Utility of measuring serum levels of anti-PGL-I antibody, neopterin and C-reactive protein in monitoring leprosy patients during multi-drug treatment and reactions.

OBJECTIVE: To verify the validity of measuring the levels of Mycobacterium leprae-specific anti-phenolic glycolipid (PGL)-I antibody, neopterin, a product of activated macrophages, and C-reactive protein (CRP), an acute phase protein, in serial serum samples from patients for monitoring the leprosy spectrum and reactions during the course of multi-drug treatment (MDT). METHODS: Twenty-five untreated leprosy patients, 15 multi-bacillary (MB) and 10 paucibacillary (PB), participated. Eight patients developed reversal reaction and five developed erythema nodosum leprosum (ENL) during follow-up. The bacterial index (BI) in slit-skin smears was determined at diagnosis and blood samples collected by venipuncture at diagnosis and after 2, 4, 6 and 12 months of MDT. PGL-I antibody and neopterin were measured by enzyme-linked immunosorbent assay, whereas the CRP levels were measured by the latex agglutination method. RESULTS: The levels of PGL-I antibodies and neopterin were higher in the sera of MB than PB patients, which correlated with the patients' BI. The serum levels of CRP did not differ significantly between the MB and PB patients. The serum levels of PGL-I and neopterin were no higher in reactional patients than non-reactional patients prone to such reactions. However, ENL patients had higher serum CRP levels than non-reactional MB patients. The serum PGL-I antibody levels declined significantly during MDT, in contrast to neopterin and CRP levels. CONCLUSION: Measuring the serum levels of PGL-I antibodies and neopterin appeared to be useful in distinguishing MB from PB patients, whereas monitoring the levels of PGL-I antibodies appeared to be useful in monitoring MB patients on MDT. Measuring serum CRP, although not useful in monitoring the patients, has limited significance in detecting ENL reactional patients.

Serum levels of interferon-gamma, tumour necrosis factor-alpha, soluble interleukin-6R and soluble cell activation markers for monitoring response to treatment of leprosy reactions.

Identifying pathogen and host-related laboratory parameters are essential for the early diagnosis of leprosy reactions. The present study aimed to clarify the validity of measuring the profiles of serum cytokines [interleukin (IL)-4, IL-6, IL-10, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha], the soluble IL-6 receptor (sIL-6R), soluble T cell (sCD27) and macrophage (neopterin) activation markers and Mycobacterium leprae-specific anti-PGL-I IgM antibodies in relation to the leprosy spectrum and reactions. Serum samples from 131 Indonesian leprosy patients (82 non-reactional leprosy patients and 49 reactional) and 112 healthy controls (HC) from the same endemic region were investigated. Forty-four (89.8%) of the reactional patients had erythema nodosum leprosum (ENL) while only five (10.2%) had reversal reaction (RR). Follow-up serum samples after corticosteroid treatment were also obtained from 17 of the patients with ENL and one with RR. A wide variability in cytokine levels was observed in the patient groups. However, IFN-gamma and sIL-6R were elevated significantly in ENL compared to non-ENL patients. Levels of IFN-gamma, TNF-alpha and sIL-6R declined significantly upon corticosteroid treatment of ENL. Thus, although the present study suggests limited applicability of serial measurement of IFN-gamma, TNF-alpha and sIL-6R in monitoring treatment efficacy of ENL, reactions it recommends a search for a wider panel of more disease-specific markers in future studies.

Serial measurement of serum cytokines, cytokine receptors and neopterin in leprosy patients with reversal reactions.

Serum levels of cytokines (IL-4, IL-5, IFN-gamma, TNF-alpha), cytokine receptors (TNFR I and II) and one monokine (neopterin) were estimated in seven leprosy patients to establish disease associated markers for reversal reactions (RR). Sera were collected at diagnosis of leprosy, at the onset of reversal reaction and at different time points during and at the end of prednisone treatment of reactions. It was expected that the serum cytokine and monokine profile before and at different time points during reactions would provide guidelines for the diagnosis and monitoring of reversal reactions in leprosy. The cytokines and cytokine receptors were measured by ELISA, whereas a radioimmunoassay was used for neopterin measurement. Six of the seven patients showed increased levels of neopterin either at the onset of RR or 1 month thereafter, and levels declined on prednisone treatment to that seen at the time of diagnosis without reactions. No consistent disease associated cytokine profile was observed in these patients. Interestingly, serum TNF-alpha levels were increased in the same patients even after completion of prednisone treatment, indicating ongoing immune activity. In conclusion, this study demonstrates that despite cytokines levels in leprosy serum being inconsistent in relation to reversal reactions, serum neopterin measurement appears to be an useful biomarker in monitoring RR patients during corticosteroid therapy.