A role for interleukin-5 in promoting increased immunoglobulin M at the site of disease in leprosy.

Leprosy is an infectious disease in which the clinical manifestations correlate with the type of immune response mounted to the pathogen, Mycobacterium leprae. To investigate which biological pathways or gene sets are over-represented in lepromatous (L-Lep) versus tuberculoid (T-Lep) patients that might be relevant in disease pathogenesis, we compared the gene expression profiles of L-lep versus T-lep skin lesions using knowledge-guided bioinformatic analysis, incorporating data on likely biological functions, including gene ontology information and regulatory data. Analysis of probe sets comparatively increased in expression in L-lep versus T-lep revealed multiple pathways and functional groups involving B-cell genes (P values all < 0.005) relevant to the dataset. Further pathways analysis of B-cell genes comparatively increased in expression in L-lep versus T-lep lesions revealed a potential network linking the expression of immunoglobulin M (IgM) and interleukin-5 (IL-5). Analysis of the leprosy lesions by immunohistology indicated that there was approximately 8% more IgM-positive cells in L-lep lesions than in T-lep lesions. Furthermore, IL-5 synergized in vitro with M. leprae to enhance total IgM secretion from peripheral blood mononuclear cells. This pathways analysis of leprosy in combination with our in vitro studies implicates a role for IL-5 in the increased IgM at the site of disease in leprosy.

Thalidomide treatment reduces tumor necrosis factor alpha production and enhances weight gain in patients with pulmonary tuberculosis.

BACKGROUND: The monocyte-derived cytokine, tumor necrosis factor alpha (TNF alpha), is essential for host immunity, but overproduction of this cytokine may have serious pathologic consequences. Excess TNF alpha produced in pulmonary tuberculosis may cause fevers, weakness, night sweats, necrosis, and progressive weight loss. Thalidomide (alpha-N-phthalimidoglutarimide) has recently been shown to suppress TNF alpha production by human monocytes in vitro and to reduce serum TNF alpha in leprosy patients. We have therefore conducted a two-part placebo-controlled pilot study of thalidomide in patients with active tuberculosis to determine its effects on clinical response, immune reactivity, TNF alpha levels, and weight. MATERIALS AND METHODS: 30 male patients with active tuberculosis, either human immunodeficiency virus type 1 positive (HIV-1+) or HIV-1-, received thalidomide or placebo for single or multiple 14 day cycles. Toxicity of the study drug, delayed type hypersensitivity (DTH), cytokine production, and weight gain were evaluated. RESULTS: Thalidomide treatment was well tolerated, without serious adverse events. The drug did not adversely affect the DTH response to purified protein derivative (PPD), total leukocyte, or differential cell counts. TNF alpha production was significantly reduced during thalidomide treatment while interferon-gamma (IFN gamma) production was enhanced. Daily administration of thalidomide resulted in a significant enhancement of weight gain. CONCLUSIONS: The results indicate that thalidomide is well tolerated by patients receiving anti-tuberculosis therapy. Thalidomide treatment reduces TNF alpha production both in vivo and in vitro and is associated with an accelerated weight gain during the study period.

Role of rifampicin in arthralgia induced by pyrazinamide

Arthralgia during daily treatment with chemotherapy regimens containing pyrazinamide was found to be considerably less in patients who received rifampicin concomitantly...