The phrase "as firstly described" is not correct in standard written English.
The correct term is "as first described," which is used to refer back to an initial description or explanation provided earlier in the text.
Example: "The process, as first described in the introduction, involves several key steps that must be followed carefully."
Alternatives: "as initially described" or "as previously mentioned."
Ultrasound B-mode aspects of lower limb enthesitis of AS was firstly described by Lehtinen et al. [ 10] in 1994, and in 2003 Balint et al. developped a ultrasound scoring system designed to assess five entheseal sites in the lower limb (GUESS) [ 18].
In addition, a group of tumors formed by PEC proliferation has been recognized as PEComas, firstly described by Bonetti and colleagues in 1992 [1] and currently recognized by the World Health Organization [4].
Natural products have been a rich source of drug discovery, Theophylline and Methylxanthine originated from tea leaves used for asthma treatment, whereas, Papaverine, a natural isoquinolein originated from Papaver somniferum traditionally used in impotency, altogether as caffeine where firstly described as PDE-inhibiting compounds.
CD244, also known as 2B4, was firstly described as an inhibitory receptor highly expressed on exhausted CD8+ T cells in line with PD-1 in chronic LCMV infection and chronic HBV infection in mice.
CGRP was firstly described as a splice product of the calcitonin gene in two well-recognized papers by Amara et al. [2] and Rosenfeld et al. [41].
Acute central sensitization phenomena were firstly described as a development of migraine aura [50] and allodynia has been confirmed a usual symptom in this type of migraine [28].
Hakai was firstly described as a RING finger-type E3 ubiquitin-ligase for the E-cadherin complex [ 3].
Cholecystokinin (CCK) was firstly described as a gastrointestinal hormone, but immune cells express their receptors, suggesting a possible involvement of this peptide in pathophysiological processes.
Although firstly described as common variable immunodeficiency, inducible co-stimulator (ICOS) molecule deficiency generally leads to a CSR-D, as shown by the increased or normal IgM levels observed in patients [ 46] (OMIM #607594).
