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Follicular helper T (TFH) cells are a subset of effector CD4+ T cells that support the differentiation of antigen-specific B cells in the germinal center. TFH cells are distinct from other established CD4+ T cell subsets and possess a list of transcription factors, including BCL6, IRF4, c-Maf, Batf, NFAT1-2, and STAT3. The mentioned factors direct several activities such as cell differentiation, migration to the follicles, cell-to-cell interaction, as well as cell programming. Given that TFH cells are essential for the germinal center formation, affinity maturation and the development of most high-affinity antibodies. TFH cells may play crucial roles in different pathologic conditions, particularly autoimmune diseases. However, the mechanisms that cause functional differences of TFH cell responses are not exactly defined. In this review first the immunological profile of TFH cells will be discussed then attempts will be made to give a broad picture on the role of this key subset of T cells in autoimmune diseases.

Major histocompatibility complex (MHC) class II deficiency is a primary immunodeficiency disease characterized by abnormality of MHC class II molecules surface expression on peripheral blood lymphocytes and monocytes. Clinical manifestations include extreme susceptibility to viral, bacterial, and fungal infections but the immunodeficiency is not as severe as SCID (severe combined immunodeficiency), as evidenced by failure to develop disseminated infection after BCG vaccination. Therefore, MHC II deficiency with BCGosis, that is disseminated BCGitis, is not reported commonly. We report an interesting case of BCGosis after vaccination that was diagnosed to have probable MHC II deficiency.

Background: Ataxia telangiectasia (AT) is one of the combined immunodeficiency syndromes with immunologic, neurologic, endocrinologic, hepatic and cutaneous abnormalities. Regarding the fact that autoimmune disorders; such as autoimmune hemolytic anemia (AIHA), are not generally expected in the course of AT, we present a patient with an unusual presentation of these two conditions., Case Presentation: An otherwise seemingly normal girl, who had developed limping at the age of 11 months old, referred to Namazi Hospital, Shiraz, Iran, due to pallor and latitude at the age of 3 yrs and was diagnosed of AIHA. After 2 years of therapeutic course she developed ocular telangiectasia and ataxic gate., Conclusion: This case emphasizes on the possibility of ataxia telangiectasia coexistence with autoimmune disorders that must be taken into consideration by physicians.