Figure 4From: Mathematical framework for human SLE Nephritis: disease dynamics and urine biomarkersHill functional of order 2. We represent the immune complexes (I) formation due to accumulation of self-antigens from debris D, by a Hill functional of order 2, . When there are only a few antigens around, not many immune complexes are produced; as antigens accumulate, more immune complexes are being created, and saturation, s id , is reached for sufficiently many self-antigens.Back to article page