Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
Autoimmunity is regular. It follows the -ies Conversion rule.
Use plural verbs: "The autoimmunities are ready" (not "is ready").
Yes. The plural autoimmunities is standard across all English variants.
The word autoimmunity follows the standard English pluralization rule. When forming the plural, autoimmunity becomes autoimmunities. This follows the -ies Conversion pattern, which is one of the most common plural rules in English.
Understanding why autoimmunity becomes autoimmunities helps with spelling and pronunciation. Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
When using autoimmunities in writing, remember that it functions as a plural noun in sentences. It pairs with plural verbs and pronouns. For example: "The autoimmunities are ready" (not "is ready"). This subject-verb agreement is essential for grammatical correctness.