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Patients with hormone receptor–positive early breast cancer have a continuous yearly rate of recurrence extending out to 15 years after having received adjuvant endocrine therapy with tamoxifen for 5 years (1). More than half of the recurrences and about two-thirds of breast cancer deaths in this group will occur beyond 5 years from diagnosis (ie, late recurrences and death) (1). The National Cancer Institute of Canada (NCIC) Clinical Trials Group MA.17 trial was a randomized, placebo-controlled trial demonstrating that extended endocrine therapy with letrozole improves disease-free survival (DFS) (2), distant DFS (DDFS), and overall survival (OS) in disease-free postmenopausal patients with hormonal receptor–positive breast cancer after 5 years of tamoxifen (3). Although extended antihormonal therapy has become standard practice and is endorsed by international clinical practice guidelines (4,5), understanding which patients will actually benefit from longer treatment is paramount to individualized therapy. The status of primary tumor estrogen receptor (ER) and progesterone receptor (PR) expression has been suggested, but not confirmed, as a way to identify patients who have increased benefit from extended letrozole (5). Patients with ER+ and PR+ tumors have been shown to have improved DFS (P = .02) when compared with patients with ER+ and PR− tumors (6). Currently, however, there are no guideline-accepted biomarkers to stratify hormonal receptor–positive patients for prediction of benefit beyond the 5 years of adjuvant endocrine therapy. In addition, standard clinico-pathological factors and clinically available genomic signatures, including the 21-gene (Recurrence Score) assay (7) and the 70-gene assay (8), have greatest prognostic performance for recurrence risk within the first 5 years of adjuvant therapy. Identification of additional biomarkers to further stratify hormone receptor–positive tumors to predict those at risk of late recurrence and those who may or may not benefit from extended endocrine therapy would be of substantial clinical utility (9). We have previously demonstrated that the two-gene expression ratio, HOXB13/IL17BR (H/I), is a prognostic biomarker in both untreated and tamoxifen-treated early-stage ER+ breast cancer patients (10–13). However, potential assessment of H/I as a predictive biomarker for endocrine therapy has been limited by the analysis of retrospective/observational cohorts or by the use of single treatment arm cohorts from randomized trials (11–13). Herein, we have conducted a prospective–retrospective (14), nested case-control study in a subset of patients from NCIC Clinical Trials Group MA.17 trial to evaluate the performance of H/I for 1) prognostication of late disease recurrence and 2) prediction of treatment benefit from extended adjuvant letrozole therapy in patients with hormone receptor–positive early breast cancer.

Background A rotavirus vaccine previously licensed in the United States was withdrawn because it caused intussusception. Data on background intussusception rates in developing countries are required to plan pre- and postlicensure safety studies for new rotavirus vaccines. Also, it is unclear whether natural rotavirus infection is associated with intussusception. Methods Passive surveillance for intussusception in a large, well-defined, poor, urban population in Delhi, India, was conducted in 2 phases. Intussusception was confirmed by ultrasonography or surgery. Fecal samples obtained from patients with intussusception at study hospitals (irrespective of their residence in study areas) and healthy control subjects were tested for rotavirus with use of enzyme immunoassay. If available, resected intestinal tissue samples were tested for rotavirus with use of immunohistochemistical analysis and reverse-transcription polymerase chain reaction. Results The incidence of intussusception requiring hospitalization was 17.7 cases per 100,000 infant-years of follow-up (95% confidence interval, 5.9-41.4 cases per 100,000 infant-years). Detection rates of rotavirus in stool samples did not differ significantly between case patients and control subjects (4 of 42 case patients vs 6 of 92 control subjects), and no evidence of rotavirus was detected in any of the 22 patients with intussusception for whom intestinal tissue samples were available. Conclusions The incidence of intussusception among Indian infants appears to be lower than that reported in other middle- and high-income countries. Natural rotavirus infection does not appear to be a major cause of intussusception in Indian infants.

Objectives: In a community randomized trial, we aimed to promote exclusive breastfeeding and appropriate complementary feeding practices in under-twos to ascertain the feasibility of using available channels for nutrition counselling, their relative performance and the relationship between intensity of counselling and behaviour change. We also assessed whether using multiple opportunities to impart nutrition education adversely affected routine activities. Methods: We conducted a community randomized, controlled effectiveness trial in rural Haryana, India, with four intervention and four control communities. We trained health and nutrition workers in the intervention communities to counsel mothers at multiple contacts on breastfeeding exclusively for 6 months and on appropriate complementary feeding practices thereafter. The intervention was not just training health and nutrition workers in counselling but included community and health worker mobilization. Findings: In the intervention group, about 32% of caregivers were counselled by traditional birth attendants at birth. The most frequent sources of counselling from birth to 3 months were immunization sessions (45.1%) and home visits (32.1%), followed closely by weighing sessions (25.5%); from 7 to 12 months, home visits (42.6%) became more important than the other two. An increase in the number of channels through which caregivers were counselled was positively associated with exclusive breastfeeding prevalence at 3 months (p = 0.002), consumption of milk/cereal gruel or mix use at 9 months (p = 0.004) and 18 months (p = 0.003), undiluted milk at 9 months (p

We sought to determine the proportion of rotavirus ( RV) infections among children with severe diarrhea in Bangalore, India, and to determine the role of neonatal infection with the asymptomatic RV strain I321 in protection against subsequent RV diarrhea. At 2 major hospitals, there was a >42% decrease in diarrhea-specific admissions during the study period. At 6 hospitals, asymptomatic infections were found in 25%-50% of neonates, when screening was performed randomly, and in >58% of neonates, when screening was performed daily, with the majority of infections occurring within the first 7 days of life. All the RVs found in asymptomatic neonates were strain I321. A 24-month follow-up of a cohort of 44 children who had been neonatally infected with strain I321 and 28 children who had not (control group) revealed comparable rates of RV detection but a marked decrease in the number of RV diarrhea episodes in the strain I321-infected group (2.3%), compared with the control group (39.3%) (P < .0001). This preliminary study suggests a possible association between neonatal infection with strain I321 and protection against subsequent RV illness.

Several autoimmune disease models depend on an imbalance in the activation of aggressor T(h)1 and CD4(+)CD25(+) regulatory T (T(reg)) cells. Here we compare the requirement for signals through the co-stimulatory molecules CD28 and inducible co-stimulator (ICOS) in chronic murine colitis, a model for inflammatory bowel disease. We used a colitis model in which disease-causing CD45RB(hi) T cells alone or in combination with CD4(+)CD25(+) T cells from either CD28-deficient or wild-type donors were transferred into T cell-deficient animals, half of which were treated with ICOS-blocking reagents. Blocking ICOS on the surface of CD28-deficient T(h)1 cells abrogated development of colitis, whereas blocking CD28 or ICOS alone had little to no effect on disease induction. In contrast to T(h)1 cells, regulatory T cell functioning depended mostly on CD28 signaling with only a minor contribution for ICOS. We conclude that CD28 and ICOS collaborate to development of murine colitis by aggressor T(h)1 cells, and that CD28 is required for T(reg) cells, which should caution against the use of CD28-blocking reagents in inflammatory bowel disease.

The animal models of inflammatory bowel disease provide a framework to define the immunopathogenesis of intestinal inflammation. Studies in these models support the hypothesis that exaggerated immune responses to normal enteric microflora are involved in the initiation and perpetuation of chronic intestinal inflammation. A major pathway involves development of acquired immune responses by the interactions of CD4+ T-cell receptor alphabeta T cells with antigen-presenting cells (dendritic cells). Immunoregulatory cells, including Tr1 cells, Th3 cells, and CD4+ CD25+ T cells and B cells, directly or indirectly affect the T-cell receptor alphabeta T cell-induced immune responses and bridge innate and acquired immunity. The study of these complicated immune networks provides the rationale for the development of new therapeutic interventions in inflammatory bowel disease.

Seroconversion of immunoglobulin A (IgA) and immunoglobulin G (IgG) (> or =4-fold rise) to rotavirus nonstructural protein 4 (NSP4) was determined, by use of enzyme-linked immunosorbent assay with fusion proteins glutathione S-transferase (GST)-NSP4 from strains SA11 (A), 116E (B), and RRV (C), in 40 children with acute rotavirus gastroenteritis and in 30 with the same disease due to other pathogens. The IgG seroconversion rates in the rotavirus group were 67.5%, 70%, and 60% when recombinant (r) NSP4A, -B, and -C, respectively, were used as antigen in the assay, and, for rotavirus-uninfected children, rates were 10%, 13%, and 7%. IgA seroconversion occurred in 57%, 70%, and 50%, respectively, of children with rotavirus gastroenteritis; in rotavirus-uninfected children, 1 child each seroconverted to the different rNSP4s. Among 9 children infected with strain NSP4A, 7, 6, and 5 children showed IgG seroconversion, and, among 18 infected with NSP4A, -B, and -C, 16, 17, and 15, respectively, showed IgG seroconversion. Between NSP4A-infected and NSP4B-infected children, IgA responses were similar to IgG responses. In conclusion, significant NSP4-specific antibody response occurs in natural rotavirus infection, and the antibody response appears to be broad and heterotypic in nature.

Although CD4(+) T cells form a major subset of TCRalphabeta T cells, only a small number of TCRgammadelta T cells express CD4. Factors contributing to the down-regulation of CD4(+) TCRgammadelta T cells have not been identified. The CD5 molecule is expressed on most TCRgammadelta T cells in the spleen, whereas only a few intestinal intraepithelial TCRgammadelta T cells express this molecule in wild-type mice and TCRbeta mutant (beta(-/-)) mice. Unexpectedly, in the present studies, the lack of CD5 led to a remarkable increase of a CD4(+) TCRgammadelta T cell subset in CD5(-/-)beta(-/-) mice. The CD4(+) TCRgammadelta T cells were also detectable in MHC II(-/-)CD5(-/-)beta(-/-) triple-mutant mice. This CD4(+) TCRgammadelta T cell subset provided help in Mycobacterium-induced germinal center (GC) formation and showed a T(h)-like cytokine profile. In contrast, CD5(+) TCRgammadelta T cells suppressed the CD4(+) TCRgammadelta T cell-mediated GC formation, presumably by eliminating this CD4(+) subset. Unlike intraepithelial gammadelta T cells,30% of TCRgammadelta T cells in the colonic lamina propria (LP) expressed CD5. The lack of CD5 also led to increased numbers of CD4(+) TCRgammadelta T cells in the colonic LP and increased susceptibility to development of chronic colitis in beta(-/-) mice. Cell transfer studies suggest that CD5(+) TCRgammadelta T cells are capable of selectively eliminating CD4(+) TCRgammadelta T cells in the intestine. The CD4(+) TCRgammadelta T cells possess immune functions similar to CD4(+) TCRalphabeta T cells.

Helicobacter pylori infection has been reported to increase the risk of cholera. This nested case-control study was conducted to determine whether H. pylori infection is associated with occurrence of typhoid fever. Eighty-three case subjects of culture-proven typhoid fever were identified through a 1-year surveillance of subjects aged 0-40 years in an urban slum. Two age- and sex-matched neighborhood control subjects were concurrently selected for each case subject. Serum anti-H. pylori immunoglobulin G antibodies were measured in case and neighborhood control subjects. For determining other risk factors, 2 additional community control subjects per case were selected. There was a significant association between the presence of serum anti-H. pylori immunoglobulin G antibodies and typhoid fever (adjusted odds ratio, 2.03; 95% confidence interval, 1.02-4.01). Illiteracy, being part of a nuclear family, nonuse of soap, and consumption of ice cream were also associated with a significantly greater risk of typhoid fever. This study provides the first empiric evidence that H. pylori infection is associated with an increased risk of typhoid fever.

SummaryWe have prepared human recombinant antibody molecules against the glycoprotein antigen of the rabies virus (GPRV) based on the single chain variable fragment (scFv) format. Anti-GPRV scFvs were selected from a human synthetic scFv phage display library with a repertoire of approximately 109 specificities. After three rounds of selection against the PV11 strain of the virus, 40% of the clones tested recognized the rabies antigen. Of the 20 positive clones that were sequenced, five distinct sequences were identified. These distinct scFvs were cloned into a mammalian expression vector carrying the human IgG1 Fc region. The specificity of the resulting scFv-Fc molecules for GPRV was established by ELISA, dot blot and western blot analyses and membrane immunofluorescence. Two of the scFv-Fc fusion proteins neutralized the PV11 strain in a standard in vivo neutralization assay where the virus was incubated with the scFv-Fc molecules before intracranial inoculation in mice. These anti-GPRV scFv-Fc molecules have the potential to be used as an alternative to the presently available HRIG, for use in post-exposure preventive treatment.

The spontaneous chronic colitis in TCR alpha mutant (TCRalpha(-/-)) mice mediated by CD4(+) TCRalpha(-)beta(+) T cells is more severe in the absence of mature B cells, suggesting a suppressive role of B cells and Ig in the development of chronic colitis. To investigate the direct role of B cells in the suppression of this colitis, cell transfer studies were performed in TCRalpha(-/-) x Igmu(-/-) (alphamu(-/-)) double-knockout mice. The chronic colitis was markedly attenuated in alphamu(-/-) mice after the adoptive transfer of peripheral B cells from TCRalpha(-/-) mice into 3- to 4-week-old alphamu(-/-) mice prior to the development of colitis. Furthermore, transfer of mature B cells from TCRalpha(-/-) mice markedly decreased the number of pathogenic colonic CD4(+) TCRalpha(-)beta(+) T cells in alphamu(-/-) mice with established colitis. This B cell effect required the presence of functional co-stimulatory molecules CD40 and B7-2 (CD86) but not B7-1 (CD80). These results indicate that mature B cells play an important role in the development of chronic colitis in TCRalpha(-/-) mice by directly regulating the pathogenic T cells (CD4(+) TCRalpha(-)beta(+) T cells).

Candidate rotavirus vaccines have been prepared with reassortant strains specifically to protect against the 4 major rotavirus G serotypes (G1 -4). Many studies using P (VP4) genotyping methods have indicated that, worldwide, rotavirus strains of the 4 common G serotypes are each associated with 1 P genotype: GI, G3, and G4 are associated with P[8], and G2 is associated with P[4]. In contrast, G and P genotyping of rotavirus in specimens from India revealed that a high percentage of the childhood diarrhea strains belong to genotype P[6], and the most common strain had an unusual G serotype, G9. Similarly, in all regions surveyed in Brazil, apparent reassortants of genotype P[8], G5 were found in children with gastroenteritis. These studies indicate that while rotavirus strains have limited diversity in many settings, reassortment between common and uncommon serotypes or animal strains can arise in some settings and, thus, lead to unusual diversity.

Since lumenal bacteria have been postulated to play an important role in the pathogenesis of inflammatory bowel disease (IBD), we investigated the humoral response to cecal aerobic bacterial antigens by Western blot analysis in TCR alpha -/- mice which spontaneously develop IBD. The sera from TCR alpha -/- mice revealed an alteration of the recognition pattern against aerobic bacterial antigens from polyclonal to oligoclonal with age. This alteration was not observed in TCR delta -/- and TCR alpha +/- mice. The alteration of the recognition pattern in TCR alpha -/- mice was associated with production of autoantibodies against tropomyosin and the development of IBD. The unique population of CD4+ TCR alpha -beta + cells in TCR alpha -/- mice may be involved in the recognition of these bacterial antigens and the absence of the alpha chain may result in the alteration of immune response.

A cohort of newborns in New Delhi who were nosocomially infected with rotavirus during their first days of life were followed twice weekly for 14-23 months to determine whether neonatal infection protected them against subsequent episodes of rotavirus diarrhea. Infection occurred in 60% by the fourth day of life, was asymptomatic, and was caused predominantly by an unusual rotavirus strain (G9 P11) not previously identified in humans. The 148 children with neonatal rotavirus infection had 46% fewer attacks of rotavirus diarrhea in the follow-up period than the 56 infants without nosocomial infection (0.23 vs. 0.42 episodes/child-year, P < .05). This protection was concentrated among infants in their first year of life and was not associated with a significant decrease in disease severity. Consideration of this strain as a vaccine candidate will require further assessment of its natural protection under field conditions.

The association between persistent diarrhoea and 'recent morbidity' defined as that occurring within the two-month period immediately preceding the onset of persistent diarrhoea was investigated in a population-based case-control study in rural North India. In two separate matched case-control analyses children with persistent diarrhoea (cases) were compared to population controls (five controls matched to each case) and acute diarrhoeal controls (three controls matched to each case). After correcting for possible confounding variables, comparing children with persistent diarrhoea and matched population controls, presence of a recent diarrhoeal illness was significantly associated with persistent diarrhoea with an odds ratio (OR) 2.6 (95%) confidence interval (CI): 1.1-7.1; p less than 0.05); during infancy this OR was 5.2 (95% CI: 1.0-31.9; p less than 0.01). Comparing children with persistent diarrhoea to matched acute diarrhoeal controls, presence of recent diarrhoeal illness was associated with an OR of 5.1 (95% CI: 1.3-20.3) in favour of the episode becoming persistent; in infants this OR was 10.4 (95% CI: 1.1-132.4; p less than 0.001).

The reliability of saliva as an indicator of rotavirus infection was assessed among 15 infants (3-12 months) with rotaviral and 15 with nonrotaviral diarrhea. Paired salivary samples collected during acute and convalescent phases were tested for rotavirus-specific IgA and IgM by an ELISA. The sensitivity of IgA or IgM alone to predict infection was 53.3% and 46.6%, respectively; used in conjunction, the sensitivity rose to 80%. It seems that infants with rotaviral diarrhea mount mucosal antibody responses as reflected in their saliva; possibly salivary antibodies could be used to evaluate vaccine "take" in rotavirus vaccine trials.

A patient with a recurrent epithelioid sarcoma of the hand was observed for five years with a diagnosis of nodular fasciitis. Eventually, the patient had a pulmonary metastasis and diffuse bone marrow spread, which was associated with a leukemoid reaction. Bone marrow dissemination by sarcoma is unusual, and its production of a leukemoid reaction very rare; this is its first reported occurrence in epithelioid sarcoma that the authors have been able to identify in the literature.

SUMMARY Biopsy specimens of papules taken from eight patients with polymorphic light eruption were examined by immunoperoxidase techniques employing monoclonal antibodies. In each case, most infiltrating mononuclear cells were T cells. The majority of T cells were T8-positive (cytotoxic/suppressor) in four cases and T4-positive (helper/inducer) in two. In two cases, approximately equal numbers of both T cell subsets were present. In only three cases were rare B cells identified by their reactivity with anti-IgM antibody. M1-positive mononuclear cells (macrophages) represented less than 5% of cells infiltrating the dermis. In five subjects, anti-T6 antibody stained increased numbers of dermal mononuclear cells considered to be Langerhans/indeterminate cells. The pathogenesis of papular polymorphic light eruption may involve injury to upper dermal venules mediated by T cells and Langerhans/indeterminate cells.

Two prostatic neoplasms that closely resemble adenoid cystic carcinoma of the salivary glands, but in the authors' opinion merit separate designation, are reported. Most of the well-documented examples of prostatic lesions interpreted as "adenoid cystic carcinoma" appear to have been similar to the cases reported herein. The lesions in this report, which the authors have designated as adenoid cystic-like tumors, occurred in men of 60 and 68 years of age who presented with urinary tract obstruction and had transurethral resection of the prostate. Both neoplasms were associated with a minor component of prostatic adenocarcinoma of the usual acinar type. Each adenoid cystic-like tumor had areas that closely resembled basal cell hyperplasia of the prostate, and one had conspicuous foci of squamous differentiation. One patient had a radical prostatectomy and is well six years after operation. The other patient was treated with transurethral resection and irradiation and is well eight months after operation. The prognosis associated with this neoplasm appears to be excellent on the basis of the limited experience to date.

Monoclonal anti-T6 antibody, which reacts with the majority of cortical thymocytes but not peripheral T cells, also reacts with human epidermal Langerhans cells, as shown by a four-step immunoperoxidase method and immunoelectron microscopy. To define whether T6-positive cells are also present in normal human dermis, we used these techniques to demonstrate two immunologically distinct populations of histiocyte-like cells in normal human dermis. The first population contains cells devoid of phagolysosomes or Birbeck granules. These cells react with anti-T6 antibody, but not with monoclonal anti-T3 antibody which defines peripheral T cells, and are found predominantly in and around dermal lymphatic vessels. The second is composed of phagolysosome-containing cells which do not react with anti-T6 antibody or anti-T3 antibody. Because to date, Langerhans cells are the only cells in normal human epidermis that react with anti-T6 antibody, these data provide immunological evidence for a specific link between Langerhans cells and a T6-positive dermal mononuclear cell, possibly the so-called indeterminate cell. In addition, application of these techniques should, for the first time, permit the immunological distinction of these T6-positive mononuclear cells from other cells bearing Ia antigens, such as dermal histiocytes and certain lymphocytes, in normal and diseased skin.

A cohort of 452 rural children was followed longitudinally for 13 mo to ascertain the role of HEp-2 cell adherent Escherichia coli and other pathogens in causing acute (less than or equal to 14 d) and persistent (greater than 14 d) diarrhea. Aeromonas, Campylobacter jejuni, E. coli manifesting localized adherence to HEp-2 cells and enterotoxigenic E. coli were significantly associated with acute diarrhea. E. coli strains that exhibit aggregative adherence, so-called enteroaggregative E. coli, a newly-described category of diarrheagenic E. coli distinct from enterotoxigenic, enteroinvasive, enterohemorrhagic, and enteropathogenic E. coli, were found significantly more often in patients with persistent diarrhea (29.5%) than with acute diarrhea (12.8%) (P = .0052) or controls (9.9%) (P = .0006).

Afghanistan is a developing, thinly populated, landlocked country with an area of 636,266 sq. km and a population of 17 million. There are vast deserts and mountainous regions and a small cultivable area. The economy is largely based on agriculture, livestock and fruit industry. Eighty percent of the population live in about 17,000 villages, many of which are remote and isolated, presenting problems of communication, especially during 3 months in winter when they are snowbound. Fourteen percent are nomadic. Other data indicate a large proportion of low age group population, a high dependency rate of 1 to 27 and an infant mortality rate of 185 per thousand. Modern medical facilities are available in the provincial capitals. Basic health services are provided through primary health centres, one for about 61,000 population. Thirty-three percent have access to safe water. Sanitary and hygienic conditions are generally unsatisfactory.

The distribution of major histocompatibility antigens HLA-A,B,C (HLA), beta 2-microglobulin (beta 2m), and Ia-like antigens (HLA-DR; Ia) in normal skin was studied in frozen tissue sections by a four-step immunoperoxidase method and an avidin-biotin method employing monoclonal antibodies. HLA and beta 2m were present on the basal and spinous keratinocytes of the epidermis, on the outer root sheath epithelium in the infundibulum of the hair follicle, and on the excretory sebaceous duct epithelium. Ia-positive dendritic cells were found in the epidermis and hair follicles, but they were more frequent in the infundibulum and isthmus of the hair follicle than in its inferior portion or in the epidermis. In the straight eccrine duct, HLA and beta 2m-positivity was most striking in its lower portion. In the superficial duct, there was a less intense staining using the four-step procedure, but when an avidin-biotin method was used, the difference was less apparent. In contrast, the acrosyringial epithelium was markedly Ia-positive with decreasing intensity of staining as the duct penetrated the dermis. No HLA or Ia antigens were identified in eccrine glands and apocrine glands. Eccrine glands were slightly beta 2m-positive. HLA and beta 2m were uniformly present in non-dilated and dilated intradermal apocrine ducts.

SUMMARY Skin biopsies from four patients with lichen planus were studied using monoclonal antibodies directed against T lymphocytes. Anti-T1 and anti-T3 antibodies, which react with all peripheral T cells, stained most cells in the dermal infiltrates. The majority of infiltrating cells also stained with anti-T4 and anti-T4b antibodies, which react with helper/inducer cells, whereas a minority of cells stained with anti-T8 antibody, which reacts with cytotoxic/suppres-sor cells. Surface IgM was not identified on any infiltrating cells, providing evidence against B cell participation. Intraepidermal and dermal cells with long cytoplasmic extensions stained with anti-T6 antibody in all cases, defining them as Langerhans cells or their precursors. T6-positive cells were seen in greater number than in normal control epidermis and dermis. The results indicate that well-developed lesions of lichen planus are characterized by an influx of helper/inducer T lymphocytes and increased numbers of Langerhans cells. These observations support the contention that cellular immunity is important in the pathogenesis of this disorder.

The presence of major histocompatibility antigens [HLA-A,B,C; beta 2 microglobulin (beta 2)m; la-like] on tumor cells and the nature and distribution of mononuclear cellular infiltrates in benign and malignant human breast tumors were studied by the use of monoclonal antibodies and immunoperoxidase techniques on frozen tissue sections. Although all benign tumors expressed HLA-A,B,C or beta 2m, 20 of 53 primary breast cancers did not react with anti-HLA-A,B,C or anti-beta 2m antibodies. Expression of la-like antigens was rarely encountered on tumor cells. The intensity of the inflammatory mononuclear cellular response did not correlate with the expression of HLA-A,B,C or beta 2m by the tumor cells. Most of the mononuclear cells were identified as T-cells. T-cells with a cytotoxic-suppressor phenotype (T8+) were generally the predominant cell type among those found as single cells in the tumor stroma or invading tumor nests. However, infiltration of tumor nests by lymphocytes was infrequently seen and was usually limited to the periphery of the tumor. In contrast, lymphocytes with a helper-inducer phenotype (T4+, Leu-3a+) predominated in the lymphoid aggregates. Anti-Leu-7 (HNK-1) antibody, which reacts with natural killer cells, stained only a few mononuclear cells in the cellular infiltrate in most cases of breast cancer.