Hi there - I think that perhaps TF = Tracoma folicular → Follicular trachoma (FT) in this context, based on these two articles:

"TF- inflamación folicular tracomatosa de más de 5 folículos mayores de 0,5 mm en el tarso superior." (http://scielo.sld.cu/pdf/rhcm/v15n3/rhcm12316.pdf) and "Tracoma folicular" (p. 6, http://www.cenetec.salud.gob.mx/descargas/gpc/CatalogoMaestr...

Regarding the "B" part, it's more tricky because of the lack of context, but it could be:

• "B lymphocyte" as Helena says
• A mysterious treatment protocol that I haven't been able to find so far (the second link above mentions the use of using protocols A, or F in different contexts, but doesn't specify them. This makes me think there must be, somewhere a 'protocol B')

• Or, I think most likely so far, is the etiological agent: Chlamydia trachomatis serotype B. This is based on the following:

“El tracoma es una queratoconjuntivitis crónica, causada por infecciones repetitivas con algunas serovariedades oculares de Chlamydia trachomatis (A, B, Ba, y C)” taken from: https://www.ins.gov.co/buscador-eventos/ZIKA Lineamientos/PR... — which also mentions "TF"