Table 5.
Human studies on ENL investigating other immunological factors.
| Reference; study site(s) | Study population | Timing of sampling | MDT status | ENL treatment status | Type of samples | Measures | Findings |
|---|---|---|---|---|---|---|---|
| Waters et al. (22); United Kingdom and Malaysia β | 38 lepromatous ENL | ND | ND | ND | Serum | Immunoglobulins | No differences in immunoglobulin levels |
| Reichlin et al. (180); Malaysia | 13 LL of which 7 ENL | ND | ND | ND | Blood | Euglobulin IgG | Levels of euglobulin IgG higher in the ENL-positive patients than in ENL-negative patients |
| Serum IgG | |||||||
| Anthony et al. (60); India β | 25 LL ENL, 10 LL without ENL | Active ENL lesions? | ND | ND | Serum | Immunoglobulins | High levels of immunoglobulins in both LL and ENL |
| Harikrishan et al. (71); India β | 20 active LL; 15 ENL during active and subsided phase; 20 HC | ENL: during the active and subsided phase | ND | ND | Plasma | Immunoglobulins IgG, IgM, IgA | Serum levels of IgG and IgM during subsidence of ENL were significantly lower compared to that during the active phase of ENL |
| Humphres et al. (181); USA | 14 LL ENL, 28 BL/LL, 21 HC | Multiple Serial sampling | 10/19 LL patients untreated, 9/19 LL patients Dapsone | Corticosteroids day prior to initial assay for NK activity and was continued through treatment | PBMC | Natural killer cell activity | Natural killer cell activity significantly depressed in ENL |
| Rea and Yoshida (182); USA | 108 leprosy (4 untreated ENL, 14 dapsone-treated active ENL, 10 dapsone-treated inactive ENL), 25 HC | ND | 54 untreated patients and others dapsone-treated | Untreated | Blood | Macrophage migration inhibition activity | Positive serum inhibitory activity strongly associated with reactional states (ENL or T1R or Lucio’s reaction) in both treated and untreated patients |
| Miller et al. (183); USA | 9 leprosy: 3 T1Rs and 2 ENL | Serial sampling from date of initiation of therapy until the first year of treatment | On MDT | Reactional episodes were treated with corticosteroids and 1 ENL received thalidomide | Plasma | Antibodies to Mycobacterial Arabinomannan | High levels of antibody to Arabinomannan in 2 ENL patients |
| Narayanan et al. (89); India γ | 35 leprosy patients: 7 LL with ENL, 6 BT, 6 BT with T1R, 4 BL, 5BL with T1R, 8 LL | ND | ND | ND | Skin | B cells | No increase of B cells in any of the lesions |
| Rea et al. (96); USA γ | 19 ENL, 67 BL/LL 4 LL with Lucio’s, 13 T1R, 18 Tuberculoid, 13 Tuberculoid long-term treatment | ND | Some patients on MDT | ENL before receiving thalidomide | PBMC | B-cells | B-cell percentage in the PBMC of ENL similar LL |
| Schwerer et al. (184); USA | 121 leprosy (including ENL), 28 contacts, 15 HC | ND | ND | ND | Serum | Anti-PGL I IgM levels | Serum anti-PGL I IgM levels lower in ENL compared to patients with comparable BI |
| Andreoli et al. (40); India | 12 ENL | ND | All patients on MDT with specified duration | Treated with prednisone and/or thalidomide | Serum | Circulatory IgM antibody levels to the PGL I; IgM, IgG, IgA antibody levels to M. leprae antigenic preparation | During ENL: decrease of circulatory IgM antibody levels to PGL I but no significant change to IgG, IgM or IgA antibody levels to the soluble antigens from M. leprae |
| Laal et al. (94); India γ | 15 ENL, 13 LL | During active ENL and 1 week to 4 months after stopping treatment | Treatment with combination antileprosy drugs was continued throughout | First sample before initiation of antireactional treatment; second sample 1 week to 4 months after treatment | PBMC | B cells | B-cell percentages in PBMC of ENL patients were similar to those of uncomplicated LL |
| Blavy et al. (185); Senegal | 34 ENL and 50 leprosy patients | ND | ND | ND | Lymphocytes | HLA phenotyping | Not significant findings of any HLA phenotype regarding ENL |
| Levis et al. (186); USA | ND | ND | ND | ND | Serum | IgM and IgG antibodies to PGL-I | ENL lower anti-PGL-I IgM than non-ENL of comparable BI |
| Rao and Rao (123); India γ | 44 ENL, 39 LL, 22 post-ENL | ENL cases before starting treatment for ENL, post-ENL after the patient had not taken anti-inflammatory drugs or steroids for at least 3 and 7 days | From 39 non-reactional: 20 untreated and 19 with dapsone for less than a year | ENL before starting ENL treatment, post-ENL after the patient had not taken anti-inflammatory drugs or steroids for at least 3 and 7 days | Blood | B lymphocytes in peripheral blood | B cells: no difference between groups |
| Sehgal et al. (76); India β | 21 patients with leprosy reactions either T1R or ENL | ND | ND | ND | B-cells | Percentage and absolute count of B-cells; Immunoglobulins IgG, IgA, IgM | During ENL a significant increase in the percentage and absolute count of B-lymphocytes Significantly elevated serum immunoglobulin values after subsidence of ENL |
| Serum | |||||||
| Levis et al. (187); USA | 40 ENL, 63 leprosy without ENL, HC | ND | ND | ND | Serum | IgM antibody to PGL-I; IgM and IgG Abs to M.tb and M. leprae LAM | No correlation between IgM or IgG Ab to LAM and bacillary index |
| Rao and Rao (85); India | 44 ENL, 39 lepromatous, 22 post-ENL | ENL blood before starting ENL treatment, post-ENL after patient does not take any anti-inflammatory drugs or steroids for the last 3 or 7 days | 20 patients no previous MDT and 19 treated with dapsone | Before starting treatment with anti-inflammatory drugs or steroids | Blood | Leukocyte migration inhibition test | Lower migratory indices to whole M. leprae during ENL |
| Rao and Rao (78); India β | 44 ENL, 39 BL/LL, 22 post-ENL | ENL before starting anti-ENL treatment, post-ENL ensuring that the patient had not taken anti-inflammatory drugs or steroids for at least 3 or 7 days | 20 BL/LL untreated and 19 BL/LL treated with dapsone | Before starting treatment with steroids or anti-inflammatory drugs | Serum | IgG, IgA, IgM | IgG and IgM decreased in ENL than lepromatous and post-ENL |
| Serum IgA elevated in ENL than lepromatous group and further increase post-ENL | |||||||
| Filley et al. (168); India δ | 7 ENL | Before, during and after the episode | All patients on MDT | ENL was treated with steroids and/or thalidomide | Serum | %GO | During ENL%GO transiently raised, and this rise parallels an increase in circulating IL2R |
| Bhoopat et al. (127); Thailand γ | 57 ENL (19 acute/38 chronic), 61 active LL, 33 control patients whose leprosy had been cured | 26 BL and 35 LL newly diagnosed and untreated | ND | When treatment with corticosteroids and/or thalidomide was initiated precise timing was recorded with respect to the time of collection of specimens | Blisters induced over a representative skin lesion | IgM antibody to PGL-I and Tac peptide | IgM antibody to PGL-I and Tac peptide levels were elevated in chronic ENL lesions |
| Corticosteroids reduced IgM antibody to PGL-I but did not change the levels of Tac peptide | |||||||
| Ramanathan et al. (49); India β | 26 BL/LL of which 11 ENL, 24 HC | Blood was taken before initiation of treatment and then to 2-month intervals up to 20 months | Untreated and then on MDT samples every 2 months | Treated but after blood sampling | Serum | IgG, IgA and IgM | ENL no significant relation with immunoglobulin levels |
| Sullivan et al. (173); USA δ | ND | ND | ND | ND | Skin | ICAM-1, ICAM-1 ligand LFA-1 | Prominent keratinocyte ICAM-1 expression |
| Scollard et al. (82); Thailand β | 4 cured leprosy, 10 leprosy (5BT, 3BL, 2LL), 8 ENL patients (5LL and 3BL), 3 T1R, 4 HC | ND | ND | ND | Blisters induced over representative skin lesion | Immunoglobulins (IgG, IgA, IgM) to whole M. leprae and to PGL-I | No statistically significant difference regarding immunoglobulins |
| Sera | |||||||
| Sehgal et al. (188); India | 25 leprosy with reactions (of which 11 ENL), 20 leprosy without reactions, 10 HC | ND | On MDT | Reactional patients on prednisolone | Lymphocytes | Lymphocyte adenosine deaminase activity (L-ADA) | The patients with leprosy reactions (both ENL and T1Rs) had higher enzyme l-ADA than controls (the enzyme has a role in activation, differentiation and proliferation of lymphocytes) |
| Sampaio et al. (139); Brazil δ | 49 BL/LL of which 24 ENL | ENL at the time of developing ENL, during thalidomide treatment, or after thalidomide treatment | MDT was continued through the study | Certain ENL during thalidomide treatment | Skin biopsies | MCH II and ICAM-1 in histology | MHC II and ICAM-1 on epidermal keratinocytes in ENL downregulated with thalidomide |
| Santos et al. (129); Brazil γ | 10 ENL, 59 LL/BL, 4 T1R, 4 post-reactional | ND | On MDT | No antireactional treatment before blood collection | PBMC, Monocytes | Monocyte activation by procoagulant activity, HLA-DR | No significant difference in monocyte activation between the different groups No significant differences in HLA-DR between groups |
| Singh et al. (189); India | 44 active ENL, 48 prior history of ENL, 125 stable lepromatous, 40 HC not endemic | ND | ND | Untreated samples | Serum | Antibodies against B cell epitopes of M. leprae recombinant protein LSR | Antibodies against a specific distinct peptide region only in patients undergoing ENL |
| Kifayet and Hussain (190); Pakistan | 67 BL/LL acute ENL, 83 non-reactional BL/LL, 77 endemic HC | ND | Most on MDT but 83 non-reactional less than 2 weeks of MDT | ND | Plasma | M. leprae-specific IgG subclasses | Lower concentrations of all IgG subclasses during ENL but lower IgG1 and IgG3 during ENL before treatment |
| Kifayet et al. (191); Pakistan | 13 ENL acute and post-remission of reaction, 16 non-reactional stable LL, 32 endemic HC | During acute ENL (n = 13) and after the reaction has subsided | ND | ND | Plasma | IgG subclasses M. leprae-specific antibodies; Detection and enumeration of antibody-secreting B cells by ELISPOT | Polyclonal IgG1 elevated in acute ENL compared LL controls and decreased when ENL subsided IgG2 antibodies lower during acute ENL and increased after reaction has subsided Discrepancy in serum concentrations and B cell frequency |
| B-cells | |||||||
| Vieira et al. (131); Brazil γ, δ | 95 MB leprosy (30 LL and 65 BL) of which 51 ENL | At leprosy diagnosis and at onset of reactional episode | Time of MDT for each ENL patients in study | Sample before thalidomide and steroids? | Serum | Circulating anti-neural and antimycobacterial antibodies | Detection of anti-neural (anti-ceramide and anti-galactocerebroside) antibodies in ENL sera |
| No difference between reactional and non-reactional lepromatous patients regarding IgM antibodies | |||||||
| Higher levels of anti-ceramide IgM and diminished levels of anti-galactocerebroside antibodies in reactional compared to non-reactional patients | |||||||
| Rojas et al. (50); Brazil β | 19 ENL, 10 BL/LL non-ENL patients, 13 family contacts; 15 healthy non-contacts | ND | Both untreated patients and patients on MDT for 1-72 months | ND | Serum | Anti-PGL-I IgM, IgG responses to recombinant 10-kDa heat shock protein | IgM anti-PGL-I and IgG anti-10-kDa heat shock protein antibodies were constituents of the immune complexes in patients with ENL while free antibody levels did not differentiate between ENL and non-ENL patients |
| Beuria et al. (192); India | 18 ENL, 44 BL/LL, 62 BT/TT, 17 HC | ND | Most patients on MDT | ND | Serum | IgG subclass levels to M. leprae sonicated antigens (MLSA) and PGL-I | ENL patients showed a significant fall in IgG3 antibody to MLSA and PGL-I compared to BL/LL leprosy controls |
| Freire et al. (193); Brazil | 59 leprosy (including 12 ENL), 60 HC | ND | 11/12 ENL were on MDT and 1/12 with dapsone | ND | Serum | Anti-neutrophil cytoplasmic antibodies (ANCA) | ANCA are present in 28.8% of leprosy patients but are not related to vasculitis in the ENL reaction and are not a marker of a specific clinical from |
| Partida-Sanchez et al. (142); Mexico δ | 9 ENL, 10 non-ENL leprosy, 10 HC | Beginning of reaction and after 1 and 2 months of thalidomide | All patients on MDT | Before thalidomide, second sample after 1 month of thalidomide and third after 2 months | Plasma | IgM and IgG antibody subclasses to M. leprae sonicated extract | ENL at the onset of reaction had slightly higher anti-M. leprae IgG1 and IgG2 antibodies compared to non-ENL but not statistically significant |
| Stefani et al. (194); Brazil | 600 leprosy: 31 ENL, 45 T1R, HC | Untreated | Before MDT treatment | Untreated | Serum | IgM and IgG anti-PGL-I | Patients presenting with T1R or ENL at leprosy diagnosis have same level of IgM anti-PGL-I antibody response as leprosy patients without reactions at diagnosis |
| Beuria et al. (195); India | 44 BL/LL, 62 TT/BT, 18 ENL, 15 T1R, 17 HC | ND | BL/LL: 90% on MDT | Steroids after collection of samples | Serum | IgG1, IgG2, IgG3 and IgG4 to LAM | Reduction in IgG3 in ENL compared to active BL/LL Higher IgG1 in ENL than T1R |
| TT/BT: mostly untreated | |||||||
| Hamerlinck et al. (196); Philippines, Netherlands | 13 ENL, 22 T1R, 26 leprosy unreactional, 10 HC | Serial samples during MDT: 2 ENL follow-up and received corticosteroids, 14 leprosy free of reactions, 4 T1R 6, 12, 18, 30 months during follow-up | 13 ENL before MDT, 2 ENL during MDT | During ENL before treatment | Serum | Neopterin | T1R and ENL higher neopterin levels compared to non-reactional individuals Corticosteroid treatment reduces levels of neopterin |
| Mahaisavariya et al. (197); Thailand | 95 leprosy patients: 63 non-reactional, 19 T1R, 13 ENL | A biopsy at time of diagnosis and an additional biopsy later, in some cases at the time of reaction | ND | Before antireactional treatment? | Skin | Mast cells | Reduction of mast cell counts in both T1R and ENL compared to non-reactional patients |
| Schon et al. (198); Ethiopia | 4 ENL, 5 T1R | ND | ENL cases: 2 MDT untreated and 2 MDT-treated | Steroids | Urine | Urinary levels of metabolites of NO | Urinary nitric oxide metabolites decreased significantly after steroid treatment |
| Antunes et al. (199); Brazil | 3 ENL, 3 T1R | First biopsy during reactional episode and second during remission | On MDT | Thalidomide for ENL | Skin | Neuropeptides; quantification of mast cells and their subsets | Increase mast cells in the inflammatory infiltrate of the reactional (both T1R and ENL) biopsies compared to non-reactional |
| Rada et al. (200); Venezuela | 29 ENL, 19 MB not reactional, 11 PB, 28 HC | Before treatment | Untreated samples | Untreated samples | Serum | Nitrite/Nitrate levels | Supernatants of PBMC from ENL patients significantly elevated levels of nitrite/nitrates compared to LL or tuberculoid leprosy |
| PBMC | |||||||
| Sunderkotter et al. (201); Brazil | Skin Biopsies: 41 non-reactional leprosy, 8 ENL, 10 T1R; Serum samples: 16ENL, 5RR, 7TT, 13BT/BB/LL, 19 HC | Untreated samples | Skin biopsies: 42 untreated non-reactional leprosy | Before treatment with steroids or thalidomide | Serum Skin |
MRP8, MRP14 | Increase of serum levels of MRP8 and MRP14 in ENL Higher percentage of MRP8+ and MRP14+ cells in ENL skin lesions than non-reactional |
| 8 ENL of which 5 MDT | |||||||
| Nigam et al. (202); India | 80 leprosy: 10 ENL and 10 T1R; 20 HC | ND | ND | ND | Serum | Deaminase | Deaminase levels were higher in patients with reaction |
| Villahermosa et al. (134); Philippines γ, δ | 22 ENL | Before thalidomide administration and at study weeks 3 and 7 during thalidomide treatment | MDT was continued during the study | Samples untreated for antireactional drugs and during thalidomide treatment | Urine | Neopterin | ENL higher neopterin values in urine than HC |
| Iyer et al. (143); Indonesia δ | 131 leprosy patients (44 ENL), 112 HC | ND | Patients were classified irrespective of MDT status | Prednisolone to treat reactions | Plasma | Neopterin | Neopterin no significant difference between ENL and non-ENL |
| Mohanty et al. (203); India | 14 ENL before and after resolution of ENL, 5 LL | Before commencing antireactional therapy and after resolution of ENL | All patients on MDT | Before commencing antireactional treatment | Urine | Urinary nitric oxide metabolites | Urinary nitric oxide metabolite higher in ENL compared to non-reactional LL |
| These levels were reduced with resolution of reaction following antireactional therapy | |||||||
| Santos et al. (204); Brazil | 8 leprosy: 3 ENL | ND | MDT during the study: length of MDT described | Thalidomide during the study | PBMC | B7-1 expression (flow cytometry and IHC) | Higher B7 expression in ENL and T1R patients than non-reactional in both PBMC and cutaneous lesions |
| Skin | |||||||
| Silva et al. (205); Brazil | 25 leprosy: 5 ENL and 8 T1R | 0, 2, 4, 6, and 12 months of MDT | All patients on MDT | Untreated | Plasma | PGL-I levels | Serum PGL-I levels did not differ significantly between ENL and non-ENL |
| Neopterin | No significant correlation of neopterin between ENL and non-ENL | ||||||
| Brito Mde et al. (206); Brazil | 104 reactions after completion of MDT (44 ENL), 104 with no post-treatment reactions (8 ENL) | ND | All patients were treated with MDT; half had finished MDT | ND | Plasma | ML flow (IgM anti-PGL-I positive serology) | The patients with positive serology after MDT presented a 10.4 fold greater chance of developing post-treatment reactions (ENL or T1R) |
| Iyer et al. (207); Indonesia | 78 leprosy (36 ENL and 3 T1R), 36 HC | ND | 30 untreated and 48 treated patients | Reactions were treated using prednisolone | Serum | Chitotriocidase | Serum chitotriosidase activity elevated in ENL compared with HC but not with non-ENL leprosy |
| Skin | Significant decline of serum chitotriosidase following corticosteroid treatment in ENL | ||||||
| Lee et al. (24); USA α | 6 ENL, 7 LL | ND | ND | ND | Skin | Microarrays and gene expression; IHC for E-selectin | Upregulation of gene expression: in ENL lesions of the selectin family of adhesion molecules |
| IHC: higher levels of E-selectin in ENL lesions | |||||||
| Massone et al. (116); Brazil γ | 20 leprosy biopsies (3 ENL) | Biopsies at the time of diagnosis | 10, 12 and 13 months after beginning of MDT for LL | Untreated | Skin | Presence, frequency and distribution of plasmacytoid dendritic cells | CD123 expression was observed in 2/3 ENL biopsies |
| Rada et al. (135); Venezuela γ | 81 LL, 41 BL, 41 BB, 3% BT | ND | ND | ND | Blood | Serological immunological tests to various mycobacterial proteins | Mean antibody values against complete mycobacterial proteins higher in non-reactional individuals |
| Teles et al. (176); Brazil δ | 32 leprosy: 10 ENL, 8 T1R | 4 ENL patients before and during reaction biopsy samples | All patients were receiving MDT | ND | Skin | MMP-2, MMP-9, TIMP-1 | RT-PCR for MMP-2 and MMP-9 versus TIMP-1 in ENL sequential samples in 4 ENL patients: TNF-α, MMP-2 and MMP-9 mRNA enhanced IHC and confocal microscopy: absence of MMP positivity in ENL epidermis ELISA in sera of ENL: elevated MMP-9 but not TIMP-1 compared to non-reactional patients |
| Serum | |||||||
| Jadhav et al. (149); India δ | 303 MB followed up for 2 years: 5 ENL | Serum samples at the time of recruitment | Newly registered MB patients: no MDT | Untreated | Serum | Antibodies to PGL-I, LAM, ceramide, S100 | No statistically significant outcome for ENL |
| Lockwood et al. (178); India δ | 303 new MB leprosy (13 ENL) | Skin biopsies at enrollment | Before MDT treatment started | Before antireactional treatment | Skin | Immunostaining for CD68 and iNOS | Reactional biopsies had significantly fewer CD68+ cells than non-reactional |
| Nearly all biopsies in the LL group had CD68+ cells present and these were not altered in ENL | |||||||
| Nerve | ENL showed some iNOS staining but not significant differences with non-ENL | ||||||
| Martiniuk et al. (179); Nepal and USA δ | 7 ENL | Pre- and post-treatment with thalidomide | ND | Pre- and post- treatment with thalidomide | Skin | RT-PCR for hRORγT, hCD70, hCD27, hPLZF-1, hCTLA4, hAHR, hiNOS2, hARNT, hIDO, hGARP, hCD46 | Reduction in CD70, GARP, IDO and increase of RORγT, ARNT following thalidomide treatment |
| Singh et al. (208); India | 240 leprosy: 19 ENL, 69 BL/LL | ND | ND | ND | Serum | IgG antibodies against keratin | No significant difference in ENL |
| Dupnik et al. (58); Brazil β, δ | 11 ENL, 11 T1R, 19 leprosy controls without reactions for microarray; additional 28 leprosy (6 ENL, 11 T1R, 11 non-reactional) for qPCR validation; 3 ENL for IHC | ND | 3/11 ENL pre-treatment, 2/11 ENL on treatment and 6/11 post-treatment; leprosy controls matched for stage of treatment | Excluded patients on steroids within 7 days and thalidomide within 28 days of enrollment | PBMC | Microarray and qPCR for transcriptional profile of PBMC; Flow cytometry for monocyte populations | Top 3 KEGG pathways in ENL were S.aureus infection, SLE, cytokine-cytokine receptor interaction |
| No significant difference in the proportion of circulating monocytes between reactional and non-reactional PBMC | |||||||
| Mandal et al. (209); India | 15 reactional (both ENL and T1R), 15 HC | ND | ND | ND | PBMC | Vitamin D receptor (VDR) mRNA | All the individuals with low VDR expression manifested ENL |
| Dias et al. (80); Brazil δ | 30 ENL, 24 BL/LL, 31 HC | Upon diagnosis of reaction | BL/LL before MDT but most ENL on MDT | Before treatment with thalidomide or steroids | PBMC (monocytes, B-cells, pDCs) | Expression of TLR9 | Skin lesions and PBMC of ENL express higher levels of TLR-9 |
| Skin | |||||||
| Schmitz et al. (25); Brazil α | 62 leprosy: 22 ENL, 16 HC | ENL: before and 7 days after thalidomide | Patients before and after MDT | Before and after thalidomide | Skin | CD64 expression by qPCR and IHC | CD64 mRNA and protein expressed in ENL lesions |
| Thalidomide reduced CD64 expression | |||||||
α, also in Table 1; β, also in Table 2; γ, also in Table 3; δ, also in Table 4.
BB, mid-borderline leprosy; BL, borderline lepromatous leprosy; BT, borderline tuberculoid leprosy; ENL, erythema nodosum leprosum; HC, healthy controls; ICAM-1, keratinocyte intracellular adhesion molecule 1; ICs, immune complexes; LAM, lipoarabinomannan; LL, lepromatous leprosy polar; MLSA, M. leprae sonicated antigens; ND, not described; PGL I, phenolic glycolipid I; SLE, systemic lupus erythematosus; TB, tuberculosis; TT, tuberculoid leprosy; polar,%GO, proportion of oligosaccharide chains on the Fc fragment of IgG which terminate with N-acetylglucosamine and not galactose.