
Previous studies have shown a direct correlation between numbers of T cells, CD1a cells with the effective immunity in both the poles of leprosy. 6,7,8
Very few studies have been published with CD 1a immuno staining to quantify Langarhans cells in skin regions of various subtypes of leprosy. The present study was planned to correlate the number of Langerhans cells in the skin with clinico- histopathological spectrum in patients with leprosy with the help of specific immuno staining of CD1a molecule.
Total cases studied were 44 including all the archive cases with paraffin blocks available in the department archives.
Relevant clinical details such as age, sex, site of biopsy, chief complaints, duration of symptoms, types of lesions and number of lesions were noted from the department tell database and hospital records. Histopathological findings were studied for each of the case using light microscopy and findings were tabulated.
Slides of diagnosed cases of leprosy stain with Hematoxicillin and Eosin where reviewed and then categorised into lepromatous leprosy (LL), borderline lepromatous (BL), borderline tuberculoid (BT) and tuberculoid leprosy (TT) according to Ridley and Jopling criteria. Sections where stained with Wade – Fite method for detection of mycobacterium where also reviewed.
From the paraffin blocks sections were cut and stained with CD1a antibody and green coloured chromosen was used instead of brown chromosome to facilitate differentiation from melanocyte. Immuno -histochemistry studies where done using UltraVision LP detection system made by ThermoFisher Scientific.
The number of epidermal dermal and hair follicle Langarhans cells was counted separately using a conventional light microscope
Statistical analysis included Mean and SD for continuous variable and for percentage of categorical variables t-test was used to compare the number of Langarhans cells in different sub types of leprosy. p value less than 0.05 considered statistically
Table 1: comparison of epidermal LC score, dermal LC score and hair follicle LC score (on IHC CD1a) with histological subtypes
|
|
Histological subtypes |
|||
|
|
LL |
BL |
BT |
TT |
Epidermal LC score |
0-1 |
1 |
0 |
0 |
0 |
1.1-2 |
8 |
6 |
1 |
0 |
|
2.1-3 |
0 |
2 |
1 |
0 |
|
3.1-4 |
0 |
1 |
6 |
3 |
|
4.1-5 |
0 |
0 |
3 |
1 |
|
5.1-6 |
0 |
0 |
4 |
0 |
|
6.1-7 |
0 |
0 |
3 |
1 |
|
7.1-8 |
0 |
0 |
2 |
0 |
|
8.1-9 |
0 |
0 |
0 |
1 |
|
Dermal LC score |
0 |
5 |
1 |
7 |
0 |
1 |
2 |
3 |
2 |
3 |
|
2 |
1 |
1 |
2 |
1 |
|
3 |
0 |
0 |
0 |
2 |
|
4 |
0 |
0 |
2 |
0 |
|
5 |
0 |
2 |
0 |
0 |
|
6 |
0 |
0 |
3 |
0 |
|
8 |
0 |
0 |
3 |
0 |
|
10 |
0 |
0 |
1 |
0 |
|
12 |
1 |
1 |
0 |
0 |
|
13 |
0 |
1 |
0 |
0 |
|
Hair follicle LC score |
2 |
0 |
0 |
2 |
0 |
3 |
1 |
1 |
0 |
0 |
|
4 |
1 |
1 |
1 |
0 |
|
5 |
1 |
0 |
0 |
0 |
|
6 |
0 |
2 |
2 |
0 |
|
7 |
0 |
0 |
1 |
0 |
|
8 |
0 |
0 |
1 |
0 |
Table 2: statistical analysis of epidermal LC score and dermal LC score (on IHC CD1a) between various histological subtypes
LC Score |
Histopathological subtype |
N |
Mean |
p value |
Epidermal LC score between LL and BL |
LL |
9 |
1.78 |
0.06 |
BL |
9 |
2.44 |
||
Epidermal LC score between BL and BT |
BL |
9 |
2.44 |
0.00 |
BT |
20 |
5.25 |
||
Epidermal LC score between BT and TT |
BT |
20 |
5.25 |
0.76 |
TT |
6 |
5.50 |
||
Epidermal LC score between LL and LT |
LL |
9 |
1.78 |
0.00 |
LT |
6 |
5.50 |
||
Epidermal LC score between Lepromatous and tuberculoid |
LEPROMATOUS |
18 |
2.1 |
0.00 |
TUBERCULOID |
26 |
5.31 |
||
Dermal LC score between LL and BL |
LL |
9 |
1.78 |
0.220 |
BL |
9 |
4.44 |
||
Dermal LC score between BL and BT |
BL |
9 |
4.44 |
0.474 |
BT |
20 |
3.30 |
||
Dermal LC score between BT and TT |
BT |
20 |
3.30 |
0.318 |
TT |
6 |
1.83 |
||
Dermal LC score between BT and TT |
LL |
9 |
1.78 |
0.974 |
TT |
6 |
1.83 |
||
Dermal LC score between Lepromatous and tuberculoid |
LEPROMATOUS |
18 |
3.11 |
0.897 |
TUBERCULOID |
26 |
2.96 |
Out of 44 cases in 14 cases 31% per female and 30 cases 69% where males.
9 cases (20%) where diagnosed as laparomatous leprosy, 9 cases (20%) where diagnosed as borderline lepromatous, 20 cases (46%) where diagnosed as border line tuberculoid and 6 cases (14%) where diagnosed as tuberculoid leprosy.
While comparing the histopathological diagnosis and clinical diagnosis it was found that all the cases where concurred with both clinical and histopathological diagnosis considering one spectrum deviation as acceptable. 9
82% of cases had received no treatment for leprosy earlier whereas 18% had received treatment for leprosy
In the present study,
23 cases of total had extensive atrophy of epidermis (1- LL, 7 - BL, 12 - BT, 3 - TT type).
9 cases of total had extensive lymphocytic infiltration (3 - LL type 2, 2 – BL, 3 – BT, 1 – TT variety).
35 cases of total had foamy macrophages (9- LL, 13 – BT, 4 – TT type).
33 cases of the total had epitheloid cell infiltration (2- LL, 5 – BL, 20 – BT, 6 – TT type).
26 cases of total had giant cell (4 – BL, 17 – BT, 5 – TT type)
29 cases of total had nerve thickening (5 – LL, 6 – BL, 15 – BT, 3 – TT type)
Atrophy, epitheloid cells, giant cells, and nerve changes was seen more in tuberculoid pole than lepromatous pole.
In a study done by Sieling et al.8 on LC using CD1a stain showed that the number of LC in epidermis with leprosy lesions is closely related to the extent of cutaneous cell mediated immune response. There was an increase of LC cells in epidermis of Tuberculoid variant, which was due to recruitment of CD1a precursor cells from the bone marrow or adjacent skin. The CD1a restricted T cells that recognize the mycobacterial antigen is now identified as CD8+ Tcell.
In a similar study done by M. F. Gimenez et al. 10 using OKT6 stain showed that there was a marked reduction in the number of LC in the epidermis of Lepromatous variant regardless of biopsy specimen taken from involved or uninvolved site. Similar reduction of CD1a+ epidermal LC per HPF was noted by R. B. Narayanan et al. 11 in lepromatous leprosy.
In the present study, mean value of epidermal LC score was significantly less in LL (1.78) and was gradually increasing from BL type (2.44), BT type (5.25) to TT type (5.50). There was a statistically significant difference in number of LC between BL and BT and between LL and TT (p=0.000). These findings were similar to the findings in other similar studies. 11,12,13
There was no statistical significance between leprosy types on comparing with the dermal LC score. Similar findings were also seen in study done by Azadeh et al.3
The present study also showed an increase in LC near the entry of hair follicle in epidermis. This is also comparable to the findings by Azadeh et al.3
Significant reduction in prevalence of leprosy was found worldwide in 2020 (0.23 / 10,000 population). Leprosy, though eliminated from India from a statistical point of view, it still remains a challenge. Financial hurdles, social stigma and even rigorous case finding programs have led to increase in number of estimated cases within the country. Since the impact of finding one new case of leprosy is huge, histopathological examination of skin biopsy is recommended in all clinically suspected cases of leprosy for accurate diagnosis and treatment and to prevent nerve damage and permanent disabilities.