3 (three) is a number, numeral and digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious or cultural significance in many societies. Evolution of the Arabic digit
The use of three lines to denote the number 3 occurred in many writing systems, including some (like Roman and Chinese numerals) that are still in use. That was also the original representation of 3 in the Brahmic (Indian) numerical notation, its earliest forms aligned vertically. However, during the Gupta Empire the sign was modified by the addition of a curve on each line. The Nāgarī script rotated the lines clockwise, so they appeared horizontally, and ended each line with a short downward stroke on the right. In cursive script, the three strokes were eventually connected to form a glyph resembling a ⟨3⟩ with an additional stroke at the bottom: ३. The Indian digits spread to the Caliphate in the 9th century. The bottom stroke was dropped around the 10th century in the western parts of the Caliphate, such as the Maghreb and Al-Andalus, when a distinct variant ("Western Arabic") of the digit symbols developed, including modern Western 3. In contrast, the Eastern Arabs retained and enlarged that stroke, rotating the digit once more to yield the modern ("Eastern") Arabic digit "٣".In most modern Western typefaces, the digit 3, like the other decimal digits, has the height of a capital letter, and sits on the baseline.
As multiple studies have demonstrated both its efficacy and safety in a clinical setting, it is also used in different minimization regimens to reduce the application of higher risk immunosuppressive agents such as corticosteroids and calcineurin inhibitors (CNIs) in solid organ transplantation. Because both corticosteroids and CNIs have been found to potentially cause long-term adverse effects in the body, a multitude of studies have been conducted to examine the efficacy of thymoglobulin in SOT either with minimal usage or without the use of either agent. Findings have indicated that use of thymoglobulin alone minimizes risk of adverse effects and thus improves long-term outcomes for transplant patients.Thymoglobulin is also an effective agent for preventing graft-vs.-host disease in patients receiving haematopoietic stem cell transplantation (HSCT). GVHD is a condition in which immune cells within the graft attack host cells and cause tissue damage. It is considered a major obstacle to successful HSCT. The T-cell depleting activity of thymoglobulin has proved to be useful in preventing GVHD. Multiple studies have indicated that thymoglobulin is favored in comparison to other induction agents for patients who have increased risk of developing post-transplant complications, such as elderly patients, patients undergoing a repeat transplantation, and patients in which minimization of use of steroids or CNIs post-operation is  recommended. == References ==