B cell hyperactivity is a function of T cell derived cytokines in systemic lupus erythematosus.
OBJECTIVE
T cell abnormalities and abnormal production of cytokines is a key event of B cell hyperactivity and antibody synthesis in systemic lupus erythematosus (SLE). We investigated T cell function and role of interleukin 4 (IL-4) and IL-6 in B cell induced Ig synthesis from SLE.


METHODS
Phenotypes and expression of activation antigens on T cells and monocytes was determined by specific monoclonal antibodies using indirect immunofluorescence technique. IL-4, IL-6 and tumor necrosis factor-alpha (TNF alpha) assays and in vitro Ig synthesis was carried out by enzyme linked immunosorbent assays.


RESULTS
CD25, CD38 and CD71 expressing T cells and monocytes were increased in circulation of patients with SLE. Patients with SLE associated with prominent clinical presentation like lymphadenopathy had a higher percentage of gamma delta T cells in blood. CD4+CD29+ T cell subsets, which were the major T cells secreting IL-6, were increased in the circulation and provide effective helper function to B cells in their enhanced in vitro Ig synthesis in SLE.


CONCLUSIONS
Our results demonstrate that CD4+CD29+ T cell subsets produced elevated levels of IL-6 in SLE and that IL-6 overproduction may contribute to the B cell hyperactivity in enhanced antibody synthesis characteristic of this autoimmune disease.
al-Janadi
M
M
Department of Internal Medicine (Rheumatology), King Saud University, College of Medicine, Abha, Saudi Arabia.
Raziuddin
S
S
D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D000943:Antigens, Differentiation / Q000032:analysis; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D001402:B-Lymphocytes / Q000737:chemistry / Q000473:pathology* / Q000502:physiology*; D015704:CD4 Antigens / Q000032:analysis; D016207:Cytokines / Q000032:analysis / Q000378:metabolism* / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D019012:Integrin beta1; D015847:Interleukin-4 / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D015850:Interleukin-6 / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D017493:Leukocyte Common Antigens / Q000032:analysis; D008180:Lupus Erythematosus, Systemic / Q000276:immunology / Q000378:metabolism* / Q000473:pathology*; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins; D009000:Monocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D010641:Phenotype; D015375:Receptors, Interleukin-2 / Q000032:analysis; D011990:Receptors, Transferrin; D016176:T-Lymphocyte Subsets / Q000378:metabolism / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000378:metabolism / Q000502:physiology
D015703:Antigens, CD; D000943:Antigens, Differentiation; D000944:Antigens, Differentiation, B-Lymphocyte; D015704:CD4 Antigens; C068126:CD71 antigen; D016207:Cytokines; D007074:Immunoglobulin G; D019012:Integrin beta1; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D015375:Receptors, Interleukin-2; D011990:Receptors, Transferrin; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4; D017493:Leukocyte Common Antigens; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1