ATASCADERO, Calif. (AP) _ A 4-year-old boy with AIDS who was removed from school after biting another student should not be allowed to return to class, school district officials recommended Friday.

The ruling of the placement committee of the Atascadero Unified School District is expected to be approved by the school board on Monday, said Paul Anderson, the district's dirctor of curriculum.

Ryan Thomas, who will be 5 on Oct. 20, contracted acquired immune deficiency syndrome from a blood transfusion. AIDS cripples the body's immune system, leaving it open to infection. The virus is believed passed through sexual contact or contact with blood or blood products.

Ryan was taken out of the Santa Rosa Road Elementary School after biting another student during a fight. Robin Thomas, the boy's father, said the teacher and the parents of the other child agreed that Ryan acted in self- defense.

He said the family has contacted the American Civil Liberties Union, and attorney Susan McGreivy said Friday that the legal aid organization would file suit against the school district seeking Ryan's reinstatement in school.

Thomas said the committee's decision came after a psychologist testified that Ryan was mentally healthy.

''Nothing that happened throughout the meeting Thursday would have pointed to a decision to keep him out of school,'' Thomas said. ''We feel they gave in to public pressure.''

The committee recommended that Ryan be tutored at home. The boy is receiving one hour of daily home instruction from a district school teacher, Anderson said. He said one hour was sufficient for a child of Ryan's age.

The Centers for Disease Control in Atlanta has recommended that children with AIDS who are designated ''problem children'' should be removed from school, he said.