Close to TBM, follicular dendritic cells (FDC) are localised in GC, which attach antigen material to their surface and, in contrast to bone marrow-derived DC, neither take it up nor present it via MHC molecules. Autoreactive B cells can accidentally emerge during somatic hypermutation and migrate into the germinal center light zone. Autoreactive B cells, maturated coincidentally, normally do not receive survival signals by antigen planted on follicular dendritic cells and perish by apoptosis. In the case of clearance deficiency, apoptotic nuclear debris accumulates in the light zone of GC and gets attached to FDC. This serves as a germinal centre survival signal for autoreactive B-cells. After migration into the mantle zone, autoreactive B cells require further survival signals from autoreactive helper T cells, which promote the maturation of autoantibody-producing plasma cells and B memory cells. In the presence of autoreactive T cells, a chronic autoimmune disease may be the consequence. Anti-nRNP autoimmunity
Anti-nRNP autoantibodies to nRNP A and nRNP C initially targeted restricted, proline-rich motifs. Antibody binding subsequently spread to other epitopes. The similarity and cross-reactivity between the initial targets of nRNP and Sm autoantibodies identifies a likely commonality in cause and a focal point for intermolecular epitope spreading. Others
Elevated expression of HMGB1 was found in the sera of people and mice with systemic lupus erythematosus, high mobility group box 1 (HMGB1) is a nuclear protein participating in chromatin architecture and transcriptional regulation.
Diagnosis
Familial multiple lipomatosis is usually diagnosed through a physical exam via palpation, medical history and imaging studies such as ultrasound, CT scan, or magnetic resonance imaging (MRI). A CT scan is an imaging method that uses x-rays to create images of cross sections of the body, while an MRI uses powerful magnets and radio waves to create images of lipomas and surrounding tissues. Both tests are useful to establish the diagnosis of multiple symmetric lipomatosis, although magnetic resonance imaging provides more details and may be used when lipomas are large, deep, or have infiltrated muscle fibers or nerves. In some cases, a biopsy of the lipomas may be necessary to confirm the diagnosis. Differential diagnoses
Liposarcoma
Dercum’s disease
Benign symmetric lipomatosis
Madelung’s disease
Cyst

Causes
The exact cause of FML is not yet known, but there are several theories of different causes:
Hormonal disorder due to the bodys inability to properly metabolize fat
Increase in fat cells (adipocytes)
Enzymatic defect or a change in the surface of the cells that could prevent the breakdown of fat
Poor lymphatic drainage
Defective regulation of mitochondria in brown fat. Brown fat is responsible for causing heat in times of stress or cold. For general callus tissue is stimulated by the sympathetic nervous system and this response is mediated by a substance called norepinephrine. This process occurs in the mitochondria
In most families, the mode of inheritance has not been determined. However, changes (mutations) in mitochondrial DNA that involve the MT-TK gene have been identified in some families who have the disease and other conditions that affect many different body systems.